ABSTRACTBILGEN, MUSTAFA. Wrinkle Recovery for Cellulosic Fabric by Means of IonicCrosslinking. (Under the direction of Pet...
WRINKLE RECOVERY FOR CELLULOSIC FABRIC                 BY MEANS OF IONIC CROSSLINKING                                     ...
DEDICATION       This thesis is dedicated to my family and my wife, Nicole, who supported me withconstant love and caring ...
BIOGRAPHY       Mustafa Bilgen was born in December 1, 1978 in Erdemli, Turkey. He graduatedfrom Erzurum Science High Scho...
ACKNOWLEDGEMENTSI would like to thank to the National Textile Center and North Carolina State Universityfor their financia...
LIST OF CONTENTSLIST OF TABLES ------------------------------------------------------------------------------- viiiLIST OF...
3.7.5 Reaction of cellobiose and dextrose with CHTAC -------------------------------- 53   3.8 Preparation of fabric sampl...
5. CONCLUSIONS ------------------------------------------------------------------------------1166. RECOMMENDATIONS FOR FUT...
LIST OF TABLESTable 3.2 Results for carboxymethylation of cellulosic fabrics ------------------------------ 32Table 3.3 Sc...
Table A.17 Breaking strength data for molecular weight of 6.11 x 105g/mole cationic    chitosan treated fabrics ----------...
LIST OF FIGURESFigure 2.1 Molecular structure of a cellulose polymer chain -----------------------------------4Figure 2.2 ...
Figure 4.11 Effect of carboxyl content on dry wrinkle recovery angles of calcium and    magnesium treated fabrics---------...
Figure 4.33 Effect of %Nitrogen fixed and concentration on whiteness index of the BTCA    treated fabrics ----------------...
1. INTRODUCTION       The textile market has shown an interest in the demand for easy care, wrinkle-resistant for cellulos...
they also impart strength loss and release formaldehyde, a known human carcinogen. [1]Today’s textile industry has for a l...
2. LITERATURE REVIEW2.1 Cellulose chemistry       We can only understand chemical as well as physical properties of cellul...
OH                        H                                     OH                        H                OH    H        ...
as esterification and etherification or in the application of dyes and finishes forcrosslinking. The hydroxyl groups also ...
modulus and better elastic recovery. After the external force is released, the energy storedin the strained covalent bonds...
formaldehyde derivatives and methylol derivatives. All of these reagents used for DP ofcellulosic fabric with varying degr...
2.3.3 Methylol derivatives of cyclic ureas       These compounds are also referred to as fiber reactants, because they onl...
It shows some chlorine retention therefore it is not recommended for white goods. It doesnot effect the lightness of the d...
cellulosic fibers have successfully been done. However, at the present time, presence offormaldehyde in the finished produ...
Several polycarboxylic acids have served as durable press agents. Carboxylicgroups in polycarboxylic acids are able to for...
COOH       COOH                                   COOH      COOH                                        BTCA              ...
Chitosan citrate has been evaluated as non-formaldehyde durable press finish toproduce wrinkle-resistance and antimicrobia...
2.5 Ionic crosslinking       Ionic crosslinking has been used in the polymer industry for various applications.It is an al...
A series of siloxane-based liquid-crystalline elastomers were synthesized by usingionic crosslinking agents containing sul...
2.6 Preparation of quaternized polymers       Conversion to quaternary ammonium salts gives products whose degree ofioniza...
neutral conditions. Both of the products have cationic properties and can be used as acationic polyelectrolyte to form ion...
2.6.2 Reaction of Cellulose with CHTAC       The cationization of cellulose with using CHTAC has been previously studied.[...
10% substitution, pad-batch and pad steam methods are more efficient, and they producedabout 25% substitution. The pad-dry...
2.7 Carboxymethylation of cellulose        Carboxymethylcellulose (CMC) is a derivative of cellulose that can be formed by...
Cellulosic fabrics can react with several materials, which impart an anioniccharacter to it, for example, chloroacetic aci...
resist wrinkling during laundering. We observed simultaneous enhancements of both wetand dry WRA. In addition, ionic cross...
3. EXPERIMENTAL PROCEDURES        The materials, equipments and experimental procedures used in this study aredescribed in...
Table 3.1 Test materials and chemicals continued               CROSSLINK RB 105, Aqueous solution of BioLab Water Additive...
3.2 Equipments       Stirring was performed using a Fisher Hot Plate. A Fisher Scientific Co. model600-pH meter was equipp...
3.3.2 Pad batch       The same size samples as in pad dry cure application were used. The fabrics werepadded through the i...
3.4.1 Nitrogen analysis       The nitrogen analysis was performed using a Leuco CHN analyzer. The analysisperformed using ...
3.4.4 Wrinkle recovery angles       Wrinkle recovery angles were measured according to AATCC Standard TestMethod 66 option...
3.5 Reaction of cellulose with chloroacetic acid       Cellulosic fabric was treated with anionic and cationic materials t...
O Na                                                             Cl                                                       ...
The carboxylic acid group content of the partially carboxymethylated cellulosicfabrics were determined. [4] Cotton fabrics...
Table 3.2 Results for carboxymethylation of cellulosic fabrics (Vblank=23.8ml)       Treatment              CAA           ...
washed with a nonionic wetting agent at boiling temperature for 10 minutes, centrifugedand dried at RT for 24 hours. Appli...
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)
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Wrinkle recovery finishing on cotton by using cyclodextrin (phd report)

  1. 1. ABSTRACTBILGEN, MUSTAFA. Wrinkle Recovery for Cellulosic Fabric by Means of IonicCrosslinking. (Under the direction of Peter Hauser and Brent Smith.) When treated with formaldehyde-based crosslinkers, cellulosic fabrics showimproved mechanical stability, wrinkle recovery angles and durable press performance,but N-methylol treatment also causes fabrics to lose strength and later to releaseformaldehyde, a known human carcinogen. We have discovered that ionic crosslinks canstabilize cellulose using high or low molecular weight ionic materials which do not releasehazardous reactive chemicals, but at the same time provide improved wrinkle recoveryangles as well as complete strength retention in treated goods. We have variedpolyelectrolyte, the ionic content of fabrics, and various features of the applicationprocedure to optimize the results and to develop an in-depth fundamental physical andchemical understanding of the stabilization mechanism.
