Microfibrillated cellulose/linear low density polyethylene composite
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摘要: 微纤化纤维素(MFC)具有优良的力学性能,常被用作增强体制备复合材料,但MFC容易团聚影响其增强能力。本研究对MFC进行低温冷冻干燥处理(FDMFC),用微型锥形双螺杆挤出机将FDMFC与线性低密度聚乙烯(LLDPE)熔融复合,并用热压-冷压的方式制备FDMFC/LLDPE复合材料,对其力学性能、动态热力学性能(DMA)、热分解过程及冷冻干燥处理的FDMFC在LLDPE基体中的分散状态进行了测试。结果表明:相对于未冷冻干燥处理的MFC,FDMFC在LLDPE基体中的分散性得到明显改善,添加一定量的FDMFC可有效提高FDMFC/LLDPE复合材料的力学性能。当FDMFC的添加量为10wt%时,相较于纯LLDPE,FDMFC/LLDPE复合材料的拉伸强度提高了60.3%,杨氏模量提高了161.9%。DMA测试结果表明,随着FDMFC含量的增加,FDMFC/LLDPE复合材料的储能模量和损耗模量都有所提高。热重分析结果表明,FDMFC的加入提高了FDMFC/LLDPE复合材料的热解温度,最大热解温度提高了14℃。
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关键词:
- 微纤化纤维素 /
- 分散性 /
- 冷冻干燥 /
- 微型锥形双螺杆挤出机 /
- 力学性能
Abstract: Because of its excellent mechanical properties and reinforcing ability, microfibrillated cellulose (MFC) has become a promising candidate for developing nanocomposite. However MFC was easy to agglomerate, which affected its enhancement ability. In this study, MFC was pretreated by freeze-drying(FDMFC). Then FDMFC and linear low density polyethylene (LLDPE) were melted and compounded by a micro-cone twin screw extruder, and the FDMFC/LLDPE composite film was prepared by hot pressing-cold pressing method. The tensile property, dynamic thermomechanical performance (DMA), thermal decomposition process and dispersibility of FDMFC/LLDPE composite were evaluated. The results show that freeze-drying make FDMFC uniformly disperse in LLDPE matrix comparing with the untreated MFC. A reasonable amount of FDMFC can effectively improve the tensile property of FDMFC/LLDPE composite. When adding 10wt% FDMFC, the FDMFC/LLDPE composite increases by 60.3% in tensile strength and 161.9% in Young's modulus comparing to LLDPE. DMA test results show that both storage modulus and loss modulus of the FDMFC/LLDPE composite are improved with the increase of FDMFC content. Thermal analysis indicates that FDMFC can increase the pyrolysis temperature of the FDMFC/LLDPE composite film, and the maximum pyrolysis temperature increases by 14℃ comparing to LLDPE.
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