酯固化纳米SiO2/酚醛树脂粘结剂的研究

利用红外光谱、透射电镜和粒度分析等研究了聚乙二醇(PEG)对纳米SiO2表面性能及分散性的改进效果。通过砂芯拉伸强度的测定研究了纳米SiO2的种类及用量对酯固化酚醛树脂粘结剂粘结强度的影响。结果表明：经过PEG改性后的纳米SiO2的表面羟基减少，粒子的分散程度提高；随着PEG浓度的增大，粒子的平均粒径先减小，后增大，在浓度为O，6％时出现最小值。多孔形纳米SiO2比球形的增强效果要好；随着纳米SiO2用量的增加，砂芯的粘结强度先增大,后减小,在加入量为0．5％左右时，出现峰值,强度增加45％。

Study on ester-cured nano-SiO2/phenol-formaldehyde resin binder

In this paper,the surface modification and dispersion of nano SiO 2 particles with PEG were studied by means of IR,TEM,and particle size analysis.The effect of the category and amount of nano SiO 2 particle on binding strength of the ester cured nano SiO 2/phenolic resin binder was also studied by means of the measurement of sand core tensile strength.The result showed that the hydroxy amount on the modified nano SiO 2 particle surface was reduced,and the particle dispersion was improved.With increasing of PEG concentration,the mean diameter of nano SiO 2 was first decreased,then increased.And with the 0.5% PEG the value reached a minimum.The result also showed the effect of porous nano SiO 2 is better than that of spherical nano SiO 2,with increasing of nano SiO 2 amount,the binding strength of sand core was first increased,then decreased, when the content of nano SiO 2 was about 0.5%,the binding strength of sand core was increased by 45%.