Research On Modifying Of Wood Surface Properties By Silicon Dioxide

In order to reach improving the wood surface properties, this study is conducted through using coating or not using two ways to deal with the wood surface, that using silicon dioxide as the reinforcing agent. Silicon dioxide powder was added to the polyurethane coating and the water-borne wood coating, and be finished on Pinusm assoniana wood surface. Or silica particles was generated directly on the wood surface by sol-gel method. Through determining wood surface coating abradability, adhesion, glossiness, impact resistance property, hardness, aging resistance and cold liquid resistance properties, silicon dioxide's effects on wood surface coating properties were studied; Through determining the wood moisture absorption, surface wearability, ultraviolet light aging resistance, the effect of formation condition of silicon dioxide by sol-gel method on wood surface modified properties were studied. Scanning electron microscopy(SEM), energy dispersive X-ray analyzer(EDXA) were utilized for analyzing silicon dioxide's dispersion in coating, sol-gel method formation silicon dioxide content, silicon dioxide existing position on wood surface; Modified effect of silicon dioxide was studied by viscosity and sedimentation test; Structure of before and after modified silicon dioxide were analyzed by fourier transform infrared spectroscopy(FTIR) and X-ray diffraction(XRD). The results are as followings:1. Silicon dioxide powder was directly added to the polyurethane coating and be finished on Pinusm assoniana wood surface, wood surface coating adhesion, impact resistance property, aging resistance got improvement; Silicon dioxide powder was added to the water-borne wood coating and be finished on Pinusm assoniana wood surface, wood surface coating adhesion, impact resistance property, hardness, aging resistance got improvement; Silicon dioxide powder was added to these two kinds of coatings, coating abradability and glossiness decreased.2. In order to solve the problem that silicon dioxide and coating mix better well, silicon dioxide powder modification treatment was studied. Silicon dioxide modification treatmen was conducted using KH-570 silane coupling agent in toluene solvent, modified silicon dioxide's dispersivity in the polyurethane coating is better than non-modified silicon dioxide's. Silicon dioxide dispersion modification in water was conducted using the dispersant sodium carboxymethy cellulose and the KH-570 silane coupling agent, modified silicon dioxide's dispersivity in the water-borne wood coating is more uniform than non-modified silicon dioxide's.3. Modified silicon dioxide was added to the polyurethane coating and be finished on Pinusm assoniana wood surface, wood surface coating abradability, adhesion, impact resistance property, hardness, aging resistance got improvement, modified silicon dioxide polyurethane coating compare with non-modified silicon dioxide polyurethane coating, its abradability, hardness, aging resistance got improvement. Modified silicon dioxide was added to the water-borne wood coating and be finished on Pinusm assoniana wood surface, wood surface coating adhesion, impact resistance property, hardness, aging resistance got improvement, and properties of modified silicon dioxide water-borne wood coating is better than non-modified silicon dioxide water-borne wood coating.4. the wood surface properties was modified by sol-gel method in situ formation silicon dioxide on wood surface. After wood surface properties was modified by sol-gel method, wood moisture absorption expanding percentage was decreased, wood wearability and anti-UV discoloration properties have significant improvement. The total color difference (AE) of the silicon dioxide modified surface wood was only one half of the blank sample after 120 h acceleration weathering. Through SEM, EDXA analysis showed that, when humidity time was short, silicon dioxide was mainly generated in the wood cell wall; With the humidity time was prolonged, silicon dioxide was generated in the wood cell wall and wood cell cavity; Wood surface Si element content increased with humidity time prolonging, wood surface Si element content first increase and then decrease with soaking time prolonging; Formation thickness of the silicon dioxide on wood surface was 15～20μm.