LAMINATING CREOSOTE-TREATED HARDWOODS

A study was conducted to investigate the bendability of four selected hardwood species after being treated with creosote. A completely rando mized block factorial design was employed. Experimental factors includ ed 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-resorcino l-formaldehyde, resorcinol-formaldehyde, emulsion polymer isocyanate, and low-viscosity formulation emulsion polymer isocyanate) and two exp osure levels (ambient room and vacuum/pressure/soak conditions). Expos ure levels effects on the different wood species resulted in highly va riable adhesive system performance. Exposure level effects were most e vident for the higher density oaks. Shear strength and percent wood fa ilure results for all wood species revealed a general trend towards a higher performance for the two phenol-resorcinol-formaldehyde systems. Resorcinol-based adhesive systems had the highest shear strength valu es. Percent wood failure values were highest for the elevated temperat ure cure phenol-resorcinol-formaldehyde system for all species. Elevat ed temperature cure adhesive systems appeared to be required to succes sfully bond high-density creosote treated species. Successful bonding of medium-density species can be accomplished at room temperatures giv en proper adhesive system selection.