The document discusses solid polymer electrolytes for lithium-ion batteries. It describes the synthesis of various copolymers containing poly(ethylene glycol) side chains, and their characterization by FTIR, NMR, DSC, and EIS. The ionic conductivity was found to increase with temperature for all polymer electrolytes. Electrolytes with methoxy end-capped side chains showed higher conductivity than those with hydroxyl end-caps, possibly due to decreased hydrogen bonding.
Perfluorocyclohexenyl Aryl Ether Polymers via Polycondensation of Decafluoroc...aaaa zzzz
ABSTRACT: A novel class of semifluorinated perfluorocyclohex- enyl (PFCH) aryl ether homo/copolymers was successfully synthesized with high yield through the step-growth polymer- ization of commercially available bisphenols and decafluorocy- clohexene in the presence of a triethylamine base. The synthesized polymers exhibit variable thermal properties depending on the functional spacer group (R). PFCH aryl ether copolymers with random and alternating architectures were also prepared from versatile bis-perfluorocyclohexenyl aryl ether monomers. The PFCH polymers show high thermal
stabilities with a 5% decomposition temperature ranging from 359 to 444 ﰀC in air and nitrogen atmosphere. These semifluori- nated PFCH aromatic ether polymers contain intact enchained PFCH olefin moieties, making further reactions such as cross- linking and application specific functionalization possible. VC 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 232–238
IOSRPHR(www.iosrphr.org) IOSR Journal of Pharmacyiosrphr_editor
The document summarizes a study on the kinetics and mechanism of the oxidation of propranolol by sodium-N-chloro-p-toluenesulphonamide (Chloramine-T or CAT) in sodium hydroxide medium. The key findings are:
1) The rate of reaction was first order with respect to CAT concentration, fractional order with respect to propranolol concentration, and zero order with respect to hydroxide ion concentration.
2) Addition of p-toluenesulphonamide, NaCl, and NaBr did not affect the reaction rate. Variation in ionic strength also did not affect the rate, indicating non-ionic species are involved in the rate-
The document describes a study of tetraphenylethene-triphenylamine (TPE-TPA) oligomers and a polymer. A series of oligomers (DATE, DTAE, DTDAE) and a polymer (PTAE) were synthesized using McMurry coupling and other reactions. All molecules showed aggregation-induced emission (AIE), emitting strongly in the solid state but very weakly in solution. Emission wavelengths and quantum yields varied with molecular structure, peaking for the largest oligomer DTDAE. The polymer had lower solubility and broader NMR peaks due to its large size. This work achieved both efficient solid-state emission and hole transport capability by combining TPE and TPA mo
Alkali P-Nitrophenolates for Short Wavelength Laser GenerationEditor IJCATR
Single crystals of alkali p-Nitrophenolates namely sodium p-nitrophenolate dihydrate (SPNP), potassium p- nitrophenolate
monohydrate (PPNP) and lithium p-nitrophenolate trihydrate (LPNP) using Group I elements (Na, K, Li) and p-nitrophenols were grown
by solvent evaporation method. Single crystal XRD analysis shows that SPNP and LPNP crystallize in noncentrosymmetric space group
while PPNP is centrosymmetric. Using Autox software, all the peaks in the recorded powder XRD spectrum of the samples were identified
and indexed. The FT – IR spectra of the sample reveals the characteristic vibrations of the functional groups present in alkalinitrophenolates.
A weak absorption band around the region 1589–1641 cm-1 confirms the presence of the phenolic ring. A broad
intermolecular hydrogen bonded OH stretching at 3325 cm-1 of p- nitrophenol is shifted which shows the increase in the polarizable nature
of p–nitrophenol and thus easily forms a metal (sodium/ potassium/ lithium) coordination compound. UV-Vis spectrum shows that all the
crystals are transparent above 400 nm and has a wide optical window in the visible region. Intense absorption peak in the UV region may
be due to the colored nature of the compound. Addition of metal ion (sodium/potassium) modifies the optical transparency of the original
molecule (p-nitro phenol) and consequently introduces a bath chromic shift of 90/40 nm in the crystal transparency of the samples. Kurtz
powder technique result shows that the relative SHG efficiency of SPNP and LPNP was nearly 5 and 9.25 times of KDP.
SintCompound: A Small Compound Database for Virtual ScreeningYasset Perez-Riverol
This document summarizes the creation of a small compound database called SintCompound for virtual screening. It contains over 20 million unique molecules purchased from various vendors. The authors developed a protocol to clean and standardize the data, generate 3D structures, compute partial charges, and remove redundant structures. The database is accessible through Instant JChem and contains vendor information to enable purchasing hits from virtual screening. Future work includes computing all conformations and assigning biological activity information to the compounds.
Poly(3-hexylthiophene) (P3HT) forms nanowires on graphene oxide (GO) and reduced graphene oxide (RGO) surfaces through a crystallization process induced by the graphene sheets. Transmission electron microscopy and atomic force microscopy show that the P3HT nanowires grow from and connect individual RGO monolayers. Raman spectroscopy indicates an interaction between the P3HT and RGO that allows manipulation of the RGO's electrical properties. The composite of P3HT nanowires on RGO forms a supramolecular structure with potential for nano-electronic applications due to improved charge transport over the individual components.
