Study On The Fabrication And Performance Of Sodium Silicate Bonded Wood-based Panel

With the rapid development of the construction market and home industry and the improvement of environmental awareness,demands for formaldehyde-free and environment-friendly panels are increasing.Inorganic adhesive panels with the advantages of formaldehyde-free,fire-proof and low cost,can be widely used in fields such as furniture,interior and exterior decorations.However,there are some key issues that hinder the practical application of inorganic adhesive panels,which are low heating curing speed,low strength and poor water resistance.Therefore,it is crucial to solve these problems so that the real industrial application of inorganic adhesive panels can be realized.In this paper,the preparation method and properties of sodium silicate bonded wood-based panel were studied.The purpose of this thesis was to study the preparation materials and technological methods of sodium silicate bonded wood-based panel,which has great theoretical and practical significance.Microwave hardening technology was applied to the process of inorganic adhesive panel for enhancing heating curing speed,and the effects of silica sol,phosphate,sodium silicate and heat hardening method on the panel's performance were studied.Results show that panels made of sodium silicate as adhesive and microwave heating curing method possess better performance.Novel sodium silicate bonded wood-based panels adopting microwave heating method have the advantages of high heating curing speed,nice strength and better compactness.Based on the above results,we design an integrating equipment of microwave hot-press forming device that can be used for panels industrial production.To study the effect of different hardening reagents and surface coatings on the panels,surface coating method and particle materials were introduced to increase the strength of sodium silicate panels.Results indicate that silica sol can penetrate through surface into internal wood gaps,which can increase the sodium silicate bonded panel's strength by forming particles inside the panels after microwave heating curing,and silica sol was dried after microwave to form the coating that also has certain strength.Particles of high hardness such as SiO₂ and Al₂O₃ can pack among wood gaps and improve the strength of sodium silicate bonded panels greatly,playing a role of particle-reinforcement.To study the effects of surface coatings and different modifiers on the properties of sodium silicate bonded wood-based panels,surface coating method and organic compounds for modifying sodium silicate were introduced to increase water resistance.Results show that,silica sol and Tung oil are effective coatings that can form compact water-proof coat layers on top of panels,thus enhancing water resistance.Modifiers,such as xylitol and disodium hydrogen phosphate,bentonite clay and silico hydrides,hydrofluoric acid can improve sodium silicate bonded wood-based panel's water resistance,and the reasonable explanation is that water-proof materials generate from the reaction of these additives with sodium silicate which may reduce stray Na⁺at the surface.