LEVEL AND KINETICS OF PVP EXTRACTION FROM BLENDS, INTERPENETRATING POLYMER BLENDS, AND SEMIINTERPENETRATING POLYMER NETWORKS

Extraction level and kinetics are key parameters that control the prop erties of materials made of polymer blends when they are in contact wi th a liquid medium. Poly(vinylpyrrolidone) (PVP)poly(methacrylate) pol ymer blends (PBs), interpenetrating polymer blends (IPBs), and semiint erpenetrating polymer networks (s-IPNs) were synthesized in the film f orm by a UV curing process (except in PBs cases). The extent of PVP ex traction from these materials by water was investigated by monitoring the PVP content in the extracting medium. PW was generally well extrac ted from PBs and from IPBs, but only partially from s-IPNs and one IPB . The strong limitation of PVP extraction in the last cases was attrib uted to the high cross-linking density of the matrices. It can be expl ained by a blocking of the reptation linear chains by nooses around br anches of the network. The diffusion coefficient of PVP in these mater ials, which was calculated by fitting kinetics data with a solution of second Fick's law, depends strongly on the network chemical nature an d PVP content in the poly(methacrylate) matrix. Extraction of a polyme r from s-IPN could then be prevented by choosing properly the composit ion of the blend and the nature of the poly(methacrylate) component.