采用乳液聚合方法将引发剂过硫酸铵(APS)和乳化剂十二烷基硫酸钠(SDS)制备出聚丙烯酸树脂乳液,再加入不同条件交联剂固化成聚丙烯酸(PAA)水凝胶,并探究使用紫外固化和热固化2种不同固化方式及不同固化时间对PAA水凝胶性能的影响。通过...采用乳液聚合方法将引发剂过硫酸铵(APS)和乳化剂十二烷基硫酸钠(SDS)制备出聚丙烯酸树脂乳液,再加入不同条件交联剂固化成聚丙烯酸(PAA)水凝胶,并探究使用紫外固化和热固化2种不同固化方式及不同固化时间对PAA水凝胶性能的影响。通过氮气等温吸脱附曲线测试(Brunauer-Emmet-Teller,BET)、扫描电子显微镜(scanning electron microscope,SEM)、热失重分析(thermogravimetric analysis,TGA)、溶胀度、力学测试等方法,对水凝胶的性能进行表征分析。结果表明,形成的PAA水凝胶主要为片状颗粒材料,在紫外固化20 min条件下,其孔径主要分布在2~4 nm;且在热固化条件下,当交联剂质量浓度为0.06、0.07 g/mL时PAA水凝胶溶胀度可达到667%,在交联剂质量浓度为0.09 g/mL时拉伸强度可达到60 k Pa。综上所述,对比紫外固化和热固化2种方法以及不同条件交联剂下制备的PAA水凝胶的差异,对理解和优化PAA水凝胶的制备具有一定的指导意义。展开更多
Surface modification on a polytetrafluoroethylene （PTFE） panel was performed with sequential nitrogen plasma treatments and surface-initiated polymerization. By introducing COO- groups to the surface of the PTFE pan...Surface modification on a polytetrafluoroethylene （PTFE） panel was performed with sequential nitrogen plasma treatments and surface-initiated polymerization. By introducing COO- groups to the surface of the PTFE panel through grafting polymerization of acrylic acid （AA）, a transparent poly （acrylic acid） （PAA） membrane was achieved from acrylic acid solution. Grafting polymerization initiating from the active group5 was achieved on the PTFE panel surface after the nitrogen plasma treatment. Utilizing the acrylic acid as monomers, with COO- groups as cross link sites to form reticulation structure, a transparent poly （acrylic acid） membrane with arborescent macromolecular structure was formed on the PTFE panel surface. Analysis meth- ods, such as fourier transform infrared spectroscopy （FTIR）, microscopy and X-ray photoelectron spectroscopy （XPS）, were utilized to characterize the structures of the macromolecule membrane on the PTFE panel surface. A contact angle measurement was performed to characterize the modified PTFE panels. The surface hydrophilicities of modified PTFE panels were significantly enhanced after the plasma treatment. It was shown that the grafting rate is related to the treating time and the power of plasma.展开更多
A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the meth...A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.展开更多
This paper has studied processing conditions and the influence of every variable to the pulp when the fluorescence in cotton linter pulp is eliminated with peracetic acid. The suitable variables of the elimination of ...This paper has studied processing conditions and the influence of every variable to the pulp when the fluorescence in cotton linter pulp is eliminated with peracetic acid. The suitable variables of the elimination of fluorescence. are found.展开更多
Bacterial cellulose/polyacrylic acid (BC/PAA) pH-responsive hydrogels were prepared by free-radical polymerization (in situ) using BC as the raw material and AA as the monomer. The hydrogels were loaded with curcumin ...Bacterial cellulose/polyacrylic acid (BC/PAA) pH-responsive hydrogels were prepared by free-radical polymerization (in situ) using BC as the raw material and AA as the monomer. The hydrogels were loaded with curcumin (Cur) to prepare pH-responsive intelligent medical dressings. The preparation process of the hydrogels was optimized by a single factor and response surface