摘要
用聚异氰酸酯(pMDI)对乙二醛-尿素(GU)树脂进行改性并用于刨花板生产。在对GU树脂的结构及固化性能进行研究的基础上,对pMDI的用量及热压工艺进行了优化。IR谱图表明,GU树脂中含有大量的OH活性基团,具有与pMDI发生反应的结构基础;差热分析表明,该体系的凝胶化温度为106.49℃,固化温度为113.37℃,后处理温度为123.29℃,固化反应表观活化能Ea=158.02kJ/mol,反应级数n=0.98,反应频率因子A=2.09×1021min-1。当pMDI与GU树脂的质量比为15∶85时生产的刨花板能达到国家标准,其适合的热压工艺为:压力2.5 MPa、温度140℃、时间5 min。
12-tungstophosphoric acid was used as catalysts for Pechmann condensation of resorcinol with ethyl acetoacetate to synthesize the 7-Hydroxy-4-Methyl Coumarin （ HMC ） under ultrasonic wave in solvent-free condition. The product structure was confirmed by IR and melting point. The results showed that ultrasonic wave was contributed to the reaction. Effects of reaction temperature, reaction time, catalyst dos- age, mole ratio of resorcinol to ethylacetoacetate on HMC yield were investigated. Under optimal reaction conditions catalyst mass fraction in reaction system 2.5%, mole ratio of ethylacetoacetate to resorcion 1.0, reaction time 40 min and reaction temperature 80℃, yield to HMC is 96.8%. Compared with conventional methods, the reaction time was shortened and reaction temperature was decreased and the yield was in- creased under the best condition of ultrasonic wave radiation method.
出处
《云南化工》
CAS
2013年第2期1-4,11,共5页
Yunnan Chemical Technology
基金
国家自然科学基金重点项目(No.30930074)
国家自然科学基金项目(No.31260160)资助
