The monodispersed latex particles were prepared by soap-free emulsion copolymerization of styrene(St) with hydroxyethyl methacrylate(HEMA). The nucleation mechanism and growth process of polymer latex particles were i...The monodispersed latex particles were prepared by soap-free emulsion copolymerization of styrene(St) with hydroxyethyl methacrylate(HEMA). The nucleation mechanism and growth process of polymer latex particles were investigated. The effects of HEMA on diameter of the latex particles and monomer conversion were discussed. The elemental analysis and XRD results showed that HEMA was dispersed mainly on the surface of the latex particles, it could stabilize the latex particles and lead the nucleation. The nucleation of particles occurs likely by homogeneous nucleation mechanism. The diameter of the latex particles decreased and the conversion increased, as HEMA′s dosage increased.展开更多
Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHE MA) copolymers were prepared by the aqueous suspension-swelling graft copolymer ization process.The grafting of HEMA on PVC was confirmed by the infr...Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHE MA) copolymers were prepared by the aqueous suspension-swelling graft copolymer ization process.The grafting of HEMA on PVC was confirmed by the infrared spect rum.The grafting degree increased with the increase of feeding mass fraction of HEMA,and a maximum grafting efficiency appeared at 10% mass fraction of HEMA i n feed.The grafting degree and efficiency increased as partially dehydrochlorin ated PVC was used.The intrinsic viscosity of graft copolymers increased slowly with the increase of the grafting degree of HEMA,and decreased at high grafting degrees.PVC-g-PHEMA copolymers exhibited a higher glass transition tempe rature (T g) in the first DSC run than that in the second run,and T g of graft copolymers increased as the grafting degree increased.展开更多
背景:聚甲基丙烯酸-2-羟乙酯载药生物材料既有优异的生物学功能,又能释放药物,是一种潜在的组织工程支架材料和缓、控释药物载体材料。目的:观察布洛芬-聚甲基丙烯酸-2-羟乙酯水凝胶膜表面形态、吸水膨胀性能及缓控释性能。设计、时间...背景:聚甲基丙烯酸-2-羟乙酯载药生物材料既有优异的生物学功能,又能释放药物,是一种潜在的组织工程支架材料和缓、控释药物载体材料。目的:观察布洛芬-聚甲基丙烯酸-2-羟乙酯水凝胶膜表面形态、吸水膨胀性能及缓控释性能。设计、时间及地点:体外观察实验,于2008-01/05在福建医科大学药学院药学综合实验室完成。材料:甲基丙烯酸-2-羟乙酯为Aldrich Chemical Company产品;布洛芬为山东新华制药股份有限公司产品;过硫酸铵为广东省化学试剂工程技术研究开发中心产品;N-N’-亚甲基双丙烯酰胺为苏州市化工研究所有限公司产品。方法:选甲基丙烯酸-2-羟乙酯为单体、过硫酸铵为引发剂、N-N’-亚甲基双丙烯酰胺为交联剂、布洛芬为模型药物水相聚合,通过分步法和同步法导入药物。主要观察指标:光学显微镜和扫描电镜观察凝胶膜的表面形态;水溶液法测定凝胶膜的膨胀性能,拟体液环境中测定凝胶膜的释药特征。结果:含有N-N’-亚甲基双丙烯酰胺的水凝胶膜表面褶皱和沟痕更少,整体面光滑。随着交联剂加入量增加,吸水溶胀度减小,水凝胶膜形成体型结构的趋势增大。不论是同步法还是分步法所制的载药水凝胶膜,其释药达到平台的时间都比未加入交联剂的凝胶膜要长,但同时也发现在交联剂加入后,膜的载药量在减少,综合各因素以N-N’-亚甲基双丙烯酰胺含量7.5g/L为较佳方案。结论:水凝胶膜表面形态理想,导入药物后的载药膜具有良好的膨胀性能和更优秀的缓、控释特征。展开更多
文摘The monodispersed latex particles were prepared by soap-free emulsion copolymerization of styrene(St) with hydroxyethyl methacrylate(HEMA). The nucleation mechanism and growth process of polymer latex particles were investigated. The effects of HEMA on diameter of the latex particles and monomer conversion were discussed. The elemental analysis and XRD results showed that HEMA was dispersed mainly on the surface of the latex particles, it could stabilize the latex particles and lead the nucleation. The nucleation of particles occurs likely by homogeneous nucleation mechanism. The diameter of the latex particles decreased and the conversion increased, as HEMA′s dosage increased.
文摘Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHE MA) copolymers were prepared by the aqueous suspension-swelling graft copolymer ization process.The grafting of HEMA on PVC was confirmed by the infrared spect rum.The grafting degree increased with the increase of feeding mass fraction of HEMA,and a maximum grafting efficiency appeared at 10% mass fraction of HEMA i n feed.The grafting degree and efficiency increased as partially dehydrochlorin ated PVC was used.The intrinsic viscosity of graft copolymers increased slowly with the increase of the grafting degree of HEMA,and decreased at high grafting degrees.PVC-g-PHEMA copolymers exhibited a higher glass transition tempe rature (T g) in the first DSC run than that in the second run,and T g of graft copolymers increased as the grafting degree increased.
文摘背景:聚甲基丙烯酸-2-羟乙酯载药生物材料既有优异的生物学功能,又能释放药物,是一种潜在的组织工程支架材料和缓、控释药物载体材料。目的:观察布洛芬-聚甲基丙烯酸-2-羟乙酯水凝胶膜表面形态、吸水膨胀性能及缓控释性能。设计、时间及地点:体外观察实验,于2008-01/05在福建医科大学药学院药学综合实验室完成。材料:甲基丙烯酸-2-羟乙酯为Aldrich Chemical Company产品;布洛芬为山东新华制药股份有限公司产品;过硫酸铵为广东省化学试剂工程技术研究开发中心产品;N-N’-亚甲基双丙烯酰胺为苏州市化工研究所有限公司产品。方法:选甲基丙烯酸-2-羟乙酯为单体、过硫酸铵为引发剂、N-N’-亚甲基双丙烯酰胺为交联剂、布洛芬为模型药物水相聚合,通过分步法和同步法导入药物。主要观察指标:光学显微镜和扫描电镜观察凝胶膜的表面形态;水溶液法测定凝胶膜的膨胀性能,拟体液环境中测定凝胶膜的释药特征。结果:含有N-N’-亚甲基双丙烯酰胺的水凝胶膜表面褶皱和沟痕更少,整体面光滑。随着交联剂加入量增加,吸水溶胀度减小,水凝胶膜形成体型结构的趋势增大。不论是同步法还是分步法所制的载药水凝胶膜,其释药达到平台的时间都比未加入交联剂的凝胶膜要长,但同时也发现在交联剂加入后,膜的载药量在减少,综合各因素以N-N’-亚甲基双丙烯酰胺含量7.5g/L为较佳方案。结论:水凝胶膜表面形态理想,导入药物后的载药膜具有良好的膨胀性能和更优秀的缓、控释特征。
