Morphology, rheology and crystallization behavior of polylactide composites prepared through addition of five-armed star polylactide grafted multiwalled carbon nanotubes
Morphology, rheology and crystallization behavior of polylactide composites prepared through addition of five-armed star polylactide grafted multiwalled carbon nanotubes
复制标题
DOI：
10.1016/j.polymer.2009.12.017
复制
发表时间：
2010-02-05
期刊：
影响因子：
4.6
通讯作者：
Wang, Zhigang
中科院分区：
文献类型：
--
作者：
Xu, Zhaohua;Niu, Yanhua;Wang, Zhigang
采用五臂星形聚乳酸共价接枝法制备了功能化多壁碳纳米管(F-MWNTs)，并用热重分析(TGA)、核磁共振(NMR)和拉曼光谱对其进行了表征。采用凝聚法制备了一系列聚乳酸/F-MWNTs复合材料。采用多种方法研究了F-MWNTs对聚乳酸复合材料的形态、熔体流变性以及结晶和熔融行为的影响。光学显微镜(OM)、场发射扫描电子显微镜(FE-SEM)和透射电子显微镜(TEM)观察表明，与未填充碳纳米管的聚乳酸相比，F-MWNTs具有更好的分散性和界面粘附性。振荡频率扫描测试表明，加入约2.0wt%的F-MWNTs后，复合材料呈现类固相响应，形成渗流网络结构，熔融状态下的流变性能较纯聚乳酸有显著改善。差示扫描量热仪(DSC)测试表明，当F-MWNTs的浓度低于渗流浓度时，其作为成核剂促进结晶，高于渗流浓度时则起到阻碍结晶的作用。DSC曲线上的双熔融峰分别归因于冷结晶阶段形成的晶体熔化和加热过程中的熔化-再结晶-重熔(MRR)事件。(C)2009爱思唯尔有限公司。保留所有权利。
Functionalized multiwalled carbon nanotubes (F-MWNTs) were prepared by covalent grafting of five-armed star polylactide (fa-PLA), and were characterized by thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy and Raman spectroscopy. A series of polylactide (PLA)/F-MWNTs composites was prepared via coagulation method. Several techniques were applied to investigate the effects of F-MWNTs on the morphology, melt rheology, and crystallization and melting behaviors of the PLA composites. The optical microscope (OM), field-emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM) observations demonstrated that, in comparison with the case of PLA filled with pristine MWNTs, F-MWNTs case showed improved dispersion and interfacial adhesion. Oscillatory frequency sweep measurements showed that addition of about 2.0 wt% F-MWNTs led to a solidlike response where a percolated network structure formed, and the composites exhibited remarkable improvement of rheological properties in the melt state as compared with that of neat PLA. DSC measurements showed that F-MWNTs acted as a nucleating agent to enhance crystallization when below the percolation concentration, while also acted as a hindrance to retard crystallization above the percolation concentration. The double melting peaks on the DSC curves were attributed to melting of the crystals formed in the cold crystallization stage and the melting-recrystallization-remelting (mrr) event during heating, respectively. (C) 2009 Elsevier Ltd. All rights reserved.