Fabrication and characterization of glassy carbon foams with controllable porosity and high compressive strength

Abstract

Glassy carbon (GC) foams for a long time have two mainly problems. First, GC foams cannot withstand heavy load application due to its relatively low strength. Second, the matrix is easy to crack during pyrolysis precursor process, leading to a long carbonization time. In this study, high-strength GC foams were fabricated by sacrificial templates method using SiO2 powder and phenolic resin as raw materials. SiO2 powder is uniformly dispersed into phenolic resin, and the interface of SiO2/phenolic resin provides fast diffusing channels for the pyrolysis gases, that reduce the risk of cracks formed in GC matrix during fast carbonization. The compressive strength of as-prepared GC foams with density ranging of 0.324–0.781 g/cm3 is 21.6–106.4 MPa. The stretch-dominated mechanical response of the porous structure accounts for the high strength of the prepared GC foams.