Redical underUV irradiation. Second theradicals extracted hydrogen from the hydroxyl group of the active ingredients in MB to from alkoxy radicals on the substrate” then the monomer molecules became accepter of the radical, resulting in chain initiation and thereafter themselves became free radical donors to neighboring molecules, which led to the growth of polymer chains. Finally, the and viny! Groups of the cross-linker (MBA) reacted with the polymer chains during chain propagation. In this way a cross-linked structure combined with network structure was formed gradually.