In-situ Grafting of Carboxylic Acid Terminated Poly(methyl methacrylate) onto Ethylene-glycidyl Methacrylate Copolymers：One-pot Strategy to Compatibilize Immiscible Poly(vinylidene fluoride)/ Low Density Polyethylene Blends

Reactive compatibilization is an effective strategy to improve compatibility of incompatible polymer blends. However, the strategy is usually limited to the polymer blends that one of the components contains reactive groups. In this work, we have succeeded in the reactive compatibilization of the immiscible poly(vinylidene fluoride)/low density polyethylene (PVDF/LDPE) blends of which both components do not contain the reactive groups. We simultaneously incorporated the carboxylic acid terminated poly(methyl methacrylate) (PMMA) oligomer (PMMA−COOH) and ethylene-glycidyl methacrylate copolymer (EGMA) into the PVDF/LDPE blend. The ring-opening reactions of the carboxylic acid groups of PMMA oligomer and epoxide groups on the EGMA main chains happen during the melt blending and the in-situ formed EGMA-g-PMMA graft copolymers enhance the compatibility of PVDF/LDPE blends significantly. The reactive compatibilized PVDF/LDPE blends have the elongation at break and fracture strength of 507% and 40.2 MPa, respectively, as compared with the 11% and 25.6 MPa of the uncompatibilization blends. Moreover, the architecture effects of the in-situ formed EGMA-g-PMMA by varying PMMA-COOH oligomer loadings, PMMA-COOH molecular weight and the processing time on the compatibilization efficiency have been investigated. It was found that compatibilizing efficiency increases with increasing the grafted density, the length of the side chain and the degree of reaction. This one-pot strategy with the in-situ formed graft compatibilizers in incompatible blends paves new possibility for unreactive blends by reactive compatibilization.