中文摘要：

采用无溶剂二氧化碳固态发泡技术，在2．5、3．5、4．0和5．0MPa饱和压力下制备了泡孔孔径为350—20um的聚乳酸支架材料．利用热重分析技术、动态热机械分析技术和扫描电子显微镜技术，测定了材料的起始分解温度、分解速率、储存／损耗模量和损耗因子等参数，并利用Kissinger、Ozawa-Doyle和Vyazovkin方程进行了热分解动力学计算，推算了氮气环境下材料的降解时间和使用寿命．结果表明，随着发泡压力的减小，支架材料的泡孔孔径增大，材料的柔韧性增强，表观活化能降低，降解时间缩短．

英文摘要：

Solvent-free solid-state foaming technology was used to fabricate microcellular polylactic acid （PLA） scaffold materials with cell sizes from 350 to 20 tJm at saturation pressures of 2.5, 3.5, 4.0, and 5.0 MPa in carbon dioxide. The corresponding thermodynamic parameters were measured, including the decomposition temperature and rate, storage/loss modulus, and loss factor, using thermogravimetric analysis, dynamic thermal mechanical analysis, and scanning electron microscopy. The Kissinger, Ozawa- Doyle, and Vyazovkin equations were used to calculate the thermal decomposition kinetics for PLA foams of different cell sizes; their lifetimes in nitrogen were also obtained. It was observed that PLA foams with larger cell sizes, lower average activation energies, and better flexibilities could be fabricated at lower saturation pressures, resulting in reduced decomposition times.