Effect of ethylene‐methyl acrylate compatibilizer on the thermo‐mechanical, rheological, and morphological properties of poly(Lactic acid)/biopolyethylene/clay biocomposites

In this study, the effect of ethylene‐methyl acrylate (EMA) compatibilizer on the thermo‐mechanical, rheological, and morphological properties of poly(lactic acid) (PLA)/biopolyethylene (BioPE)/OMMT clay biocomposites was investigated. The biocomposites containing 1 and 3 phr of OMMT clay were characterized by X‐ray diffraction (XRD), mechanical properties, scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), and rheological properties under oscillatory shear flow. XRD results indicated that bionanocomposites with an intercalated structure were obtained for the PLA/BioPE/EMA/OMMT system containing 1 and 3 phr of OMMT clay. The addition of OMMT clay to PLA/BioPE blend led to a decrease in the modulus and tensile strength, while the impact strength was increased. The increase in the clay content from 1 to 3 phr did not affect the modulus and the tensile strength of the PLA/BioPE blend, while the impact strength was decreased. The impact strength of the PLA/BioPE/EMA/OMMT biocomposite containing 3 phr of clay was superior to that containing 1 phr of clay. The addition of EMA to PLA/BioPE/OMMT biocomposites substantially decreased the average size of the BioPE phase domains. DMTA results showed a decrease in the glass transition temperature (T_g) of PLA with the addition of OMMT clay to PLA/BioPE blend. Rheological measurements showed an increase in the viscosity at low frequencies with the addition OMMT to PLA/BioPE blend. Further increase in the viscosity was observed when EMA compatibilizer was added to PLA/BioPE/OMMT biocomposite. The results of DMTA and rheological measurements were ascribed to the morphology refinement and corroborated the results obtained by SEM. POLYM. COMPOS., 39:E164–E173, 2018. © 2016 Society of Plastics Engineers