The Effects of Mixing Bark Residues from Radiata Pine on Properties of Particleboard

• Main Authors: Tien-Tien Chen, 陳恬恬
• Other Authors: Prof. Hong-Ding Soong
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/25017155717934636914

碩士 === 國立嘉義大學 === 森林暨自然資源研究所 === 94 === The demand for wood products has been increasing for recent years, resulting in much more wood wastes. Bark can be regarded as an utilization indicator of overall wood wastes. Bark from some species contains abundant lignin and poly-phenols such as tannin, which can be used for making bio-based adhesives and eliminating free formaldehyde emission. In addition, in order to make the most of wood waste, various types of particleboard can be produced by mixing bark and wood particle in different ratios. In this study, wood particle/bark mixtures were made in different ratios. Several types of particleboard were produced, according to the following parameters：glue content, bark/wood particle size, bark mixed ratio and additive(e.g. furfural) . To evaluate the feasibility of the mass production of particleboard made of radiata pine bark/ wood particle, density (D), moisture content (MC), internal bond strength (IB), bending strength (BS), thickness swelling (TS), and the free formaldehyde emission were investigated. The results showed that the compression ratio of the particle board is inversely correlated with the proportion of the bark mixed in the boards. The density of single-layered particleboard ranged from 0.63 to 0.65 g/cm3 and the moisture content ranged from 7.99 to 9.02%. The thickness swelling increased as the glue content and bark size decreased. Increased bark proportion also resulted in increased thickness swelling. Free formaldehyde emission decreased as bark mixed ratio increased and glue content decreased. The amount of free formaldehyde from most of our boards meets the requirement described in the E1 criterion from CNS 2215 standards for normal particleboard. Internal bond strength decreased as glue content decreased and bark size got finer; increased bark proportion also resulted in decreased internal bond strength. The modulus of elasticity was slightly increased when the board manufactured under mixing 5% bark, but decreased when the board manufactured under mixing over decreased 10% of bark. The modulus of elasticity also decreased as glue content and bark size got finer. The modulus of rupture was slightly increased when the board manufactured under mixing 5% bark (－60＋100 mesh), but it decreased when the board manufactured under mixing over 10% of bark. The modulus of rupture also decreased as glue content and bark size got finer. The mechanical strength of the board could be improved by increasing the furfural additives according to the increased bark proportion. After being tested with CNS 2215 standards for normal particle board, all the boards manufactured in the study did not meet the MOE standard, and a small number of the boards did not meet the type 8 criterion; however, most of our boards are of a quality higher than type 8 criterion, some of them even having a quality higher than type 13 criterion.