  2. 2. WRINKLE RECOVERY FOR CELLULOSIC FABRIC BY MEANS OF IONIC CROSSLINKING by MUSTAFA BILGEN A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science TEXTILE CHEMISTRY Raleigh 2005 APPROVED BY:Dr. Peter Hauser (Chair) Dr. Brent Smith (Co-Chair) Dr. Charles Boss (Minor)
  3. 3. DEDICATION This thesis is dedicated to my family and my wife, Nicole, who supported me withconstant love and caring and inspired my interest in studying textile chemistry. ii
  4. 4. BIOGRAPHY Mustafa Bilgen was born in December 1, 1978 in Erdemli, Turkey. He graduatedfrom Erzurum Science High School in June 1995. He received the Bachelor of Sciencedegree in Textile Engineering from Department of Engineering and Architecture, UludagUniversity, Bursa, Turkey in July 1999.After he graduated he worked as a dyeing and finishing supervisor in Akay TextileDyeing & Finishing Company for one year before he started to help his father for takingcare of the family business.He came to North Carolina State University in January 2004, to continue his educationand started his master program in Textile Chemistry under the direction of Dr. BrentSmith and Dr. Peter Hauser. iii
  5. 5. ACKNOWLEDGEMENTSI would like to thank to the National Textile Center and North Carolina State Universityfor their financial support. I also would like to thank to my advisors, Dr. Hauser and Dr.Smith, for their crucial help and patience during my research and preparation of my thesis. iv
  6. 6. LIST OF CONTENTSLIST OF TABLES ------------------------------------------------------------------------------- viiiLIST OF FIGURES --------------------------------------------------------------------------------x1. INTRODUCTION -------------------------------------------------------------------------------12. LITERATURE REVIEW ----------------------------------------------------------------------3 2.1 Cellulose chemistry ---------------------------------------------------------------------------3 2.2 Cellulosic fabric’s nature of wrinkling -----------------------------------------------------5 2.3 Durable Press finishing of cotton -----------------------------------------------------------6 2.3.1 Urea-Formaldehyde derivatives--------------------------------------------------------7 2.3.2 Melamine-Formaldyhe derivatives ----------------------------------------------------7 2.3.3 Methylol derivatives of cyclic ureas --------------------------------------------------8 2.3.4 Effects of formaldehyde based DP finishes on cellulose ---------------------------9 2.4 Recent developments in non-formaldehyde DP applications ------------------------- 10 2.5 Ionic crosslinking --------------------------------------------------------------------------- 14 2.6 Preparation of quaternized polymers ----------------------------------------------------- 16 2.6.1 Chitosan and its reaction with CHTAC --------------------------------------------- 16 2.6.2 Reaction of Cellulose with CHTAC------------------------------------------------- 18 2.7 Carboxymethylation of cellulose---------------------------------------------------------- 20 2.8 Proposed Research -------------------------------------------------------------------------- 213. EXPERIMENTAL PROCEDURES ------------------------------------------------------- 23 3.1 Test Materials-------------------------------------------------------------------------------- 23 3.2 Equipments ---------------------------------------------------------------------------------- 25 3.3 Application procedures--------------------------------------------------------------------- 25 3.3.1 Pad dry cure ---------------------------------------------------------------------------- 25 3.3.2 Pad batch-------------------------------------------------------------------------------- 26 3.3.3 Exhaustion ------------------------------------------------------------------------------ 26 3.4 Analysis and physical property tests------------------------------------------------------ 26 3.4.1 Nitrogen analysis ---------------------------------------------------------------------- 27 3.4.2 FT-IR analysis-------------------------------------------------------------------------- 27 3.4.3 1H- NMR analysis --------------------------------------------------------------------- 27 3.4.4 Wrinkle recovery angles -------------------------------------------------------------- 28 3.4.5 Tensile strength ------------------------------------------------------------------------ 28 3.4.6 Whiteness index------------------------------------------------------------------------ 28 3.4.7 Stiffness --------------------------------------------------------------------------------- 28 3.5 Reaction of cellulose with chloroacetic acid -------------------------------------------- 29 3.6 Reaction of Cellulose with CHTAC ------------------------------------------------------ 32 3.7 Synthesis of compounds ------------------------------------------------------------------- 35 3.7.1 Molecular weight determination of chitosan --------------------------------------- 35 3.7.2 Depolymerization of chitosan and characterization ------------------------------- 37 3.7.3 Reaction of chitosan with CHTAC -------------------------------------------------- 39 3.7.4 Reaction of glycerin and ethylene glycol with CHTAC -------------------------- 51 v
  7. 7. 3.7.5 Reaction of cellobiose and dextrose with CHTAC -------------------------------- 53 3.8 Preparation of fabric samples-------------------------------------------------------------- 53 3.9 Crosslinking of carboxymethylated cellulosic fabric----------------------------------- 54 3.9.1 Treatment with cationic chitosan ---------------------------------------------------- 54 3.9.2 Treatment with cationic glycerin ---------------------------------------------------- 54 3.9.3 Treatment with cationic cellobiose, cationic dextrose and cationic ethylene glycol------------------------------------------------------------------------------------------- 55 3.9.4 Treatment with calcium chloride and magnesium chloride ---------------------- 55 3.10 Crosslinking of cationic cellulosic fabric----------------------------------------------- 57 3.10.1 Treatment with PCA and BTCA --------------------------------------------------- 57 3.10.2 Treatment with EDTA, NTA and HEDTA --------------------------------------- 59 3.10.3 Treatment with oxalic acid, citric acid and malic acid -------------------------- 594. RESULTS & OBSERVATIONS AND DISCUSSION---------------------------------- 60 4.1 Wrinkle recovery angles of conventional durable press finished fabrics ------------ 60 4.2 Wrinkle recovery angles of polycation treated anionic cellulosic fabrics ----------- 60 4.2.1 Wrinkle recovery angles of cationic chitosan treated fabrics -------------------- 60 4.2.2 Application of paired t-test analysis on cationic chitosan treatments ----------- 68 4.2.3 Wrinkle recovery angles of cationic glycerin treatments ------------------------- 71 4.2.4 Wrinkle recovery angles of cationic cellobiose and cationic dextrose treated fabrics ------------------------------------------------------------------------------------------ 76 4.2.5 Wrinkle recovery angles of calcium chloride and magnesium chloride treated fabrics ------------------------------------------------------------------------------------------ 76 4.2.6 Discussion of wrinkle recovery angles for polycation treatments --------------- 79 4.3 Wrinkle recovery angles of polyanion treated cationic cellulosic fabrics ----------- 82 4.3.1 Wrinkle recovery angles of PCA and BTCA treated fabrics --------------------- 82 4.3.2 Wrinkle recovery angles of EDTA, NTA and HEDTA treated fabrics --------- 87 4.3.3 Wrinkle recovery angles of oxalic acid, citric acid and malic acid treatments 89 4.3.4 Discussion of wrinkle recovery angles for polyanion treatments---------------- 90 4.4 Strength data --------------------------------------------------------------------------------- 92 4.4.1 Tensile strength of conventional durable press finished fabric ------------------ 92 4.4.2 Strength data of polycation treated anionic cellulosic fabrics-------------------- 93 4.4.3 Strength data of polyanion treated cationic cellulosic fabrics-------------------- 96 4.4.4 Discussion of strength data of untreated and treated fabrics --------------------- 98 4.5 CIE whiteness index data -----------------------------------------------------------------101 4.5.1 CIE whiteness index of conventional durable press treated fabric -------------101 4.5.2 CIE whiteness index of polycation treated anionic cellulosic fabrics----------102 4.5.3 CIE whiteness index of polyanion treated cationic cellulosic fabrics----------104 4.5.4 Discussion of whiteness index of untreated and treated fabrics ----------------106 4.6 Stiffness data -------------------------------------------------------------------------------108 4.6.1 Stiffness of conventional durable press treated fabrics --------------------------109 4.6.2 Stiffness data of polycation treated anionic cellulosic fabrics ------------------109 4.6.3 Stiffness data of polyanion treated cationic cellulosic fabrics ------------------111 4.6.4 Discussion of stiffness data of untreated and treated fabrics --------------------113 vi
  8. 8. 5. CONCLUSIONS ------------------------------------------------------------------------------1166. RECOMMENDATIONS FOR FUTURE WORK--------------------------------------1187. LIST OF REFERENCES--------------------------------------------------------------------1218. APPENDIX-------------------------------------------------------------------------------------126 8.1 Wrinkle recovery angles ------------------------------------------------------------------126 8.2 Breaking strength --------------------------------------------------------------------------133 8.3 CIE whiteness index -----------------------------------------------------------------------137 8.4 Stiffness -------------------------------------------------------------------------------------141 8.5 Nitrogen analysis---------------------------------------------------------------------------145 vii