Perfluorocyclohexenyl Aryl Ether Polymers via Polycondensation of Decafluoroc...aaaa zzzz
ABSTRACT: A novel class of semifluorinated perfluorocyclohex- enyl (PFCH) aryl ether homo/copolymers was successfully synthesized with high yield through the step-growth polymer- ization of commercially available bisphenols and decafluorocy- clohexene in the presence of a triethylamine base. The synthesized polymers exhibit variable thermal properties depending on the functional spacer group (R). PFCH aryl ether copolymers with random and alternating architectures were also prepared from versatile bis-perfluorocyclohexenyl aryl ether monomers. The PFCH polymers show high thermal
stabilities with a 5% decomposition temperature ranging from 359 to 444 ﰀC in air and nitrogen atmosphere. These semifluori- nated PFCH aromatic ether polymers contain intact enchained PFCH olefin moieties, making further reactions such as cross- linking and application specific functionalization possible. VC 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 232–238
IOSRPHR(www.iosrphr.org) IOSR Journal of Pharmacyiosrphr_editor
The document summarizes a study on the kinetics and mechanism of the oxidation of propranolol by sodium-N-chloro-p-toluenesulphonamide (Chloramine-T or CAT) in sodium hydroxide medium. The key findings are:
1) The rate of reaction was first order with respect to CAT concentration, fractional order with respect to propranolol concentration, and zero order with respect to hydroxide ion concentration.
2) Addition of p-toluenesulphonamide, NaCl, and NaBr did not affect the reaction rate. Variation in ionic strength also did not affect the rate, indicating non-ionic species are involved in the rate-
The document describes a study of tetraphenylethene-triphenylamine (TPE-TPA) oligomers and a polymer. A series of oligomers (DATE, DTAE, DTDAE) and a polymer (PTAE) were synthesized using McMurry coupling and other reactions. All molecules showed aggregation-induced emission (AIE), emitting strongly in the solid state but very weakly in solution. Emission wavelengths and quantum yields varied with molecular structure, peaking for the largest oligomer DTDAE. The polymer had lower solubility and broader NMR peaks due to its large size. This work achieved both efficient solid-state emission and hole transport capability by combining TPE and TPA mo
Alkali P-Nitrophenolates for Short Wavelength Laser GenerationEditor IJCATR
Single crystals of alkali p-Nitrophenolates namely sodium p-nitrophenolate dihydrate (SPNP), potassium p- nitrophenolate
monohydrate (PPNP) and lithium p-nitrophenolate trihydrate (LPNP) using Group I elements (Na, K, Li) and p-nitrophenols were grown
by solvent evaporation method. Single crystal XRD analysis shows that SPNP and LPNP crystallize in noncentrosymmetric space group
while PPNP is centrosymmetric. Using Autox software, all the peaks in the recorded powder XRD spectrum of the samples were identified
and indexed. The FT – IR spectra of the sample reveals the characteristic vibrations of the functional groups present in alkalinitrophenolates.
A weak absorption band around the region 1589–1641 cm-1 confirms the presence of the phenolic ring. A broad
intermolecular hydrogen bonded OH stretching at 3325 cm-1 of p- nitrophenol is shifted which shows the increase in the polarizable nature
of p–nitrophenol and thus easily forms a metal (sodium/ potassium/ lithium) coordination compound. UV-Vis spectrum shows that all the
crystals are transparent above 400 nm and has a wide optical window in the visible region. Intense absorption peak in the UV region may
be due to the colored nature of the compound. Addition of metal ion (sodium/potassium) modifies the optical transparency of the original
molecule (p-nitro phenol) and consequently introduces a bath chromic shift of 90/40 nm in the crystal transparency of the samples. Kurtz
powder technique result shows that the relative SHG efficiency of SPNP and LPNP was nearly 5 and 9.25 times of KDP.
SintCompound: A Small Compound Database for Virtual ScreeningYasset Perez-Riverol
This document summarizes the creation of a small compound database called SintCompound for virtual screening. It contains over 20 million unique molecules purchased from various vendors. The authors developed a protocol to clean and standardize the data, generate 3D structures, compute partial charges, and remove redundant structures. The database is accessible through Instant JChem and contains vendor information to enable purchasing hits from virtual screening. Future work includes computing all conformations and assigning biological activity information to the compounds.
Poly(3-hexylthiophene) (P3HT) forms nanowires on graphene oxide (GO) and reduced graphene oxide (RGO) surfaces through a crystallization process induced by the graphene sheets. Transmission electron microscopy and atomic force microscopy show that the P3HT nanowires grow from and connect individual RGO monolayers. Raman spectroscopy indicates an interaction between the P3HT and RGO that allows manipulation of the RGO's electrical properties. The composite of P3HT nanowires on RGO forms a supramolecular structure with potential for nano-electronic applications due to improved charge transport over the individual components.
Dynamics of Poly(ethylene oxide) in the bulk and in close proximity to silica...Eleni 'Hellen' Papananou
The behavior of polymers when they are restricted in space can be very different from that in the bulk especially when the molecules are confined to dimensions comparable to their sizes. The dynamics of polymer chains under confinement and its difference from the respective of the bulk has attracted the scientific interest because it greatly affects many of the material macroscopic properties. Besides planar polymer films, other experimental geometries have been utilized to study the effect of confinement on the various polymer relaxation processes such as: polymer / nanoparticle, polymer / nanorods and polymer / layered silicate nanocomposites to name a few.
In the past, we have systematically pursued the understanding of the parameters that influence the structure and dynamics under confinement in intercalated PEO / layered silicate nanocomposites. The confined polymer chains remain purely amorphous; crystallinity is observed only for hybrids with high polymer content and shows an abrupt drop to zero at a certain composition. The study of dynamics in confinement in comparison to the respective in the bulk utilizing dielectric relaxation spectroscopy showed an acceleration of the PEO segmental dynamics that display an Arrhenius temperature dependence with very low activation energy, whereas the local β-process remains unaffected.
