| Summary: | Biodeterioration tests were done to investigate the decay resistance property of slurry brominated wet-process high-density hardboard. The advantage of resistance against decay will increase the marginal economics of the brominated board which was developed initially as a fire-resistant materials only. Non-brominated and brominated hardboards were examined, using a soil-jar method, for their resistance to decay by four brcwn-rot and two white-rot fungi. Six types of hardboard were used; fiber only, fiber plus phenolic resin, and fiber plus polyethyleniffline resin, as well as three brominated counterparts for these three control treatments. Although the influence of the adhesive on the rates of decay was small, the polyethylenimine resin, which contained high amount of nitrogen compound, showed some stimulatory effect. Bromination significantly increased the resistance of hardboard to decay by brown-rot fungi, although this resistance could be reduced by leaching the brcminated board in cold water before attack by the fungi. It is probable that the formation of bromhydrins of lignin by bromination of the hardboard prevented the attack of the hardboards by two white-rot fungi. Among the brown-rot fungi, Lenzites trabea Pers. ex Pr, was the most sensitive to growing on brominated board. It was also found that brown-rot fungi were more active in decaying both non-brominated and brominated hardboard which were initially at a moisture content of 8% compared with 20%, Using either wet heat or ethylene oxide, as sterilization treatments of the boards, gave no difference in the subsequent decay rates of non-brominated boards by the brown-rot fungi. With brominated boards, the ethylene oxide treatment appeared to increase their susceptibility to decay by these fungi. The soil-jar method, modified from ASTM D1413-76, proved to be a suitable technique for evaluating the decay resistance of hardboard. === Forestry, Faculty of === Graduate
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