Abstract

The biodegradable thermoresponsive shape memory blends with polycaprolactone (PCL) as reversible phase and polylactide (PLA) as fixed phase were prepared by the melt blending of PCL and PLA. The scanning electron microscopy (SEM) shows that the PCL/PLA blends are partially miscible blends. According to XRD analysis, a diffraction peak appears at 16.7° (200/110), it may be the crystal diffraction peak of PLA. The results of differential scanning calorimetry (DSC) shows that the blends have two melting temperature (around 56 °C and 155 °C). According to thermal and shear stability analysis, as the addition of PLA, the balance torque increases from 0.7 to 1.5, it indicates that the macromolecular chains are entangled with each other. Thus, the physical crosslinking network is formed by the entanglement of the microcrystals and macromolecules. Furthermore, we used the melting point of PCL as the switching temperature (T_s) of the blends for the shape memory test. The results show that the PLA has a positive effect on shape memory property and the recovery rate first increases and then decreases. It is observed in thermogravimetric analysis (TGA) that PLA has little effect on the high temperature stability of material.

摘要

以聚己内酯（PCL）为可逆相，聚丙交酯（PLA）为固定相，通过熔融共混制备了可生物降解的热响应形状记忆共混物。扫描电子显微镜 (SEM) 显示 PCL/PLA 共混物是部分混溶的共混物。根据XRD分析，衍射峰出现在16.7°（200/110）处，可能是PLA的晶体衍射峰。差示扫描量热法 (DSC) 的结果表明共混物具有两个熔化温度（约 56 °C 和 155 °C）。根据热稳定性和剪切稳定性分析，随着PLA的加入，平衡扭矩从0.7增加到1.5，表明大分子链相互缠绕。因此，物理交联网络是通过微晶和大分子的缠结形成的。用于形状记忆测试的混合物的T _s )。结果表明，PLA对形状记忆性能有积极影响，恢复率先升高后降低。在热重分析 (TGA) 中观察到 PLA 对材料的高温稳定性影响很小。