Effect of treatments with polyethylene glycol on the properties of particleboard

• Main Authors: Ju-Ping Hsieh, 謝如萍
• Other Authors: Chuan-Ting Tsai
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/93562429474758542957

碩士 === 國立嘉義大學 === 森林暨自然資源研究所 === 95 === For increasing the usage of wood waste, the wood-based board was produced .But its dimension was not stable, so how to keep its stability is the first target to improve. This study used PEG as a stabilizing agent.Two methods, i.e. soaking wood particles and adding into the adhesive were carried out, the concentration of PEG were 5%、10%、15% and 20%, respetively. After pressing, the boards were put into conditioning room(20℃,65%RH) for 7 days. The physical mechanical and dimensional stability were measured. According to the FTIR spectrogram of various particles, control and soaking with polyethylene glycol, there was no new absorption peak in soaking sample compared to the control, but the amount of hydroxyl group was increased.Besides, the density for the two different treatment methods of particleboards was between 0.64 and 0.66g/cm3. That was no significant difference between them. The moisture content of soaked board was lower. The release amount of free formaldehyde of all the conditioned particleboard unmatched F2 standard (below 0.5mg/L). As regards the modulus of elasticity and modulus of rupture,the strength of these two treatments will be lower obviously because of the increasing of concentration of polyethylene glycol, but it was a better method by additive , and it was no significant difference with non-treated wood. As for the dimensional stability, percentage of shrinkage for particleboard by soaking was obviously low because of the increasing of its concentration. Its volumetric anti-shrink efficiency reached the biggest (93.26%) at the concentration of 20%. Percentage of shrinkage of adding was higher than soaking. Volumetric anti-shrink efficiency could only reach to 58.91%, so particleboard’s volumetric anti-shrink efficiency was better by soaked, it could keep the dimension more stable. On the other hand, at the conditions of 40℃, RH75% and 90%, the percentage of swelling was low while increasing concentration by the way of soaking, and the volumetric anti-swelling efficiency was higher than by additing. The higher concentration of polyethylene glycol, the lower percentage of moisture absorption, moisture-excluding efficiency of soaking was higher than additing. It revealed that soaking had the better efficiency of stability. Forejudging this kind of particleboard will decrease the moisture absorption, maybe the particles were covered by polyethylene glycol, as a protective layer. And owing to its moisture absorption ability was stronger than woods, so moisture was hard to combine with hydroxyl groups of wood. As for moisture-excluding efficiency, it was not so obviously by additing than by soaking, but the strength was higher than by soaking.Therefore,consider the treatment operation of these two methods, it could have less time to make the boards and saved the cost by adding. By through modifying particleboard with PEG, although the mechanical properties were lower than normal particleboard, but the dimensional stability was inreased. If they are used for non-construction,treating with PEG may be a feasible treatment method.