Study On The Decorative Properties Of Strengthened Poplar Wood

The modification of fast-growing wood resin is a method of changing the physical and mechanical properties of wood.The modified wood can increase the density,mechanical index,dimensional stability and so on,so that the fast-growing wood can be more applied.However,when resin enters wood and reacts with wood,it will inevitably change the wettability and surface energy of wood,and at the same time bring formaldehyde and VOCs pollution.In this paper,The contact angle and surface energy of low molecular weight urea formaldehyde resin and isocyanate were studied.The relationship between the weight percent gain and the surface bonding strength of two kinds of reinforced wood veneers was studied.At the same time,the release rules of free formaldehyde and VOCs after two kinds of fortified materials were analyzed.Using waterborne wood lacquer,nitro lacquer and polyurethane lacquer to finish the finishing of poplar wood strengthening material with 30%weight gain,adding different quality nano TiO2 and nano ZnO to three kinds of paint,detecting the change of the quality of the film and the VOCs release of the specimen after the finishing.The main conclusions are as follows:(1)The wettability of poplar wood was improved by two kinds of resin impregnated poplar wood.The surface free energy of urea-formaldehyde resin poplar reinforcements increased with the increase of weight gain rate,and both non-polar and polar components increased.As the weight percent gain increases,The surface free energy of poplar reinforcements decreases,both the non-polar component and the polar component are reduced.(2)The weight percent gain of the surface bond strength increased first and then decreased after the veneer of urea formaldehyde resin was strengthened.The surface binding strength was the highest when the weight gain rate was 20%.The surface bonding strength of the veneers strengthened with isocyanate decreased continuously with the increase of weight gain rate.The surface bonding strength was lowest when the weight gain rate was 70%.The effect of different sizing amount on the surface bonding strength was studied by using isocyanate fortified material with 30%weight gain as base material.(3)After release,the release of formaldehyde from the two reinforcing materials increased first and then decreased.Urea-formaldehyde resin impregnated reinforcements have higher free formaldehyde emission than isocyanate impregnated reinforcements.VOCs after finishing mainly include aromatic hydrocarbons,alkanes and lipids,also contains small amounts of aldehydes and ketones,olefins and other substances.(4)The addition of nano oxide enhanced the hardness,wear resistance and adhesion of the three coatings.The amount of TVOC released from different parts of waterborne wood coatings,nitro lacquers and polyurethane coatings decreased with the addition of two different gradient catalysts.The amount of TVOC released when the amount of water-based paint was 0.05%added was the lowest after the addition of titanium dioxide,and the amount of TVOC released when the amount of nitrocellulose paint was 0.3%was the lowest,and the amount of the release of the polyurethane paint was the lowest when the amount of the polyurethane paint added was 0.1%.The latter three kinds of paints have the lowest release amount when added in 0.05%.When Zinc Oxide was added to the three kinds of lacquer,the amount of the 0.3%lacquer was the lowest.