Reactive & Functional Polymers 53 (2002) 173–181 www.elsevier.com / locate / react Radiation vulcanization of acrylonitrile–butadiene rubber with polyfunctional monomers a, a b b * Tariq Yasin , Shamshad Ahmed , Fumio Yoshii , Keizo Makuuchi a Applied Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P .O Nilore, Islamabad, Pakistan b Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, Watanuki-Machi, Takasaki, Gunma-Ken 370-12, Japan Received 10 May 2002; received in revised form 18 July 2002; accepted 29 August 2002 Abstract The efficiency of six polyfunctional monomers (PFMs) as crosslinking coagents for radiation vulcanization of acrylonitrile–butadiene rubber (NBR) by electron beam was studied. It was found that among the polyfunctional monomers having same functionality, short chain PFMs are better than long chain PFMs. Comparison is also made to select more efficient PFMs among methacrylates and acrylates for radiation vulcanization of NBR. The methacrylate monomers showed preference over acrylate monomers. Physical properties of NBR are greatly improved by PFMs at lower doses. Radiation vulcanization of NBR with diethyleneglycol dimethacrylate (2G), at 20 kGy showed results similar to those obtained by conventionally vulcanized NBR.  2002 Elsevier Science B.V. All rights reserved. Keywords: Radiation vulcanization; Acrylonitrile–butadiene rubber; Electron beam irradiation; Polyfunctional monomers; Rubber vulcanization 1. Introduction for machinery and automobile industry [1]. The chemical structure of NBR is shown below: Acrylonitrile–butadiene rubber (NBR), com- monly known as nitrile rubber, has been com- mercially available for more than 50 years. NBR has great potential in industry because of its moderate cost, excellent resistance to oils, NBR belongs to the crosslinking type rubber fuels and greases, easy processibility and very when exposed to high energy radiation. Com- good resistance to swelling by aliphatic hydro- pared with the conventional chemical processes carbons. About 80% of NBR produced is used used for crosslinking of rubber, radiation cross- linking has advantages over them for being faster, more versatile, for bringing about uni- form crosslinking, for consuming less energy *Corresponding author. E-mail address: yasintariq@yahoo.com (T. Yasin). and finally for the inherently waste-free nature 1381-5148 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S1381-5148(02)00171-2