Abstract

Composites based on ethylene-acrylic rubber and 1 mm short aramid fibers (AF) were developed by varying the fiber content from 3 to 40 phr. At 10 phr short fiber loading, the tensile modulus (10 % modulus) of the neat matrix was around 11 times increased. However, its breaking elongation was decreased from 408 to 58 %. This drastic reduction in the breaking elongation even at a 10 phr fiber loading leads to a brittle failure with inferior toughness. The tensile-fractured surface of the fiber-filled composite showed an intact matrix with no plastic deformation during fiber pulled-out. To solve this problem, carbon black (CB) was used as a toughening agent. Surprisingly, the addition of 20 phr CB onto a 10 phr AF-filled composite enhanced its 10 % modulus in the longitudinal direction by 70 % and also enhanced its breaking elongation from 58 to 351 %. From the morphological analysis, it has been presumed that the addition of CB enhanced the friction between the fiber and the matrix at a very low strain and also facilitate the matrix for a plastic deformation at a higher strain. This enhanced friction between the fiber and the matrix is considered as the improved low strain modulus and the subsequent plastic deformation at a higher strain is responsible for the improved toughness.

中文翻译：

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炭黑在增强短芳纶纤维增强乙丙橡胶机械性能中的作用

摘要

通过将纤维含量从3 phr更改为40 phr，开发了基于乙烯丙烯酸橡胶和1 mm短芳族聚酰胺纤维（AF）的复合材料。在10 phr的短纤维载荷下，纯基质的拉伸模量（10％模量）增加了约11倍。但是，其断裂伸长率从408降低到58％。即使在10 phr的纤维载荷下，断裂伸长率的急剧降低也导致脆性破坏，韧性降低。纤维填充复合材料的拉伸断裂表面显示出完整的基质，在拉出纤维期间没有塑性变形。为了解决这个问题，炭黑（CB）被用作增韧剂。出奇，在10 phr AF填充的复合材料中添加20 phr CB，可将其在纵向的10％模量提高70％，并将断裂伸长率从58％提高至351％。从形态分析可以推测，CB的添加在非常低的应变下增强了纤维与基体之间的摩擦，并且还促进了在较高应变下基体的塑性变形。纤维和基体之间的这种增强的摩擦被认为是改善的低应变模量，并且随后在较高应变下的塑性变形导致改善的韧性。