Polylactide (PLA) and PLA composites with void fractions as high as 65% were fabricated using low-pressure foam injection molding (FIM) and high-pressure FIM (HPFIM) equipped with mold opening and gas
counter pressure. The cellular morphology and crystallinity were characterized using scanning electron
microscopy and differential scanning calorimetry, respectively. The mechanical (flexural and impact
resistance) and thermal insulation properties were also measured. Unlike, talc, the addition of nanoclay
markedly enhanced the ductility of solid PLA samples as well as significantly improved the cell morphology of foamed samples, which resulted in the increased specific modulus, strength and impact resistance.
In all the PLA samples made using HPFIM, with an increased void fraction up to 55%, the flexural rigidity
increased up to four times, the specific impact resistance increased up to 15%, and the thermal insulation
increased up to three times. The results of this investigation revealed that low-density PLA composite
foams with improved rigidity, impact strength, and thermal insulation can be developed using HPFIM
for various applications such as transportation and construction industries.