Park Hye-Seon, Hong Chang-Kook
Polymer Energy Materials Laboratory, School of Chemical Engineering, Chonnam National University, Gwangju 61186, Korea.
Polymers (Basel). 2021 Jun 2;13(11):1851. doi: 10.3390/polym13111851.
Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.
聚（L-乳酸）（PLLA）是一种具有广阔应用前景的生物医学高分子材料。PLLA的不同对映体形式为通过立体复合形成实现热性能和机械性能增强提供了巨大机遇。添加聚（D-乳酸）（PDLA）作为成核剂并形成立体复合结晶（SC）已被证明是改善PLLA结晶和机械性能的有效方法。在本研究中，通过熔融共混工艺将PLLA与不同量的PDLA共混，并计算它们的性能。通过热重分析（TGA）、差示扫描量热法（DSC）、X射线衍射（XRD）、偏光显微镜（POM）、动态力学分析（DMA）和拉伸试验，系统研究了PDLA对PLLA结晶行为、热性能和机械性能的影响。基于我们的研究结果，当PDLA含量增加时，SC易于形成，并作为成核位点。在PLLA/PDLA共混物中观察到了SC和均聚物晶体（HC）。随着PDLA含量的增加，结晶度增加，机械强度也增加。
