Sensitizing effect of polyfunctional monomers on radiation crosslinking of polychloroprene

Radiation-induced crosslinking of polychloroprene containing nine different polyfunctional monomers (PFM) has been investigated. The PFMs were kneaded into polychloroprene on a Labo Plastomill at 80°C, and then the mixtures were irradiated using an electron beam accelerator, to initiate the crosslinking reaction. The results showed that the crosslinking density (1/M_c) of the product is linearly proportional to the absorbed dose (D) and the initial PFM content (C₀), i.e. 1/M_c=(A+KC₀)D, where A and K are constants. The values of K increased quickly with the specific unsaturation (moles of double bonds per 100 g of the monomer) of the PFMs. The tensile strength of crosslinked polychloroprene with 4G (Polyethyleneglycol 200 dimethylacrylate) or UA101H (Urethane prepolymer) was found to be the best.