摘要
木塑复合材料属于生物质复合材料的范畴,是一种无毒、可循环利用的环境友好型材料,从20世纪末开始到现在经历了20多年的高速产业化发展。但木塑复合材料力学性能偏低,特别是韧性差,导致应用领域偏窄,是目前制约木塑复合材料发展的主要因素之一。众多研究表明,将纤维添加到木塑复合材料中形成多元结构复合材料,可提高木塑复合材料的力学性能。本文概述了纤维增强木塑复合材料的研究现状,按天然纤维素纤维、合成纤维、非金属纤维、金属纤维4大类归纳了常用作增强复合材料的纤维,综述了采用玻璃纤维、矿物质纤维、碳纤维、芳纶纤维、聚对苯二甲酸乙二醇酯纤维和天然纤维素纤维等增强木塑复合材料的制备方法和增强效果。结果表明,不同种类的纤维对木塑复合材料均有不同程度的增强或增韧作用。短切纤维在添加量上存在"临界值",在"临界值"之前,添加量与增强效果呈正相关,在"临界值"之后呈负相关。连续玻璃纤维的增强效果尤为明显,其中冲击强度可增加20倍。天然纤维素纤维在木塑复合材料中的应用虽然较少,但目前在欧洲已被用于高附加值的汽车零部件领域。本文还介绍了银纹剪切带机制、刚性粒子增强理论、多缝开裂理论和复合力学理论等用于解释纤维增强复合材料的作用机制,这些理论均被用于解释纤维对于木塑复合材料基体的作用效果,其中后2种理论最常用于解释纤维对于复合材料强度提高的作用机制。本文同时指出,目前尚没有哪一种理论能全面揭示由于纤维加入后结构趋于复杂的木塑复合材料的力学行为。总结了纤维的添加对材料力学性能、吸湿性和热性能的影响,发现纤维的添加不仅可以提高木塑复合材料的力学强度,对于降低吸湿性和提高热稳定性也有积极效果,一些纤维的添加还可以提高基体的结晶度。本文最后提出纤维增强木塑复合材料产业化发展前景和需要解决的问题,包括进一步提高生产效率,研制纤维增强木塑复合材料专用装备,开发连续纤维增强木塑复合材料技术和开拓高性能、高附加值木塑复合材料市场。
Wood-plastic composite（ WPC） belonging to bio-composites is a kind of non-toxic,recyclable and eco-friendly material. It has developed rapidly for two decades since the end of the 20 th century. But now the development of WPC comes to a bottleneck. Low mechanical properties,especially poor toughness,make the application of WPC narrow,which is one of the main reasons what restrict the development of the WPC. Many researches show that adding fibers into WPC to produce multiple structural composite,is an effective way to improve the strength of WPC. In this paper,the current research status of fiber reinforced WPC is summarized. Fibers used as reinforcement for composites are divided into natural cellulose fibers,synthetic fibers,inorganic non-metallic fibers and metal fibers. The production methods and reinforcing effects of the WPCs reinforced with fiber,such as glass fiber,mineral fiber,carbon fiber,aramid fiber,polyethylene terephthalate fiber and hemp fiber et al.,are reviewed. The results show that different fibers have different effects on strength or toughness of WPCs. There is a＂critical value＂for the addition quantity of short fibers. When the fiber content is less than the ＂critical value ＂,the addition quantity and enhancement effects are positively correlated,however,contrarily negative correlated is observed when the fiber content above the＂cirtical value＂. It is obviously that the effect of continuous glass fiber on the impact strength which increases 20 times. The natural cellulose fiber（ NCF） reinforcedWPCs have been used in auto parts field with high added value in Europe,though the application is not very popular. The enhanced mechanisms of fiber reinforced WPCs such as crazing mechanism of shearing band,rigid particles strengthening theory,multiple slit theory and the theory of composite mechanics,et al. are also summarized. These theories can be used to explain the mechanism of fiber reinforced WPC. And the latter two theories are most used. This article also points out that there is no one theory which can fully disclose mechanical behavior of WPC because of its complex structure tend after adding fiber. The influences of fiber addition on the mechanical properties,moisture and thermal properties of the composites are summarized. It is find that adding fiber can not only improve the mechanical strength of WPC,but also have a positive effect on reducing the moisture absorption and improving the thermal stability. Besides,some fibers can also improve the crystallinity of the matrix. The article concludes with the industry prospects and the problems of fiberreinforced plastic composites. These issues include that improving production efficiency,developing special equipment for fiber-reinforced plastic composites,developing technology for continuous fiber-reinforced plastic composites and pioneering markets for high performance and high value-added WPC.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2016年第6期130-139,共10页
Scientia Silvae Sinicae
基金
林业公益性行业科研专项(201204802)
国家自然科学基金项目(31270608)
关键词
木塑复合材料
纤维
力学性能
冲击强度
增强机制
wood-plastic composites
fiber
mechanical properties
impact strength
enhanced mechanism
