Synthesis of low molecular weight poly(vinyl acetate) and its application as plasticizer

Poly(vinyl acetate), PVAc, with a degree of polymerization X_n = 10 was prepared by chain‐transfer radical polymerization using carbon tetrachloride and used as oligomeric plasticizer for commercial PVAc. However, the chlorinated chain ends cause a low thermal stability requiring mild Cl/H substitution. The product exhibits high thermal stability and excellent melt‐compounding properties. Blends of oligomeric and commercial PVAc show single glass transition temperatures which decrease with higher oligomer content and exhibit small negative deviations from Fox' linear additivity rule. This indicates plasticization and miscibility being mainly due to entropic effects. Injection‐moulded thick specimens show ductile behaviour at oligomer contents >10 wt %, while sheets with a thickness of 0.2–0.5 mm appear flexible already at 7.5 wt %. The oxygen permeability coefficients are an order of magnitude lower than those of low‐density polyethylene. Due to the sum of their properties, the plasticized sheets present a promising alternative in the preparation of barrier materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40226.