Three kinds of high molecular weight polymers were synthesized by ring-opening polymerization with various monomer feeding ratios (named as PLLA, PLCL 95/5 and PLGC 80/15/5, respectively). Then oriented monofilament was produced through melt-extrusion and tensile orientation based on each kind of polymer. In vitro degradation properties of the monofilaments were studied over a range of degradation time from 1 to 21 days at 60 °C by using SEM, GPC, DSC, XRD and tensile test. Degradation results showed that the mass loss, T_g and morphology integrity of the PLLA monofilament basically remained unchanged, and partial degradation in amorphous region emerged with slight increase of crystallinity. For the PLCL 95/5 monofilament, the crystallinity was increased and the monofilament was fractured at 14 days accompanying with obvious decrease of the mass and T_m, indicating that most part of the amorphous region was degraded. Apparently, the PLGC 80/15/5 monofilament showed the fastest degradation rate with considerable mass loss and decrease of T_g. The amorphous region was degraded sharply in the early stage due to its good water absorbability and lower structural regularity, and the initially-formed crystalline region was degraded slowly later evidenced from the change of crystallinity and it was fractured at 3 days. The accelerated effects calculated according to the first-order kinetic model demonstrated that the PLCL 95/5 monofilament was degraded 2.5 times faster than pure PLLA and the PLGC 80/15/5 monofilament was degraded 7.5 times faster than PLLA. These were nearly consistent with those based on [η] (2.5 and 6.9 times respectively). The comparative study of in vitro degradation behavior of PLLA-based copolymer monofilaments would provide useful information for controlling the monomer composition of PLLA-based materials with specific degradation requirements.

通过开环聚合反应，以不同的单体进料比例合成了三种高分子量聚合物（分别命名为PLLA，PLCL 95/5和PLGC 80/15/5）。然后通过基于每种聚合物的熔融挤出和拉伸取向制备取向的单丝。通过使用SEM，GPC，DSC，XRD和拉伸试验，在60°C下1至21天的降解时间范围内研究了单丝的体外降解性能。降解结果表明，质量损失T _gPLLA单丝的形态和完整性基本保持不变，无定形区域出现部分降解，结晶度略有增加。对于PLCL 95/5单丝，在14天时结晶度增加且单丝断裂，同时质量和T _m明显降低，这表明大部分非晶区已降解。显然，PLGC 80/15/5单丝表现出最快的降解速度，且质量损失显着，T _g降低。非晶态区域由于其良好的吸水性和较低的结构规则性而在早期急剧降解，并且最初形成的结晶区域随后缓慢地降解，这由结晶度的变化证明，并且在3天时断裂。根据一级动力学模型计算的加速效应表明，PLCL 95/5单丝的降解速度是纯PLLA的2.5倍，而PLGC 80/15/5单丝的降解速度是PLLA的7.5倍。这些与基于[ η ]的结果几乎一致（分别为2.5倍和6.9倍）。体外比较研究 PLLA基共聚物单丝的降解行为将为控制具有特定降解要求的PLLA基材料的单体组成提供有用的信息。