Studies on Structure and Physical Properties of Poly (lactic acid)-Based Biodegradable Polyesters

本研究的目的是（1）开发新的方法，如表面改性（碱处理，生物降解聚合物涂层），共混（亲水性生物可降解聚合物、对映体PLA和无机颗粒）和通过使用相分离的孔形成，以控制聚（丙交酯）[聚（丙交酯）]的物理性质和生物可降解性。（2）研究所制备材料的生物降解机理;（3）开发一种通过使用高温高压水将PLA再循环成其单体的新方法。结果发现，对于可生物降解的聚酯，包括PLA，表面改性是有效的加速和减速的生物降解没有侵蚀的核心部分的材料，共混是倾向于加速其生物降解时，共混物相分离，和孔的形成是有效的软材料的制备和加速其生物降解。此外，在球晶中的结晶区域之间的“限制性无定形区域”被发现比球晶外的“自由无定形区域”更耐水解，并且通过使用高温高压水在熔体中水解被证明是将聚（L-丙交酯）[聚（L-乳酸）]回收为L-乳酸的有力方法。

The purposes of this study were(1)to develop new methods such as surface modification (alkaline treatment, biodegradable polymer coating), blending (hydrophilic biodegradable polymers, enantiomeric PLAs, and inorganic particles), and pore formation by the use of phase separation, to control physical properties and biodegradability of the poly (lactide) s [poly (lactic acid) s (PLAs)]-based biodegradable polyesters,(2)to investigate biodegradation mechanisms of the prepared materials, and(3)to develop a novel method for recycling PLAs to their monomers by the use of high-temperature and high-pressure water. It was found for biodegradable polyesters including PLAs that surface modification is effective both for acceleration and deceleration of their biodegradation without erosion of the core part of the materials, that blending is inclined to accelerate their biodegradation when the blends are phase-separated, and that pore formation is effective both for preparation of soft materials and acceleration of their biodegradation. Moreover, "restricted amorphous region" between the crystalline regions in spherulites was found to be much more hydrolysis-resistant than "free amorphous regions" outside spherulites and hydrolysis in the melt by the use of high-temperature and high-pressure water was shown to be a powerful method to recycling poly (L-lactide) [poly (L-lactic acid)] to L-lacticacid.