Electron‐beam curing of hydrogenated acrylonitrile–butadiene rubber

Abstract

ABSTRACT:The electron-beam-induced crosslinking of hydrogenated acrylonitrile-butadiene rubber (HNBR) was investigated. HNBR sheets were exposed to electron-beam irradiation in air at a room temperature of 25 Ϯ 2°C over a dose range of 0 -20 Mrad. An attempt was made to correlate the structure of the irradiated rubber with the properties. The ratio of chain scission to crosslinking and the gelation dose were determined by a method proposed elsewhere. The gel content and dynamic storage modulus increased with the radiation dose. Fourier transform infrared studies revealed the formation of double bonds and carbonyl and ether groups. These observations were further supported by a thermogravimetric analysis of the carbonaceous residue of irradiated HNBR.

Electron beam processing of nylon 6 and hydrogenated nitrile rubber (HNBR) blends: 1. Development of high strength heat‐ and oil‐resistant thermoplastic elastomers

“…A significant reduction in the elongation at break was observed after ageing, the extent of which increased with radiation dose, and the effect of ageing was severe above 4 Mrad. This may be explained by the fact that electron beam irradiation induces oxidation and incorporates unsaturation in HNBR,8 leading to an increase in degradation of the blend during heat ageing at higher radiation doses. Nylon is also expected to produce more peroxide residues at higher radiation doses,15 which, in turn, enhances the degradation of the macromolecular chains under the influence of heat.…”

“…In such cases, there is the possibility of formation of linkages between molecules of the two polymers, which could reduce the interfacial tension and provide a material with improved final properties. Electron‐beam‐radiation‐induced cross‐linking of hydrogenated nitrile rubber (HNBR) has been reported 8. Van Dyke et al 9 studied the effect of electron beam irradiation on the thermal and mechanical properties of polyamide and butyl rubber blends.…”

Electron‐beam processing of nylon 6 and HNBR blends. Part II: development of high strength, heat‐ and oil‐resistant thermoplastic elastomers

“…It is apparent that the insoluble content increases with increasing radiation dose, indicating that more and more HNBR molecules are crosslinked with radiation dose. In a previous article,5 we found that the gel content of HNBR increases with electron‐beam radiation dose. The insoluble content of sheets irradiated after injection molding and sample sheets made from irradiated pellets via injection molding were compared to find out whether the irradiation‐induced chemical changes of the blends are affected by sample geometry (sheet and pellet).…”

“…In such cases, there is a possibility of formation of linkages between molecules of the two polymers, which could reduce the interfacial tension and provide a material with improved ultimate properties. Electron‐beam radiation‐induced crosslinking of hydrogenated nitrile rubber (HNBR) has been discussed 5. Van Dyke et al 6 studied the effect of electron‐beam radiation on thermal and mechanical properties of polyamide and butyl rubber blends.…”

Temperature Dependent Dynamic Mechanical Properties of Hydrogenated Nitrile Butadiene Rubber and the Effect of Peroxide Cross-linkers

“…Other authors have applied dynamic mechanical analysis merely as a technique to characterize variously cured HNBR samples [12], a variety of HNBR and other components' blends (poly(vinyl chloride) blends [13,14,16], polycarbonate blends [15], epoxidized natural rubber blends [16], polychloroprene blends [16], poly(ethylene-vinyl acetate) blends [17], fluorocarbon elastomer blends [18]) , HNBR with different amounts of additives (iodine [19], carbon black [16,20], silica [16,20], propyl triethoxysilane [20], vinyl triethoxysilane [20], zinc diacrylate [20]), different processing conditions (vulcanization of HNBR at material/press interface and of the bulk material [21], hot air and fuel aging [22,23]) and comparison to other materials [24][25][26]; once again the dynamic mechanical properties have been reported strictly for different temperature intervals, however, not for a certain frequency range. Wrana et al [10], on the other hand, investigated the dynamic mechanical properties of vulcanized HNBR with several additives at three different frequencies, yet still within a relatively narrow frequency range (1-79 Hz) and dynamic temperature program, but no isothermal experiments were performed.…”