Using nanoparticles to restrict the polymer can provide the advantage of altering the polymer confinement by changing the nanoparticle size and loading. Thus, in this work, we utilize PEO / SiO2 nanohybrids to control the thickness of the confined polymer film. DSC measurements showed decreasing crystallinity with the amount of additive whereas in hybrids with polymer content lower than 50wt%, a second crystallization and melting appears, indicating that the polymer crystallizes differently, when forced to crystallize near the silica surface.
The PEO dynamics is studied utilizing dielectric spectroscopy for hybrids with different composition to investigate the effect of the chain proximity to the surface on dynamics. The results are compared to the respective results on PEO / clay nanocomposites and the effect of the geometry of the filler on the behavior will be explored, as well.
Effect of inorganic fillers on Poly(ethylene oxide) crystallization and dynamicsEleni 'Hellen' Papananou
Polymer morphology, crystallization and chain conformation are investigated in hydrophilic poly(ethylene oxide)/SiO2 nanocomposites. PEO was able to crystallize in all cases; nevertheless differences were observed for high silica content hybrids. The crystallization process as well as the conformation of the chains close to the inorganic surfaces exhibit different characteristics than that of the neat polymer melt. The effect of the proximity to the silica surfaces on polymer dynamics is investigated as well.
This document discusses the use of polysaccharide-based nanoparticles for drug delivery applications. It describes how nanoparticles between 10-700nm in size can encapsulate and provide controlled release of drugs while decreasing side effects. Polysaccharides are promising materials for nanoparticles due to their biocompatibility, low cost, and reactive groups. The document outlines methods for preparing nanoparticles from chitosan, alginate, pectin, and other polysaccharides using techniques like ionic crosslinking. Characterization of the nanoparticles in solution and solid form is presented, showing properties like particle size and surface charge. Future work aims to use the nanoparticles to encapsulate drugs and study their release, uptake, and shape evolution in physiological conditions.
The PEG complexes were noncytotoxic in the dark but became very cytotoxic upon irradiation, with photodynamic indices ranging from 12.9 to 88.2 μM. The PEG complexes localized to mitochondria and generated reactive oxygen species upon irradiation, inducing oxidative stress and photo-induced cytotoxicity. In vivo, the complex accumulated in the zebrafish yolk sac, cardiac cavity, and brain ventricle after microinjection, demonstrating its potential for photodynamic therapy applications.
Thermal stability, complexing behavior, and ionic transport ofSHALU KATARIA
This document describes a study on polymeric gel membranes composed of poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) polymer and an ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]). The membranes were synthesized by solution casting and characterized using various techniques. It was found that the ionic liquid partly complexes with the PVdF-HFP polymer chains and partly remains dispersed. The ionic conductivity of the membranes increases with increasing ionic liquid content, reaching a maximum of 1.6 × 10−2 S·cm−1 for a membrane with 90% ionic liquid
Effect of inorganic fillers on Poly(ethylene oxide) crystallization and dynamicsEleni 'Hellen' Papananou
It is well known that the behaviour of polymers when they are restricted in space or when they are close to surfaces can be very different from that in the bulk. In this work, we investigate the morphology, crystallization and dynamics of a hydrophilic, semi-crystalline polymer, poly(ethylene oxide), PEO, when mixed with silica, SiO2, nanoparticles in a broad range of compositions. The good dispersion of the nanoparticles was verified by Transmission Electron Microscopy (TEM), whereas the morphology and crystallization behaviour of the hybrids were investigated with, X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). All techniques show a gradual decrease of polymer crystallinity with increasing the amount of nanoparticles; nevertheless, polymer crystallization is observed for all silica loadings. Moreover, DSC measurements showed the existence of two melting and crystallization transitions in hybrids with polymer content lower than 50wt%, indicating that the polymer crystallizes differently than the bulk near the silica surface
Phase behavior and characterization of PECs AIChE 2014 David Scheuing
Presented Nov. 2014 at AIChE meeting. Examines the use of polyelectrolyte complexes for surface modification in consumer products such as cleaners. Summarizes synthesis and characterization of stable complexes in solution via light scattering. Illustrates characterization of adsorbed layers of complexes on germanium and silica surfaces via Fourier Transform Infrared spectroscopy and gravimetry via a quartz crystal microbalance.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document describes the synthesis and characterization of a novel redox-based chiroptically switching polymer. The polymer was prepared by grafting electrochromic viologen groups onto the side chains of an optically active conjugated polymer backbone containing 1,1'-binaphthyl units. The resulting polymer exhibited a much larger optical rotation and intense circular dichroism signal compared to a small molecule model compound, indicating secondary chirality in the main polymer chain. The polymer undergoes distinctive and reversible color changes from light yellow to dark blue upon electrochemical or chemical reduction/oxidation of the viologen units, accompanied by changes in its circular dichroism spectrum. This allows for redox-driven chiroptical switching behavior
This document provides an introduction to polymers for A-level chemistry students. It discusses the two main types of polymerization: addition and condensation. Addition polymerization involves monomers joining together with all atoms incorporated into the polymer chain. Condensation polymerization involves monomers joining together with the elimination of small molecules, so not all original atoms are present. Common examples of addition and condensation polymers are discussed, along with their properties and uses.
