The interrelation among network structures, molecular transport of solvent, and creep behaviors of TiB₂ ceramic containing butyl rubber composites

Abstract

Swelling of polymer composites in solvents has become one of the major problems in the use of polymer composites exposed to petroleum products. As a possible solution to the problem, this experimental study was conducted to examine the potential application of TiB 2 ceramic in butyl rubber (IIR) composites. The effect of TiB 2 content on the curing kinetics of IIR composites was studied using a torque rheometer technique. The effect of TiB 2 on the network structure was investigated in terms of the crosslinking density, interparticle distance between conducting particles, surface tension, glass transition temperature, degree of crystallinity, scanning electron microscopy, and X-ray analysis. Moreover, the effect of TiB 2 content on the molecular transport of solvent (kerosene) was examined by means of degree of swelling, solvent interaction parameters, volume fraction of rubber, interparticle distance after swelling, penetration rate of solvent, mean diffusion coefficient, cohesive energy density of polymer, standard entropy, standard enthalpy, and standard free energy of IIR composites. It was ascertained that with increasing TiB 2 content the degree of swelling shifts to a lower value. The main reason was interpreted as the introduction of good interface adhesion of TiB 2 with rubber matrix, which tends to block the diffusion of solvent molecules. The effect of TiB 2 content on hardness, tensile strength, Young's modules, and elongation at break is discussed. An apparent steady-state creep of butyl rubber IIR/ TiB 2 composites is evident under different constant stresses at room temperature. The strain rate of steady-state creep showed a dependence on stress and TiB 2 volume fraction. The stress sensitivity parameter, viscosity coefficient, and activation volume for samples loaded with different content of TiB 2 were estimated. It is apparent that these new composites should be very useful for solvent permeation resistance at high TiB 2 loading level with good mechanical properties.

Epoxy resin/plasticized carbon black composites. Part II. Correlation among network structure and mechanical properties

“…Conductive composites made by mixture of electrical conductive fillers such as metallic powders, graphite powders, carbon black (CB), and others have gained great attentions in the last decades [1][2][3][4]. CB is the most important reinforcing filler in the rubber industry because of its abundant source, low density, permanent conductivity, and low cost [5][6][7][8][9].…”

New antistatic charge and electromagnetic shielding effectiveness from conductive epoxy resin/plasticized carbon black composites

“…CB/epoxy composites are a kind of EMI shielding materials with good prospect of application because of its electrical conductivity and dielectric constant. The EMI is defined in terms of the ratio of the electric field of incoming and outgoing waves by the following expression [2,18]:…”

“…The hardness of the specimen was also measured, according to ASTM D 2240-81 using Shore A type durometer. The cross linking density (n) was calculated according to the theory of rubber elasticity by using the following equation [2,26].…”

“…1b the sample CB30 exhibits a spherical morphology, and the particles are held together by short range surface forces. The forces may be electrostatic and van der Waal's attraction between particles or liquid capillary forces due to the presence of the plasticizer within the granules [1,2]. Furthermore, the CB particles are segregated in the interfacial zones of epoxy particles, and they formed conductive pathways throughout the composites.…”

“…Conducting polymer composites (CPCs) are ubiquitous in technological applications and constitute an ongoing topic of tremendous commercial interest [1][2][3]. Electrically conductive polymer composite is obtained when conductive particles such as metal powder, carbon black (CB), and carbon fiber etc.…”