Surface grafting of hyperbranched dendritic polymer onto glass fiber

This paper describes surface grafting of hyperbranched dendritic polyamidoamine, a new class of topological macromolecules, onto glass fiber for modification of the glass fiber surface. Glass fiber having surface amino groups as initiator sites was prepared by treatment of the glass fiber with 3-aminopropyltriethoxysilane. Grafting reaction of the hyperbranched dendritic polyamidoamine from the glass fiber surface was achieved by repeating Michael addition of methyl acrylate to surface amino groups followed by amination of end groups, which is the reaction of the resulting ester moieties with ethylenediamine or hexamethylenediamine. Both the amount of terminal amino groups and the percentage of grafting of the resulting polyamidoamine increased with an increase in the number of generations. Ethylenediamine as a reactant in amination was more effective than hexamethylenediamine for the propagation of the hyperbranched dendritic polyamidoamine. However, the propagation of the polyamidoamine from glass fiber surface was found to proceed imperfectly because the amount of terminal amino groups determined by titration was considerably smaller than the theoretical value. Furthermore, living poly(isobutyl vinyl ether) and living poly(2-methyl-2-oxazoline) with controlled molecular weight and narrow molecular weight distribution readily postgrafted to the hyperbranched dendritic polyamidoamine grafted onto the glass fiber surface by termination of the corresponding living polymer cation with terminal amino groups of the polyamidoamine.