Poly(L‐lactide)/polypropylene blends: Evaluation of mechanical, thermal, and morphological characteristics

Abstract Poly( L lactide) (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‐ g ‐PP 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. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011