Poly(L-lactide)/Polypropylene Blends: Evaluation of Mechanical, Thermal, and Morphological Characteristics

Poly(Llactide) (PLA) was blended with polypropylene (PP) at various ratios (PLA: PP = 90 : 10, 80 : 20, 70 : 30, and 50 : 50) with a melt-blending technique in an attempt to improve the melt processability of PLA. Maleic anhydride (MAH)-grafted PP and glycidyl methacrylate were used as the reactive compatibilizers to induce miscibility in the blend. The PLA/PP blend at a blend ratio of 90 : 10, exhibited optimum mechanical performance. Differential scanning calorimetry and thermogravimetric analysis studies showed that the PLA/PP/MAH-gPP blend had the maximum thermal stability with the support of the heat deflection temperature values. Furthermore, dynamic mechanical analysis findings revealed an increase in the glass-transition temperature and storage modulus with the addition of MAH-g-PP compatibilizer. The interaction between the compatibilizers and constituent polymers was confirmed from Fourier transform infrared spectra, and scanning electron microscopy of impact-fractured samples showed that the soft PP phase was dispersed within the PLA matrix, and a decrease in the domain size of the dispersed phase was observed with the incorporation of MAH-g-PP, which acted as a compatibilizer to improve the compatibility between PLA and PP. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3223-3237, 2011