Use of organic copolymers as compatibilizers for organic-inorganic composites

Random, block, and graft copolymers of polystyrene and poly(4-vinylphenol) were studied as compatibilizers for organic-inorganic composite (OIC) materials. The concept is to use these polymers to reduce the interfacial tension in incompatible OIC materials. This should reduce the particle size of the dispersed inorganic phase and improve adhesion between the components, resulting in better optical and mechanical properties. Dynamic mechanical and ultimate physical properties, as well as transmission electron micrographs, are provided as evidence for the compatibilization of polystyrene and titania produced in situ. These results clearly show that the domain size of the dispersed phase can be reduced and the mechanical properties improved with compatibilizers. Perhaps surprisingly, poly(4-vinylphenol) homopolymer was also found to be an effective compatibilizer in polystyrene-titania composites. An alternate compatibilization mechanism is proposed for the homopolymer.