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-copolymer, due to different reactivities of vinyl groups in the end of the bi-functional monomer. graft 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 H-1 NMR and C-13 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. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.