Pine tannin-based rigid foams: mechanical and thermal properties.

摘要

Pine bark tannin foams were prepared for the first time. The high reactivity of pine tannins in relation to other tannins induced the change in the tannin foam formulations in order to coordinate foam resin hardening, reaction exotherm and solvent blowing allowing the formation of a rigid foam. Pine tannin foams with and without formaldehyde were prepared. Their characteristics were tested as regards stress-strain curves, thermal conductivity, Young's modulus, compression strength, densification, densification rate and energy absorbed under compression. Mostly, properties the pine tannin foams with formaldehyde have properties similar to mimosa tannin foams, in some cases slightly lower and in others slightly higher. Pine tannin foams without formaldehyde showed lower mechanical strength and more elastic behaviour.