EFFECT OF MOLECULAR-WEIGHT DISTRIBUTION ON FATIGUE CRACK-PROPAGATION IN POLY(METHYL METHACRYLATE)

被引：13

作者：

KIM, SL ^{[1
]}

JANISZEWSKI, J ^{[1
]}

SKIBO, MD ^{[1
]}

MANSON, JA ^{[1
]}

HERTZBERG, RW ^{[1
]}

机构：

[1] LEHIGH UNIV, MAT RES CTR, BETHLEHEM, PA 18015 USA

来源：

POLYMER ENGINEERING AND SCIENCE | 1979年 / 19卷 / 02期

关键词：

D O I：

10.1002/pen.760190218

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

It is well established that both molecular weight (M) and its distribution (MD) affect many polymer properties such as mechanical behavior. Thus studies have shown that fatigue life is enhanced by increases in M. Research here has shown that with notched specimens fatigue crack propagation (FCP) rates are dramatically decreased by increasing M, even when the M is high enough that the static fraeture energy has essentially reached its asymptotic limit. In this study, specimens of poly(methyl methacrylate) containing either high‐ or low‐M tails were prepared and characterized. The earlier finding that FCP rates are inversely related to average M was confirmed, but specific effects of M distribution were observed. At constant Mn, a low‐M tail had little effect on FCP resistance, while a high‐M tail improved FCP resistance of polymers whose average M was too low for effective entanglements. Thus with high‐M tails, it was possible to test specimens whose average M's were too low to permit machining. It is proposed that the effects noted are due to relative stabilization or destabilization of crazes ahead of the crack. Copyright © 1979 Society of Plastics Engineers, Inc.

引用

页码：145 / 150

页数：6

共 29 条

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[2]

Berry G. C., 1968, ADV POLYM SCI, V5, P261

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