Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carbo...Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn（II） （n）, pH, background electrolyte, etc on the rejection rate （R） and permeate flux （J） were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn（II） with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength.展开更多
Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chit...Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.展开更多
The emeraldine base form of polyaniline (PANI) can be doped by a photo-induced doping method. In this method a. copolymer of vinylidene chloride and methyl acrylate (VCMAC) was used as photo acid generator which can r...The emeraldine base form of polyaniline (PANI) can be doped by a photo-induced doping method. In this method a. copolymer of vinylidene chloride and methyl acrylate (VCMAC) was used as photo acid generator which can release proton when it is exposed to ultraviolet light (lambda = 254 nm). The structure of PANI-VCMAC system before and after irradiation was characterized by elemental analysis, IR, XTP, anti SEM images. Results obtained indicate that the photo-induced doping characteristics, such as doping position and type of charge carriers, are similar to that of PANI doped with HCl. The poor room-temperature conductivity (similar to 10-S-5/cm) of PANI-VCMAC system after irradiation may be due to low doping degree (similar to pH=3) and the difference in morphology as compared with PANI-HCl film.展开更多
How to optimize and regulate the distribution of phosphoric acid in matrix,and pursuing the improved electrochemical performance and service lifetime of high temperature proton exchange membrane(HT-PEMs)fuel cell are ...How to optimize and regulate the distribution of phosphoric acid in matrix,and pursuing the improved electrochemical performance and service lifetime of high temperature proton exchange membrane(HT-PEMs)fuel cell are significant challenges.Herein,bifunctional poly(p-terphenyl-co-isatin piperidinium)copolymer with tethered phosphonic acid(t-PA)and intrinsic tertiary amine base groups are firstly prepared and investigated as HT-PEMs.The distinctive architecture of the copolymer provides a well-designed platform for rapid proton transport.Protons not only transports through the hydrogen bond network formed by the adsorbed free phosphoric acid(f-PA)anchored by the tertiary amine base groups,but also rely upon the proton channel constructed by the ionic cluster formed by the t-PA aggregation.Thorough the design of the structure,the bifunctional copolymers with lower PA uptake level(<100%)display prominent proton conductivities and peak power densities(99 mS cm^(-1),812 mW cm^(-2)at 160℃),along with lower PA leaching and higher voltage stability,which is a top leading result in disclosed literature.The results demonstrate that the design of intermolecular acid-base-pairs can improve the proton conductivity without sacrificing the intrinsic chemical stability or mechanical property of the thin membrane,realizing win-win demands between the mechanical robustness and electrochemical properties of HT-PEMs.展开更多
A new copolymer was synthesized by free radical polymerization in solution from methyl 3α-methylacryloyl-7α, 12α-dihydroxy-5β-cholan-24-oate (MACAME) and maleic anhydride (MAN). The copolymer was characterized by ...A new copolymer was synthesized by free radical polymerization in solution from methyl 3α-methylacryloyl-7α, 12α-dihydroxy-5β-cholan-24-oate (MACAME) and maleic anhydride (MAN). The copolymer was characterized by FT-IR and functional group analysis. The reactivity ratios of the two monomers were estimated [r_1 = 11.6 (MACAME), r_2 = 0.01(MAN)] by conducting a series of copolymerizations with a variety of monomer feed compositions and analyzing thecopolymer composition. Thermogravimetric and differential scanning calorimetric analyses of the samples indicate that thecopolymer possesses good thermal stability. The temperature at which the copolymer samples experienced a 10% weight loss(T_(WL)) is over 287℃, and the T_g ranged from 174 to 185℃ for the copolymers.展开更多
The copolymer of acrylic acid and acrylonitrile has been synthesized and pervaporation properties of the copolymeric membranes have been investigated. In order to elucidate the influence of membrane-permeate interacti...The copolymer of acrylic acid and acrylonitrile has been synthesized and pervaporation properties of the copolymeric membranes have been investigated. In order to elucidate the influence of membrane-permeate interaction on the pervaporation of water-ethanol mixtures and to prepare much improved membranes, the membranes have been treated with alkali metal, alkali earth metal and transition metal salt aqueous solutions. The treated membranes (ionized membranes) exhibited higher separation factors than the untreated membranes. The separation factors of various alkali metal cation membranes decreased in the following order : Li^+>Na^+>K^+, and the permeation rates showed an opposite tendency. The dependence of pervaporation behavior on the copolymer composition ,feed concentration and operating temperature have been studied with both ionized and non-ionized membranes. The apparent activation energies of water and ethanol permeation were calculated.展开更多
