木质素酚醛树脂胶粘剂黏度的研究

Study on Viscosity of Lignin Phenol Formaldehyde Adhesive

木质素胶粘剂高黏度的特征阻碍了其工业化应用,该文考察了木质素酚醛树脂(LPF)胶粘剂的pH、质量分数、氯化钠与尿素的加入、贮存时间等因素对其黏度的影响,作为对比,同时测试了这些因素对酚醛树脂胶粘剂和麦草碱木素(WSSL)碱性溶液黏度的影响。结果表明,LPF胶粘剂的黏度随着尿素的加入降低,而随着其质量分数的增加、pH的降低、氯化钠的加入急剧升高,并分别在w(LPF)=30.0%、pH=10.2、w(NaCl)=8.3%处有一个转折点;LPF胶粘剂的黏度曲线与WSSL碱性溶液相似,而与酚醛树脂胶粘剂相差较大;要制得高含量的LPF胶粘剂,其pH应大于10.2,w(NaCl)<8.3%,并且w(尿素)=2%～3%。

The characterization of high viscosity of lignin adhesive hinders its industrialization. The effects of the pH value, mass fraction, addition of sodium chloride and urea, storage time of lignin phenol formaldehyde （LPF） adhesive on its viscosity were studied. At the same time for comparison purpose ,the effects of various factors on the viscosity of phenol formaldehyde （PF） adhesive and that of alkaline solution of wheat straw soda lignin （WSSL） were also investigated. Results show that the viscosity of LPF adhesive decreases with the addition of urea, however, increases rapidly with the increase of its mass fraction, the decrease of its pH value and the addition of chloride sodium. There was a turning point at w（LPF） = 30. 0% ,pH = 10. 2,w（NaCl） = 8.3%. The curve of the viscosity of LPF adhesive is similar to that of alkaline solution of WSSL and far different from that of PF adhesive. In order to prepare the LPF adhesive with high content,its pH must be higher than 10. 2 ,the content of chloride sodium must be lower than 8.3% and 2% -3% of urea should be added.