微波辐射与碳基纳米材料协同实现聚乳酸结晶形态调控与高性能化

Synergistic effect of microwave radiation and carbon-based nanomaterials on crystallization morphology and high performance of polylactic acid

为提高左旋聚乳酸(PLLA)的结晶性能,以氧化石墨烯(GO)和碳纳米管(CNT)为功能化纳米补强剂,在微波场下辐射5 min后制备PLLA/GO-5和PLLA/CNT-5复合薄膜材料;采用偏光显微镜和扫描电子显微镜观察复合薄膜在微波辐射下的晶体形态。结果表明微波辐射和碳基纳米材料对PLLA的结晶性能形成了显著的协同增强效应,增加PLLA成核密度,诱导球晶生长;向PLLA基体添加质量分数为0.5%的GO或CNT可显著提升其拉伸强度及断裂伸长率;PLLA/GO-5和PLLA/CNT-5的氧气渗透系数分别为13.5×10^(5)和9.2×10^(5) cm^(3)·mm·cm^(-2)·d^(-1)·Pa^(-1),较纯PLLA分别下降了51.2%和67.3%,说明复合薄膜对氧气具有良好的阻隔性;功能化碳基纳米材料的加入提高了PLLA复合薄膜的热稳定性。

To improve the crystallization performance of poly(L-lactic acid)(PLLA),GO or CNT was utilized as the functional nano-reinforcing agent,through which the PLLA/GO-5 and PLLA/CNT-5 composite films were prepared by being exposed to the microwave radiation for 5 min.POM and SEM were used to observe the crystal morphology of the composite films.The results demonstrate that microwave radiation and carbon nanoparticles have a significant synergistic effect on the crystallization performance of PLLA,which increases the PLLA nucleation density and induces the spherulite growth.Adding 0.5%of GO or CNT to the PLLA matrix can significantly increase its tensile strength and elongation at break.The oxygen permeability coefficients of PLLA/GO-5 and PLLA/CNT-5 are 13.5×10^(5) and 9.2×10^(5) cm^(3)·mm·cm^(-2)·d^(-1)·Pa^(-1),respectively,which fall 51.2%and 67.3%compared to neat PLLA-5,indicating that the composite film shows good barrier performance to oxygen.The addition of functional carbon nanoparticles improves the thermal stability of the PLLA composite film.