Block copolymer polystyrene-b-poly（acrylic acid）（PS-b-PAA） was used as structural template for the synthesis of CaCO3 microparticles. Through this procedure, acid resistant hybrid CaCO3 micro- spheres were obtaine...Block copolymer polystyrene-b-poly（acrylic acid）（PS-b-PAA） was used as structural template for the synthesis of CaCO3 microparticles. Through this procedure, acid resistant hybrid CaCO3 micro- spheres were obtained. Acid resistant properties of this type of hybrid CaCO3 were studied. Size measurement shows that the acid resistant properties of the hybrid particles are different in different solutions, such as HCl, EDTA, and H2SO4 solutions.展开更多
A novel kind of copolymer with ABA-type block structure was synthesized by anionic ring-opening polymerization of beta-butyrolactone (beta-BL) in the presence of a PEG-based dicarboxylates as macroinitiators which wer...A novel kind of copolymer with ABA-type block structure was synthesized by anionic ring-opening polymerization of beta-butyrolactone (beta-BL) in the presence of a PEG-based dicarboxylates as macroinitiators which were prepared by the esterification of aliphatic cyclic anhydride and poly(ethylene glycol) (PEG) oligomers (M-n = 2000, 4000 and 6000) and conversion of potassium dicarboxylates. The resultant copolymers as well as the intermediates were characterized by IR, H-1-NMR and GPC.展开更多
A series of porous microspheres of linear and ethylene diacrylate (M') cross-linked copolymers of 2-vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dic...A series of porous microspheres of linear and ethylene diacrylate (M') cross-linked copolymers of 2-vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol-acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.展开更多
L-lactic acid (L-LA) based copolymer/hydroxylation vermiculites composites (PLLA-co-bis A/HVMTs) were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites (HVMTs) using bisphen...L-lactic acid (L-LA) based copolymer/hydroxylation vermiculites composites (PLLA-co-bis A/HVMTs) were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites (HVMTs) using bisphenol-A epoxy resin as chain extending agent. HVMTs were obtained by sulfuric acid-leaching of lamellar vermiculites (VMTs). The effects of sulfuric acid leaching on the VMTs structure were characterized by X-ray diffraction (XRD), 29Si magic-angle spinning nuclear magnetic resonance(29Si NMR), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). FTIR, FE-SEM, and TGA were used to characterize the reaction activity of HVMTs. The results indicated that VMTs with increased hydroxyl groups had been successfully obtained and could react with -COOH of the reaction system. The amount of L-LA based copolymer grafted on the surface of HVMTs was more than 22%. The onset decomposition temperature of L-LA based copolymer grafted on the surface of HVMTs was 30℃ higher than that of free L-LA based copolymer.展开更多
The starch-g-lactic acid copolymer was synthesized with catalysis of sulfuric acid by onestep process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, 13C-NMR, HMBC, XRD, and SEM....The starch-g-lactic acid copolymer was synthesized with catalysis of sulfuric acid by onestep process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, 13C-NMR, HMBC, XRD, and SEM. The experimental results show that the maximum grafting degree of starch can reach 75% when the starch-g-lactic acid copolymer is activated at 80 ℃ for 2 h and reacted with lactic acid at 90 ℃ for 4 h in vacuum.展开更多
An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by graf...An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications展开更多
In this article,alkali lignin separated from paper pulp waste was grafted into a novel copolymer LSAA (a copolymer of lignin,starch, acrylamide,and acrylic acid).Its practical application effect and environmental safe...In this article,alkali lignin separated from paper pulp waste was grafted into a novel copolymer LSAA (a copolymer of lignin,starch, acrylamide,and acrylic acid).Its practical application effect and environmental safety were studied.The results of field simulation experiment indicated that the application of LSAA significantly affected the output of the runoff and pollutants.The runoff quantity was decreased by 16.67%-47.00%and the loads of total suspended solids (TSS),chemical oxygen demand (COD),total nit...展开更多
This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acr...This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.展开更多
