Research On Radiation Crosslinking Of EPDM With Sensitizers And Reinforcement Filler

Radiation crosslinking is an effective means of polymer vulcanization and preparation of new materials. Compared with traditional vulcanization methods of ethylene-propylene-diene terpolymer(EPDM), radiation crosslinking can react at room temperature and normal pressure, won’t release pollution and make product properties better. In this paper, selected amount(0~6 phr) of trimethylol propane trimethylacrylate(TMPTMA) was kneaded into EPDM, and then irradiated to selected doses(0~150 k Gy) by a 60 Co γ –ray source. Effects of TMPTMA on gel content, crosslink density, tensile strength and elongation at break of the irradiated EPDM samples were investigated. The filler could made rubber products properties more valuable while reducing the cost. In order to improve the performance of reinforcing filler in EPDM, we used in-situ modification of ultrafine calcium carbonate and precipitated silica to make these fillers having reinforced properties in the radiation crosslinked EPDM.Much more crosslinks in the irradiated EPDM were detected by increasing TMPTMA content. The crossliking density and gel content of irradiated EPDM rose with the increase of TMPTMA content. But little additional change was found of the gel content while TMPMTMA content exceeded 3.07 phr higher. Maximum tensile of crosslinked EPDM was achieved by kneading 2.0 phr TMPTMA into EPDM and being irradiated to 10 k Gy.Calcium carbonate was mainly used as a filler to reduce the cost of rubber products. This paper adopted in-situ modified calcium carbonate with titanate coupling agent 105 that contained unsaturated functional group. Research showed that 105 would react with the surface of calcium carbonate, and improved the surface properties of carbonate and the interaction force of the surface of calcium carbonate between EPDM, which made the mechanical properties of the composites improved.Precipitated silica surface contained abundant Si-OH which would result precipitated silica formation filler-network in the matrix through hydrogen bonding. After being oleic acid in-situ modified, the hydrogen bonding of the filler-network would be destroyed, which reduced the interaction between EPDM matrix and filler and decreased physical crosslinking density of irradiated EPDM. After being irradiated, the chemical bond produced between the oleic acid and EPDM. Although the total crosslinking density decreased of the composites, the chemical crosslinking density slightly elevated. The total crosslink density had significant effect on stressing at definite elongation, but the tensile strength decided by the chemical crosslinking density of the irradiated EPDM.After modified, the filler had a certain reinforced effect on radiation crosslinked EPDM and the functionality of the filler was extended, which had certain significance of application.