初始含水率对SiO2溶胶在两种木材中渗透性的影响

摘要

In order to investigate the influence of initial moisture content on penetration of SiO2 Sols in wood, SiO2 Sols with two different particle sizes(30 nm and 150 nm)are used to impregnate sapwood of Scots pine and Southern pine with different initial moisture contents(oven dried, air dried and conditioned)after vacuum process, then the time-dependent liquid absorption during 24 h and the weight percent gain at 24 h are investigated. In addition, the longitudinal SiO2 concentration gradients of wood are obtained with a mass method. The research results show:(1)For both wood species, the liquid adsorptions in wood under oven dried conditions are always the lowest. In addition, the liquid adsorptions of 30 nm and 150 nm silica sols are the highest under air dried and conditioned moisture content conditions respectively.(2)The influence of initial moisture content on weight percent gain(WPG)is different from that on liquid adsorption. That is, the WPGs of both wood species at conditioned state after penetration by 30 nm silica sol are lower than that under oven dried conditions. And for Scots pine, the WPG under air dried conditions is the highest.(3)The influence of initial moisture content on the whole SiO2 in samples is basically consistent with WPG results. The longitudinal distribution gradients of SiO2 in Scots pine are much higher than those in southern pine, demonstrating the poor uniformity of penetration in it.%采用两种粒径（30 nm和150 nm）的SiO2溶胶真空浸渍不同含水率（绝干、气干、调湿）的欧洲赤松和南方松边材，比较其24 h内吸液率变化规律和24 h增重率，并通过质量法分析硅溶胶处理材轴向SiO2的浓度梯度，从而考察处理材的初始含水率对SiO2溶胶在木材中渗透性的影响。研究结果表明：（1）两种木材均在绝干状态下吸液率最低，30 nm硅溶胶在气干状态下吸液率最高，而150 nm硅溶胶在调湿状态下吸液率最高。（2）初始含水率对增重率的影响与吸液率不同，30 nm硅溶胶在调湿状态下浸渍木材的增重率低于绝干状态，欧洲赤松气干状态的增重率最高。（3）初始含水率对试材中整体SiO2量的影响与增重率结果基本一致，欧洲赤松中SiO2轴向分布梯度远高于南方松，其渗透的均匀性较差。