The β-hydroxybutyrate and β-hydroxyvalerate copolymers( PHBV) /polylactic acid( PLA) is a new biocompatible material,which is developed through bacterial fermentation in vivo systems.The PHBV / PLA material could be...The β-hydroxybutyrate and β-hydroxyvalerate copolymers( PHBV) /polylactic acid( PLA) is a new biocompatible material,which is developed through bacterial fermentation in vivo systems.The PHBV / PLA material could be used to make continuous filaments.However,features of artificial blood vessels,especially small diameter vascular grafts made of PHVB / PLA materials are not known.This research are to evaluate and improve weavability of the PHBV / PLA material, and to explore feasibility of using it in artificial blood vessels.Preliminary results showed that weavability of PHBV / PLV was not good,but its weavability could be improved by using methods of weak chemical,such as sizing.In this research,scanning electron microscope( SEM) was adopted to evaluate weavability of PHBV / PLV after sizing and observe surfaces of yarns and fabrics.Also,in order to set proper parameters in heat settings,differential scanning calorimetry( DSC) was used to identify glass transition temperature.展开更多
Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprola...Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprolactone (ε-CL) with tin (Ⅱ) 2-ethylhexanoate as catalyst and n-butyl alcohol as initiator.Secondly,the PCL reacted with isophorone diisocyanate (IPDI) to prepare PCL with isocyanate functional group (PCL-NCO).Hydroxylamine was used to degrade gelatin by the cleavage between asparagine and glycine residues of gelatin.PCL-NCO reacted with the hydroxyl/amino groups of degraded gelatin in a homogeneous system and yielded the PCL modified gelatin copolymers.The gelatin grafted PCL copolymers were measured by means of XRD,FTIR,DSC and 1 H NMR.The results confirmed the conjugation of PCL onto gelatin chains.The PCL modified gelatin can be used as biomaterials owing to their biocompatibility and biodegradation.展开更多
In this study a low molecular weight triblock copolymer derived fromε-caprolactone and tetrahydrofuran was used as a non-reactive compatibilizer of immiscible PLA/PCL blends.Ternary blends with 0,1.5 wt%,3 wt%and 5 w...In this study a low molecular weight triblock copolymer derived fromε-caprolactone and tetrahydrofuran was used as a non-reactive compatibilizer of immiscible PLA/PCL blends.Ternary blends with 0,1.5 wt%,3 wt%and 5 wt% copolymer and about 75 wt%PLA were prepared by single screw extrusion and characterized by scanning electron microscopy(SEM),differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),tensile and Izod impact testing.SEM micrographs showed that the size of the dispersed PCL domains was practically constant regardless of copolymer concentration.This result can be explained by the low shear rate employed during processing step and a decrease of PCL viscosity by presence of the triblock copolymer.However,when the copolymer concentration increased,strain at break of PLA/PCL blends also increased.PLA/PCL blend with 0 wt% copolymer presented 2%strain at break,whereas PLA/PCL blend with 5 wt%copolymer exhibited 90%.展开更多
In this report,zinc acrylate copolymers were synthesized by used different organic acid as the side chain structure.These copolymers were further characterized by GPC,DSC and Water absorption analysis respectively,and...In this report,zinc acrylate copolymers were synthesized by used different organic acid as the side chain structure.These copolymers were further characterized by GPC,DSC and Water absorption analysis respectively,and then the effects of the chain structure of organic acid on hydrolysis degradation and copper release rate were also discussed.In the meantime,the result shows that the biocide release rate could be controlled by used different chain structure of organic acid.展开更多
A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- no...A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- nous octoate as catalyst. The copolymers were characterized by means of ~H-NMR and FT-IR spectroscopy. Gel permeation chromatography （GPC） test shows that the average-number relative molecular mass and average-weight rela- tive molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry （DSC） demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.展开更多
基金Project (21176264) supported by the National Natural Science Foundation of ChinaProject (11JJ2010) supported by Hunan Provincial Natural Science Foundation of ChinaProject (LC13076) supported by Undergraduate Innovation Foundation of Central South University,China
文摘Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn（II） （n）, pH, background electrolyte, etc on the rejection rate （R） and permeate flux （J） were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn（II） with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength.
