碱对CO_2固化甲阶酚醛树脂粘结剂性能的影响

Influences of Alkali on Properties of CO_2-Cured Phenol-Formaldehyde Resol Resin Binder

利用溶液粘度和砂芯抗压强度的测定、粘结桥断口的扫描电镜(SEM)和盐成分的电子能谱(ESCA)分析,研究了碱在CO2固化甲阶酚醛树脂粘结剂中的作用及对性能的影响。结果表明,碱是甲阶酚醛树脂水溶液的一种有效分散剂,与NaOH和LiOH相比,用KOH配制的树脂溶液粘度较低;随着KOH浓度的增大,树脂溶液的粘度逐渐增大,粘结剂的粘结强度则先增大,后减小,在25%时出现极大值;在强碱性粘结剂的作用下,砂粒表面会部分溶解,溶解部分固化后与粘结剂中的碱一起形成复盐;碱对甲阶酚醛树脂/硼砂水溶液的稳定性有较大的影响,只有在较强的碱性条件下体系才能稳定存在。

The influences of alkali on properties of CO2cured phenolformaldehyde resol resin investigated by the measurements of the solution viscosity and the compressive strength of core sample, the scanning electron microscope analysis of bonding bridge fracture and the electron spectrum analysis of salt component. The results showed that alkali is a dispersant for resin in aqueous solution. The viscosity of the solution prepared with KOH is the lowest in KOH, NaOH and LiOH. The viscosity of the resin aqueous solution increases with increasing of the alkali content, but the compression strength increases first and then decreases. At the strong base, the surface of sand would been dissolved partly, and form a double salt with alkali in binder after hardening. Alkali content can affect the stability of the binder. Only at strong alkali condition, the system is a stable state in thermodynamics.