Tannin and lignin are organic materials that are more cost-effective than synthetic, non-renewable phenolic compounds. In this paper, tannin-lignin-formaldehyde (TLF) composites were used to synthesize thermally insulative mesoporous aerogels. A thermal analyzer measured the thermal conductivity of two TLF samples using the transient plane source (TPS) method. Results showed that the TLF aerogels had better thermal insulation properties than any other organic aerogels reported in the literature, and were well ...