基于TG-FTIR的杨木热解过程中脲醛树脂影响机理的模型物研究

Influence of Urea Formaldehyde Resin on Pyrolysis of Biomass: A Modeling Study by TG-FTIR

热解是废弃人造板高效回收利用的方式，人造板中所含胶黏剂是其不同于生物质的主要特征。为了有效环保地利用热解技术处理废弃人造板，解明人造板热解过程中其所含脲醛树脂胶黏剂（UF）对木材热解特性的影响，深入探索UF对人造板中木材各组分的作用机制，以杨木及木材的三种主要组分（纤维素、半纤维素、木素）为研究对象，创新性地依据杨木的化学组成，以纤维素、木聚糖和木素配制成模型物，并加入UF模拟人造板的构成。利用热重红外光谱联用（TG-FTIR）分析法，对比分析了加入UF前后模型物以及杨木各主要组分的热失重特性及气相演变规律。热重及红外结果表明，UF促进了纤维素热解过程中水和羧酸类物质的生成。UF与木素结合生成热不稳定的含氮结构，释放大量氨气，并且在200～300℃区间内参与了木素的热解并直接影响木素热解产物的生成。由此推测，在人造板热解过程中，木材三种主要组分中与UF作用的主要成分是木素。

Pyrolysis is an efficient and recycling way to utilize waste wood-based panels,in which urea-formaldehyde resin （UF） is the main difference between wood-based board and other kinds of biomass.The present paper studied the three main compo-nents （cellulose,hemicelluloses,lignin）of poplar wood,in order to effectively and environmentally utilize or dispose of waste wood-based panels with pyrolysis technique,to study the influence of urea formaldehyde resin on pyrolytic characteristic of wood during the process of the pyrolysis of waste wood-based panels,and to in-depth explore the mechanism of the effect of UF on each component of wood.Innovatively,the weight-loss character and gas evolution rule of the model （made from cellulose,xylan and lignin,based on the chemical components stud of poplar wood）,the main components as well as the ones mixed with UF were analyzed by TG-FTIR （thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer）.Results indicated that UF promoted the generation of water and carboxylic acid substances during the cellulose pyrolysis process.UF combined with lignin,formed some kind of unstable nitrogenous structure which produced a large amount of NH3 ,which took part in the low-temperature （200~300 ℃）pyrolysis of lignin,and directly affected the production of pyrolysis products.It can be conclu-ded that during the process of the pyrolysis of waste wood-based panels,lignin was the one that UF mainly impacted among the three main components of wood.