Compatibility, morphology and mechanical properties of polylactic acid/polyolefin elastomer foams

In this study, different blends based on polylactic acid (PLA)/polyolefin elastomer (POE) and compatibilized PLA/POE was prepared by melt mixing. The compatibilizer glycidyl methacrylate-grafted-polyolefin elastomer (POE-g-GMA) was synthesized in a separate process. The Fourier transform infrared spectrum confirmed the reaction of POE and glycidyl methacrylate. Meanwhile, the morphology of dispersed phase was observed by scanning electron microscope. The results indicated that the compatibilizer has improved the compatibility and interfacial adhesion between PLA and POE phase. The rheological test results revealed that the introduction of compatibilizer could enhance the storage modulus and melt complex viscosity of PLA/POE blends. The foamability was studied in the presence of azodicarbonamide as a chemical blowing agent in the batch foaming process. Morphology of foams such as porous cell size, porous cell population density, and foam density were studied. It was found that the presence of POE in PLA foams has a great influence on their mechanical properties and the toughness. Addition of POE-g-GMA in samples increased elastic modulus of foams and decreased their strain at break.