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

Abstract

Poly(Llactide) (PLA) was blended with polypropylene (PP) at various ratios (PLA: PP ¼ 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.

Chitosan and Poly(Methyl Methacrylate-Co-Butyl Methacrylate) Bioblends: A Compatibility Study

“…Analysis of all the SEM images show clearly a decrease in the size of the particles when the concentration of PMMA-co-BMA decreases, and there is a good homogeneity for all the bioblends at least in the magnification of the measurement, and no obvious phase separation boundary could be seen. This last comment also strongly suggest a good compatibility between the two polymers, which is in a good agreement with literature [48] .…”

Thermal characterization of a series of lignin-based polypropylene blends

“…The explanation of the different trends found for our blends is twofold: PLA is present in the Liquid Wood mixture as shown by the thermal and microscopic characterization reported above; MAPP and lignin itself can interact to enhance the interfacial adhesion of the blends components. As reported by Reddy et al [28] and Choudhary et al [29], PP/PLA blends can show enhanced mechanical properties, despite the incompatibility of the pure polymers, when proper compatibilizers, like MAPP, are used. The ester groups of PLA can interact with lignin, and the anhydride groups of MAPP can react with cellulose.…”

Physico-mechanical characterization and biodegradability behavior of polypropylene/poly(L-lactide) polymer blends

“…However, addition of MAPP introduced compatibility between PP and PLLA in their blend, and as shown in the micrograph of PP80C6, PLLA was almost uniformly dispersed in the PP matrix, which resulted in increase in the tensile strength of PP80C6 sample, as described earlier. Therefore, it may be concluded that MAPP has improved the interfacial adhesion between PP and PLLA due to reaction between PLLA functional group and the anhydride group present in MAPP [9].…”

“…Blends of PP with poly(L-lactide) (PLLA) have been studied earlier to improve dyeability of PLLA [8], melt processability of PLLA [9], and rheological and mechanical properties [3]. PP and PLLA form incompatible blends, and a compatibilizer is needed to improve compatibility between them.…”

“…Maleic anhydride grafted polypropylene (MAPP) is a well-known compatibilizer used for PP-based blends and composites. It follows the free-radical mechanism -the anhydride part of MAPP has free radical site at α-carbon of carbonyl group, which forms ester linkages with PLLA, and the PP part of MAPP shows compatibility with PP matrix [9]. In this way, it acts as a bridge and helps in improving the interfacial adhesion between PP and PLLA.…”