超声波法活化麦草碱木素及用于PF胶黏剂的研究

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。

Ultrasonic-activated Wheat-straw Alkali Lignin and Its Usage for Preparing PF Resin Adhesive

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 formaldehyde (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 typeⅠplywood according to Chinese standard(GB 9846—2004),and could be compared favorably with the PF resin adhesive.