  9. 9. LIST OF TABLESTable 3.2 Results for carboxymethylation of cellulosic fabrics ------------------------------ 32Table 3.3 Scheme of intrinsic viscosity measurement for the low viscosity chitosan ----- 36Table 3.4 Properties of the Low Viscosity chitosan.------------------------------------------- 37Table 3.5 The intrinsic viscosity and Mv of depolymerized chitosans----------------------- 39Table 4.1 Paired t-test results for dry wrinkle recovery angles of cationic chitosan treated fabrics ------------------------------------------------------------------------------------------ 69Table 4.2 Paired t-test results for wet wrinkle recovery angles of cationic chitosan treated fabrics ------------------------------------------------------------------------------------------ 70Table 4.3 Paired t-test results for dry/wet wrinkle recovery angles of Ca++ and Mg++ treated fabrics --------------------------------------------------------------------------------- 79Table 4.4 Paired t-test results for dry/wet wrinkle recovery angles of PCA and BTCA treated fabrics --------------------------------------------------------------------------------- 87Table A.1 Dry and wet wrinkle recovery angles for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics -----------------------------------------------------------126Table A.2 Dry and wet wrinkle recovery angles for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics -----------------------------------------------------------127Table A.3 Dry and wet wrinkle recovery angles for molecular weight of 6.11 x 105g/mole cationic chitosan treated fabrics -----------------------------------------------------------127Table A.4 Dry and wet wrinkle recovery angles for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics by exhaustion method --------------------------------128Table A.5 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics----128Table A.6 Dry and wet wrinkle recovery angles for cationic glycerin treated fabrics by exhaustion method---------------------------------------------------------------------------129Table A.7 Dry and wet wrinkle recovery angles for cationic cellobiose and cationic dextrose treated fabrics ---------------------------------------------------------------------129Table A.8 Dry and wet wrinkle recovery angles for calcium chloride and magnesium chloride treated fabrics ---------------------------------------------------------------------130Table A.9 Dry and wet wrinkle recovery angles for PCA treated fabrics------------------130Table A.10 Dry and wet wrinkle recovery angles for BTCA treated fabrics --------------131Table A.11 Dry and wet wrinkle recovery angles for EDTA treated fabrics --------------131Table A.12 Dry and wet wrinkle recovery angles for NTA treated fabrics ----------------132Table A.13 Dry and wet wrinkle recovery angles for HEDTA treated fabrics ------------132Table A.14 Dry and wet wrinkle recovery angles for oxalic, malic and citric acid treated fabrics -----------------------------------------------------------------------------------------133Table A.15 Breaking strength data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------134Table A.16 Breaking strength data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------134 viii
  10. 10. Table A.17 Breaking strength data for molecular weight of 6.11 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------135Table A.18 Breaking strength data for cationic glycerin treated fabrics -------------------135Table A.19 Breaking strength data for calcium chloride and magnesium chloride treated fabrics -----------------------------------------------------------------------------------------136Table A.20 Breaking strength data for PCA treated fabrics ---------------------------------136Table A.21 Breaking strength data for BTCA treated fabrics -------------------------------137Table A.22 Whiteness index data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------138Table A.23 Whiteness index data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------138Table A.24 Whiteness index data for molecular weight of 6.11 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------139Table A.25 Whiteness index data for CG treated fabrics-------------------------------------139Table A.26 Whiteness index data for calcium and magnesium chloride treated fabrics -140Table A.27 Whiteness index data for PCA treated fabrics -----------------------------------140Table A.28 Whiteness index data for BTCA treated fabrics---------------------------------141Table A.29 Stiffness data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics --------------------------------------------------------------------------------142Table A.30 Stiffness data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics --------------------------------------------------------------------------------142Table A.31 Stiffness data for molecular weight of 6.11 x 105g/mole cationic chitosan treated fabrics --------------------------------------------------------------------------------143Table A.32 Stiffness data for cationic glycerin treated fabrics ------------------------------143Table A.33 Stiffness data for calcium chloride and magnesium chloride treated fabrics 144Table A.34 Stiffness data for PCA treated fabrics --------------------------------------------144Table A.35 Stiffness data for BTCA treated fabrics ------------------------------------------145Table A.36 Nitrogen analysis data for molecular weight of 3.2 x 104g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------146Table A.37 Nitrogen analysis data for molecular weight of 1.4 x 105g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------146Table A.38 Nitrogen analysis data for molecular weight of 6.11 x 104g/mole cationic chitosan treated fabrics ---------------------------------------------------------------------147Table A.39 Nitrogen analysis data for cationic glycerin treated fabrics--------------------147 ix
  11. 11. LIST OF FIGURESFigure 2.1 Molecular structure of a cellulose polymer chain -----------------------------------4Figure 2.2 Crystalline and amorphous structure of cellulose -----------------------------------4Figure 2.3 Molecular structure of DMDHEU-----------------------------------------------------8Figure 2.4 Molecular structure of BTCA-------------------------------------------------------- 12Figure 2.5 Reaction of chitosan with CHTAC in alkaline conditions ----------------------- 17Figure 2.6 Reaction of cellulose with CHTAC in alkaline conditions----------------------- 19Figure 2.7 Molecular structure of carboxymethyl cellulose ---------------------------------- 20Figure 3.1 Reactions of cellulose with CAA that impart an anionic character ------------- 30Figure 3.2 Reactions of cellulose with CHTAC that impart a cationic character ---------- 34Figure 3.3 Huggins plot of ήsp/c versus c for the cationic chitosan -------------------------- 37Figure 3.4 Reaction of chitosan with CHTAC-------------------------------------------------- 41Figure 3.5 Conductometric titration curve of cationic chitosan ------------------------------ 43Figure 3.6 FTIR spectrum of deacetylated chitosan ------------------------------------------- 46Figure 3.7 FTIR spectrum of cationic chitosan ------------------------------------------------- 47Figure 3.8 1H-NMR spectrum of deacetylated chitosan --------------------------------------- 48Figure 3.9 1H-NMR spectrum of O-substituted and N-substituted cationic chitosan ----- 50Figure 3.10 Reaction of glycerin with CHTAC ------------------------------------------------ 52Figure 3.11 Crosslinked anionic cellulose with calcium -------------------------------------- 56Figure 3.12 Crosslinked cationic cellulose with BTCA --------------------------------------- 58Figure 4.1 Effect of carboxyl content and concentration on dry wrinkle recovery angles of cationic chitosan treated fabrics ------------------------------------------------------------ 62Figure 4.2 Effect of carboxyl content and concentration on wet wrinkle recovery angles of cationic chitosan treated fabrics ------------------------------------------------------------ 62Figure 4.3 Effect of carboxyl content and concentration on %Nitrogen content of cationic chitosan treated fabrics ---------------------------------------------------------------------- 64Figure 4.4 The relationship between %Nitrogen content of the fabrics and dry/wet wrinkle recovery angles ------------------------------------------------------------------------------- 65Figure 4.5 Effect of molecular weight of chitosan and concentration on dry wrinkle recovery angles of cationic chitosan treated fabrics ------------------------------------- 67Figure 4.6 Effect of molecular weight of chitosan and concentration on wet wrinkle recovery angles of cationic chitosan treated fabrics ------------------------------------- 67Figure 4.7 Effect of carboxyl content and concentration on dry wrinkle recovery angles of cationic glycerin treated fabrics ------------------------------------------------------------ 72Figure 4.8 Effect of carboxyl content and concentration on wet wrinkle recovery angles of cationic glycerin treated fabrics ------------------------------------------------------------ 72Figure 4.9 Effect of carboxyl content and concentration on %Nitrogen content of cationic glycerin treated fabrics----------------------------------------------------------------------- 74Figure 4.10 The relationship between %Nitrogen content of the fabrics and dry/wet wrinkle recovery angles --------------------------------------------------------------------- 75 x