Thermally Stimulated Discharge Current study of PMMA:PVP blendsinventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The document summarizes research on adding BaTiO3 nanoparticles to a PVdF/PMMA polymer blend electrolyte to improve its ionic conductivity. Key findings:
1) The addition of 15 wt% BaTiO3 nanoparticles resulted in the highest ionic conductivity of 1.335 x 10-3 S/cm, compared to other ratios tested.
2) XRD and FTIR analysis showed the BaTiO3 disrupted polymer crystallization and formed an amorphous complex with the polymers.
3) Conductivity increased with temperature for all compositions and followed the Vogel–Tamman–Fulcher relationship.
4) The composite with 15 wt% BaTiO3 was stable up
Polyamides, also known as nylons, were the first commercial synthetic polymers. Nylon 66 was the first synthetic fiber invented in 1935. This document discusses modifying polyamide 6 (PA6) through solid-state polymerization or solution polymerization to improve properties while retaining good mechanical properties. It examines two approaches - synthesizing multiblock polyesteramide copolymers from short PA and polyester blocks to enhance biodegradability, and incorporating a semi-aromatic nylon salt into the PA6 backbone to modify properties. The results of these studies on synthesis, properties, degradation and morphology are presented.
The document discusses the thermal degradation kinetics of linear polycarbonate (LPC) and branched polycarbonate (BPC) using thermogravimetric analysis. The Vyazovkin model-free kinetics method was used to determine the activation energy of degradation as a function of conversion and temperature. The results showed that LPC starts degrading slightly over 350°C while BPC starts over 400°C, indicating BPC has greater thermal resistance. The activation energy for BPC degradation was also higher than for LPC, meaning higher temperatures are required to process BPC without damaging its molecular structure.
This show has been presented in The 7th Symposium of The School of Physics and Astronomy in The University of Leeds/ UK.
It summaries four years of hard working on the polymer gel electrolyte investigations. I hope this presentation can help the other researchers to understand these novel materials behavior in better way.
31015 Waeghe 1045 am Systematic Method Development with Novel Inert Solid-CoreThomas Waeghe
The document describes the use of novel encapsulated bonding technology (EBT) stationary phases for systematic LC method development. EBT provides exceptional inertness and stability from pH 1.5 to 11.0. The ability to vary stationary phase, organic modifier, and pH is advantageous for UHPLC and HPLC method development. Examples are provided demonstrating the orthogonality and selectivity of ACE UltraCore SuperC18 and SuperPhenylHexyl columns across different pH and organic modifiers for the separation of appetite suppressants and drugs of abuse.
The document describes using reversible addition-fragmentation chain transfer (RAFT) polymerization to synthesize novel block copolymers containing both a polyolefin block and a poly(styrene-co-maleic anhydride) block. Specifically, it details:
1) Using a commercially available polyolefin (Kraton L-1203) modified with a dithioester group to serve as a macroinitiator for RAFT polymerization and form the polyolefin block.
2) Conducting RAFT polymerizations of styrene and styrene-co-maleic anhydride using this macroinitiator and a small molecule RAFT agent to form the second block and yield polyolefin
The cholesteric liquid-crystal poly[oxycarbonyl-1,4-phenylene-oxy-1,4 terephthaloyl-oxy-1,4-phenylenecarbonyloxy(
1,2-dodecane)] [C34H36O8]n, named PTOBDME, synthesized by polycondensation reaction from
equimolar quantities of TOBC and the racemic mixture of glycol (R-S-1,2 dodecanediol), exhibits unexpected
optical activity and chiral morphology. The structure of racemic-PTOBDME, under different polymerization
kinetics conditions, is analyzed by conventional NMR techniques and compared with those of polymer
enantiomers R-PTOBDME and S-PTOBDME obtained starting R(+)1,2 and S(-)1,2-dodecanediol respectively.
Molecular models based on the NMR signals intensities are proposed. The optical activity of racemic-
PTOBDME is evaluated by measuring the ORD values during kinetics study, and compared to the chiral
polymers. Each enantiomeric polymer seems to present the same stereoregular head-tail, isotactic structure than
the racemic, which we explain by the higher reactivity of the primary hydroxyl than the secondary one in the
glycol through polycondensation. For each enantiomer, two independent sets of signals were observed by NMR,
explained as two diastereomeric helical conformers: gg and gt, related with two possible staggered
conformations, along the copolymer backbone. Chirality in racemic-PTOBDME is proposed to be due to the
kinetic resolution of a preferable helical diastereomer, such as Sgt, with respect to the possible four forms, while
the R/S ratio of asymmetric carbon atoms remained 50:50. Chiral amplification is observed in R-PTOBDME and
S-PTOBDME due to a helical screw sense excess. Optimum yield was obtained for racemic PTOBDME, after
120 minutes polycondensated and decanted in toluene for 24 hours. Two weeks later a second fraction
precipitated from the toluene mother liquor with 67.6% chiral excess. After eight months and two weeks a third
fraction precipitated with 85.2% chiral excess.
The document summarizes recent research on new electro-optic properties of polysiloxane liquid crystal polymers. A series of polysiloxane-based side-chain liquid crystal polymers were prepared with systematic variation in spacer length between the mesogenic units and the polymer backbone. Electro-optic measurements showed that threshold voltage decreased with increasing spacer length. This was attributed to changes in intrinsic curvature elasticity rather than orientational order. Threshold voltage also decreased with increasing temperature and orientational order parameter. The results were consistent with existing models of curvature deformation in liquid crystals and provided insight into the effects of constraints from coupling mesogenic units to the polymer backbone.
