超声波法活化麦草碱木素及用于PF胶黏剂的研究

摘要

麦草碱木素是我国造纸工业重要的剩余物,但是麦草碱木素的结构决定了其反应活性较低,从而使其应用受到较大的限制.笔者根据麦草碱木素的特点分别对比超声破碎仪不同的超声条件(时间:10、20、30、40min;振幅:60、80、100)和不同的溶液质量比( 100∶0,60∶1,20∶1)对麦草碱木素的活化效果,并探索用活化后的木素代替部分苯酚(10％、20％、30％、40％)制备酚醛树脂胶黏剂的可行性.研究结果表明:超声波作用可显著提高酚羟基的含量.超声波作用时间在20min、振幅80、溶液质量比20∶1时效果相对较好.经过超声波活化的木素按20％的量替代苯酚制备LPF,压制的胶合板的胶合强度都达到国家Ⅰ类胶合板的要求,并能与未改性的酚醛树脂(PF)胶黏剂相媲美.%Wheat-straw alkali lignin is the important by-product in pulp and papermaking industry in China. But its application is limited for its complex structure which can result in lower reaction activation. According to wheat-straw alkali lignin' characteristics, the authors of this paper compared the activation effect of diffident ultrasonic conditions(time:10min/20min/30min/40min;amplitude:60/80/100; the different solution mass ratio[(water:lignin,m/m),100:1,60:1,20:1)] on alkali lignin.And then explored the feasibility of using activated lignin to replace part(10%,20%,30%,40%) of phenol to make phenol formalde-hyde(PF) resin adhesive. The results showed that using ultrasonic could significantly improve the content of phenol hydroxyl of the lignin. When the ultrasonic processing s time was 20min, amplitude was 80, and the solution mass ratio was 20 :1, the effect of activation was better. 20% of phenol was replaced by alkali lignin after ultrasonic activation respectively to make alkali lignin-phenol formaldehyde resin (LPF)adhesive,The bond strength of plywood bonded with LPF adhesive could meet the requirement of type I plywood according to Chinese standard (GB 9846-2004), and could be compared favorably with the PF resin adhesive.