Effect of vulcanizing system on the crosslink density of nitrile rubber compounds

Abstract

ABSTRACT:The synergistic activity of binary accelerator systems in rubber vulcanization is well known. Binary accelerator systems are being widely used in industry and are becoming increasingly popular because of the fact that such mixed systems can produce a vulcanizate with superior mechanical properties compared to those of stock cured with a single accelerator. The authors have studied the performance of a binary accelerator system based on cyclohexyl benzothiazole sulfenamide (CBS), tetramethyl thiuram disulphide (TMTD) in the sulfur vulcanization of nitrile rubber. The amount of sulfur and accelerator was varied to change the network crosslink density of vulcanizates. The observed mutual activity has been discussed based on the mechanical properties and crosslink density. The physical crosslink density of the various nitrile rubber mixes was estimated using the Kinetic Theory of Elasticity. The mechanical properties of the various rubber compounds were related to the corresponding crosslink density estimated for each compound.

Ultrasonic and mechanical measurements for the detection of crosslink density of SBR and NBR based on various curing systems

“…This expression is: where C 1 and C 2 are constants characterizing the vulcanizates. However, Lawandy and Halim14 showed that at strain values less than 16%, the parameter C 2 tends to be zero.…”

“…The ultrasonic technique was successfully used as a tool to investigate many polymeric properties. [11][12][13] However, in our previous work, 14 the crosslink density of various nitrile mixes was calculated using the kinetic theory of elasticity. In this study, we are trying to calculate the crosslink density of SBR vulcanizates, containing different vulcanizing system, by stressstrain measurements and ultrasonic technique.…”

Basic Features and Techniques

“…Thiurams can be used for a wide range of sulfur accelerator ratio [108] . Combination of thiurams as a secondary accelerator with rapid accelerators such as xanthate and dithiocarbamate, imparts a retarding effect without affecting the crosslink density of the vulcanizate, whereas the curing rate is enhanced with an accelerator such as thiazole [109] .…”

Novel in situ coordinated cerium salt/acrylonitrile-butadiene rubber composite

“…During dynamic vulcanization, the rubber phases are finely dispersed to the mean particle size of a few microns through intense mixing and then are cross-linked with each other. Usually, the vulcanization is achieved by covalent bondings, such as sulfur crosslinking and carbon crosslinking [6,7]. However, there are still some problems which need to be solved to improve the rubber properties.…”