  12. 12. Figure 4.11 Effect of carboxyl content on dry wrinkle recovery angles of calcium and magnesium treated fabrics------------------------------------------------------------------- 77Figure 4.12 Effect of carboxyl content on wet wrinkle recovery angles of calcium and magnesium treated fabrics------------------------------------------------------------------- 78Figure 4.13 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of PCA treated fabrics ----------------------------------------------------------------------- 83Figure 4.14 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles of PCA treated fabrics ----------------------------------------------------------------------- 84Figure 4.15 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of BTCA treated fabrics --------------------------------------------------------------------- 85Figure 4.16 Effect of% Nitrogen fixed and concentration on wet wrinkle recovery angles of BTCA treated fabrics --------------------------------------------------------------------- 86Figure 4.17 Effect of %Nitrogen fixed and concentration on dry wrinkle recovery angles of EDTA treated fabrics --------------------------------------------------------------------- 88Figure 4.18 Effect of %Nitrogen fixed and concentration on wet wrinkle recovery angles of EDTA treated fabrics --------------------------------------------------------------------- 89Figure 4.19 Effect of treatment on dry wrinkle recovery angles ----------------------------- 91Figure 4.20 Effect of treatment on wet wrinkle recovery angles ----------------------------- 92Figure 4.21 Effect of carboxyl content and concentration on breaking strength of the cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics-------------- 94Figure 4.22 Effect of carboxyl content and concentration on breaking strength of the cationic glycerin treated fabrics ------------------------------------------------------------ 95Figure 4.23 Effect of carboxyl content and concentration on breaking strength of the calcium and magnesium treated fabrics --------------------------------------------------- 95Figure 4.24 Effect of %Nitrogen content and concentration on breaking strength of the PCA treated fabrics--------------------------------------------------------------------------- 97Figure 4.25 Effect of %Nitrogen content and concentration on breaking strength of the BTCA treated fabrics ------------------------------------------------------------------------ 97Figure 4.26 Effect of treatment on breaking strength------------------------------------------ 99Figure 4.27 Correlation between wet wrinkle recovery angles of cationic chitosan (molecular weight of 1.4 x 105g/mole) treatment and tensile strength ---------------100Figure 4.28 Correlation between wet wrinkle recovery angles of PCA treatment and tensile strength -------------------------------------------------------------------------------101Figure 4.29 Effect of carboxyl content and concentration on whiteness index of the cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics-------------103Figure 4.30 Effect of carboxyl content and concentration on whiteness index of the cationic glycerin treated fabrics -----------------------------------------------------------103Figure 4.31 Effect of carboxyl content and concentration on whiteness index of the calcium chloride and magnesium chloride treated fabrics -----------------------------104Figure 4.32 Effect of %Nitrogen fixed and concentration on whiteness index of the PCA treated fabrics --------------------------------------------------------------------------------105 xi
  13. 13. Figure 4.33 Effect of %Nitrogen fixed and concentration on whiteness index of the BTCA treated fabrics --------------------------------------------------------------------------------106Figure 4.34 Effect of treatment on whiteness index ------------------------------------------108Figure 4.35 Effect of carboxyl content and concentration on stiffness of the cationic chitosan (molecular weight of 1.4 x 105g/mole) treated fabrics -----------------------110Figure 4.36 Effect of carboxyl content and concentration on stiffness of the cationic glycerin treated fabrics----------------------------------------------------------------------110Figure 4.37 Effect of carboxyl content and concentration on stiffness of the calcium chloride and magnesium chloride treated fabrics----------------------------------------111Figure 4.38 Effect of %Nitrogen fixed and concentration on stiffness of the PCA treated fabrics -----------------------------------------------------------------------------------------112Figure 4.39 Effect of %Nitrogen fixed and concentration on stiffness of the BTCA treated fabrics -----------------------------------------------------------------------------------------113Figure 4.40 Effect of treatment on stiffness----------------------------------------------------115 xii
  14. 14. 1. INTRODUCTION The textile market has shown an interest in the demand for easy care, wrinkle-resistant for cellulosic fabrics over the years. Untreated cellulose has poor recovery,because cellulose is stabilized by hydrogen bonds within and between cellulose chains.Moisture between the polymer chains can invade the cellulose structure and cantemporarily release the stabilizing hydrogen bonds and hydrogen bonds in celluloseexperience frequent breaking and reforming when extended and newly formed hydrogenbonds tend to hold cellulose chain segments in new positions when external stress isreleased. Preventing wrinkling of cellulosic fabric can be accomplished by thecrosslinking of polymer chains, thus making intermolecular bonds between chains thatwater cannot release. In a typical durable-press (DP) treatment, some hydrogen bonds arereplaced with covalent bonds between the finishing agent and the fiber elements. Becausecovalent bonds are much stronger than hydrogen bonds, they can resist higher externalstress. Hence, treated cellulose has a higher initial modulus and better elastic recovery.After the external force is released, the energy stored in the strained covalent bondsprovides the driving force to return chain segments back to their original positions. Formaldehyde-based cellulose crosslinking was a very important textile chemicalbreakthrough of the 1930s, and is still the basis for a vast array of modern finished cottonproducts today. N-methylol crosslinkers have the biggest use in durable press finishing.They give fabrics crease resistance, shrinkage control, anti-curl, and durable press, but 1
  15. 15. they also impart strength loss and release formaldehyde, a known human carcinogen. [1]Today’s textile industry has for a long time been searching for durable press finishes thatcan give same results as formaldehyde based finishes, but cause less strength loss and noformaldehyde release. For example, polycarboxylic acids and citric acid have been usedwith varying degrees of success. [2, 3] We have developed multiple methods of forming ionic crosslinks to give non-wrinkle effects to cellulosic fabric. [4] These includes, (1) treatment of cellulose with ananionic material and reacting with a polycation, (2) treatment of cellulose with a cationicmaterial and then application of a polyanion, (3) treatment of cellulose with aprecondensate of an ionic reactive material and a polyelectrolyte of the opposite charge.The performance of crosslinkers can be measured by dry and wet wrinkle recovery angle(WRA). Dry WRA is important for outerwear clothing to help resist dry wrinkling duringwearing, but wet WRA is more important for bedding which is almost never ironed andmust resist wrinkling during laundering. We observed simultaneous enhancements of bothwet and dry WRA as well as significant strength gain and excellent washing durability.Polyelectrolytes are strongly bond and thus do not desorb during laundering. Thechemicals are common industrial reactants and do not have unusual safety orenvironmental issues. Processes use existing equipment and no high temperature curing isnecessary. In addition, ionic crosslinks may have other important advantages, such asantimicrobial activity and enhanced dyeability. 2
  16. 16. 2. LITERATURE REVIEW2.1 Cellulose chemistry We can only understand chemical as well as physical properties of cellulose by theknowledge of both chemical nature of the cellulose molecules and their structural andmorphological arrangement in the solid, mostly fibrous, state. For example reactivity ofthe functional sites in the cellulose molecules and structural characteristics of polymerssuch as; inter- and intramolecular interactions, and size of crystallites and fibrils. Thesestructural characteristics of the cellulosic polymers influence the physico-mechanicalproperties utilized in the textile industry. The largest part of the cellulosic polymers usedfor textile substrates comes from cotton. Cotton is a soft fiber that grows around the seeds of the cotton plant. The fiber ismost often spun into thread and used to make a soft, breathable textile. Cotton is avaluable crop because only about 10% of the raw weight is lost in processing. [5] Oncetraces of wax, protein, etc. are removed, the remainder is a natural polymer of purecellulose. This cellulose is arranged in a way that gives cotton unique properties ofstrength, durability, and absorbency. After scouring and bleaching, cotton is 99% purecellulose. [6] Cellulose is a macromolecule made up of anhydroglucose units united by 1,4, oxygen bridges as shown in Figure 2.1. The anhydroglucose units are linked together asbeta-cellobiose; therefore, anhydro-beta-cellobiose is the repeating unit of the polymerchain. The number of these repeat units that are linked together to form the cellulosepolymer is referred to as the degree of polymerization and is between 1000 and 15000. [7] 3
