聚乳酸/碳纳米管复合材料的结晶及流变性能

Crystallization Properties and Rheological Behavior of PLA/MWCNTs Composites

采用熔融共混的方法制备了聚乳酸/多壁碳纳米管复合材料(PLA/MWCNTs)复合材料,研究了MWCNTs对复合材料的结晶性能、热性能和流变性能的影响。研究结果表明MWCNTs的加入不会改变其晶型结构,但可起到异相成核作用,降低PLA基体的冷结晶温度,提高结晶度。MWCNTs可显著提高PLA的热稳定性,添加1 wt%MWCNTs的PLA/MWCNTs复合材料的初始热分解温度比纯PLA初始热分解温度提高了28.8℃。在低频区,PLA/MWCNTs复合材料的储能模量和复数黏度随着MWCNTs含量的增加而增加,当MWCNTs添加量为3 wt%时达到PLA/MWCNTs复合材料的流变逾渗值。随着频率的增加,PLA/MWCNTs复合材料仍表现出传统的剪切变稀行为。

Polylactic acid/carbon nanotubes composites(PLA/MWCNTs)were prepared by melt mixing.The effect of MWCNTs on crystallization and thermal properties,rheological behaviors were investigated by X-ray diffraction(XRD),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA)and rotational rheometer.The research results show that the addition of MWCNTs did not change the crystal structure of PLA.Acted as heterogeneous nucleating agents,MWCNTs could reduce the cold crystallization temperature of the PLA matrix,and increase the crystallinity.The thermal stability of PLA/MWCNTs composites were significantly improved.The initial thermal decomposition temperature of PLA/MWCNTs composite with 1 wt%MWCNTs increased by 28.8℃than that of pure PLA.The rotational rheometer experiment showed that at low-frequency region,the storage modulus and complex viscosity of PLA/MWCNTs composites increased with the increasing content of MWCNTs.The rheological percolation value of PLA/MWCNTs composite was 3 wt%.With the increase of frequency,PLA/MWCNTs composites still exhibited traditional shear thinning behavior.