Influence of Polyolefin Elastomer Content on Morphology, Rheology and Thermal Behavior of Toughened Polylactic Acid/Polyolefin Elastomer Blends

Abstract

Improving the processability and melt strength of sustainable bio-based polymers using elastomers is essential to preserve their biodegradability making them suitable for many applications. Hence, different blends based on polylactic acid (PLA)/polyolefin elastomer (POE) were prepared by the melt mixing. The droplet-matrix morphology of blends was observed by the Field Emission Scanning Electron Microscopy. Structural development of PLA/POE blend was examined depending on the POE content (10–30 wt%). The droplet size of the dispersed POE phase initially decreased and then increased as the POE content increased. The rheological test results indicated that the incorporation of polyolefin elastomer could enhance the storage modulus and the melt complex viscosity of PLA/POE blends. Within all the compositions prepared, the blend containing 20 wt% of POE showed significant increase in the melt strength compared to neat PLA. The thermal behavior showed two different PLA crystal structures after the cooling cycle. The thermograms analysis also exhibited that the glass transition temperature was slightly decreased with the increased content of POE in PLA/POE blends. The results of structural development and the rheological properties of the blends showed that the blend performance was strongly dependent on the composition of POE in the blend.