PolytetrafluoroethyleneIn Situ Nanofiber-Induced Stabilized Cyclic Olefin Copolymer Microporous Foam As a Thermal Insulation Material

A microporous high-strength foam material with low thermal conductivity and high strength was developed for potential use as a wall-insulation material. Polytetrafluoroethylene (PTFE) was introduced to a matrix of cyclic olefin copolymer (COC) molecular chains containing norbornadiene, a natural heat insulator, using in situ fibrosis technology. The PTFE additive improved the melt strength of the COC matrix and greatly enhanced its foaming performance. The optimal COC–PTFE microporous foam obtained through scCO2 foaming technology exhibited a higher cell density (2.44 × 1010 cells/cm3) and smaller cell size (6.35 μm) than COC foam (4.09 × 108 cells/cm3 and 31.12 μm, respectively). Regulating the structure of the COC microporous foam improved the strength and reduced the thermal conductivity of the foam. In the optimal COC–PTFE foam, the compression performance exceeded that of COC by 434% and the thermal conductivity decreased to 37 mW/(m K) (from 46 mW/(m K) in COC).