Crystallization behavior and mechanical properties of poly(ethylene oxide)/poly(L-lactide)/poly(vinyl acetate) blends



Poly(vinyl acetate) (PVAc) was added to the crystalline blends of poly(ethylene oxide) (PEO) and poly(L-lactide) (PLLA) (40/60) of higher molecular weights, whereas diblock and triblock poly(ethylene glycol)–poly(L-lactide) copolymers were added to the same blend of moderate molecular weights. The crystallization rate of PLLA of the blend containing PVAc was reduced, as evidenced by X-ray diffraction measurement. A ringed spherulite morphology of PLLA was observed in the PEO/PLLA/PVAc blend, attributed to the presence of twisted lamellae, and the morphology was affected by the amount of PVAc. A steady increase in the elongation at break in the solution blend with an increase in the PVAc content was observed. The melting behavior of PLLA and PEO in the PEO/PLLA/block copolymer blends was not greatly affected by the block copolymer, and the average size of the dispersed PEO domain was not significantly changed by the block copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3618–3626, 2001