  17. 17. OH H OH H OH H H H OH OH O O HHO H HO H HO H H H HO H O H O HO H O O O OH OH H H H H H H OH OH n Cellulose Figure 2.1 Molecular structure of a cellulose polymer chain The cellulose chains within the cotton fibers tend to be held in place by hydrogenbonding. These hydrogen bonds occur between the hydroxyl groups of adjacent moleculesand are more prevalent between the parallel, closely packed molecules in the crystallineareas of the fiber as shown in Figure 2.2. [8] Figure 2.2 Crystalline and amorphous structure of cellulose The chemical characters of the cellulose molecules are determined by thesensitivity of the three-hydroxyl groups, one primary and two secondary, in each repeatingcellobiose unit of cellulose, which are chemically reactive groups. These groups canundergo substitution reactions in procedures designed to modify the cellulose fibers such 4
  18. 18. as esterification and etherification or in the application of dyes and finishes forcrosslinking. The hydroxyl groups also serve as principal sorption sites for watermolecules. Directly sorbed water is firmly chemisorbed on the cellulosic hydroxyl groupsby hydrogen bonding. [8] Of particular interest in the case of cellulosic fibers is theresponse of their strength to variations in moisture content. Generally, in the case ofregenerated and derivative cellulosic fibers, strength decreases with increasing moisturecontent. In contrast, the strength of cotton generally increases with increased moisture.The contrast seen between the fibers in their response to moisture is explained in terms ofintermolecular hydrogen bonding between cellulose chains and their degree ofcrystallinity. [8]2.2 Cellulosic fabric’s nature of wrinkling The textile market has shown an interest in the demand for easy care, wrinkle-resistant for cellulosic fabrics over the years. Improvements in crease angle recoveryproperty are obtained by chemical treatments, which improve the ability of fibers tomaintain configurations in which they are treated. [9] Untreated cellulose has poorrecovery, because hydrogen bonds in cellulose experience frequent breaking andreforming when extended, and newly formed hydrogen bonds tend to hold cellulose chainsegments in new positions when external stress is released. In a typical durable-presstreatment, some hydrogen bonds are replaced with covalent bonds between the finishingagent and the fiber elements. Because covalent bonds are much stronger than hydrogenbonds, they can resist higher external stress. Hence, treated cellulose has a higher initial 5
  19. 19. modulus and better elastic recovery. After the external force is released, the energy storedin the strained covalent bonds provides the driving force to return chain segments back totheir original positions. However, chemical treatment on cellulose also causes the loss ofmechanical properties. [10] The classical explanation to this problem is that traditionalcrosslinks are too rigid to allow cellulose chain segments to move.2.3 Durable Press finishing of cotton Durable press is shaping a garment and then treating it in such a way that afterwearing and washing it will return to its pre-set shape. In order to produce non-wrinklecellulosic fabrics the durable press finishing has been developed.The original process for the production of crease resistant fabrics was developed in 1928.[11] DP finishes have been marketed ever since. Durable press is accomplished by resintreatments. The main purpose of resin treatments is to overcome a serious drawback ofcellulosic fabrics, for example their ease of wrinkling, which requires ironing afterwashing. [12] Ideally, a DP finished fabric will wash and dry to a completely smoothstate. The usual method of production of crease resistant fabric consists of padding fabrictrough a crosslinking agent along with a catalyst and other additives, drying at 100-110oCfollowed by curing at 155-175oC for 2-3 minutes. [13] The resulting fabric has the abilityof recovering from creases both when fabric is wet and dry. The selection of crossslinkingagents for DP finishing is important. There are a large number of cross linker available.Some of the most common reagents are urea-formaldehyde derivatives, melamine- 6
  20. 20. formaldehyde derivatives and methylol derivatives. All of these reagents used for DP ofcellulosic fabric with varying degrees of success.2.3.1 Urea-Formaldehyde derivatives The first widely used crosslinking agent for DP finishing was urea-formaldehydeadducts. These products are mostly prepared at the finishing plant; also precondensate areavailable in the market. The treatment of fabrics with urea-formaldehyde resin involvespadding the fabric through precondensate and an acid catalyst, drying, curing andwashing. The advantages of urea-formaldehyde resins are the low cost and highefficiency. The disadvantages are poor stability of the agent, poor durability and impartingchlorine retention to the fabric. The chlorine retention is due to the presence of the –NHgroups which react with chlorine from the bleach or laundry bath. [14, 15, 16] Thereaction of –NH groups and chlorine produces hydrochloric acid and it is a strong acidthat causes tendering and yellowing of cellulose.2.3.2 Melamine-Formaldyhe derivatives The most commonly used melamine product is trimethylol melamine. It has goodstability and durability. Trimethylol-melamine is more expensive than urea-formaldehyde.It picks up and retains chlorine, it also yellows the bleached fabric but the fiberdegradation due to strong acid is avoided because of basicity of the compound. [17, 18] 7
  21. 21. 2.3.3 Methylol derivatives of cyclic ureas These compounds are also referred to as fiber reactants, because they only reactwith the cellulose instead of themselves. As a result insoluble resin on the surface of thefabric is absent hence the finished fabric have a softer hand. The members of this groupare:(a) Dimethylol ethylene urea (DMEU) has high reaction efficiency and low price. [19] Itcan produce high wrinkle recovery angles at low add-ons. The finish with DMEU issensitive to acids and can be destroyed by acid treatment during laundering. (b)Dimethylol propylene urea (DMPU) is suitable for white goods, since it does not produceyellowing on heating. [20] Another advantage of it is that not giving any odor. But thefinish is not susceptible to chlorine retention damage. It is more expensive than others inthe group. (c) Dimethylol dihydroxy ethylene urea (DMDHEU) as shown in Figure 2.3. Itis the most commonly used DP finish agent and gives excellent crease angle recovery.[21, 22] O N N HO OH HO OH DMDHEU Figure 2.3 Molecular structure of DMDHEU 8
  22. 22. It shows some chlorine retention therefore it is not recommended for white goods. It doesnot effect the lightness of the dyes hence it is dominating the colored garments durablepress finishing.2.3.4 Effects of formaldehyde based DP finishes on cellulose Formaldehyde-based N-methylol reagents are the most common DP reagents. Butthese reagents produce losses in tensile strength of cotton due to depolymerization ofcellulose chains. Cellulose depolymerization occurs with a polycarboxylic acid or a Lewisacid, which are catalysts for formaldehyde based resins. As a result they cause a highdegree of depolymerization. A direct correlation between tensile strength loss of thetreated cotton and the molecular weight of cellulose was found. [23] Severe tensilestrength loss is a major disadvantage of DP finished cotton fabrics, and it continues to bethe major obstacle for DP applications. Most of the studies of mechanical strength ofdurable press finished cotton fabrics in the past have focused on changes in the grossproperties of cotton fabrics, such as tensile strength and abrasion resistance. Anotherdisadvantage of N-methylol reagents is later formaldehyde release. In recent years therehave been extensive efforts to find non-formaldehyde alternatives due to increasingconcern with health risks associated with formaldehyde. On the other hand, the finaltextile products not only have to be eco-friendly, but also have to be produced by cleantechnologies. Crosslinking of cellulose with N-methylol crosslinking agents to impartwrinkle-resistance, shrink proofing, and smooth drying properties by virtue of chemicalreaction with cellulosic hydroxyl groups to form covalent crosslinks in the interior of 9
  23. 23. cellulosic fibers have successfully been done. However, at the present time, presence offormaldehyde in the finished product, working atmosphere, as well as in wastewaterstreams is considered as highly objectionable due to the mutagenic activity of variousaldehydes, including formaldehyde. [24]2.4 Recent developments in non-formaldehyde DP applications Extensive research has attempted to develop nonformaldehyde crosslinking agentsto replace N-methylol compounds that release formaldehyde during production andstorage, which is proven to be carcinogenic. [25] Durable press finishing, used toovercome wrinkling problems in cotton fabric for some years, involves chemicalcrosslinking agents that covalently crosslink with hydroxyl groups of adjacent cellulosepolymer chains within cotton fibers. This crosslinking not only results in the fabricswrinkle resistance, but also in discoloration and impairment of fabric strength and of othermechanical properties. The early chemical agents used for crosslinking with cellulosewere mostly formaldehyde and formaldehyde derivatives, which can form ether bondswith cellulose. DMDHEU is the most widely used crosslinking agent because it providesgood durable press properties at a lower cost and an acceptable level of detrimental effectson fabric strength and whiteness compared to other N-methylol agents. However, fabrictreated with DMDHEU tends to release formaldehyde vapors during processing, storage,and consumer use. Because formaldehyde is toxic to human beings, several attempts havebeen made to replace it with formaldehyde-free crosslinking agents. 10
