Radiation grafting functionalization of poly (vinylidene fluoride) to compatibilize its blends with polyolefin ionomers

Blends of a crystalline vinylidene fluoride copolymer (PVDF) and a polyolefin ionomer were produced by melt mixing and characterized by a variety of techniques to examine the effect of increasing the level of salt formation on morphology. The PVDF component was also grafted with methacrylic acid by irradiating the polymer powder and subsequently treating it with an aqueous monomer solution. The effect of neutralizing the acid in both polymer components to produce the corresponding zinc salt was also investigated. Compatibilization was accomplished by the addition of zinc acetyl acetonate (ZnAcAc) to the mixture. This increased the viscosity of the polyolefin ionomer phase, comparable to that of the PVDF. The viscosity of the grafted PVDF component did not increase appreciably after neutralization with ZnAcAc. The grafted polymer precipitated and formed a particulate dispersion with in a largely graft-free polymer matrix. The addition of ZnAcAc to the blend of grafted PVDF and polyolefin ionomer produced a large enhancement in compatibilization, giving rise to the formation of co-continuous phases that contained encapsulated particles of different size and in various locations.