Synthesis of a robust, water-stable, and biodegradable pulp foam by poly-lactic acid coating towards a zero-plastic earth

Biodegradable cellulosic pulp foams with robustness and water resistance are urgently needed in nowadays to replace petroleum-based plastic foams for environmental sustainability. In this work, a facile protocol to fabricate robust poly-lactic acid (PLA) coated cellulose foams (PCCF) was developed through a combined water-based foaming and PLA melt-coating process using pulp as the raw material. In the synthesis, the so-called PLA coating was realized through melting PLA powders dispersed between fibers by an in-situ heating and post cooling process. Performance tests revealed that the incorporation of PLA coating significantly enhances mechanical strength, water stability, and biodegradability of the synthesized PCCF samples compared with conventional cellulosic foams. Specifically, the low-density PCCF were observed with mechanical strength up to 81.24 kPa, high water stability, and more than 95% degradation in 56 days. As the fabrication process is simple and pulp is highly cost competitive, our proposed synthesis strategy makes the PCCF a promising substitute for petroleum-based plastic foams at large-scale production.