文摘Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.
基金The work was supported by the National Natural Science Foundation of China
文摘The emeraldine base form of polyaniline (PANI) can be doped by a photo-induced doping method. In this method a. copolymer of vinylidene chloride and methyl acrylate (VCMAC) was used as photo acid generator which can release proton when it is exposed to ultraviolet light (lambda = 254 nm). The structure of PANI-VCMAC system before and after irradiation was characterized by elemental analysis, IR, XTP, anti SEM images. Results obtained indicate that the photo-induced doping characteristics, such as doping position and type of charge carriers, are similar to that of PANI doped with HCl. The poor room-temperature conductivity (similar to 10-S-5/cm) of PANI-VCMAC system after irradiation may be due to low doping degree (similar to pH=3) and the difference in morphology as compared with PANI-HCl film.
基金supported by the National Key Research and Development Program(2018YFA0702002)the National Key Research and Development Program(Japan-China Joint Research Program)(2017YFE0197900)
文摘How to optimize and regulate the distribution of phosphoric acid in matrix,and pursuing the improved electrochemical performance and service lifetime of high temperature proton exchange membrane(HT-PEMs)fuel cell are significant challenges.Herein,bifunctional poly(p-terphenyl-co-isatin piperidinium)copolymer with tethered phosphonic acid(t-PA)and intrinsic tertiary amine base groups are firstly prepared and investigated as HT-PEMs.The distinctive architecture of the copolymer provides a well-designed platform for rapid proton transport.Protons not only transports through the hydrogen bond network formed by the adsorbed free phosphoric acid(f-PA)anchored by the tertiary amine base groups,but also rely upon the proton channel constructed by the ionic cluster formed by the t-PA aggregation.Thorough the design of the structure,the bifunctional copolymers with lower PA uptake level(<100%)display prominent proton conductivities and peak power densities(99 mS cm^(-1),812 mW cm^(-2)at 160℃),along with lower PA leaching and higher voltage stability,which is a top leading result in disclosed literature.The results demonstrate that the design of intermolecular acid-base-pairs can improve the proton conductivity without sacrificing the intrinsic chemical stability or mechanical property of the thin membrane,realizing win-win demands between the mechanical robustness and electrochemical properties of HT-PEMs.
基金NSERC of Canada and Nankai University for financial support. H. Li thanks the National Natural Science Foundation of China for a travel award in support of the collaborative research program (No. 20074016).
文摘A new copolymer was synthesized by free radical polymerization in solution from methyl 3α-methylacryloyl-7α, 12α-dihydroxy-5β-cholan-24-oate (MACAME) and maleic anhydride (MAN). The copolymer was characterized by FT-IR and functional group analysis. The reactivity ratios of the two monomers were estimated [r_1 = 11.6 (MACAME), r_2 = 0.01(MAN)] by conducting a series of copolymerizations with a variety of monomer feed compositions and analyzing thecopolymer composition. Thermogravimetric and differential scanning calorimetric analyses of the samples indicate that thecopolymer possesses good thermal stability. The temperature at which the copolymer samples experienced a 10% weight loss(T_(WL)) is over 287℃, and the T_g ranged from 174 to 185℃ for the copolymers.
