Properties and structures of polylactide filled with poly(ε‐caprolactone)‐coated calcium carbonate

Abstract

Abstract The poly(ε‐caprolactone) (PCL)‐coated microsized calcium carbonate (CaCO 3 ) was prepared by high‐speed hybrid mechanical coating. Polylactide (PLA) was melt‐blended with neat and modified CaCO 3 particles. Phase morphology, microstructure, and thermal dynamic rheological and mechanical properties of the composites were investigated. Differential scanning calorimetry reveals that the addition of coated CaCO 3 remarkably makes the cold crystallization temperature decrease but has little influence on the final degree of crystallinity of PLA. Dynamic rheological tests indicate that complex viscosity and loss modulus of modified CaCO 3 system are lower than those of neat CaCO 3 system. Scanning electron microscopic results show that the coated CaCO 3 microparticles disperse more uniformly in the PLA matrix compared with neat particles. The smooth and round coated particles promote the dispersion of CaCO 3 particles in the PLA matrix, and PCL enhances the interfacial adhesion between CaCO 3 particles and the PLA matrix. From mechanical tests, it is found that toughness of the composites is greatly improved by the incorporation of PCL‐coated CaCO 3 microparticles. It is glad to see that the elongation at break of the composite with 15 phr coated CaCO 3 is as high as 310%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012