The preparation and characterization of biodegradable PCL/PLA shape memory blends
Huimin Zhou, Ying Xia, Guangqing Mu, Yuanmei Gao, Si Liang, Guozhong Li, Qian Yang, Xiaojian Lin, Fang Qian
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 (Ts) 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.