文摘The copolymer of acrylic acid and acrylonitrile has been synthesized and pervaporation properties of the copolymeric membranes have been investigated. In order to elucidate the influence of membrane-permeate interaction on the pervaporation of water-ethanol mixtures and to prepare much improved membranes, the membranes have been treated with alkali metal, alkali earth metal and transition metal salt aqueous solutions. The treated membranes (ionized membranes) exhibited higher separation factors than the untreated membranes. The separation factors of various alkali metal cation membranes decreased in the following order : Li^+>Na^+>K^+, and the permeation rates showed an opposite tendency. The dependence of pervaporation behavior on the copolymer composition ,feed concentration and operating temperature have been studied with both ionized and non-ionized membranes. The apparent activation energies of water and ethanol permeation were calculated.
基金Supported by the National Natural Science Foundation of China(Nos.50803055, 30872902).
文摘Block copolymer polystyrene-b-poly（acrylic acid）（PS-b-PAA） was used as structural template for the synthesis of CaCO3 microparticles. Through this procedure, acid resistant hybrid CaCO3 micro- spheres were obtained. Acid resistant properties of this type of hybrid CaCO3 were studied. Size measurement shows that the acid resistant properties of the hybrid particles are different in different solutions, such as HCl, EDTA, and H2SO4 solutions.
文摘A novel kind of copolymer with ABA-type block structure was synthesized by anionic ring-opening polymerization of beta-butyrolactone (beta-BL) in the presence of a PEG-based dicarboxylates as macroinitiators which were prepared by the esterification of aliphatic cyclic anhydride and poly(ethylene glycol) (PEG) oligomers (M-n = 2000, 4000 and 6000) and conversion of potassium dicarboxylates. The resultant copolymers as well as the intermediates were characterized by IR, H-1-NMR and GPC.
基金This work was supported by a Grant from the National Natural Science Foundation of China
文摘A series of porous microspheres of linear and ethylene diacrylate (M') cross-linked copolymers of 2-vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol-acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.
基金National High-Tech Research and Development Program of China ( 863 Program ) ( No. 2007AA03Z336) Program for New Century Excellent Talents in University,China ( No. NCET-07-0174) +1 种基金National Natural Science Foundations of China ( No. 21074021,No.50673018) The Fundamental Research Funds for the Central Universities ( No. 2011D10543)
文摘L-lactic acid (L-LA) based copolymer/hydroxylation vermiculites composites (PLLA-co-bis A/HVMTs) were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites (HVMTs) using bisphenol-A epoxy resin as chain extending agent. HVMTs were obtained by sulfuric acid-leaching of lamellar vermiculites (VMTs). The effects of sulfuric acid leaching on the VMTs structure were characterized by X-ray diffraction (XRD), 29Si magic-angle spinning nuclear magnetic resonance(29Si NMR), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). FTIR, FE-SEM, and TGA were used to characterize the reaction activity of HVMTs. The results indicated that VMTs with increased hydroxyl groups had been successfully obtained and could react with -COOH of the reaction system. The amount of L-LA based copolymer grafted on the surface of HVMTs was more than 22%. The onset decomposition temperature of L-LA based copolymer grafted on the surface of HVMTs was 30℃ higher than that of free L-LA based copolymer.
文摘The starch-g-lactic acid copolymer was synthesized with catalysis of sulfuric acid by onestep process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, 13C-NMR, HMBC, XRD, and SEM. The experimental results show that the maximum grafting degree of starch can reach 75% when the starch-g-lactic acid copolymer is activated at 80 ℃ for 2 h and reacted with lactic acid at 90 ℃ for 4 h in vacuum.
