Miscibility of poly(vinyl acetate) and vinyl acetate‐ethylene copolymers with styrene‐acrylic acid and acrylate‐acrylic acid copolymers

Abstract

AbstractPoly(vinyl acetate) and vinyl acetate‐ethylene (VAE) copolymers compose one of the more important polymeric materials, widely employed in coating and adhesive applications. A new class of miscible polymer blends involving poly(vinyl acetate) and VAE with styrene‐acrylic acid and acrylate‐acrylic acid copolymers has been found. Experimental windows of miscibility as a function of the ethylene content for VAE copolymers and the acrylic acid content of the acrylate‐acrylic acid copolymers are observed (acrylate = methyl acrylate, ethyl acrylate, n‐butyl acrylate, and 2‐ethylhexyl acrylate). Employing well‐established analog heat of mixing measurements, predicted windows of miscibility were compared with experimental results. Fair qualitative agreement was observed and supported the hypothesis that specific rejection arguments can be employed to explain the observed miscibility. Failure to quantitatively predict miscibility based on the analog heat of mixing measurements may be due to the higher association tendencies of the model compounds relative to acrylic acid units in the high molecular weight polymers. No miscible combinations were found for methyl methacrylate‐acrylic acid copolymers or acrylate‐methacrylic acid copolymers in admixture with poly(vinyl acetate) or the VAE copolymers, thus indicating the sensitivity of phase behavior to minor structural changes. VAE (30 wt % ethylene) copolymers were also noted to be miscible with several polymers previously noted to be miscible with poly(vinyl acetate), namely, poly(vinylidene fluoride), poly(ethylene oxide), and nitrocellulose. © 1995 John Wiley & Sons, Inc.