母粒法制备聚丙烯/炭化纤维素纳米晶复合材料

Preparation of Polypropylene/Carbonized Cellulose Nanocrystals Composites by Master Batch Method

将冷冻干燥的纤维素纳米晶(CNC)进行高温处理,制成炭化纤维素纳米晶(CCNC),采用超声母料法将CCNC以母料的形式与聚丙烯(PP)制成PP/CCNC复合材料。使用SEM观察了CNC炭化前后的形貌变化情况以及CCNC在复合材料的分散情况;通过拉伸性能测试考察了CCNC对复合材料力学性能的影响;采用DMA测试了CCNC对复合材料黏弹性的影响。SEM结果表明:CNC经过冷冻干燥、高温炭化后,由纳米棒状结构变成有序带状结构;复合材料的断面表明CCNC可以以纳米片的形式分散在PP基体中。拉伸测试结果表明:CCNC的加入使复合材料的拉伸强度和断裂伸长率下降,模量上升。强度下降表明CCNC与基体的界面相容性有待进一步提高。DMA测试结果发现:CCNC可明显增加复合材料的储能模量,30%的CCNC即可使模量提高135.7%;复合材料的损耗模量随着CCNC的加入呈现上升趋势。

The freeze-dried cellulose nanocrystals(CNC) were prepared into cellulose carbonization nanocrystals(CCNC) at high temperature.The composite material of PP/CCNC was made from CCNC and polypropylene(PP) in the form of masterbatch by ultrasonic master batch method.The morphology changes of CNC before and after carbonization and the dispersion of CCNC in the composites were observed by SEM;the effect of CCNC on the mechanical properties of the composites was tested by tensile properties;and the effect of CCNC on the viscoelasticity of the composites was tested by DMA.SEM results show that CNC changes from nanorod structure to ordered band structure after freeze-drying and high temperature carbonization,and the cross section of the composite showes that CCNC can be dispersed in PP matrix in the form of nanosheets.Tensile test results show that the addition of CCNC decreases the tensile strength and elongation at break and increases the modulus of the composites.The decrease of strength indicates that the interface compatibility between CCNC and matrix needs to be further improved.The results of DMA test show that CCNC can obviously increase the storage modulus of the composites,and 30% CCNC can increase the storage modulus by 135.7%.The loss modulus of the composites increases with the addition of CCNC.