Abstract
This paper deals with the photograft polymerization of vinyl monomers on glass fibre surfaces initiated by alkylazo groups introduced onto the fibre surface. The introduction of azo groups onto the glass fibre surface was achieved by the reaction of isocyanate groups previously attached to the surface with an azo initiator, 4,4'-azobis(4-cyanopentanoic acid). The amount of surface azo groups introduced was determined to be 1.2 x 10-5 molg-1 by nitrogen analysis. The photograft polymerization of methyl methacrylate and styrene were initiated in the presence of the glass fibre having surface azo groups, and part of the resultant polymer effectively grafted onto the surface. Compared with radical graft polymerization using the thermal initiating system of the azo groups, the percentage grafting and the grafting efficiency were larger, and the molecular weight of the grafted polymer estimated by gel permeation chromatography was smaller in the photograft polymerization. The number of grafted polymer chains calculated from the percentage grafting value and the molecular weight, therefore, was much higher in the photoinitiating system than in the thermal initiating system.