This document summarizes recent developments in side chain liquid crystal polymers, focusing on polysiloxane based polymers. It discusses how a series of these polymers were prepared with systematic variation in the spacer length between the mesogenic units and the polymer backbone. Electro-optic measurements found that increasing the spacer length lowered the threshold voltage for molecular reorientation. A simple model indicates this is due to changes in intrinsic curvature elasticity rather than orientational order as the constraints from the polymer backbone are reduced with longer spacers.
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Dynamics of Poly(ethylene oxide) in the bulk and in close proximity to silica...Eleni 'Hellen' Papananou
The behavior of polymers when they are restricted in space can be very different from that in the bulk especially when the molecules are confined to dimensions comparable to their sizes. The dynamics of polymer chains under confinement and its difference from the respective of the bulk has attracted the scientific interest because it greatly affects many of the material macroscopic properties. Besides planar polymer films, other experimental geometries have been utilized to study the effect of confinement on the various polymer relaxation processes such as: polymer / nanoparticle, polymer / nanorods and polymer / layered silicate nanocomposites to name a few.
In the past, we have systematically pursued the understanding of the parameters that influence the structure and dynamics under confinement in intercalated PEO / layered silicate nanocomposites. The confined polymer chains remain purely amorphous; crystallinity is observed only for hybrids with high polymer content and shows an abrupt drop to zero at a certain composition. The study of dynamics in confinement in comparison to the respective in the bulk utilizing dielectric relaxation spectroscopy showed an acceleration of the PEO segmental dynamics that display an Arrhenius temperature dependence with very low activation energy, whereas the local β-process remains unaffected.
Using nanoparticles to restrict the polymer can provide the advantage of altering the polymer confinement by changing the nanoparticle size and loading. Thus, in this work, we utilize PEO / SiO2 nanohybrids to control the thickness of the confined polymer film. DSC measurements showed decreasing crystallinity with the amount of additive whereas in hybrids with polymer content lower than 50wt%, a second crystallization and melting appears, indicating that the polymer crystallizes differently, when forced to crystallize near the silica surface.
The PEO dynamics is studied utilizing dielectric spectroscopy for hybrids with different composition to investigate the effect of the chain proximity to the surface on dynamics. The results are compared to the respective results on PEO / clay nanocomposites and the effect of the geometry of the filler on the behavior will be explored, as well.
Effect of inorganic fillers on Poly(ethylene oxide) crystallization and dynamicsEleni 'Hellen' Papananou
Polymer morphology, crystallization and chain conformation are investigated in hydrophilic poly(ethylene oxide)/SiO2 nanocomposites. PEO was able to crystallize in all cases; nevertheless differences were observed for high silica content hybrids. The crystallization process as well as the conformation of the chains close to the inorganic surfaces exhibit different characteristics than that of the neat polymer melt. The effect of the proximity to the silica surfaces on polymer dynamics is investigated as well.
This document discusses the use of polysaccharide-based nanoparticles for drug delivery applications. It describes how nanoparticles between 10-700nm in size can encapsulate and provide controlled release of drugs while decreasing side effects. Polysaccharides are promising materials for nanoparticles due to their biocompatibility, low cost, and reactive groups. The document outlines methods for preparing nanoparticles from chitosan, alginate, pectin, and other polysaccharides using techniques like ionic crosslinking. Characterization of the nanoparticles in solution and solid form is presented, showing properties like particle size and surface charge. Future work aims to use the nanoparticles to encapsulate drugs and study their release, uptake, and shape evolution in physiological conditions.
The PEG complexes were noncytotoxic in the dark but became very cytotoxic upon irradiation, with photodynamic indices ranging from 12.9 to 88.2 μM. The PEG complexes localized to mitochondria and generated reactive oxygen species upon irradiation, inducing oxidative stress and photo-induced cytotoxicity. In vivo, the complex accumulated in the zebrafish yolk sac, cardiac cavity, and brain ventricle after microinjection, demonstrating its potential for photodynamic therapy applications.
Thermal stability, complexing behavior, and ionic transport ofSHALU KATARIA
This document describes a study on polymeric gel membranes composed of poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) polymer and an ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]). The membranes were synthesized by solution casting and characterized using various techniques. It was found that the ionic liquid partly complexes with the PVdF-HFP polymer chains and partly remains dispersed. The ionic conductivity of the membranes increases with increasing ionic liquid content, reaching a maximum of 1.6 × 10−2 S·cm−1 for a membrane with 90% ionic liquid
Effect of inorganic fillers on Poly(ethylene oxide) crystallization and dynamicsEleni 'Hellen' Papananou
It is well known that the behaviour of polymers when they are restricted in space or when they are close to surfaces can be very different from that in the bulk. In this work, we investigate the morphology, crystallization and dynamics of a hydrophilic, semi-crystalline polymer, poly(ethylene oxide), PEO, when mixed with silica, SiO2, nanoparticles in a broad range of compositions. The good dispersion of the nanoparticles was verified by Transmission Electron Microscopy (TEM), whereas the morphology and crystallization behaviour of the hybrids were investigated with, X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). All techniques show a gradual decrease of polymer crystallinity with increasing the amount of nanoparticles; nevertheless, polymer crystallization is observed for all silica loadings. Moreover, DSC measurements showed the existence of two melting and crystallization transitions in hybrids with polymer content lower than 50wt%, indicating that the polymer crystallizes differently than the bulk near the silica surface
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Presented Nov. 2014 at AIChE meeting. Examines the use of polyelectrolyte complexes for surface modification in consumer products such as cleaners. Summarizes synthesis and characterization of stable complexes in solution via light scattering. Illustrates characterization of adsorbed layers of complexes on germanium and silica surfaces via Fourier Transform Infrared spectroscopy and gravimetry via a quartz crystal microbalance.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document describes the synthesis and characterization of a novel redox-based chiroptically switching polymer. The polymer was prepared by grafting electrochromic viologen groups onto the side chains of an optically active conjugated polymer backbone containing 1,1'-binaphthyl units. The resulting polymer exhibited a much larger optical rotation and intense circular dichroism signal compared to a small molecule model compound, indicating secondary chirality in the main polymer chain. The polymer undergoes distinctive and reversible color changes from light yellow to dark blue upon electrochemical or chemical reduction/oxidation of the viologen units, accompanied by changes in its circular dichroism spectrum. This allows for redox-driven chiroptical switching behavior
This document provides an introduction to polymers for A-level chemistry students. It discusses the two main types of polymerization: addition and condensation. Addition polymerization involves monomers joining together with all atoms incorporated into the polymer chain. Condensation polymerization involves monomers joining together with the elimination of small molecules, so not all original atoms are present. Common examples of addition and condensation polymers are discussed, along with their properties and uses.
