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
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
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
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
Chitosan-graft-poly（lactic acid） （CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phas...Chitosan-graft-poly（lactic acid） （CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phase was made up of PLA in chloroform. The W/O microemulsion was fabricated in the presence of surfactant span-80 and the self-assembly was performed between PLA and CS under the effect of N-（3-dimethylaminopropyl）-N＇ethylcarbodiimide hydrochloride （EDC＇HCI）. FTIR and IH-NMR analysis indicated PLA was grafted onto the backbone of CS via the reaction between the carboxyl groups in PLA and the amino groups in CS. 1H-NMR characterization further revealed the grafting content of PLA was 16%. The obtained CS-g-PLA could self-assemble to form micelles, their size distributed in the range of 125-375 nm with average diameter of 142 nm. The present design integrates the favorable biological properties of CS and the excellent mechanical properties of PLA, which makes CS-g-PLA copolymer a promising candidate as a carrier for targeted bioactive molecules delivery.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.
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%.
基金financially supported by the National Natural Science Foundation of China(Nos.11272038,50803032,11032012,10925208,11202017 and 11120101001)the Fundamental Research Funds for the Central Universities(No.YWF-13-T-RSC-024)+2 种基金the 111 Project(No.B13003)the International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of Chinathe Program of Pearl River Young Talents of Science and Technology in Guangzhou,China(No.2013Z2200010)
文摘Chitosan-graft-poly（lactic acid） （CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phase was made up of PLA in chloroform. The W/O microemulsion was fabricated in the presence of surfactant span-80 and the self-assembly was performed between PLA and CS under the effect of N-（3-dimethylaminopropyl）-N＇ethylcarbodiimide hydrochloride （EDC＇HCI）. FTIR and IH-NMR analysis indicated PLA was grafted onto the backbone of CS via the reaction between the carboxyl groups in PLA and the amino groups in CS. 1H-NMR characterization further revealed the grafting content of PLA was 16%. The obtained CS-g-PLA could self-assemble to form micelles, their size distributed in the range of 125-375 nm with average diameter of 142 nm. The present design integrates the favorable biological properties of CS and the excellent mechanical properties of PLA, which makes CS-g-PLA copolymer a promising candidate as a carrier for targeted bioactive molecules delivery.
