拉伸对聚左旋乳酸结晶的影响

摘要

The influence of stretching under different temperatures on the crystallization behavior of poly(L-lactic acid)(PLLA) was investigated by the combinational investigation of FTIR, DSC, and XRD. It was found that stretching could remarkably improve the crystallization rate and crystallinity of PLLA films.Stretched at a draw ratio of 3, PLLA forms α-form crystals in the temperature range of 90-95 ℃. Further increasing the draw ratio, the crystallinity remains almost constant. With increasing the stretching temperature up to 105 ℃, the PLLA films cannot crystallize under stretching. Contrary to the unstretched PLLA film, the stretched PLLA films gradually crystallize during the heating process, indicating that pre-stretching can change the crystallization behavior of PLLA.%采用红外光谱、差示扫描量热分析及X射线衍射等方法研究了在不同温度下拉伸对聚左旋乳酸(PLLA)结晶行为的影响.结果表明,在合适的温度条件下,拉伸能迅速提高PLLA的结晶速度和结晶度.对经过拉伸预处理但未结晶的PLLA样品进行等温及非等温结晶的研究发现,经过拉伸预处理的PLLA样品的结晶速率和结晶度都得到提高,表明预拉伸会影响PLLA在后续过程中的结晶行为.