Laminating creosote-treated hardwoods

Abstract

A study was conducted to investigate the bondability of four selected hardwood species afier bcing treated with creosote.A completely randomized block factorial design was employed.Experimental factors included five wood species (chestnut oak, red oak, red maple, yellow-poplar, and southern pine).five adhesive systems (elevated temperature cure phenol-resorcinol-formaldehyde, room temperature cure phenol-resorcinol-formaldehyde, resorcinol-formaldehyde, emulsion polymer isocyanate, and low-viscosity formulation emulsion polyn~er isocyanate) and two exposure levels (ambient room and \~acuurnlpressurelsoak conditions).Exposu~re levels effects on the different wood species resulted in highly variable adhesive Yystem performance.Exposure level effects were most evident for the higher density oaks.Shear strength and percelnt wood failure results for all wood species revealed a general trend towards a higher performance for the two phenol-resorcinol-formaldehyde systems.Resorcinol-based adhesibe systems had the highest shear strength values.Percent wood failure values werc highest for the elevated temperature cure phenol-resorcinol-forrnaldehydc system for all species.Elevated temperature cure adhesive systems appeared to be required to successfully bond high-density creoso!e treated species.Successful bonding of medium-density species can be accomplished at room temperatures given proper adhesive system selection.