Tailoring Impact Toughness of Poly(L-lactide)/Poly(ε-caprolactone) (PLLA/PCL) Blends by Controlling Crystallizatior of PLLA Matrix
Tailoring Impact Toughness of Poly(L-lactide)/Poly(ε-caprolactone) (PLLA/PCL) Blends by Controlling Crystallizatior of PLLA Matrix
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DOI：
10.1021/am201564f
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发表时间：
2012-02-01
影响因子：
9.5
通讯作者：
Fu, Qiang
中科院分区：
文献类型：
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作者：
Bai, Hongwei;Xiu, Hao;Fu, Qiang
聚L-丙交酯（PLLA）与各种可生物降解聚合物的熔融共混被认为是在不影响其生物降解性的情况下增韧PLLA的最经济有效的途径。不幸的是，只有非常有限的改善缺口冲击韧性可以实现，虽然大多数这些共混物显示出显着的增强拉伸韧性。本研究以可生物降解的聚己内酯（PCL）为抗冲改性剂，采用成核剂对PLLA进行改性。根据成核剂在基体中的浓度和注射成型中的模具温度，通过实际注射成型制备了具有宽范围的基体结晶度（10-50%）的PLLA/PCL共混物。结果表明，PLLA基体结晶度与冲击韧性呈线性关系。随着PLLA结晶含量的增加，增韧变得更容易实现。PLLA晶体被认为提供了一个路径，为有效的冲击能量吸收所需的剪切屈服的传播，然后，当这些晶体渗透通过整个基体时，可以获得优异的增韧效果。这项研究不仅提供了一种新的路线，以制备可持续的PLLA产品具有良好的冲击韧性，但也有一个新的见解基体结晶的重要性，在半结晶，聚合物与柔性聚合物的增韧。
Melt blending poly(L-lactide) (PLLA) with various biodegradable polymers has been thought to be the Most economic and effective route to toughen PLLA without compromising its biodegradability. Unfortunately, only very limited improvement in notched impact toughness can be achieved, although most of these blends show significant enhancement in tensile toughness. In this work, biodegradable poly(e-caprolactone) (PCL) was used as an impact modifier to toughen PLLA and a nucleating agent was utilized to tailor the crystallization of PLLA matrix. Depending on the nucleating agent concentrations in the matrix and mold temperatures in injection molding, PLLA/PCL blends with a wide range of matrix crystallinity (10-50%) were prepared by practical injection molding. The results show that there is a linear relationship between PLLA matrix crystallinity and impact toughness. With the increase in PLLA crystalline content, toughening becomes much easier to achieve. PLLA crystals are believed to provide a path for the propagation of shear yielding needed for effective impact energy absorption, and then, excellent toughening effect can be obtained when these crystals percolate through the whole matrix. This investigation provides not only a new route to prepare sustainable PLLA products with good impact toughness but also a fresh insight into the importance of matrix crystallization in the toughening of semicrystalline, polymers with a flexible polymer.