experiment using their swelling degree as an index. The structures of BC/PAA pH-responsive hydrogels were characterized by scanning electron microscope (SEM), Fourier Transform Infrared spectrometer (FTIR), X-ray diffraction (XRD), and tensile tester, and the swelling properties, mechanical properties, bacteriostatic properties, and drug release behavior were investigated. The results showed that the BC/PAA pH-responsive hydrogel has a three-dimensional network structure with the swelling rate up to 1600 g/g, compressive strength of up to 8 KPa, and good mechanical properties, and the drug release behavior was in line with the logistic dynamics model, and it has good inhibitory effects on common pathogens of wound infection: E. coli, S. aureus, and P. aeruginosa.展开更多
[目的]评价安全保鲜剂过氧乙酸(PAA)结合氯化钙处理对枇杷贮藏效果,为解决枇杷果实采后腐烂和品质劣变问题提供实践技术。[方法]以青种品种枇杷果实为材料,采用0.2%、0.4%、0.8%PAA分别结合0.8%CaCl2浸泡枇杷果实4min,对照处理为0.8%Ca...[目的]评价安全保鲜剂过氧乙酸(PAA)结合氯化钙处理对枇杷贮藏效果,为解决枇杷果实采后腐烂和品质劣变问题提供实践技术。[方法]以青种品种枇杷果实为材料,采用0.2%、0.4%、0.8%PAA分别结合0.8%CaCl2浸泡枇杷果实4min,对照处理为0.8%CaCl2和清水处理,晾干并经0.02 mm PE袋包装后在非冷害低温(7±1)℃下贮藏,每隔3天随机抽样测定一次枇杷果实贮藏品质相关指标,分析变化情况。[结果]与2个对照处理、0.2%PAA和0.8%PAA结合钙处理相比,0.4%PAA+0.8%CaCl2复合处理能显著抑制枇杷果实贮藏期间腐烂指数、失重率、硬度和细胞膜渗透率的上升,有效阻延可滴定酸、维生素C、可溶性固形物含量及出汁率的降低,并使果实呼吸强度维持在较低水平,贮藏25d时果实外观与风味品质良好。[结论 ]0.4%PAA复合0.8%CaCl2处理是一种高效、安全、经济的枇杷采后防腐与品质保鲜实用技术。展开更多
文摘采用乳液聚合方法将引发剂过硫酸铵(APS)和乳化剂十二烷基硫酸钠(SDS)制备出聚丙烯酸树脂乳液,再加入不同条件交联剂固化成聚丙烯酸(PAA)水凝胶,并探究使用紫外固化和热固化2种不同固化方式及不同固化时间对PAA水凝胶性能的影响。通过氮气等温吸脱附曲线测试(Brunauer-Emmet-Teller,BET)、扫描电子显微镜(scanning electron microscope,SEM)、热失重分析(thermogravimetric analysis,TGA)、溶胀度、力学测试等方法,对水凝胶的性能进行表征分析。结果表明,形成的PAA水凝胶主要为片状颗粒材料,在紫外固化20 min条件下,其孔径主要分布在2~4 nm;且在热固化条件下,当交联剂质量浓度为0.06、0.07 g/mL时PAA水凝胶溶胀度可达到667%,在交联剂质量浓度为0.09 g/mL时拉伸强度可达到60 k Pa。综上所述,对比紫外固化和热固化2种方法以及不同条件交联剂下制备的PAA水凝胶的差异,对理解和优化PAA水凝胶的制备具有一定的指导意义。
基金supported by National Natural Science Foundation of China (No. 10975162)Knowledge Innovation Project of Young Talent, Hefei Institutes of Physical Science, CAS (Nos. 075FCQ0126, Y05FCQ0127)
文摘Surface modification on a polytetrafluoroethylene （PTFE） panel was performed with sequential nitrogen plasma treatments and surface-initiated polymerization. By introducing COO- groups to the surface of the PTFE panel through grafting polymerization of acrylic acid （AA）, a transparent poly （acrylic acid） （PAA） membrane was achieved from acrylic acid solution. Grafting polymerization initiating from the active group5 was achieved on the PTFE panel surface after the nitrogen plasma treatment. Utilizing the acrylic acid as monomers, with COO- groups as cross link sites to form reticulation structure, a transparent poly （acrylic acid） membrane with arborescent macromolecular structure was formed on the PTFE panel surface. Analysis meth- ods, such as fourier transform infrared spectroscopy （FTIR）, microscopy and X-ray photoelectron spectroscopy （XPS）, were utilized to characterize the structures of the macromolecule membrane on the PTFE panel surface. A contact angle measurement was performed to characterize the modified PTFE panels. The surface hydrophilicities of modified PTFE panels were significantly enhanced after the plasma treatment. It was shown that the grafting rate is related to the treating time and the power of plasma.
