Curing conditions effects on the characteristics of thermosetting adhesives-bonded wood joints - part 1: Substrate influence on TTT and CHT curing diagrams of wood adhesives

摘要

lignocellulosic substrates such as wood were found to have a marked modifying influence on a well-definite re- gion of CHT diagrams during hardening of phenol-form- aldehyde(PF) and urea-formaldehyde (UF)polyconden- sates. This was ascribed to more complex resin phase transitions due to resin/substrate interactions peculiar to these substrates. The chemical and physical mechanisms of the interactions of resin and substrate causing such CHT diagram modifications are presented and discussed. The Di Benedetto equation describing the glass transition Temperature Tg of the system as a function of the resins Degree of conversion ρ has been slightly modified to take Into account the modified CHT diagram.