Tuning the mechanical properties of cellulose nanofibrils reinforced polyvinyl alcohol composites via altering the cellulose polymorphs
Tuning the mechanical properties of cellulose nanofibrils reinforced polyvinyl alcohol composites via altering the cellulose polymorphs
复制标题
通过改变纤维素多晶型物来调节纤维素纳米原纤增强聚乙烯醇复合材料的机械性能
DOI：
10.1039/c6ra14517e
复制
发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
Zhang Xiangzhi
中科院分区：
文献类型：
--
作者：
Miao Xiaran;Tian Feng;Lin Jinyou;Li Hui;Li Xiuhong;Bian Fenggang;Zhang Xiangzhi
纤维素纳米纤丝（CNF）具有纤维素Ⅰ和纤维素Ⅱ的多晶型（CNF-I和CNF-II），它们在形态、长径比、官能团密度和力学性能等方面存在差异，影响着对聚合物复合材料的增强效果。本研究以黄麻纤维为原料，采用TEMPO氧化法制备了两种不同的纳米纤维，并对其进行了机械粉碎。采用蒸发法制备了不同CNF含量的聚乙烯醇（PVA）/CNF复合薄膜。研究了PVA/CNF复合材料的力学性能和热性能。CNF-I导致制备的复合材料的杨氏模量高于相同含量的CNF-II。CNF-II表面的高密度官能团增强了PVA分子链与CNF之间的界面相互作用，从而使复合材料具有更好的韧性。同时，CNF-I和CNF-II均能提高PVA的热稳定性，降低PVA的降解速率。这项工作提供了一个洞察CNF增强复合材料的设计与所需的性能，通过改变CNF的多晶型。
Cellulose nanofibrils (CNF) with polymorphs of cellulose I and II (i.e. CNF-I and CNF-II) are different in morphology, aspect ratio, the density of functional groups and mechanical properties, which influence the reinforcement effect for polymer composites. In this work, two kinds of CNFs were fabricated from jute fibers by the TEMPO-mediated oxidation method followed by a mechanical disintegration. Highly transparent polyvinyl alcohol (PVA)/CNF composite films containing varying contents of CNF were obtained via evaporating solution blends of PVA and CNF. The mechanical and thermal properties of the PVA/CNF composites were extensively investigated. CNF-I led to a higher Young's modulus of the as-prepared composites than CNF-II did at the same content. The high density of functional groups on the surface of CNF-II enhances the interface interaction between PVA molecular chains and CNF, which result in a better toughness of the resultant composites. Meanwhile, both of CNF-I and CNF-II can improve the thermal stability and lower the degradation rate of PVA. This work provides an insight into the design of CNF reinforced composites with desired properties by altering the polymorphs of CNF.