Thermal behavior of elastomer–resin mixtures used as friction materials

Abstract

ABSTRACT:This study looks at the thermal behavior of mixtures of nitrile-butadiene rubber (NBR) with a resol or a novolac resin. When heated in the 200 -300°C range, NBR became hard and insoluble because of exothermic curing and cyclizing chain reactions involving the double bonds of its butadiene units and the nitrile groups of its acrylonitrile units. The NBR proved to be compatible with the novolac but not the resol. Heating increased the modulus of elasticity of the mixtures, which was due to crosslinking of the resin and the rubber. Preliminary linking of the resin resulted in phase separation in the novolac and prevented curing of the rubber when the mixture was heated.

Effects of rubber curing ingredients and phenolic‐resin on mechanical, thermal, and morphological characteristics of rubber/phenolic‐resin blends

“…These results suggest that the degradation temperature of the rubber/resin blend is dominated by the rubber component. Camino et al16 reported that the weight loss of NBR, degradation of NBR obtained by thermogravimetric analysis, begins at about 350°C, which is in agreement with the results obtained in this study. They16 also came into the same conclusion about the mixture of NBR and novolac PH, that the degradation temperature is dominated by NBR.…”

“…Literature shows a limited number of studies devoted to the rubber/PH systems 14–16. In addition, the patents on this subject have provided a few technical details due to proprietary reasons 9–11.…”

“…Kosfeld and Borowitz14, 15 studied dynamic mechanical and viscoelastic properties of blends of PH with NBR and SBR with full range of the resin content, i.e., 0–100 vol %. There exists only one recent article on the rubber/PH blends to be used specifically as binder of friction material in which the role of heating on the properties of NBR and PH mixtures has been investigated 16…”

“…12,13 Literature shows a limited number of studies devoted to the rubber/PH systems. [14][15][16] In addition, the patents on this subject have provided a few technical details due to proprietary reasons. [9][10][11] Kosfeld and Borowitz 14,15 studied dynamic mechanical and viscoelastic properties of blends of PH with NBR and SBR with full range of the resin content, i.e., 0-100 vol %.…”

Friction and wear properties of semimetallic friction composites with bionic non-smooth structure

“…10 A typical semimetallic friction composite is composed of many ingredients, including metal, fillers, polymer matrix and abrasive particles. [11][12][13] Semimetallic friction composites have good performance, such as stable friction coefficient, high wear resistance and heat conductivity, low heat fade at high temperature and environment friendly components. 14,15 Therefore, they are widely used in the automobile industry at present.…”