Bonding strength of heat treated compressed Eastern redcedar wood

Abstract

The objective of this study was to evaluate effect of heat treatment and compression on some properties of Eastern redcedar (Juniperus virginiana) including bonding strength, hardness and surface quality. Specimens were exposed to three temperature levels of 120 degrees C, 160 degrees C and 190 degrees C for 6 h before they were compressed using 2.5 MPa pressure for 5 min. Polyvinyl acetate (PVAc) bonded specimens showed 23.6% reduction in their shear strength when they were exposed to a temperature of 120 degrees C. Such strength reduction values were 44.4% and 64.1% for the specimens exposed to temperature levels of 160 degrees C and 190 degrees C, respectively. The lowest average Janka hardness value of 214.08 kg was determined for the samples exposed to a temperature of 190 degrees C while those treated with a temperature of 120 degrees C had the highest hardness value of 397.73 kg. It appears that combination of heat treatment and compression enchanced overall surface quality of the samples in the form of their roughness determined using stylus type equipment. (c) 2012 Elsevier Ltd. All rights reserved.