Environmentally friendly packaging foams: Investigation of the compostability of poly(lactic acid)-based syntactic foams

We investigated how the compostability of polymeric foam samples is influenced by the d-lactide content of poly(lactic acid) and the presence and dosage of an expandable microspheres-type foaming agent. Our results show that the poly(lactic acid)-based foam sheet with higher d-lactide content decomposed faster (49 days) than the foam sheet with lower d-lactide content (63 days), when 8 wt% foaming agent was applied. As the degradation time is shorter for amorphous PLA due to the water diffusion through amorphous PLA. Furthermore, we found that in a poly(lactic acid)-based syntactic foam structures, thermally expandable microspheres decreased the rate of degradation, because not only matrix hydration should take place, but other mechanism like the hydration of the expandable microsphere and the polymer matrix interface as well. However, even the medium-density foams degraded before day 70.