Effects of superheated steam treatment on turpentine content and softening point of pine resin
Resin in pine wood possesses fluidity,particularly evident as temperatures rise,leading to resin softening and an augmented fluidity.This leads to resin exudation during the use of pine products,resulting in both unsightly appearance and diminished performance.Therefore,the removal and fixation of resin are necessary for resinous wood.The purpose of this study is to investigate the effect of superheated steam treatment on the turpentine content and sof-tening point of resin,so as to provide a theoretical basis for the drying schedule of resinous wood.Hence,the resin is heat-treated using a two-stage superheated steam process.Using the thermogravimetric analyzer(TGA),thermome-chanical analyzer(TMA),colorimeter,and liquid chromatography-mass spectrometry(HPLC-MS)techniques,the effects of superheated steam treatment on the residual turpentine content,softening point,color,and chemical compo-sition of resin were analyzed,and the anti-resin exudation effect of the superheated steam treated wood was also tested and evaluated.The results showed that,in the superheated steam treatment stage Ⅰ,with the increase of treatment time,the turpentine content decreased,and the removal efficiency also decreased,because the resin became sticker after the turpentine content decreased.In superheated steam treatment stage Ⅱ,with the increase of temperature and treatment time,the residual turpentine content decreased and the softening point of pine resin increased.The residual turpentine content was highly correlated with the softening point of the resin.The lower the turpentine content,the higher the softening point of the resin.The resin sample treated at 160 ℃ for 9 h exhibits a softening point exceeding 60 ℃.However,the softening point of resin is not only affected by the content of residual turpentine,but also by the modification of high temperature,because the superheated steam treatment can deepen the color of resin and lead to dehydrogenation,isomerization,and oxidation of resin.The anti-resin exudation test of wood shows that the superhea-ted steam treatment can effectively avoid resin exudation of resinous wood.Therefore,the superheated steam treatment process of resin can be adjusted and applied to the drying of pine sawn timber to avoid resin exudation during the use of wood products.By employing this strategy,the quality of resinous wood can be enhanced,thereby broadening its potential applications.
国家科技期刊平台
NSTL
万方数据
维普