基金Project(20704011) supported by the National Natural Science Foundation of ChinaProject(09JJ3027) supported by the Natural Science Foundation of Hunan Province,ChinaProject(50725825) supported by the National Science Foundation for Distinguished Young Scholars
文摘A new multifunctional mPEG-b-PAA-grafted chitosan copolymer possessing amino and carboxyl groups,mPEG-b-PAA-g-CHI(compound 6) ,was designed for a potential application in gene/drug delivery and synthesized by the methods of reversible addition-fragmentation chain transfer(RAFT) polymerization of acrylic acid(AA) and grafting reaction of a biodegradable chitosan(CHI) derivative.Completion of the reactions and characterization of the resulting compounds were demonstrated by 1 H NMR,FTIR and gel permeation chtomatography(GPC) studies.The results show that the molar ratio of amino groups to carboxyl groups in the copolymer(compound 6) is 0.41-0.59.
文摘This paper has studied processing conditions and the influence of every variable to the pulp when the fluorescence in cotton linter pulp is eliminated with peracetic acid. The suitable variables of the elimination of fluorescence. are found.
文摘Bacterial cellulose/polyacrylic acid (BC/PAA) pH-responsive hydrogels were prepared by free-radical polymerization (in situ) using BC as the raw material and AA as the monomer. The hydrogels were loaded with curcumin (Cur) to prepare pH-responsive intelligent medical dressings. The preparation process of the hydrogels was optimized by a single factor and response surface experiment using their swelling degree as an index. The structures of BC/PAA pH-responsive hydrogels were characterized by scanning electron microscope (SEM), Fourier Transform Infrared spectrometer (FTIR), X-ray diffraction (XRD), and tensile tester, and the swelling properties, mechanical properties, bacteriostatic properties, and drug release behavior were investigated. The results showed that the BC/PAA pH-responsive hydrogel has a three-dimensional network structure with the swelling rate up to 1600 g/g, compressive strength of up to 8 KPa, and good mechanical properties, and the drug release behavior was in line with the logistic dynamics model, and it has good inhibitory effects on common pathogens of wound infection: E. coli, S. aureus, and P. aeruginosa.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest "Tec-hnology Research and Experimental Demonstration of Loquat Industry"(201003073)~~
文摘[目的]评价安全保鲜剂过氧乙酸(PAA)结合氯化钙处理对枇杷贮藏效果,为解决枇杷果实采后腐烂和品质劣变问题提供实践技术。[方法]以青种品种枇杷果实为材料,采用0.2%、0.4%、0.8%PAA分别结合0.8%CaCl2浸泡枇杷果实4min,对照处理为0.8%CaCl2和清水处理,晾干并经0.02 mm PE袋包装后在非冷害低温(7±1)℃下贮藏,每隔3天随机抽样测定一次枇杷果实贮藏品质相关指标,分析变化情况。[结果]与2个对照处理、0.2%PAA和0.8%PAA结合钙处理相比,0.4%PAA+0.8%CaCl2复合处理能显著抑制枇杷果实贮藏期间腐烂指数、失重率、硬度和细胞膜渗透率的上升,有效阻延可滴定酸、维生素C、可溶性固形物含量及出汁率的降低,并使果实呼吸强度维持在较低水平,贮藏25d时果实外观与风味品质良好。[结论 ]0.4%PAA复合0.8%CaCl2处理是一种高效、安全、经济的枇杷采后防腐与品质保鲜实用技术。
