CATIONIC GRAFTING OF VINYL-POLYMERS ONTO A CARBON WHISKER, INITIATED BY ACYLIUM PERCHLORATE GROUPS INTRODUCED ONTO THE SURFACE

The cationic graft polymerization of vinyl monomers onto a carbon whis ker, vapor-grown carbon fiber, initiated by acylium perchlorate groups introduced onto the surface, was investigated. The introduction of ac ylium perchlorate groups onto a carbon whisker was achieved by the tre atment of a carbon whisker having acyl chloride groups, which were int roduced by the reaction of surface carboxyl groups with thionyl chlori de, with silver perchlorate in nitrobenzene. It was found that the cat ionic polymerization of vinyl monomers, such as styrene, indene, N-vin yl-2-pyrrolidone, and n-butyl vinyl ether, is initiated by acylium per chlorate groups on a carbon whisker. In the polymerization, the corres ponding vinyl polymers were grafted onto a carbon-whisker surface base d on the propagation of polymer from the surface: the percentage of gr afting of polystyrene and polyindene reached 42.5 and 100.3%, respecti vely. The percentage of polystyrene grafting decreased with increasing polymerization temperature because of preferential chain transfer rea ctions at higher temperatures. Polymer-grafted carbon whisker gave a s table colloidal dispersion in a good solvent for grafted polymer.