A novel synergistic enhancement for UHMWPE foam via HDPE homologous reinforcement and MWCNTs-induced “window-broken” effect for advanced biphasic separation and heating insulation

Efficient oil spill remediation and heating insulation are crucial for energy sustainability and environmental protection. This study proposes a novel synergistic enhancement strategy by integrating high-density polyethylene (HDPE) homologous reinforcement with the “window-broken” effect of multi-walled carbon nanotubes (MWCNTs) to optimize the foaming properties of ultra-high molecular weight polyethylene (UHMWPE). Using microcellular foaming technology, high-porosity UHMWPE/HDPE/MWCNTs open-cell foams with outstanding multifunctional properties were fabricated. Functionalization of MWCNTs with triethoxy-1 H,1 H,2 H,2 H-Tridecafluoro-N-octylsilane (PFOTS) significantly improved their dispersion within polymer, leading to improved crystallinity, thermal stability, and elasticity of the polymer. The optimized foam (containing 0.5 wt% MWCNTs) achieved an expansion ratio of 44.8 and a foaming window of 26.0 °C, improving by 307.3% and 2500.0%, respectively, over pure UHMWPE foam. Notably, this expansion ratio is the highest reported to date for UHMWPE foam. Additionally, it demonstrated superior biphasic separation, characterized by a water contact angle of 148.6° and a carbon tetrachloride adsorption capacity of 50.2 g/g, maintaining excellent recyclability over 15 cycles. Its ultra-low thermal conductivity of 32.8 mW/m·K highlights its outstanding heating insulation. This work presents an innovative strategy for the development of high-performance polymer foams for environmental and energy applications.