Mercerization of cotton   <ul><li>John Mercer 1791-1866 British Chemist </li></ul><ul><li>Expts on measurement of viscosit...
Mercerization of cotton <ul><li>1850 patented process under the name Mercerization </li></ul><ul><li>Claims </li></ul><ul>...
Mercerization of cotton <ul><li>Main drawback: Fabric shrinkage </li></ul><ul><li>Commercial loss:  </li></ul><ul><li>Decr...
Horace Lowe   <ul><li>Horace Lowe 1869-1930 British chemist  </li></ul><ul><li>Read the patent of Mercer 1889 </li></ul><u...
Thomas and Prevost   <ul><li>1895 two German patents </li></ul><ul><li>Application of tension during NaOH treatment and du...
Effect of NaOH concentration <ul><li>Behaviour of cotton fibre (Microscopic study) </li></ul><ul><li>Upto 15deg. Tw NaOH N...
Untwisting of cotton fibre in NaOH solution
Effect of twist (tpi) on deconvolution count and cotton variety <ul><ul><li>Deconvolution count </li></ul></ul><ul><ul><li...
Effect of NaOH  on cross section of cotton
Changes in cross section of cotton on treatment with NaOH 18%
Lusture and Staple length  <ul><li>Cotton Staple length Lusture Lusture </li></ul><ul><li>Unmerc Merc </li></ul><ul><li>Ma...
Swelling in alkaline solutions <ul><li>% swelling  %Alkali  </li></ul><ul><li>97 9.5 LiOH </li></ul><ul><li>78 18 NaOH </l...
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Mercerization of cotton

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Mercerization of cotton

  1. 1. Mercerization of cotton <ul><li>John Mercer 1791-1866 British Chemist </li></ul><ul><li>Expts on measurement of viscosity of solutions of different concentrations. </li></ul><ul><li>Tried to filter the solution of NaOH 45-55 deg. TW (Unit of viscosity, approx. twice the %conc.) through cotton fabric </li></ul><ul><li>Observation </li></ul><ul><li>Shrinkage in the area of fabric i.e. reduction in dimensions of fabric in width and length direction. </li></ul><ul><li>Left expts. Till 1849 </li></ul>
  2. 2. Mercerization of cotton <ul><li>1850 patented process under the name Mercerization </li></ul><ul><li>Claims </li></ul><ul><li>Shrinkage in the area of cloth </li></ul><ul><li>Increase in strength </li></ul><ul><li>Increase in hygroscopicity </li></ul><ul><li>Increased capacity for dye absorption </li></ul><ul><li>Preferential absorption of NaOH </li></ul><ul><li>Increased action at lower temperature </li></ul><ul><li>Possible soda cellulose formation </li></ul><ul><li>These basic claims are valid even today </li></ul>
  3. 3. Mercerization of cotton <ul><li>Main drawback: Fabric shrinkage </li></ul><ul><li>Commercial loss: </li></ul><ul><li>Decrease in length and width of fabrics </li></ul><ul><li>No body showed commercial interest </li></ul><ul><li>Process did not become commercial till the death of Mercer in 1866 </li></ul>
  4. 4. Horace Lowe <ul><li>Horace Lowe 1869-1930 British chemist </li></ul><ul><li>Read the patent of Mercer 1889 </li></ul><ul><li>Started working to remove the problem of shrinkage on tretment with concentrted NaOH solutions </li></ul><ul><li>Thought of applying tension during NaOH treatment </li></ul><ul><li>Not only reduced shrinkage the fabric acquired lustre </li></ul><ul><li>Patented the process in 1890 </li></ul>
  5. 5. Thomas and Prevost <ul><li>1895 two German patents </li></ul><ul><li>Application of tension during NaOH treatment and during washing to remove NaOH </li></ul><ul><li>The process was commercialized in 1895 </li></ul><ul><li>Initial experiments on fabric </li></ul><ul><li>Later process developed for yarn mercerization in hank form </li></ul><ul><li>First German developed for mercerization of hank on commercial scale </li></ul><ul><li>Since 1895 hank mercerization and fabric mercerization processes are used on commercial scale through out the world </li></ul>
  6. 6. Effect of NaOH concentration <ul><li>Behaviour of cotton fibre (Microscopic study) </li></ul><ul><li>Upto 15deg. Tw NaOH No change </li></ul><ul><li>16-18 deg. Tw Incomplete untwisting </li></ul><ul><li>26 deg.Tw Rapid untwisting </li></ul><ul><li>35 deg. Tw Un twisting followed by swelling </li></ul><ul><li>40 deg Tw and above Untwisting and swelling together </li></ul>
  7. 7. Untwisting of cotton fibre in NaOH solution
  8. 8. Effect of twist (tpi) on deconvolution count and cotton variety <ul><ul><li>Deconvolution count </li></ul></ul><ul><ul><li>Twist 12 20 35 45 </li></ul></ul><ul><ul><li>Deconvolution 69 58 53 30 </li></ul></ul><ul><ul><li>Count </li></ul></ul><ul><ul><li>Cotton variety </li></ul></ul><ul><ul><li>Deconvolution counts after mercerization </li></ul></ul><ul><ul><li>Cotton Yarn Fibre </li></ul></ul><ul><ul><li>Uppers 79 82 </li></ul></ul><ul><ul><li>Texas 45 71 </li></ul></ul><ul><ul><li>Zaria 28 56 </li></ul></ul><ul><ul><li>Deconvolution count decreases with decrease in fibre maturirity </li></ul></ul>
  9. 9. Effect of NaOH on cross section of cotton
  10. 10. Changes in cross section of cotton on treatment with NaOH 18%
  11. 11. Lusture and Staple length <ul><li>Cotton Staple length Lusture Lusture </li></ul><ul><li>Unmerc Merc </li></ul><ul><li>Mako 22 mm 25.3 70 </li></ul><ul><li>Luisiana 18 17.8 39 </li></ul>
  12. 12. Swelling in alkaline solutions <ul><li>% swelling %Alkali </li></ul><ul><li>97 9.5 LiOH </li></ul><ul><li>78 18 NaOH </li></ul><ul><li>64 32 KOH </li></ul><ul><li>53 40RbOH </li></ul>

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