乳酸接枝纳米二氧化钛/聚乳酸复合物的制备

Preparation of Lactic Acid-g-TiO_2/Poly( lactic acid) Composites

将乳酸低聚物接枝到纳米二氧化钛(TiO_2)的表面,获得接枝改性二氧化钛(g-TiO_2),采用溶液共混的方法制备出聚左旋乳酸(PLLA)和g-TiO_2复合物。通过扫描电子显微镜、差示扫描量热仪、紫外-可见吸收光谱仪和动态力学分析仪等技术系统研究了g-TiO_2的加入对PLLA结构和性能的影响。结果表明,在辛酸亚锡做催化剂的条件下,乳酸低聚物可接枝到纳米TiO_2的表面,接枝率为6.5%。TiO_2经过表面接枝改性后,在乙醇分散体系中团聚粒子的平均粒径由93 nm降低为58 nm。在质量分数低于1.5%时,g-TiO_2在PLLA中的分散性显著提升,可均匀分散在基体中。g-TiO_2的加入可提高PLLA的结晶速率和结晶度,同时可改善PLLA的抗紫外性能和储能模量。

Lactic acid grafted TiO2 catalyzed with stannous octoate and poly（lactic acid） （PLLA） composites were prepared by solution casting. The structures and properties of composites were characterized by SEM, DSC, ultraviolet-visible absorption spectrometry and DMA. The results show that lactic acid oligomer are successfully grafted onto the surface of nanometer TiO2 catalyzed with stannous octoate and the grafting ratio is 6.5 %. The average size of particles dispersing in ethanol system decreases from 93 nm to 58 nm after modification. In PLLA matrix, comparing with easy aggregation of TiO2, g-TiO2 can be uniformly dispersed with the content less than 1.5 %. The crystallization rate and crystaUinity of PLLA are markedly improved when the conent of TiO2 is below 1.5 %, and simultaneously, its hgat stability, ultraviolet resistance and storage modulus increase.