铸造用CO2硬化酚醛树脂粘结剂固化机理研究.pdf

学兔兔 铸 造 Nov．2008 · 1188· FOUNDRY VoI．57 NO．11 铸造用CO2硬化酚醛树脂粘结剂固化机理的研究 刘伟华，李英民，任玉艳 (沈阳工业大学材料科学与_T-程学院，辽宁沈阳110023) 摘要：通过核磁共振、红外光谱等手段，对铸造用CO 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 CO，硬化的酚醛树脂粘结剂的固化机理是，在吹入cO 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／LCO 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。 关键词：C02硬化酚醛树脂；固化机理；配位反应；放热反应 中图分类号：TG221 文献标识码：A 文章编号：1001—4977(2008)1l一1188—04 Research on the Mechanism of COz-Cured ResoI Phenol—Formaldehyde Resin Used in Foundry LIU Wei—hua，LI Ying—min，REN Yu—yan (School of Materials Science and Engineering，Shenyang University of Technology Shenyang 1 1 0023，Liaoning，China) Abstract：The structure of resoI phenol—formaldehyde resin and the mechanism of COz-cured resoI phenol—formaldehyde resin have been investigated by using 1 H-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 faIIs down and the complexation reaction occurs at alkalescence condition between negative ion of borate and phenol hydroxyl groups on the resoI phenoI 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 hydroxymethyI groups has reacted with borate and after C02 blown into the binder，there are a Iot of