RETENTION OF COPPER AZOLE AND ALKALINE COPPER QUAT IN WOOD-BASED COMPOSITES POST - TREATED BY VACUUM IMPREGNATION

摘要

Inductively coupled plasma (ICP) analyses were conducted to determine the amounts of elemental copper in wood-based composites that had been post-treated with alkaline copper quat (ACQJ or copper azole (CA) by vacuum impregnation. Specimens prepared from 5 commercially available, structural-use, wood-based composites softwood plywood (SWP), hardwood plywood (HWP), medium density fiberboard (MDF), oriented strand board (OSB) and particleboard (PB) were treated with ACQ_and CA at different retentions.The analytical results demonstrated that there was a remarkable retention gradient between surface and core sections of SWP and HWP: there was greater retention in the surface than in the core. However, there was less or equal amounts of rjoth preservatives in the surface compared to the core for MDF, OSB and PB. This prominent difference may have been due to the homogeneity of the composites as a result of the shape and thickness of the raw materials. While the current ICP analyses could not fully explain the difference in biological resistance among the tested composites and softwood sapwood, they clearly support a profile of biocidal gradients in various composites. The combined effects of retention gradients, selective absorption and a possible non-uniform distribution of active ingredients in the microstructure of the composites should also be to gain a better understanding of the biological performance of composites.