Thermally Stimulated Discharge Current study of PMMA:PVP blendsinventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The document summarizes research on adding BaTiO3 nanoparticles to a PVdF/PMMA polymer blend electrolyte to improve its ionic conductivity. Key findings:
1) The addition of 15 wt% BaTiO3 nanoparticles resulted in the highest ionic conductivity of 1.335 x 10-3 S/cm, compared to other ratios tested.
2) XRD and FTIR analysis showed the BaTiO3 disrupted polymer crystallization and formed an amorphous complex with the polymers.
3) Conductivity increased with temperature for all compositions and followed the Vogel–Tamman–Fulcher relationship.
4) The composite with 15 wt% BaTiO3 was stable up
Polyamides, also known as nylons, were the first commercial synthetic polymers. Nylon 66 was the first synthetic fiber invented in 1935. This document discusses modifying polyamide 6 (PA6) through solid-state polymerization or solution polymerization to improve properties while retaining good mechanical properties. It examines two approaches - synthesizing multiblock polyesteramide copolymers from short PA and polyester blocks to enhance biodegradability, and incorporating a semi-aromatic nylon salt into the PA6 backbone to modify properties. The results of these studies on synthesis, properties, degradation and morphology are presented.
The document discusses the thermal degradation kinetics of linear polycarbonate (LPC) and branched polycarbonate (BPC) using thermogravimetric analysis. The Vyazovkin model-free kinetics method was used to determine the activation energy of degradation as a function of conversion and temperature. The results showed that LPC starts degrading slightly over 350°C while BPC starts over 400°C, indicating BPC has greater thermal resistance. The activation energy for BPC degradation was also higher than for LPC, meaning higher temperatures are required to process BPC without damaging its molecular structure.
This show has been presented in The 7th Symposium of The School of Physics and Astronomy in The University of Leeds/ UK.
It summaries four years of hard working on the polymer gel electrolyte investigations. I hope this presentation can help the other researchers to understand these novel materials behavior in better way.
31015 Waeghe 1045 am Systematic Method Development with Novel Inert Solid-CoreThomas Waeghe
The document describes the use of novel encapsulated bonding technology (EBT) stationary phases for systematic LC method development. EBT provides exceptional inertness and stability from pH 1.5 to 11.0. The ability to vary stationary phase, organic modifier, and pH is advantageous for UHPLC and HPLC method development. Examples are provided demonstrating the orthogonality and selectivity of ACE UltraCore SuperC18 and SuperPhenylHexyl columns across different pH and organic modifiers for the separation of appetite suppressants and drugs of abuse.
The document describes using reversible addition-fragmentation chain transfer (RAFT) polymerization to synthesize novel block copolymers containing both a polyolefin block and a poly(styrene-co-maleic anhydride) block. Specifically, it details:
1) Using a commercially available polyolefin (Kraton L-1203) modified with a dithioester group to serve as a macroinitiator for RAFT polymerization and form the polyolefin block.
2) Conducting RAFT polymerizations of styrene and styrene-co-maleic anhydride using this macroinitiator and a small molecule RAFT agent to form the second block and yield polyolefin
The cholesteric liquid-crystal poly[oxycarbonyl-1,4-phenylene-oxy-1,4 terephthaloyl-oxy-1,4-phenylenecarbonyloxy(
1,2-dodecane)] [C34H36O8]n, named PTOBDME, synthesized by polycondensation reaction from
equimolar quantities of TOBC and the racemic mixture of glycol (R-S-1,2 dodecanediol), exhibits unexpected
optical activity and chiral morphology. The structure of racemic-PTOBDME, under different polymerization
kinetics conditions, is analyzed by conventional NMR techniques and compared with those of polymer
enantiomers R-PTOBDME and S-PTOBDME obtained starting R(+)1,2 and S(-)1,2-dodecanediol respectively.
