Photo-reactive particle prepared from natural rubber and 3-acryloyloxy-2-hydroxypropyl methacrylate

Photo-reactive particle was prepared by graft-copolymerization of 3-acryloyloxy-2-hydroxypropyl methacrylate (AHM) as a bi-functional monomer onto natural rubber (NR) in latex stage with potassium persulfate (KPS) as an initiator, after deproteinization with urea in the presence of surfactant. A terminal vinyl group of AHM was used for the graft-copolymerization, while the other remained in the resulting graft-copolymer, due to different reactivities of vinyl groups in the end of the bi-functional monomer. After graft-copolymerization, the resulting latex was UV-crosslinked to make chemical linkages between the residual pendant vinyl groups of grafted polymers linking up to the rubber particle. The resulting products were characterized by 1H NMR and 13C NMR measurements. Effects of amount of rubber, monomer concentration and reaction time on conversion, grafting efficiency and amount of residual carbon–carbon double bond after graft-copolymerization were investigated. Under the optimum condition, high conversion of monomer and high amount of residual carbon–carbon double bond after graft-copolymerization were achieved without side reaction. A dramatic increase in modulus after UV-irradiation was associated with the connection of the functional polymer linking up to NR particle. [Display omitted]