论文部分内容阅读
用成纤模压法制备了弯曲强度和剪切强度分别为 2 50～ 2 80MPa和 1 70～ 1 85MPa的聚 (L 乳酸 )(PLLA)园棒 .由于PLLA对热的不稳定性 ,在模坯制备过程中 ,PLLA的分子量下降 65%～ 70 % ,但模压过程对分子量影响较小 .扫描电子显微镜 (SEM)显示PLLA模坯在模压过程中发生了取向形变并形成纤维结构 ,这是PLLA棒材的力学性能得以增强的主要原因 .差示扫描量热 (DSC)分析和X 射线衍射 (XRD)分析表明PLLA模压成棒后 ,PLLA的结晶熔点下降 ,微晶尺寸变小 ,而结晶度增大 .
Poly (L-lactic acid) (PLLA) garden bar with flexural strength and shear strength of 2 50 ~ 2 80MPa and 1 70 ~ 1 85MPa respectively was prepared by fiber-forming embossing method.Due to the instability of PLLA to heat, The molecular weight of PLLA decreased by 65% -70% during the preparation process, but the molding process had little effect on the molecular weight.According to scanning electron microscopy (SEM), PLLA billet deformed in orientation and formed fibrous structure, which was PLLA rod The main reason for the enhancement of the mechanical properties of the composites was analyzed by DSC and XRD.The results showed that the crystallization melting point of PLLA decreased, the crystallite size decreased and the crystallinity increased Big .