Injection-Molded Solid and Microcellular Polylactide and Polylactide Nanocomposites

Abstract

Microcellular injection molding is capable of producing lightweight, dimensionally stable plastic components with less material and energy. This process allows the material to be processed at lower temperatures and pressures, making it suitable for temperature-sensitive biobased plastics and/or additives. This paper presents the effects of adding montmorillonite nanoclay (Cloisite®20A and Cloisite®30B) on the mechanical properties (specific modulus, specific tensile strength, specific toughness, and strain at break) of both solid and microcellular polylactide components, as well as their effects on the cell morphology of the microcellular components. In general, the addition of nanoclay into biobased polylactide improved the specific moduli of both solid and microcellular components and facilitated the formation of smaller cell sizes and higher cell densities. Adding nanoclay also reduced the strain at break and the specific toughness of solid polylactide nanocomposite components. However, the strain at break and specific toughness of microcellular polylactide nanocomposite components were largely improved in comparison with microcellular polylactide components, especially when the loading level of the nanoclay was at 3% and 5%, presumably due to the lack of large voids, as well as the smaller cell size and higher cell density.