壳聚糖季铵盐改性水性环氧树脂对木材尺寸稳定性及防腐防霉性能的影响OA

As one of the most essential renewable fundamental materials in the world,wood has been extensively utilized in various fields like furniture,construction,decoration and innovative materials.However,the wider applications and development are significantly limited by their inherent defects,including dimensional instability and susceptibility to deformation,decay and mold.In this study,the waterborne epoxy resin modified by chitosan quaternary ammonium salt(QCS-WEP)was prepared using the method of phase inversion.The QCS-WEP was then injected into wood under vacuum-pressure treatment,followed by in situ curing reaction up on heating.The effect of QCS-WEP on the morphological structure,dimensional stability,decay and mold resistance was investigated.The results showed that QCS-WEP was able to be impregnated into the porous structures of wood,and the weight percentage gain and bulking efficiency of the treated wood reached 28.7%and 4.0%,respectively.After three cycles of water soaking and drying experiments,the shrinkage and swelling rates of the treated wood were reduced to 8.9%and 9.5%,respectively,while the anti-shrinkage and anti-swelling efficiencies reached 33.0%and 33.3%,respectively.These results demonstrated a significant improvement in the wood·s dimensional stability.Fourier transform infrared(FT-IR)spectral analysis further confirmed that QCS-WEP penetrated the porous structures of the wood and cured within them.Hydrogen bonds readily formed between the hydroxyl groups of the cured epoxy resin·s network structure and the wood components,indicating strong interaction and compatibility between the wood and the epoxy resin.Decay resistance results for the untreated and treated wood samples were evaluated after a three-month exposure to brown-rot and white-rot fungi.It was clearly shown that both the brown-rot and white-rot fungi grew easily on the untreated wood samples,while the growth of fungi was significantly restricted on the treated wood specimens.The mass loss values for untreated wood samples against brown-rot and white rot fungi were 79.1%and 35.2%,respectively,while the values were significantly dropped to 3.6%and 5.6%,respectively,for QCS-WEP with 5%chitosan quaternary ammonium salt addition treated wood.Besides,the anti-mold test showed that the QCS-WEP cured inside the wood could significantly delay the germination of mold and inhibit its growth.The whole surfaces of untreated wood samples were covered with mold on the 16th day with the infection value of 4,while the infection value for the treated wood was fixed around 0.5,implying the significant improvement in the anti-mold performance of the wood.