Transparent blown films from poly(lactide) and poly(ethylene-co-vinyl acetate) compounds: Structure and property
Transparent blown films from poly(lactide) and poly(ethylene-co-vinyl acetate) compounds: Structure and property
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DOI：
10.1016/j.polymdegradstab.2016.05.010
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发表时间：
2016-07
影响因子：
5.9
通讯作者：
Pengwu Xu;P. Ma;M. Hoch;E. Arnoldi;Xiaoxia Cai;W. Dong;Mingqing Chen
中科院分区：
文献类型：
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作者：
Pengwu Xu;P. Ma;M. Hoch;E. Arnoldi;Xiaoxia Cai;W. Dong;Mingqing Chen
聚乳酸薄膜的脆性和缺口敏感性限制了其应用范围。本文采用熔融吹塑法制备了聚乳酸（PLA）与乙烯-醋酸乙烯酯共聚物（伊娃）共混物的薄膜。薄膜厚度与卷绕速度有关，当卷绕速度超过14 m/min时，薄膜厚度可达10 μm左右。伊娃的加入不仅显著提高了PLA薄膜的拉伸韧性和耐缺口性，而且保持了高的透光率。原子力显微镜分析表明，薄膜的力学性能各向异性与薄膜的收卷方向（DD）和横向（TD）的微观形貌差异有关。此外，VA含量为80%的伊娃对PLA膜的改性效果优于VA含量为60%的伊娃。PLA/伊娃（80/20）共混物在DD方向上的拉伸强度为50-60 MPa，断裂伸长率高达230%，撕裂强度为85 kN/m，具有良好的上级力学性能。同时，在TD方向上也实现了平衡的性质。此外，对于PLA/伊娃膜获得了约90%的透射率，这与纯PLA膜相当。足够高的VA单元含量对于上级机械性能和高透明度是至关重要的。
The application range of poly(lactide), PLA, films is limited due to the brittleness and notch-sensitivity. In this work, thin films with balanced properties were fabricated by melt blowing of PLA and poly(ethylene-co-vinyl acetate) (EVA) blends. The film thickness is dependent on the taken-up speed and reached to around 10 μm at the taken-up speed over 14 m/min. The presence of EVA not only significantly enhanced the tensile toughness and notch-resistance of the PLA films but also retained high transmittance. The films exhibited anisotropic mechanical performances which were correlated to the micro-morphology differences between the take-up direction (DD) and the transversal direction (TD) as characterized by atomic force microscope. In addition, the EVA with 80 wt% VA units showed better overall modification effect on the PLA films than the EVA with 60 wt% VA units. Superior mechanical properties of PLA/EVA (80/20) blends such as tensile strength of 50–60 MPa, elongation at break up to 230% and tear strength of 85 kN/m were achieved in the DD direction. Meanwhile, balanced properties were also achieved in TD direction. Moreover, a transmittance of around 90% was obtained for the PLA/EVA films which are comparable to neat PLA films. A high enough VA unit content is crucial for superior mechanical properties and high transparency.