Green coniferous wood pulp–polyurethane composites by planetary centrifugal mixing technology for high energy buffering applications

Traditional cushioning materials (such as EPS and EPE) cause severe microplastic pollution due to their non-biodegradability. It is crucial to develop alternative materials that combine excellent cushioning performance with biodegradability. In this study, a novel planetary centrifugal mixing technology was adopted to prepare the high-filling coniferous wood pulp/polyurethane composite buffer material (HAS-X), achieving the uniform dispersion of up to75 wt. % pulp and constructing the interpenetrating network structure of “rigid fiber skeleton - flexible elastomer”. Experiments show that the maximum impact force of HAS-25% and HAS-50% samples in the drop ball impact test is 40%-60% lower than that of traditional materials, and they have excellent energy dissipation characteristics. HAS-75% achieves the lowest density (0.1234 g/cm 3 ) among HAS-X series, enabling lightweight biodegradation while maintaining thermal conductivity of 0.025 W/(m·K), with outstanding heat insulation performance. The soil burial degradation experiment shows that the biodegradation rate of the material exceeds 50% within 100 days, and the degradation rate is positively correlated with the increase of pulp content. Studies have proved that HAS-X composite materials are significantly superior to traditional petroleum-based materials in terms of mechanical strength, energy absorption efficiency, heat insulation and biodegradability, providing key technologies and theoretical support for solving white pollution and promoting the industrialization of green cushion-absorbing packaging materials.