| With the rapid development of wood-based panel industry, the contradiction between supply and demand of wood raw material and release of free formaldehyde are growing problems. In addition, wood-based panel is combustible material with great fire hazards. Fire is one of the major disasters which threaten public safety and block the development of society. In this study, crop residues were used as raw materials for manufacturing high-performance indoor load-bearing binderless particleboard without applying any adhesives and additives, which alleviate the problem of shortage of the wood-based panel materials and solve the problem of free formaldehyde release. Afterwards, using bagasse as raw materials, adding flame retardant ammonium polyphosphate (APP), developed fire-retardant indoor load-bearing binderless particleboard, expand the application range of the environmental material——binderless wood-based panel.Using bagasse as raw material, this paper discusses the relationship between bagasse particle size (A, B, C), hot pressing pressure (5,7,9 MPa), hot pressing temperature (180, 190,200℃), hot pressing time (8,10,12 min), raw material moisture content(5,10, 15%), the board density (0.8,1.0,1.2 g/cm3) with the physical and mechanical properties of binderless particleboard. The results show that the optimum parameters within the scope of the study are hot-pressing pressure 7MPa, hot-pressing temperature 190℃, hot-pressing time 10min, raw materials moisture content 10%, the target density of 1.2g/cm3, the target board thickness 6mm. After using FTIR, hot water extract content analysis and X-ray diffraction analysis, the following conclusions are obtained: hydrolysis of cellulose and hemicellulose and lignin degradation leads self-bonding of bagasse. Hot water extract content of binderless particleboard raise as the temperature increases. Greater cellulose relative crystallinity was associated with greater board density.Bagasse / straw binderless composite was developed, the effect of bagasse / straw ratio (100:0,75:25,50:50,25:75,0:100) and hot-pressing temperatures (180,190℃) on the physical and mechanical properties of the board was discussed, and the material properties of these two materials were contrast. The results showed that: board strength decreases as the bagasse / straw ratio decreases, especially the internal bond strength. The increase of hot-pressing temperature from 180℃ to 190℃ has little effect on board strength, but is able to improve the water resistance of the board. The optimal parameters to produce bagasse / straw bindeless composite are: bagasse / straw ratio 75:25, hot-pressing temperature 190℃, hot-pressing pressure 7MPa, hot-pressing time 10min, raw material moisture content of 10%. TGA results show that the thermal decomposition of straw in advance than bagasse, so bagasse’s thermal stability is better. FTIR results showed that changes of chemical composition of bagasse and straw before and after hot-pressing are basically the same.Using bagasse as raw material, explore the relationship between APP application amount (0%,4%,8%,12%) and the board properties, and using TGA and CONE to investigate the combustion performance of flame retardant binderless particleboard. The results showed that: the addition of APP reduce board strength. TGA results showed that APP effectively suppresses thermal decomposition of bagasse, promote char formation. CONE results showed that addition of APP reduce the heat release rate and total heat release, and the more the APP content, its flame-retardant effect is more obvious; Addition of APP also reduces the smoke production rate and the total smoke production of flame retardant binderless particleboard, but with the increasing content of APP, the total smoke production will be increased. |
PDF Full Text Request