Shearing of polymer drops with interface modification

The influence of block copolymers (BCP) and interfacial reaction on the def ormation of 30-100 mu m polymer drops inside an immiscible polymer matrix w as visualized in a parallel plate, counterrotating apparatus. Symmetric dib lock copolymers were blended into polypropylene (PP), poly(methyl methacryl ate) (PMMA), and polyethylene (PE) homopolymers. These were dispersed as dr ops in a polystyrene (PS) matrix. Addition of BCP significantly increased t he amount of area the deforming drop generates when subjected to simple she ar flow. Polymers with terminal amine groups (PMMA and PS) were coupled wit h maleic anhydride functional PS and PE. This reaction results in the forma tion of graft copolymer at the interface. These reactive pairs appear to be even more effective than BCP at generating interfacial area. The enhanceme nt in area may be attributed to reduction in interfacial tension or to redu ction in slip, but more likely a combination of both and a gradient in inte rfacial tension.