  24. 24. Several polycarboxylic acids have served as durable press agents. Carboxylicgroups in polycarboxylic acids are able to form ester bonds with hydroxyl groups incellulose. The main advantages of polycarboxylic acids are that they are formaldehyde-free, do not have a bad odor, and produce a very soft fabric hand. BTCA (1.2,3,4-butcnetetracarboxylic acid) is the most effective polycarboxylic acid for use as a durablepress agent as shown in Figure 2.4. In the presence of sodium hypophosphite monohydrateas catalyst, BTCA provides almost the same level of durable press performance and finishdurability with laundering as the conventional DMDHEU reactant, but its high cost maybe an obstacle to a mills decision to use it as a replacement for the conventional durablepress reactant. As with DMDHEU, fabrics treated with polycarboxylic acids generallylose their strength, [26] probably due to excess crosslinking with cellulose chains. Thismay be tackled by using long-chain polycarboxylic acids, which can be obtained throughcopolymerization of two unsaturated polycarboxylic acids. BTCA satisfies many desirable requirements such as durability to laundering anddurable press performance. Crosslinking of cellulose molecules with BTCA increasesfabric wrinkle resistance at the expense of mechanical strength. [27] 11
  25. 25. COOH COOH COOH COOH BTCA Figure 2.4 Molecular structure of BTCA Severe tensile strength loss diminishes the durability of finished cotton garments.The factors involved in strength loss of cotton fabric treated with BTCA include acidcatalyzed degradation of cellulose molecules and their crosslinking. The commoncatalysts for polycarboxylic acids are phosphorous-containing compounds, although theiruse has disadvantages such as high cost, strength loss and raises some environmentalconcerns. In order to decrease strength retention other catalysts have been proposed;among these is boric acid, [28] which was added to increase strength of the treated fabrics.With this treatment, durable press properties were similar to those obtained with sodiumhypophosphite; moreover the mechanical resistance improved. A previous study [29] indicated that cellulosic fabric treated with a copolymermade with maleic and acrylic acids possesses the same level of wrinkle resistance as withBTCA, while tensile strength retention improves slightly. Another disadvantage ofpolycarboxylic acid finishing is yellowing of the treated fabric. It is proposed that the useof a copolymer between acrylic and maleic acids as a durable press finishing agent canimprove crease angle recovery for cotton fabric. [29] However, the copolymer treatmentdoes not provide as good tensile strength and whiteness as DMDHEU. 12
  26. 26. Chitosan citrate has been evaluated as non-formaldehyde durable press finish toproduce wrinkle-resistance and antimicrobial properties for cotton fabrics. [30] Thecarboxylic groups in the chitosan citrate structure were used as active sites for its fixationonto cotton fabrics. The fixation of the chitosan citrate on the cotton fabric was done bythe padding of chitosan citrate solution onto cotton fabrics followed by a dry - cureprocess. The factors affecting the fixation processes were systematically studied. Theantimicrobial activity and the performance properties of the treated fabrics, includingtensile strength, wrinkle recovery, wash fastness and whiteness index, were evaluated. Thefinished fabric shows adequate wrinkle resistance, sufficient whiteness, high tensilestrength and more reduction rate of bacteria as compared to untreated cotton fabric. A non-polluting system of applying an easy-care finish to cotton fabrics has beenproposed. [31] The new formulation is based on an aqueous system of BTCA-chitosan-sodium hypophosphite and was applied by the traditional pad-dry-cure method to anEgyptian poplin. The variables studied were the concentrations of BTCA and chitosan, thetime and temperature of polymerisation. The study also included a comparison with othertraditional or recommended systems. The treated fabric was tested for crease recoveryangle, resistance to traction, elongation to breakage, rigidity, wetability, whiteness,nitrogen content and dyeability. It was concluded that the new formulation gavecomparable if not better results than the traditional treatments. 13
  27. 27. 2.5 Ionic crosslinking Ionic crosslinking has been used in the polymer industry for various applications.It is an alternative to covalent crosslinks. It is well known that the thermal resistance,durability, abrasion resistance, chemical resistance, etc., of a polymer are improved bycrosslinking. For example, acrylic copolymer sizes have been used for improving theweaving properties of polyester filament warps. [32] Acrylic sizes produce good abrasionresistance, high strength, good adhesion and easy removability. But when exposed to highhumidity many of the acrylics absorb water and cause blocking on the beam. In order toimprove the stability of acrylic sizes divalent cations are used for reduction of themoisture regain. Calcium and magnesium ions were used [32] for reducing the watersensitivity of sizes. These cations form ionic crosslinks between the polymer chains andstabilize the structure against moisture. Also these crosslinks improved the strengthproperties of the polymer film. The copolymer of propylene and maleic anhydride is also crosslinked by ionicbonding. It is considered that the ionic crosslinking by maleic anhydride groups ispossible by using not only of magnesium hydroxide but also of other metal compounds.Magnesium 12-hydroxy stearate, zinc oxide, and zinc sulfide were chosen for ioniccrosslinking. Accordingly, by changing the kind and content of the metal compounds, theviscosity can be freely controlled. Considering also other rheological characteristics, theseionically crosslinked compounds are assumed to show ideal flow processabilities exceptfor the extrudate appearance [33,34] 14
  28. 28. A series of siloxane-based liquid-crystalline elastomers were synthesized by usingionic crosslinking agents containing sulfonic acid groups. The ions aggregated in domainsforces the siloxane chains to fold and form an irregular lamellar structure. Ionicaggregates and liquid crystalline segments may be dispersed among each other to formmultiple blocks with increasing ionic crosslinking content. [35] In a previous work [36] a vulcanized carboxylated nitrile rubber compound wasprepared using a mixed crosslinking system employing a mixture of zinc peroxide andsulphur accelerators as vulcanizing agents to produce ionic and covalent structures.Because of the existence of carboxyl groups in the polymeric chain, crosslinked polymersof ionic nature can be obtained when a bivalent metal oxide, such as zinc oxide, is used asa crosslinking agent. Ionic vulcanized compounds with properties equal to or better thanthose produced using sulphur accelerators can also be obtained in the same way usingmetal peroxides. Polyurethanes are a versatile class of materials; their end applications dictate thestructure and morphology during synthesis. From the prepolymer stage through chainextension and in the required cases of final crosslinking, there are many ways to influencethe final characteristics of the polyurethanes. Crosslinked networks are obtained throughionic crosslinking and the different approaches produce cationic, anionic and Zwitter ionicpolyurethanes. These networks find a variety of applications as coatings, adhesives,shoe soles, and vibration damping materials. [37] 15
  29. 29. 2.6 Preparation of quaternized polymers Conversion to quaternary ammonium salts gives products whose degree ofionization is pH-independent. Such polymers can be prepared by reaction of polymerswith 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC).2.6.1 Chitosan and its reaction with CHTAC Chitosan is the deacetylated form of chitin, poly [β-(1→4)-2-deoxy-D-glucopyranose], is the second most abundant natural polymer next to cellulose. Chitosanis a linear copolymer composed mainly β-(1→4)-2-amino-2-deoxy-D-glucopyranose andpartially β-(1→4)-2-acetamido-2-deoxy-D-glucopyranose residues. [38] Chitosan can bedissolved in diluted acids by being protonated to soluble polyammonium salt. Hydroxyland amino groups of chitosan can react with epoxides by a ring opening reaction in eitherpresent of a base or neutral conditions. These reactions were performed previously. [4, 39]Kim at al performed the reaction between chitosan and CHTAC at neutral conditions.They proved by FTIR and H1-NMR that the product they produced had a degree ofsubstitution larger than 60% and substitutions formed at NH2 sites. Because the hydroxylgroups of chitosan are not sufficiently nucleophilic under neutral conditions, N-substitutedcationic chitosan can be obtained under neutral conditions. On the other hand; in alkali conditions the hydroxyl groups of chitosan arenucleophilic therefore reaction of chitosan and CHTAC produce O-substituted cationicchitosan. Hasem at al performed the reaction under highly alkaline (pH=11-12) conditionsand they believe that the product was O-substituted cationic chitosan and soluble at 16
  30. 30. neutral conditions. Both of the products have cationic properties and can be used as acationic polyelectrolyte to form ionic crosslinks and anti-microbial finish for cellulosicfabrics. [30, 40] Figure 2.5 shows the reaction of chitosan with CHTAC in alkalineconditions. C H 3 Cl C H 3 Cl + N CH3 Na OH + N CH3 Cl OH CH3 3 CH O3 -chloro- 2 -hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride (CHTAC) (EPTAC) C H 3 Cl + N CH3 CH3 O + OH OH H OH H H H H NH 2 NH 2 O O H HO H HO H HO H H H HO H O H O HO H O O O NH 2 NH 2 H H H H H H OH OH n Chitosan CH3 CH3 Cl + Cl + N CH3 N CH3 CH3 CH3 O OH O OH OH H H H H H NH2 NH2 O O HHO H HO H HO H H H HO H O H O HO H O O O CH3 NH2 NH2 H + H H H H O N CH3 O CH3 H + n OH C H 3 Cl N CH3 OH C H Cl 3 Cationic chitosan Figure 2.5 Reaction of chitosan with CHTAC in alkaline conditions 17
