This paper presents techniques for the functionalization of polymer materials with alkoxy-silane groups. Alkoxy-silane groups are key intermediates in bonding organic materials onto glass-fibre surfaces. Two reaction routes are described: (1) Chain copolymerization of butyl acrylate (BuA) and γ-methacryloxypropyltrimethoxy-silane (MPS) and (2) grafting of MPS onto polyethylene (PE) and poly(styrene-block-ethylene-co-1-butene-block-styrene) (SEBS). It is concluded that chain copolymerization is the superior route since it gives almost unlimited possibilities of adjusting the degree of alkoxy-silane functionality. The paper also demonstrates the advantage of performing graft copolymerization in the melt instead of in solution. Solution grafting is of low efficiency and is probably directed to chains having reactive sites, e.g. branch points. It is proposed that the primary cause is the lower temperatures used in solution grafting in comparison to the melt reaction.