Modification of different polylactides by reactive extrusion to enhance their melt properties

Abstract

The importance of the bioplastic polylactide has increased significantly in the recent years. Due to its quite similar properties to fossil-based polystyrene (PS), it has the potential to substitute foamed PS products and consequently can increase the sustainability and material efficiency of foamed products. However, the low molecular weight of commercial PLA, its sensitivity to hydrolysis during processing and its low rate of crystallization inhibit the production of low density foams and uniform cell morphology. The addition of different modifiers to optimize the melt strength and melt viscosity was performed by means of reactive extrusion. The rheological and thermal properties as well as the foam densities were examined. The melt viscosity and melt strength was increased. Foams with fine and closed-cell structure with relatively thin cell walls were made in batch foaming experiments.