  31. 31. 2.6.2 Reaction of Cellulose with CHTAC The cationization of cellulose with using CHTAC has been previously studied.[41,42,43] The process basicly takes place in two stages. From practical point this occursin a single process. Sodium hydroxide (NaOH) is the base catalyst. The cationic characterof cellulose is independent from pH. In the first stage the epoxide form of CHTAC formedin the presence of NaOH. In the second stage this epoxide reacts with a hydroxyl group inthe cellulose. The reaction efficiency for cationization of cellulose is low due to hydrolysisreaction of CHTAC. Hydrolyzed CHTAC is no longer reactive therefore the efficiency isless than perfect. There are many ways to perform the reaction for example, pad-batch,pad-steam, exhaust, and pad-dry-cure methods. [42] All of these procedures give differentvalues of efficiency. The pad-batch process is consist of padding the fabric through amixture of NaOH and CHTAC solution at room temperature and followed by holding atroom temperature for 24 hours. The exhaustion procedure was studied at 75oC for 90minutes. The mole ratio of NaOH and CHTAC varied. Also different solvent systemswere experimented such as; water, acetone, ethanol, isopropanol, and methanol. Thehighest cationization level was obtained with acetone. The pad-steam application wasconsist of padding the fabric through the mixture of CHTAC and NaOH and steaming at100oC for 30 minutes. The pad-dry-cure method investigated at using different drying andcuring times and temperatures. The mole ratio of NaOH and CHTAC was also varied. Thebest conditions for this application was after padding the fabrics drying at 35oC for 5minutes followed by curing at 110oC for also 5 minutes. The exhaust method gave under 18
  32. 32. 10% substitution, pad-batch and pad steam methods are more efficient, and they producedabout 25% substitution. The pad-dry-cure methods give fixations around 85%. Theefficiencies for all the methods decreased when increasing in concentration of CHTAC.The optimum mole ratio was determined as 1.8 or greater. [42] C H 3 Cl C H 3 Cl + N CH3 Na OH + N CH3 Cl OH CH3 3 CH O 3 -chloro- 2 -hydroxypropyl trimethyl ammonium chloride Epoxypropyl trimethyl ammonium chloride (CHTAC) (EPTAC) CH3 Cl + N CH3 CH3 O + OH OH H OH H H H H OH OH O O H HO H HO H HO H H H HO H O H O HO H O O O OH OH H H H H H H OH OH n Cellulose C H 3 Cl C H 3 Cl + + N CH3 N CH3 OH CH3 O OH CH3 H O OH H H H H OH OH O O HHO H HO H HO H H H HO H O H O HO H O O O CH3 OH OH H + H H H H O N CH3 CH3 H O + OH C H 3 Cl N CH3 n OH C H 3 Cl Cationic cellulose Figure 2.6 Reaction of cellulose with CHTAC in alkaline conditions 19
  33. 33. 2.7 Carboxymethylation of cellulose Carboxymethylcellulose (CMC) is a derivative of cellulose that can be formed byits reaction with alkali and chloroacetic acid. The CMC structure is based on the β-(1→4)-D-glucopyranose polymer of cellulose as shown in Figure 2.7. Different preparations mayhave different degrees of substitution. [44] CMC molecules are somewhat shorter, onaverage, than native cellulose with uneven derivatization giving areas of high and lowsubstitution. This substitution is mostly 6-O-linked, followed in order of importance by 2-O, 2,6-di-O- then 3-O-, 3,6-di-O-, 2,3-di-O- lastly 2,3,6-tri-O-.linked. It appears that thesubstitution process is a slightly cooperative (within residues) rather than random processgiving slightly higher than expected unsubstituted and trisubstituted areas. O O O H O OH H H H H OH O OH O O O HHO H HO H HO H H H HO H O H O HO H O O O OH O H H H O OH H H H O O O n O Figure 2.7 Molecular structure of carboxymethyl celluloseCMC molecules are most extended (rod-like) at low concentrations but at higherconcentrations the molecules overlap and coil up. The average chain length and degree ofsubstitution are of great importance. At low pH, CMC may form cross-links throughcarboxylic acid and free hydroxyl groups. 20
  34. 34. Cellulosic fabrics can react with several materials, which impart an anioniccharacter to it, for example, chloroacetic acid (CAA) and chlorosulfonic acid [4] andsodium, 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate [45].In a perivious study [4] carboxymethylation process was experimented first padding thecellulosic fabric through sodium hydroxide solution, which opens the struchture ofcellulose, drying at a mild temperature and then padding through chloroacetic acidsolution and holding the fabric in a plastic bag at 70oC for 1 hour.2.8 Proposed ResearchToday’s textile industry has for a long time been searching for durable press finishes thatcan give the same advantages as formaldehyde based finishes, but cause less strength lossand no formaldehyde release. We have developed multiple methods of forming ionic crosslinks to give non-wrinkle effects to cellulosic fabric. These include, (1) treatment of cellulose with ananionic material and reacting with a polycation, (2) treatment of cellulose with a cationicmaterial and then application of a polyanion, (3) treatment of cellulose with aprecondensate of an ionic reactive material and a polyelectrolyte of the opposite charge.Methods 1 and 2, which we studied in this research, involve a pretreatment step for thecellulosic fabric, but the third method is very similar to commercial DP applications. Theperformance of crosslinkers can be measured by dry and wet wrinkle recovery angle(WRA). Dry WRA is important for outerwear clothing to help resist dry wrinkling duringuse, but wet WRA is more important for bedding which is almost never ironed and must 21
  35. 35. resist wrinkling during laundering. We observed simultaneous enhancements of both wetand dry WRA. In addition, ionic crosslinks may have other important advantages, such asantimicrobial activity and enhanced dyeability. Cellulose can react with several materials, which impart an anionic character to it,such as chloroacetic acid (CAA). On the other hand, cellulose can also react with cationicmaterials that impart cationic character to it, for instance 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHTAC). Our work is based on Methods 1 and 2, the firstconsisting of the reaction of cellulose with CAA, which producing partiallycarboxymethylated cellulose, followed by a treatment with a polycation, such as,cationized chitosan, cationized glycerine, cationized ethylene glycol, cationized dextroseor cationized D-celobiose. We also observed WRA improvements with divalent cationssuch as Ca++ and Mg++. Method 2 consists of the reaction of cellulose with CHTAC toproduce cationic cellulose, followed by the application of polyanion, such as,polycarboxylic acids (PCA), 1,2,3,4-butanetetracarboxylic acid (BTCA),ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid, trisodium salt, monohydrate(NTA), ethylenediamine di(o-hydroxyphenylacetic acid (HEDTA), oxalic acid, citric acid,or malic acid. Both methods gave promising results with excellent washing durability.Polyelectrolytes are strongly bond and thus do not desorb during washing. Thesechemicals are common industrial reactants and there is also no unusual safety orenvironmental issues. No high temperature curing is necessary. The processes utilizeexisting equipment and similar processes are already widely used. 22
  36. 36. 3. EXPERIMENTAL PROCEDURES The materials, equipments and experimental procedures used in this study aredescribed in this section. The fabric is characterized, and the chemicals are identified theirmanufacturers and chemical names. The equipment is described, and manufacturers arenamed. Also the synthesis of experimental products and their application are presented.The test procedures are listed, and detailed descriptions can be found in the appropriatereferences.3.1 Test Materials The materials that used in this project are given in the table below includingnames, brief descriptions and manufacturers. Table 3.1 Test materials and chemicalsName or Description ManufacturerGroupCotton fabric Plain weave, style 400, 102 g/m2, 44”- 45”, Testfabrics Inc 78 X 76, ISO 105/F02Cationic 3-chloro-2-hydroxypropyl trimethyl Dow Chemicalagent (CHTAC) ammonium chloride, 69% solutionOxidation Sodium nitrate, 97.25%,m.p. 306°C, b.p. Acros Organicsagent 380°CBase Sodium hydroxide, 50% aqueous solution Fisher Chemicals Calcium chloride dehydrate, 77-80% CaCl2 Fisher ChemicalsSalts Magnesium chloride hexahydrate, 99% Fisher Chemicals MgCl2 Ethylene glycol dimethyl ether 99+%, b.p. 84 Fisher Chemicals oAlcohols C -86oC Glycerol, 99+%, b.p. 290°C Fisher Chemicals 23
  37. 37. Table 3.1 Test materials and chemicals continued CROSSLINK RB 105, Aqueous solution of BioLab Water Additives polycarboxylic acids CROSSLINK RB 120, 1,2,3,4- BioLab Water Additives Butanetetracarboxylic acid HEDTA, Ethylenediamine di(o- Lynx Chemical Group, hydroxyphenylacetic) acid, trisodium salt LLC NTA, Nitrilotriacetic acid, trisodium salt Hampshire ChemicalPolyanions monohydrate, 92-94% aqueous solution Corporation EDTA, Ethylenediaminetetraacetic acid, BASF Corporation tetrasodium salt, 39% aqueous solution Chitosan, medium viscosity with nominal Vanson HaloSource, degree of deacetylation of 91.5% Inc. Dextrose, D-(+)-Glucose, anhydrous Acros organicsPolysaccharides Cellobiose, D (+)-Cellobiose, 98% ,m.p. Acros Organics 239°C Monochloro acetic acid, 99 + % Aldrich Chemical Company, Inc. Oxalic acid anhydrous 98%, m.p. 189°C Acros Organics DL-Malic acid 99%, m.p. 130°C to 132°C Acros OrganicsAcids Citric acid anhydrous 99%, m.p. 153°C to Acros Organics 154.5°CIon exchange Amberlite IRA-402 (Cl- form), 200g, 1.25 Fisher Chemicalsresin meq/mL, 4.1 meq/g 24
