铸造用CO_2硬化酚醛树脂粘结剂固化机理的研究  

Research on the Mechanism of CO_2-Cured Resol Phenol-Formaldehyde Resin Used in Foundry

作　　者：刘伟华[1] 李英民[1] 任玉艳[1] 

机构地区：[1]沈阳工业大学材料科学与工程学院,辽宁沈阳110023

出　　处：《铸造》2008年第11期1188-1190,1194,共4页Foundry

基　　金：辽宁省自然科学基金项目(20042026)

摘　　要：通过核磁共振、红外光谱等手段,对铸造用CO2硬化酚醛树脂粘结剂的结构以及固化机理进行了研究,认为CO2硬化的酚醛树脂粘结剂的固化机理是,在吹入CO2后使粘结剂体系的pH值降低,在弱碱性的条件下,硼酸盐的负离子与甲阶酚醛树脂的酚羟基进行了配位交联。研究中发现:羟甲基与硼砂的反应活性比酚羟基与硼砂的反应活性要大得多,在粘结剂的配制过程中,树脂中羟甲基已经参与了与硼砂的反应;在吹入CO2气体硬化后,有大量硼酯键的生成,由于大部分的羟甲基已经发生了反应,在这一阶段发生B-O配位反应的是酚羟基;吹气硬化过程的体系放热反应的热作用对硬化也起到了很大的促进作用。The structure of resol phenol-formaldehyde resin and the mechanism of CO2-cured resol phenol-formaldehyde resin have been investigated by using 1H-NMR and by analyzing their structure change with Infrared Spectrometry （IR）. The results show that after CO2 blown into the binder, the pH of the binder falls down and the complexation reaction occurs at alkalescence condition between negative ion of borate and phenol hydroxyl groups on the resol phenol formaldehyde resin. The reactivity of the hydroxymethyl groups with borate is much higher than that of the reactivity of phenol hydroxyl groups with borate, and in the course of the preparing binder, the hydroxymethyl groups has reacted with borate and after CO2 blown into the binder, there are a lot of boron-ester bond formed, and the main part in the complexation with negative ion of borate is phenol hydroxyl groups then. The curing reaction procedure is studied by measuring the pH and temperature of resol phenol-formaldehyde resin solution, and the exothermic reaction is regarded helpful to the cure of binder.

关 键 词：CO2硬化酚醛树脂 固化机理 配位反应 放热反应 

分 类 号：TG221[金属学及工艺—铸造]