胶粘剂
木质素
材料科学
异氰酸酯
聚氨酯
傅里叶变换红外光谱
玻璃化转变
固化(化学)
复合材料
单体
高分子化学
化学工程
聚合物
有机化学
化学
工程类
图层(电子)
作者
Ravindra V. Gadhave,Pratik S. Kasbe,Prakash A. Mahanwar,Pradeep T. Gadekar
标识
DOI:10.1016/j.ijadhadh.2019.102427
摘要
The present work aims to evaluate the influence of addition of kraft lignin in moisture curing polyurethane (PU) based wood adhesives. The mechanical, thermal properties and chemical structure of the adhesive were studied. The lignin-PU adhesives were obtained by replacing 1%, 3% and 5% of polypropylene glycol (PPG) by Kraft lignin and further reacted with monomeric diphenylmethanediisocyanate (MDI). The aliphatic hydroxyl level of lignin was not taken into consideration in the stoichiometry, in order to find out effect on % free NCO of the final product. The chemical structure of the synthesized lignin-PU adhesives were analyzed by Fourier transform infrared spectroscopy (FTIR). The lap shear strength of the adhesives was tested by bonding canarium wood substrates. The results illustrated that by increasing the weight % of lignin in such lignin-PU adhesives, a decrease in the free isocyanate content, leading to slower setting time but higher shear strength values, were observed. Similarly, the thermal properties of lignin-PU adhesive were also studied, showing an increase in glass transition temperature (Tg) with increase in lignin content.
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