This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The ke...This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The key is to add the curing agent in the vicinity of the phase inversion point at low temperature so as to control the emulsifier capability of the pre\|curing oligomers at a low level,which ensures the achievement of incomplete phase inversion emulsification.Scanning electron micrographs of the spheres reveal that the particles size is mainly in the range of 1～10 μm with sub\|micron cavities within the spheres.DSC is used to measure the curing behavior of the spheres.Two broad exothermic peaks around 120 and 162℃ are found in the as\|prepared particles,while the first peak shifts to higher temperature 135℃ and the onset temperature exceeds 100℃ in the thermally treated sample at 95℃ for 1 5?h.This indicates that the initial step curing process under the post\|treatment conditions is nearly completed.After further treated at high temperature for example 200℃,a glass transition temperature about 130℃ is found,and the two peaks disappear due to a full achievement of the curing process.Extraction results show that after treated at 95℃ for 1 5?h in water,the micro\|sized spheres become insoluble.It is concluded that the entitled waterborne microspheres are crosslinkable and multiporous.A preliminary result demonstrates a potential application of the entitled multi\|hollow spheres as opacifiers due to their intensive light scattering within the hollows.展开更多
目的以可溶性淀粉为原料,N,N'-亚甲基双丙烯酰胺为交联剂,双氯芬酸钠为主药,通过反相乳化交联法制备双氯芬酸钠载药淀粉微球。方法以微球平均粒径和包封率为指标,采用单因素及正交实验优化微球的处方和制备工艺。采用光学显微镜、...目的以可溶性淀粉为原料,N,N'-亚甲基双丙烯酰胺为交联剂,双氯芬酸钠为主药,通过反相乳化交联法制备双氯芬酸钠载药淀粉微球。方法以微球平均粒径和包封率为指标,采用单因素及正交实验优化微球的处方和制备工艺。采用光学显微镜、透射电镜、红外光谱仪及差热分析仪对所获微球的外观和结构进行表征,并通过透析法对载药微球的体外释药情况进行考察。结果经正交实验优化后的制备条件为:淀粉浓度10%,交联温度55℃,交联剂用量0.2 g,油水体积比5∶1,乳化剂用量5 m L,交联时间60 min,此条件制得的淀粉微球平均粒径为9μm,形状近球形,包封率为67.52%。红外光谱和差热分析表明淀粉已发生交联。结论载药淀粉微球具有较好的缓释作用,药物的体外释放符合Weibull方程。展开更多
文摘This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The key is to add the curing agent in the vicinity of the phase inversion point at low temperature so as to control the emulsifier capability of the pre\|curing oligomers at a low level,which ensures the achievement of incomplete phase inversion emulsification.Scanning electron micrographs of the spheres reveal that the particles size is mainly in the range of 1～10 μm with sub\|micron cavities within the spheres.DSC is used to measure the curing behavior of the spheres.Two broad exothermic peaks around 120 and 162℃ are found in the as\|prepared particles,while the first peak shifts to higher temperature 135℃ and the onset temperature exceeds 100℃ in the thermally treated sample at 95℃ for 1 5?h.This indicates that the initial step curing process under the post\|treatment conditions is nearly completed.After further treated at high temperature for example 200℃,a glass transition temperature about 130℃ is found,and the two peaks disappear due to a full achievement of the curing process.Extraction results show that after treated at 95℃ for 1 5?h in water,the micro\|sized spheres become insoluble.It is concluded that the entitled waterborne microspheres are crosslinkable and multiporous.A preliminary result demonstrates a potential application of the entitled multi\|hollow spheres as opacifiers due to their intensive light scattering within the hollows.
文摘目的以可溶性淀粉为原料,N,N'-亚甲基双丙烯酰胺为交联剂,双氯芬酸钠为主药,通过反相乳化交联法制备双氯芬酸钠载药淀粉微球。方法以微球平均粒径和包封率为指标,采用单因素及正交实验优化微球的处方和制备工艺。采用光学显微镜、透射电镜、红外光谱仪及差热分析仪对所获微球的外观和结构进行表征,并通过透析法对载药微球的体外释药情况进行考察。结果经正交实验优化后的制备条件为:淀粉浓度10%,交联温度55℃,交联剂用量0.2 g,油水体积比5∶1,乳化剂用量5 m L,交联时间60 min,此条件制得的淀粉微球平均粒径为9μm,形状近球形,包封率为67.52%。红外光谱和差热分析表明淀粉已发生交联。结论载药淀粉微球具有较好的缓释作用,药物的体外释放符合Weibull方程。
