Flexible poly(butylene adipate-co-butylene terephthalate) enabled high-performance polylactide/wood fiber biocomposite foam

Development of high-performance, environmentally friendly polylactide (PLA) foam to replace petroleum-based polymer foam is crucial for promoting the sustainable and green development. Herein, flexible poly (butylene adipate-co-butylene terephthalate) (PBAT) is introduced into the PLA/wood fiber composite, and the PLA/PBAT/wood fiber composite foam is prepared by supercritical CO2 batch foaming technology. The results show that the introduction of PBAT can reduce the storage modulus and Tanδ value of PLA/wood fiber composite, accelerate the rate of crystallization of composite, expand the temperature range for the crystallization of composite, improve the crystallinity of composite, leading to the improved foamability of composite. Compared with PLA/wood fiber composite foam, the volume swelling ratio of PLA/PBAT/wood fiber composite foam is increased to 10 times when the loadings of PBAT is 15 wt%. What’s more, the apparent density of the composite foam is decreased to 0.13 g/cm3, the cell distribution is more uniform, and the ratio of closed cell is significantly improved. More importantly, when the content of PBAT is 15 wt%, the composite foam shows a superior compressive strength (1.66 MPa), which is 7.97 times higher than that of neat PLA foam. The excellent foamability of PLA/PBAT/wood fiber composite is attributed to the improved crystallization kinetics and melt elasticity due to the introduction of flexible PBAT. The as-prepared high-performance PLA/PBAT/wood fiber composite foam will be expected to have broad prospects in green and sustainable packaging, sound absorption, and thermal insulation materials.