Degradation of electron beam irradiated hydrogenated butadiene-acrylonitrile rubber.
Influence of bounded acrylonitrile content
Polimery 2005, No 4, 266
Influence of polarity of hydrogenated butadiene-acrylonitrile rubber (HNBR) on its crosslinking and radiation degradation was investigated. HNBR samples differing in bounded acrylonitrile (AN) content (34, 39 or 43 wt. %) (denoted with the symbols H34, H39 and H43, respectively) were irradiated with 10 MeV electron beam. Doses varied from 20 to 300 kGy. The following properties have been determined: Mooney-Rivlin elasticity constant (2C1N), sol content (S), radiation crosslinking efficiency (E) and gel dose (Dg). It was found HNBR undergoes radiation crosslinking and its network density is directly proportional to the dose (D). Bounded acrylonitrile content does not influence the processes of HNBR crosslinking and degradation. Ratio of scission acts (p) and crosslinking acts (q) has been determined using Charlesby-Pinner equation. It has been found that the process of HNBR radiation crosslinking was accompanied with moderate degradation of the chains (p/q = 0.05-0.10) going probably according to β-scission mechanism. Relative intensity of absorption band at 810 cm-1 related to >C=CH2 end groups was determined by internal reflection spectroscopy (IRS).
Key words: hydrogenated butadiene-acrylonitrile rubber, acrylonitrile content, electron radiation, crosslinking, degradation
Degradation of electron beam irradiated hydrogenated butadiene-acrylonitrile rubber. Influence of bounded acrylonitrile content