Reactively compatibilized polymer blends: Interfacial chemical reactions during melt-extrusion

Reactive compatibilization of immiscible polymer blends is a method which is very often used to obtain well dispersed and stabilized phase morphologies (ref. 1,2). The technique of reactive compatibilization is based on the in-situ formation of a block- or graft copolymer at the interface between the phases of a polymer blend during melt-mixing. In some cases, a third polymer, which is miscible with one of the blend components and reactive with the other, can be used for the formation of a compatibilizing copolymer at the interface (ref. 1,2). This strategy is applied here : SMA2 is miscible with PS (and PPO) and its anhydride groups can react with the amino end groups of PA-6 giving rise to the formation of a graft copolymer at the interface. In this paper, a comparison will be made between the reactively compatibilized blend systems PA-6/(PS/SMA2) and PA-6/(PPO/SMA2). The interfacial reaction was analyzed in the extruded blends PA-6/(PS/SMA2) and PA-6/(PPO/SMA2). An extraction procedure was developed to remove the PA-6 phase from these extruded blends and to characterize the remaining phase PS/SMA2 (or PPO/SMA2) with FTIR. In this way, the amount of reacted MA-groups can be determined.