Molecular models based on the NMR signals intensities are proposed. The optical activity of racemic-
PTOBDME is evaluated by measuring the ORD values during kinetics study, and compared to the chiral
polymers. Each enantiomeric polymer seems to present the same stereoregular head-tail, isotactic structure than
the racemic, which we explain by the higher reactivity of the primary hydroxyl than the secondary one in the
glycol through polycondensation. For each enantiomer, two independent sets of signals were observed by NMR,
explained as two diastereomeric helical conformers: gg and gt, related with two possible staggered
conformations, along the copolymer backbone. Chirality in racemic-PTOBDME is proposed to be due to the
kinetic resolution of a preferable helical diastereomer, such as Sgt, with respect to the possible four forms, while
the R/S ratio of asymmetric carbon atoms remained 50:50. Chiral amplification is observed in R-PTOBDME and
S-PTOBDME due to a helical screw sense excess. Optimum yield was obtained for racemic PTOBDME, after
120 minutes polycondensated and decanted in toluene for 24 hours. Two weeks later a second fraction
precipitated from the toluene mother liquor with 67.6% chiral excess. After eight months and two weeks a third
fraction precipitated with 85.2% chiral excess.
The document summarizes recent research on new electro-optic properties of polysiloxane liquid crystal polymers. A series of polysiloxane-based side-chain liquid crystal polymers were prepared with systematic variation in spacer length between the mesogenic units and the polymer backbone. Electro-optic measurements showed that threshold voltage decreased with increasing spacer length. This was attributed to changes in intrinsic curvature elasticity rather than orientational order. Threshold voltage also decreased with increasing temperature and orientational order parameter. The results were consistent with existing models of curvature deformation in liquid crystals and provided insight into the effects of constraints from coupling mesogenic units to the polymer backbone.
This document summarizes recent developments in side chain liquid crystal polymers, focusing on polysiloxane based polymers. It discusses how a series of these polymers were prepared with systematic variation in the spacer length between the mesogenic units and the polymer backbone. Electro-optic measurements found that increasing the spacer length lowered the threshold voltage for molecular reorientation. A simple model indicates this is due to changes in intrinsic curvature elasticity rather than orientational order as the constraints from the polymer backbone are reduced with longer spacers.
Similar to Synthesis and Characterization of Comb-Polymethacrylate (20)
4. Type
Ion
conductivity
Mechanical
strength
Safety Price
Liquid Good Poor Unsafe Expensive
Gel Good Good Unsafe Not cheap
Polymer Poor Good Safe Cheap
Glass Poor Good Safe Not cheap
Solid polymer electrolyte is an ionically conducting but electronically
insulating solution of a salt in a polymer.
Ionic conductivity
SPEs: 10-6-10-9 S/cm(room temperature), 10-4-10-5S/cm (80-100 °C)
Liquid electrolyte: 10-2-10-3 S/cm (room temperature)
5. Both cations and anions in polymer electrolyte may contribute to its
conductivity, but their transport mechanisms are different.
Cations-each lithium-ion is complexed to PEO through roughly five ether
oxygens. The transport of lithium-ion is connected with the movement of
the complexing segment of the PEO chain.
Anions- hopping mechanism between different occupied sites and
vacancies, which are large enough to hold the ion.
6. C uI
B r/P M D E TA C uII
B r/P M D E TA +
+ e-
H 3C
O
C
C H
O
C H 3
B r
+ e- H 3C
O
C
C
O
C H 3
H
+ B r-
B r-
+ C uII
B r/P M D E TA +
B r-C uII
B r/P M D E TA
Initiator
transition m etalcatalyst/ligand
7. H 3C
O
C
C
O
C H 3
H
+
O
O
H 3C
O
C
C H
O
C H 3
C
H 2
C O
O
H
( R ') ( M 1) ( R '-M 1)
M 2 =
C H 2
C
O O
O H6
M 3=
C H 2
C
O O
O
C H 3
8.5
R '-M 1 + M R '-M 1-M
R '-M 1-M + n M R '-M 1-M n
IN ITIA TIO N
P R O P A G A TIO N M = M 1,M 2 orM 3
R adicalcoupling:
R 1-C H 2-C X H + H X C -C H 2-R 2 R 1-C H 2-C X H -H X C -C H 2-R 2
R adicaldisproportionation:
R 1-C H 2-C X H + H X C -C H 2-R 2 R 1-C H 2-C X H 2 + X H C =C H -R 2
TE R M IN A TIO N
10. The PMAPEGOH-70-30 polymer could not be dissolved in
chloroform, even after stirring for 10 days at 50 °C. This can
possibly be due to that the increased amount of hydroxyl (-OH)
end-group monomers formed much more hydrogen bonds in
the polymer, making it more difficult to dissolve.
*PMAPEGCH3-90-10, which had a molecular weight of 20000
g/mol. The polymer was too difficult to handle in any of the
following steps due to its severe stickiness and somewhat
liquid-like state. Perhaps since no hydrogen bond can form in
the polymers with methoxy-group (-OCH3) end-capped side-chains,
these hydrophilic side chains present high stickiness.
11.
12. The structures of the polymers are somewhat complex and contain
several protons which have similar chemical shift coupled with
each other. Furthermore, they are random copolymers, i.e., the
protons are placed in slightly different chemical environments when
their neighbors are different, which may lead to different chemical
shifts of the protons even if they originate from similar functional
groups. These factors make it difficult to analyze the NMR spectra in
more detail.
14. The influences on Tg come from several factor:
the lithium ions in the salt (LiTFSI) leads to the formation
of cross-links in the PEO part, and should thus increase
Tg due to increased rigidity;
the anions (TFSI-) from the salt is a common plasticizer
and will decrease Tg;
while high amounts of methacrylate monomers and
hydrogen bond formation in the polymers will raise the
Tg.
All of the factors are work at the same time, and it is
difficult to say which is stronger or weaker. There is no
obvious trend in changes in Tg when the salt is dissolved
in the polymer matrix.
