Effect of biodegradable poly(ethylene adipate) with low molecular weight as an efficient plasticizer on the significantly enhanced crystallization rate and mechanical properties of poly(l-lactide)

Abstract

The slow crystallization rate and low elongation at break are the main drawbacks of biodegradable poly(L-lactide) (PLLA) from a viewpoint of practical application. Such disadvantages of PLLA have been successfully resolved by blending with low molecular weight biodegradable poly(ethylene adipate) (PEA) in the present work. As a biodegradable plasticizer, PEA not only formed fully miscible and biodegradable polymer blends with PLLA but also apparently reduced the glass transition temperature of the blends. The increased chain mobility favored the nonisothermal cold and melt crystallization behaviors, increased the spherulitic growth rate, and accelerated the overall isothermal melt crystallization process of the blends; however, the blends had the same crystallization mechanism and crystal structures as neat PLLA. One of the exciting results was that the elongation at break value of an 80/20 PLLA/PEA blend was dramatically increased; therefore, for a wider practical application, the preparation of PLLA-based materials with fast crystallization rate, good mechanical properties, and complete biodegradability could be accomplished by the blending with a small amount of PEA with low molecular weight as an efficient plasticizer.