文摘An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications
文摘In this article,alkali lignin separated from paper pulp waste was grafted into a novel copolymer LSAA (a copolymer of lignin,starch, acrylamide,and acrylic acid).Its practical application effect and environmental safety were studied.The results of field simulation experiment indicated that the application of LSAA significantly affected the output of the runoff and pollutants.The runoff quantity was decreased by 16.67%-47.00%and the loads of total suspended solids (TSS),chemical oxygen demand (COD),total nit...
基金the National Metallurgical Laboratory,Jamshedpur for their kind support
文摘This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.
文摘The β-hydroxybutyrate and β-hydroxyvalerate copolymers( PHBV) /polylactic acid( PLA) is a new biocompatible material,which is developed through bacterial fermentation in vivo systems.The PHBV / PLA material could be used to make continuous filaments.However,features of artificial blood vessels,especially small diameter vascular grafts made of PHVB / PLA materials are not known.This research are to evaluate and improve weavability of the PHBV / PLA material, and to explore feasibility of using it in artificial blood vessels.Preliminary results showed that weavability of PHBV / PLV was not good,but its weavability could be improved by using methods of weak chemical,such as sizing.In this research,scanning electron microscope( SEM) was adopted to evaluate weavability of PHBV / PLV after sizing and observe surfaces of yarns and fabrics.Also,in order to set proper parameters in heat settings,differential scanning calorimetry( DSC) was used to identify glass transition temperature.
基金Supported by International Cooperation from Ministry of Science and Technology of China(No.2008DFA51170)
文摘Hydrophilic degraded gelatin was modified with hydrophobic poly(ε-caprolactone) (PCL) via a chemical grafting route.Firstly,PCL with one hydroxyl end group was prepared by the ring-opening polymerization of εcaprolactone (ε-CL) with tin (Ⅱ) 2-ethylhexanoate as catalyst and n-butyl alcohol as initiator.Secondly,the PCL reacted with isophorone diisocyanate (IPDI) to prepare PCL with isocyanate functional group (PCL-NCO).Hydroxylamine was used to degrade gelatin by the cleavage between asparagine and glycine residues of gelatin.PCL-NCO reacted with the hydroxyl/amino groups of degraded gelatin in a homogeneous system and yielded the PCL modified gelatin copolymers.The gelatin grafted PCL copolymers were measured by means of XRD,FTIR,DSC and 1 H NMR.The results confirmed the conjugation of PCL onto gelatin chains.The PCL modified gelatin can be used as biomaterials owing to their biocompatibility and biodegradation.
文摘In this study a low molecular weight triblock copolymer derived fromε-caprolactone and tetrahydrofuran was used as a non-reactive compatibilizer of immiscible PLA/PCL blends.Ternary blends with 0,1.5 wt%,3 wt%and 5 wt% copolymer and about 75 wt%PLA were prepared by single screw extrusion and characterized by scanning electron microscopy(SEM),differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),tensile and Izod impact testing.SEM micrographs showed that the size of the dispersed PCL domains was practically constant regardless of copolymer concentration.This result can be explained by the low shear rate employed during processing step and a decrease of PCL viscosity by presence of the triblock copolymer.However,when the copolymer concentration increased,strain at break of PLA/PCL blends also increased.PLA/PCL blend with 0 wt% copolymer presented 2%strain at break,whereas PLA/PCL blend with 5 wt%copolymer exhibited 90%.
文摘In this report,zinc acrylate copolymers were synthesized by used different organic acid as the side chain structure.These copolymers were further characterized by GPC,DSC and Water absorption analysis respectively,and then the effects of the chain structure of organic acid on hydrolysis degradation and copper release rate were also discussed.In the meantime,the result shows that the biocide release rate could be controlled by used different chain structure of organic acid.
基金Supported by Chinese Program for New Century Excellent Talents in University "NCET",Ministry of Education of P.R. China(No.2008DFA51170)
文摘A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- nous octoate as catalyst. The copolymers were characterized by means of ~H-NMR and FT-IR spectroscopy. Gel permeation chromatography （GPC） test shows that the average-number relative molecular mass and average-weight rela- tive molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry （DSC） demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.