15. The impedance of the cell was measured
by applying a sinusoidal potential
excitation in the frequency range between
1×10-2 Hz and 1×107 Hz, and the AC
current signal was recorded. The AC
root-mean-square voltage was set to 1V,
and the measurements were performed at
room temperature, 30 °C, 40 °C, 50 °C and
60 °C. Thereafter, the AC frequency (F),
and the real (Cp’) and imaginary (Cp’’) parts
of the capacitance is given by the
computer.
19. The ionic conductivities of
PMAPEGOH-90-10 and
PMAPEGCH3-90-10 are
lower than for the PEO
electrolyte for all investigated
temperatures, probably due
to the low content of the
PEO-based monomer –
only 10 %. This also means
that there is much lower
salt concentration in the co-
polymer electrolyte.
20. When comparing the two
systems, it can be seen that the
methoxy-group end-capped
generally show higher
conductivity. This could well be
due to that they have longer
PEO-side chains, hence
higher salt concentration.
Furthermore, the hydroxyl-
group can form hydrogen
bonds in the systems, which
then decrease the mobility of
the side-chains and thus
result in lower ionic
conductivity.
21. The ionic conductivity of a polymer
electrolyte can be calculated from the
equation:
23. The overall ionic mobility can be estimated from:
The lithium-ion mobility
is very low in PEO
system at room
temperature, but
relatively high above
its melting temperature
(Tm = 52°C) at 60 °C.
The reason is that the
ion mobility is much
higher in the liquid state
than in the solid state.
24. The overall ionic mobility can be estimated from:
The ion mobility for the
bipolar system is much higher
than the PEO system,
because the dual polarity of
the SPE system promotes a
nano-scale separation and
ordering of the
macromolecular
constituents, thus offer
structures which have shown
to significantly promote ionic
transport.
25. The overall ionic mobility can be estimated from:
The ion mobility
increases with higher
portion of the PEO-
based monomers
because the ion
transport generally
occurred in the
amorphous portions of
PEO.
26. The overall ionic mobility can be estimated from:
The PMAPEGCH3
system higher ion
mobility, due to its
longer EO units side-
chains and no
hydrogen bonds
formed in this system.
28. SEM images of cross-section view of polymer electrolytes (PMAPEGOH-80-20,
left; PMAPEGCH3-80-20, right) coated onto LiFePO4 electrode.
29.
30. The special characteristic of this polymer is that it comprises both
hydrophobic polymethacrylate backbones, and short (6 or 8.5 EO
units) PEO side-chains, which are hydrophilic. The bipolar structure
could result in a nano-scale phase-separation, which can offer higher
ionic conductivity than linear amorphous PEO, as suggested in previous
Molecular Dynamic studies.
From the results, it is seen that the lithium-ion mobility is
comparatively low in a conventional PEO electrolyte system at
room temperature, but relatively high above its melting
temperature (Tm = 52°C) at 60 °C. The ionic mobility is much
higher in the synthesized bipolar systems at ambient
temperatures, in accordance with previous MD simulation studies.
Problems with the half-cell batteries: pinholes & contamination
During discharge, the oxidation reaction occurs within the anode, hence lithium-ions are transported across the electrolyte towards the cathode, while the electrons pass through the external circuit to the cathode. During charging, the reverse reactions take place.
Both cations and anions in polymer electrolyte may contribute to its conductivity, but their transport mechanisms are different.
Mtn-Y/Ligand is the transition metal complexes, where Mtn is the transition metal and Y is either a ligand or a counterion; R is the polymer chain; and R-X is the initiator for the reaction, where X is a halogen atom. Radicals are generated from a reversible redox process of the transition metal ion: Mtn+1/ Mtn. There is a dynamic equilibrium between the alkyl halide (R-X) and the corresponding active site (R•) with the transition metal complex. The equilibrium is kept shifted towards the left side in Fig. 6 in order to maintain the concentration of radicals as small as possible, thereby restricting the radical termination reactions
Mtn-Y/Ligand is the transition metal complexes, where Mtn is the transition metal and Y is either a ligand or a counterion; R is the polymer chain; and R-X is the initiator for the reaction, where X is a halogen atom. Radicals are generated from a reversible redox process of the transition metal ion: Mtn+1/ Mtn. There is a dynamic equilibrium between the alkyl halide (R-X) and the corresponding active site (R•) with the transition metal complex. The equilibrium is kept shifted towards the left side in Fig. 6 in order to maintain the concentration of radicals as small as possible, thereby restricting the radical termination reactions
All monomers were passed through a column of neutral aluminum oxide to remove inhibitors directly before the polymerization.
CuBr (270.5 mg) was first added to a 50-mL flask. Thereafter, the mixture of monomers (10mL), PMDETA (0.4 mL), and 2-MBP (0.11mL) were added to the flask. These steps were taken in the glove-box, since the whole polymerization process is sensitive to water and oxygen.
The flask was put into a water bath with a thermostat at 50℃ for several hours. The reaction time was different for different polymers, as discussed above (see Fig. 5). The polymerization was terminated by putting the flask into liquid nitrogen.
Chloroform was used to dissolve the product, after which the dissolved polymer solution was filtered through a neutral aluminum oxide column to remove the copper catalyst.
The resulting solution was concentrated and precipitated in hexane three times.
The reasons for this lack of any obvious trend are probably similar to the –OH end-capped systems, i.e., TFSI- decreases Tg while lithium ions increases Tg, and the different effects are differently strong depending on the monomer composition.