Surface tension, adhesive wettability, and bondability of artificially weathered CCA-treated southern pine

The surface tension, adhesive wettability, and bondability of chromated copper arsenate (CCA)-treated southern pine, exposed to artificial accelerated weathering, was evaluated to examine the recycling potential of weathered CCA-treated wood in composite materials. Accelerated weathering was carried out in a QUV-Accelerated Weathering Tester. Surface tension of the CCA-treated and untreated artificially weathered southern pine wood was determined by means of static contact angle analysis using the Lifshitz-van der Waals/acid-base approach. Adhesive wettability was assessed by static contact angle analysis using resorcinol-formaldehyde (RF) adhesive. The surface tension of both the CCA-treated and untreated southern pine increased as a result of exposure to artificial accelerated weathering. There was no statistically significant difference in RF wettability or wood/RF interfacial adhesive shear strength as the result of the accelerated cyclic weathering examined in this study. The percent wood failure data were not normally distributed, and only showed minor decreases as the result of the accelerated weathering. The percent wood failure was greater for the CCA-treated wood than the untreated wood. From the adhesive wetting and shear strength results, it appears that the accelerated-weathering conditions examined in this study do not severely influence the bondability of CCA-treated southern pine.