  38. 38. 3.2 Equipments Stirring was performed using a Fisher Hot Plate. A Fisher Scientific Co. model600-pH meter was equipped with a standard combination pH electrode. Intrinsic viscosityand viscosity average molecular weight determinations and cationization reactions wereperformed in a water bath with an electrical temperature controller and a heavy-dutystirrer. Application of finishes and ionic materials were performed using a 14-inchLaboratory padding machine manufactured by Werner Mathis AG. Fabrics were dried andcured, to their original dimensions on 7 X 12 inch metal pin frames, in a forced air ovenmanufactured by Werner Mathis AG.3.3 Application procedures The ionic crosslinkers were applied to untreated and ionic cellulosic fabrics byusing three kinds of procedure. The procedures are given below.3.3.1 Pad dry cure Approximately 7 X 12 inch fabric samples were used. The fabrics dipped into thevarious concentrations of aqueous polyelectrolyte solutions, followed by squeezing to awet pick up of approximately 100%. Then the wet fabric samples were pinned to theoriginal 7 X 12 inch dimensions, dried at 85oC for 5 minutes and cured at 140oC for 1.5minutes. Finally the treated samples were washed using 2g/L nonionic wetting agent at100oC for 10 minutes, rinsed with hot and cold water, centrifuged and dried at roomtemperature for 24 hours. 25
  39. 39. 3.3.2 Pad batch The same size samples as in pad dry cure application were used. The fabrics werepadded through the ionic crosslinker solutions and squeezed to a wet pick up ofapproximately 100%. Then the wet fabrics put into plastic bags, sealed and hold for 18hours at room temperature. Followed by washing and drying the treated samples asdescribed above.3.3.3 Exhaustion The samples were put into 500mL glass beaker. Ionic crosslinker solution wascharged into the beaker. The bath ratio of fabric weight to weight of the bath was 1:15.Then the beakers were located into a water bath and temperature raised to 95oC with a rateof approximately 2oC/minutes and hold for 1 hour. The solution was stirred using anelectrical stirrer. Finally the samples were washed and dried as described previously.3.4 Analysis and physical property tests Including nitrogen, Fourier Transform Infrared Spectroscopy (FTIR), and NuclearMagnetic Resonance (NMR) were performed. Physical properties of untreated and treatedcellulosic fabrics including wrinkle recovery angles; tensile strength, stiffness andwhiteness index were also tested. The precise procedures are given below. 26
  40. 40. 3.4.1 Nitrogen analysis The nitrogen analysis was performed using a Leuco CHN analyzer. The analysisperformed using EDTA as standard and 3 independent samples approximately 0.1g each.3.4.2 FT-IR analysis FTIR analysis needs only a small sample size and it doesn’t take a long timetherefore it is one of the most useful techniques in polymer characterization. All IRspectra in this work were obtained by using a Nicolet 510P FT-IR spectrophotometer. Thedata collection parameters were 2.0 cm-1 resolution and 64 scans. The samples wereprepared as KBr pellets and were scanned against a blank KBr pellet backround. Thespectra contain absorbance on the y-axis and wavelength on the x-axis.3.4.3 1H- NMR analysis Nuclear Magnetic Resonance spectroscopy is a powerful technique fordetermining the structure of simple inorganic to complex biochemical compounds. [46]The usefulness of this technique in chemistry can be attributed to the very detailedinformation obtained by NMR. For example in IR spectroscopy the spectroscopic featuresare correlate with groups of atoms but in NMR spectroscopy the features correlates withthe individual atoms. Therefore much more detailed information can be obtained. The 1H-NMR analysis was performed using GE NMR 300Ω (300 MHz) spectrometer at roomtemperature and sodium 3-(trimethylsilyl) propane sulfonate was used as an internalreference. 27
  41. 41. 3.4.4 Wrinkle recovery angles Wrinkle recovery angles were measured according to AATCC Standard TestMethod 66 option 2, Wrinkle Recovery of Fabrics: Recovery Angle Method. The wrinklerecovery angles were recorded as the added total of warp and weft averages.3.4.5 Tensile strength The tensile strength of untreated and treated fabrics was determined with aSyntech tensile strength tester according to ASTM Test Method D5035. Cellulosic fabricswere tested only at warp direction and the breaking load (Lb) of the fabrics recorded.3.4.6 Whiteness index Using Spectraflush SF600X a double beam spectrophotometer, manufactured byDataColor, CIE standard illuminant D65 and 1964 10o observer the CIE Whiteness Indexmeasurements of the cellulosic fabrics were performed according to AATCC test method110, whiteness of textiles. Six measurements were obtained for each sample and averagevalue was calculated and recorded.3.4.7 Stiffness Stiffness measurements of fabrics were determined according to ASTM D 1388-96Option A, Cantilever Test method. The bending length (cm) and the flexural rigidity (mgX cm) of the fabrics were calculated and recorded. The fabrics were tested in the warpdirection. 28
  42. 42. 3.5 Reaction of cellulose with chloroacetic acid Cellulosic fabric was treated with anionic and cationic materials to produce ioniccellulose. This approach gave us the opportunity of forming ionic crosslinks with usingboth cationic and anionic polyelectrolytes. The optimum conditions for carboxymethylation of cotton using CAA anddetermination of carboxyl content were extracted from previous work. [4] Cotton fabricsamples were soaked in 20% NaOH aqueous solution for 10 minutes at room temperatureand squeezed to a wet pick up of approximately 100%. The samples were dried at 60oCfor 10 minutes. Then, the alkali treated samples were steeped in aquous solutions ofsodium salt of CAA with concentrations of 0, 0.5, 1, 1.5, and 2.5M, for 5 minutes andsqueezed to approximately 100% wet pick up. Sodium salt of CAA was prepared withsodium carbonate. After the samples are packed in polyethylene bags and held at 70oC for1 hour, they were washed several times with water (hot and cold), acidified with 0.2Macetic acid and washed with distilled water to adjust pH of 7. Finally, they were dried atRT for 24 hours.Figure 3.1 shows the production of anionic cellulose in three steps. Note that thecrosslinks are bonded to cellulose through a very stable ether linkage. 29
  43. 43. O Na Cl O Chloroacetic acid (Sodium salt) + OH H OH H OH H H H OH OH O O H HO H HO H HO H H H HO H O H O HO H O O O OH OH H H H H H H OH OH n Cellulose Na OH O O O H O OH H H H H OH O OH O O O HHO H HO H HO H H H HO H O H O HO H O O O OH O H O OH H H H H H O O O n O Anionic cellulose Figure 3.1 Reactions of cellulose with CAA that impart an anionic character 30
  44. 44. The carboxylic acid group content of the partially carboxymethylated cellulosicfabrics were determined. [4] Cotton fabrics were cut into small pieces, 100mL of 0.5%aqueous HCl solution prepared and fabric samples were steeped in it for 16 hours. Thesamples were then filtered off and washed several times with distilled water until freefrom HCl and having a pH of 7. Silver nitrate drop test was performed and it showed nopresence of chloride. The samples were dried at 105oC for 3 hours. Accurate weight ofsamples (exactly 0.2g each) was soaked in 25mL of 0.05N aqueous NaOH solutions atroom temperature for 4 hours. First, a blank solution (solution without any sample) wastitrated with 0.05N aqueous HCl solution. Phenolphthalein pH indicator was used. Thevolume of HCl solution (mL) spent was recorded for the blank. Then, each of thesolutions with different carboxymethylated samples was titrated in the same way as theblank. The carboxyl contents of samples were calculated as follows:mmols carboxymethyl content per 100 grams = 100 Χ (Vblank - Vsample)HCl Χ NHCl / 0.2Where Vblank is the volume of HCl used for titration of blank solution, Vsample is thevolume of HCl used for titration of sample solution, and NHCl is the normality ofHCl titrant. Finally, we obtained five different carboxymethylation: 6.2, 30.2, 60.7, 87.1,and 114.5 mmols of carboxymethyl groups per 100g of fabric, as determined by titration.Table 3.2 shows the summary of the titration process. 31
  45. 45. Table 3.2 Results for carboxymethylation of cellulosic fabrics (Vblank=23.8ml) Treatment CAA Sample Weight of Vsample Carboxyl concentration no sample content (M) (g) mmol/100g None 0 0 0.243 23.5 6.24 Carboxymethylation 0.5 1 0.258 22.25 30.21 Carboxymethylation 1 2 0.256 20.7 60.73 Carboxymethylation 1.5 3 0.253 19.45 87.12 Carboxymethylation 2.5 4 0.26 17.85 114.543.6 Reaction of Cellulose with CHTAC Cationic cellulose was produced by cold pad batch treatment of fabrics withmixtures of different mole ratios of CHTAC, cationization reagent, and NaOH. [42] Weused four different mol ratios, 0.46 /0.95, 1.28 /1.53, and 1.83 /2.2 respectively. Aqueoussolutions of each reactant were prepared separately as follows: A known amount of NaOHwas charged into a 1L beaker and filled with distilled water to 500mL and cooled to RT.In the same way, a known amount from CHTAC solution was charged into another beakerand filled with distilled water to 500mL. These two solutions were mixed in a 1000mLbeaker and cooled to RT in ice and immediately applied onto cotton as follows: fabricswere padded through the CHTAC/NaOH solutions, squeezed to a wet pick up ofapproximately 100% and rolled on to a beam. The fabrics were then covered with plasticto stop air interaction and held overnight at RT. Finally, fabrics were 32
  46. 46. washed with a nonionic wetting agent at boiling temperature for 10 minutes, centrifugedand dried at RT for 24 hours. Application with the last mole ratio (1.83/2.2) was repeatedmultiple times in order to accomplish higher degrees of cationization. The possible reaction mechanism is shown in Figure 3.2. Note that the crosslinksare also bonded to cellulose through a very stable ether linkage. Percent nitrogen fixedonto cellulosic fabric used for quantitatively characterization of cationic cellulose. Thelevel of nitrogen fixed for each treatment was determined by Nitrogen analysis. Thenitrogen levels of untreated and treated fabrics were as follows: 0.24%, 0.45%, 0.73%,1.15% and 1.54% respectively. 33

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