木材硅石改性剂的制备工艺

Preparation Technology of Wood Silica Modifier

为了降低木材硅化改性成本促其应用,直接将固态硅石粉高效液态活化,通过正交试验和极差分析优化制备了木材硅石改性剂,测试分析了浸渍改性杨木的性能。结果表明:①反应时间和原料n(SiO2)∶n(NaOH)对活化溶液的pH值、黏度和密度影响不显著,碱料种类和反应温度对活化溶液的黏度、密度、SiO2转化率、固体质量分数和生产成本影响显著,对溶液性能综合影响最大的是反应温度和碱料种类,其次是n(SiO2)∶n(NaOH)和反应时间;②pH值随反应时间、温度和n(SiO2)∶n(NaOH)增大而减小,密度、黏度、固体质量分数、SiO2转化率和模数随反应时间、温度和n(SiO2)∶n(NaOH)增大而增大,KOH活化效果更好但价格较高,综合平衡优化工艺为:反应温度200℃、碱料为NaOH、n(SiO2)∶n(NaOH)=1.715∶1、反应时间4 h;③硅石改性剂能充分渗入杨木,使其吸药量达252%,密度提高81%,抗弯强度提高69.6%,炭化温度减小89℃,残炭率提高41%,改性效果优于硅溶胶。

In order to reduce the cost of silicified modification of wood to promote its application,the silica powder was directly liquefied.Through range analyses of orthogonal experiments,the high-efficiency liquefaction process was obtained and wood silica modifier was prepared,then planted poplar wood was impregnated with it,and its properties were measured.Reaction time and ratio of silicon to alkali had a little influence on pH value,viscosity and density of wood silica modifier.But its viscosity,density,SiO2 conversion rate,solid content and production cost were greatly affected by reaction temperature and base type.The comprehensive influencing order on the properties of the silica modifier was reaction temperature,base type,ratio of silicon to alkali and reaction time.Its pH value decreased with the increase of reaction time,temperature and ratio of silicon to alkali;and its density,viscosity,solid content,SiO2 conversion rate and modulus increased with increasing reaction time,temperature and ratio of silicon to alkali;KOH had the best activation effect but the highest price;through comprehensive balance the optimized liquefaction conditions were:liquefying temperature 200℃,alkali NaOH,molar ratio of silicon to alkali 1.715 and liquefying time 4 h.The silica modifier could effectively impregnate into poplar wood with solution uptake rate up to 252%,causing wood density,modulus of rupture and residual carbon rate increased by 81%,69.6%and 41%,respectively,and its modification effect was better than that of silica sol.