Study On The Formaldehyde-free Flame Retardant Wood Particleboard And Its Adhesive

As the shorting of wood increasingly, the main solution, to overcome the contrary of supply and demand, is using the remains of machining and cutting as raw materials for making wood particleboard. Nowadays, wood particleboard is not only applied in furniture industry, but also in building, transport and shipping industry. However, it is easily flammable and this fateful drawback restricts its wider application. Therefore, it is necessary to investigate on the flame retardant of wood particleboard. The conventional flame retardant of wood particleboard has many disadvantages, such as the high loadings, high sensitivity to moisture, and health hazards because of formaldehyde releases due to the additive of formaldehyde in the wood particleboard. In this paper, efforts are taken to solve the problems by using higher effective flame retardant and formaldehyde-free flame retardance-adhesive.DOPCP and DDPPU containing phosphorus were synthesized and characterized by FTIR and NMR. The flammability of wood particleboard which was treated with DOPCP, DDPPU DDPPU/conventional flame retardant was investigated by Limit Oxygen Index (LOI) respectively. The flame retardant mechanism of DDPPU for wood particleboard was demonstrated by X-ray Photoelctron Spectroscopy(XPS) and FTIR.The results of LOI showed that the addtions of both the DOPCP and DDPPU could improve the flammability of wood particleboard and the latter showed a better flame retardance at the same loading. When 15%(wt) DDPPU was added, the LOI of wood particleboard was 38.1. When the content of DDPPU and H3BO3 was 10% and 5%, respectively, the LOI of the wood particleboard was 46.0. It can be included that there existed a synergistic effect between DDPPU and H3BO3. The results of TGA indicated that the wood particleboard added DDPPU had high char yield at high temperature due to the DDPPU was an effective charring agent. The synergistic system of DDPPU/ H3BO3 can take the flame retardance effect in solid and gas phase simultaneously. As a result, the flame retardance of wood particleboard was improved.The effect of different adhesives on the flammability of wood particleboard was also investigated in this paper. PU adhesives containing phosphorus based on P-PVA and H3PO4-PVA and sodium silicate solution adhesive was prepared respectively. The flammability of wood particleboard treated with the three varieties adhesive were studied by LOI, and the results of LOI indicated that, PU adhesives containing phosphorus can increase the flame retardace of wood particleboard significantly. When the add-on of three varieties of adhesive reached 18%, the LOI of wood particleboard prepared based on P-PVA, H3PO4-PVA and sodium silicate solution adhesive was 27.9 and 32.8, 33.5, respectively. Their thermal stability and Physical - mechanical properties of wood particleboard were studied. The results showed that wood particleboard prepared by PU adhesives containing phosphorus based on P-PVA, H3PO4-PVA can achieve the standards of GB. The sodium silicate solution adhesive exhibit the best flame retardace of wood particleboard, unfortunately, the thickness swelling is higher than the standard. More work is needed to improve the performance of sodium silicate solution adhesive.