增韧聚苯乙烯银纹化微观机理模型  

Micromechanical Model for Crazing in Toughened Polystyrene

作　　者：吴中伟[1] 潘智勇[1] 梁立[1] 刘元坤[1] 焦清介[2] 

机构地区：[1]北京雷特新技术实业公司,北京100074 [2]北京理工大学机电学院,北京100081

出　　处：《科技导报》2009年第15期92-96,共5页Science & Technology Review

摘　　要：银纹化是颗粒增韧聚苯乙烯(PS)的一种主要机制。在已有研究基础上,选取独立的弹性体颗粒单元,将空穴嵌入到基体材料中(空穴用圆孔表示),其直径、间距与银纹面内空洞、微纤的直径相同,采用有限元法模拟了应变为1%时增韧PS的银纹化过程。结果表明,银纹首先在弹性体赤道面附近萌生,并向切向方向扩展。随着载荷的不断增加,微纤长度增加。此时,弹性体赤道面附近的微纤首先达到断裂的临界值,最终导致银纹转化为裂纹。这一过程中,微纤增长方向与载荷方向存在一定的夹角。这与实验现象吻合。而在θ=30°弹性体外附近,由于弹性体的变形牵动,区域内的分子链发生收缩变形,从而导致材料收缩。Crazing is a kind of mechanism in toughening polystyrene by particles. In this paper, an independent elastomer particle unit is selected, and holes are embedded into the matrix （with cavities being represented by circular holes）. Their diameter and distance are the same as cavities in crazing plane and the diameter of fibril. The crazing model is used to simulate the 1% strain crazing process with the finite element method. It is shown that the crazing initiates near the elastomer equator firstly, and is extended to the tangential direction. As the load increases, the fibril near the equator of elastomer is the first to reach the fracture critical value, then eventually crazing turns into crack. In this process, the fibril growth is in the direction of a certain angle with the load, which agrees with the experimental observation. From the elastomer with 0=30°, the molecular chains start to shrink because of the deformation of elastomer, then follows the materials contraction.

关 键 词：聚苯乙烯 银纹 细观力学 微纤 

分 类 号：TQ325.2[化学工程—合成树脂塑料工业]