纳米SiO_2接枝聚消旋乳酸的制备和表征

Preparation and Characterization of SiO_2-g-PDLLA

为使聚乳酸/二氧化硅复合材料既有纳米效应又有有机材料的优点,文中使用硅烷偶联剂KH-550对纳米二氧化硅进行表面改性,采用原位聚合法,将D,L-丙交酯在改性二氧化硅表面开环聚合制备聚消旋乳酸/纳米二氧化硅接枝聚合物.使用傅里叶红外变换光谱仪(FTIR)和热重分析仪(TG)对其结构和热性能进行表征.实验结果表明:接枝效果最佳的反应时间为24h,失重率为17%.改性后的纳米二氧化硅的分散稳定性和聚消旋乳酸的热稳定性得到了明显改善,聚消旋乳酸的起始分解温度由100℃提高到130℃,SiO_2-g-PDLLA在丙酮中能稳定分散2个月以上.

In order for SiO_2/PLA composite to have nano-size effect and the advantages of organic materials,the silica surface modification was carried out by using silane coupling agent KH-550 and then the nano silica grafted by poly（D,L-lactide）（SiO_2-g-PDLLA）was obtained by surface ring-opening polymerization of D,L-lactide（D,L-LA）.According to the characterization obtained by the Fourier Transform Infrared Spectroscopy（FTIR）and Thermo Gravimetric（TG）,the optimum reaction time for SiO_2-g-PDLLA with a weight-loss ratio of 17% was 24 hours.As a result,the dispersion of nano silica and the thermal stability of poly（D,L-lactide）were obviously improved：the onset temperature of degradation was elevated from 100 ℃to 130 ℃;SiO_2-g-PDLLA could be dispersed in acetone stably for more than two months.