纳米ZnO改性PLA/PBS及其发泡体系的性能

采用熔融共混法制备了纳米氧化锌(ZnO)填充聚乳酸/聚丁二酸丁二酯(PLA/PBS)复合材料。研究了ZnO质量分数对复合材料的力学性能、结晶性能以及动态流变性能的影响。结果表明,随着ZnO含量的增加,复合材料的力学性能和结晶度先升高后降低,当ZnO质量分数为0.5%时,复合材料的拉伸强度和冲击强度分别达到最大值40.99 MPa和8.82 k J/m~2,比未添加ZnO时分别提高了6.3%和28.2%,同时结晶度达到24.4%。动态流变性能测试表明,ZnO的质量分数为0.5%时,复合材料的损耗模量和储能模量均为最大值,反映出此时复合材料内部氢键和交联网络最完善,协同作用效果达到最佳状态,因此力学性能也最优。在ZnO质量分数为0.5%的基础上,采用超临界二氧化碳发泡法对复合材料进行间歇发泡,结果显示添加ZnO的发泡材料泡孔密度比未添加的高出一个数量级,泡孔尺寸分布更加集中,体积膨胀率更高。

Properties of Nano-ZnO Modiifed PLA/PBS Composite and Foaming System

Poly lactide (PLA) and poly(butylene succinate) (PBS) were blended with the nano-ZnO through a twin-screw ex-truder to prepare PLA/PBS/Nano-ZnO composite. The mechanical properties,crystallization,and dynamic rheological properties of the composites were investigated. The results show that with the increase of nano-ZnO contents,the mechanical properties and crystallinity of the composites increase firstly and decrease lastly. When the mass fraction of nano-ZnO is 0.5%,the tensile strength and impact strength of the composite reach the maximum value of 40.99 MPa and 8.82 kJ/m2,increased by 6.3%and 28.2%,re-spectively,than that without nano-ZnO,the crystallinity is 24.4%. Furthermore,the dynamic rheological properties tests show that when the mass fraction of nano-ZnO is 0.5%,the loss modulus and storage modulus of the composite reach the maximum values, which reflects the excellent internal hydrogen bond and crosslinking network of the composite,also the synergy effect and the me-chanical properties of the composite achieve optimal state. On the basis of 0.5%nano-ZnO,using supercritical CO2 foaming method for batch foaming the composite materials. Foaming results show that compared with the foaming material with not adding nano-ZnO,the cell density of the foaming material with adding 0.5%nano-ZnO improves by an order of magnitude,the cell size distribu-tion is more focus and the volume expand ratio is higher.