Pore structure and cushioning properties of waste paper pulp-reinforced starch-based foams

Foamed plastics do not readily degrade, but degradable starch foam has uneven pores and poor mechanical properties. To improve the cushioning performance of starch foams, a sustainable starch-based packaging cushioning material is prepared via microwave foaming using waste corrugated paper fibers as the reinforcement material. The effects of different fiber contents on the structure and cushioning properties of starch-based foams are studied, and the possibility of replacing petroleum-based foams is discussed through comparisons with conventional cushioning materials. The results indicate that the pore structure of starch-based foaming materials can be controlled by changing the fiber dosage, and a small or excessive amount of fiber is not conducive to the uniform foaming of starch-based composite foams. When 3 g of waste-paper fiber (17.6% by weight of the starch) is added, the average diameter of the starch-based foam pores is small, the pore size distribution is relatively uniform, the minimum buffer coefficient is 4.38, and the mechanical properties are closer to those of expanded polystyrene (EPS). A peak acceleration of 942.89 m/s2 is obtained from the packaging parts with starch-based foaming materials after drop testing, which reduced the impact load by nearly 50% compared to packaging without the cushioning liner. This has the potential to become a sustainable alternative to petroleum-based packaging foams.