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

Abstract

Poly(vinyl acetate), PVAc, with a degree of polymerization X n 5 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.

Petro‐based and bio‐based plasticizers: Chemical structures to plasticizing properties

“…In the case of PVA, water‐soluble plasticizers are used (ethylene and propylene glycol, glycerine, and soy lecithin) for improvement of film flexibility, gas permeability, and biodegradability . The last polyvinylic is PVAc which can be “self‐plasticized” by a partial hydrolysis or by the use of phthalates, citrates, and water‐soluble plasticizers containing ethylene and propylene glycol and glycerine …”

“…Finally, citrate plasticizers are also used with PVAc according to a self‐plasticization phenomenon, rubber or PHB…”

“…34 The last polyvinylic is PVAc which can be "self-plasticized" by a partial hydrolysis or by the use of phthalates, citrates, and water-soluble plasticizers containing ethylene and propylene glycol and glycerine. 35 Among acrylics, poly(butyl methacrylate), poly(ethyl methacrylate), and poly(methyl methacrylate) (PMMA) 36 are frequently plasticized with phthalate and adipates to produce sealants, adhesives and coatings.…”

“…Water uptake of films and permeation rate of drugs are the best near this temperature. 235 Finally, citrate plasticizers are also used with PVAc according to a self-plasticization phenomenon, 35 rubber or PHB. 17 Itaconates are produced by esterification of itaconic acid, which come from the distillation of citric acid.…”

Fabrication of High‐Performance Cationic UV Curable Cycloaliphatic Epoxy/Silicone Hybrid Coatings

“…However, their toughness is poor because of the extremely high crosslinking density, which is ascribed to the homopolymerization mechanism in the curing process. To obtain excellent comprehensive performance of cycloaliphatic epoxy resin materials, the introduction of oligomers or prepolymers into the network structure of polymers are usually used . In particular, acrylates have excellent optical clarity, mechanical properties, and chemical stability, which are widely used in UV curing technology .…”