Study On Improving Bond Strength Of Furan Resin Modified By Phenolic

Furan resin modified by phenolic belongs to non-nitrogen furan resin. During the period of casting, it doesn’t release nitrogen which gives rise to casting blowhole and other defects. Furan resin modified by phenolic is mainly suitable for casting high-temperature steel, especially for high alloy and large steel castings, because it has excellent high temperature resistant performance and the advantages of strong ability to resist adhering sand. But the furan resin modified by phenolic with the defect of low room temperature strength, poor through time and casting sand brittleness limits its application in the production of steel castings.The objective of this thesis is to synthesize furan resin modified by phenolic with high bond strength and excellent performance by using phenol, formaldehyde and furfuyl alcohol. The optimum technological conditions were determined by optimizing the synthesis process. When cardanol and polyol were added as modifiers, the influence on bond strength and other property were explored. Effect of the addition of silane coupling agent and ethyl silicate into PF/FA was studied. The results of this research in this paper mainly include four following aspects:(1) Comparing bond strengths before and after the optimization of PF/FA, the initial strength increased from 0.47MPa to 0.52MPa, increased by 10.6%, and final strength increased from 1.25MPa to 1.44MPa, increased by 15.2%.(2) PCF/FA was prepared by the method in which cardanol was used for partly substitution of phenol. The initial strength of resin sand was 0.5MPa, and final strength was 1.67MPa. In addition, the bond strength of PCF/FA less affected by the environment humidity.(3) The performance of polyol modified PF/FA, which was added in the acid reaction stage, was better. The optimal adding amount of polyol L, polyol M and polyol N was 10%, 10% and 15% of the amount reacting of furfuryl alcohol by weight respectively. Comparing to before modification, the bond strength increased by 6.25%,11.8% and 14.6% respectively.(4) When 0.3% of silane coupling agent was added into PF/FA, the final strength of resin sand increased from 0.94MPa to 1.45MPa. When 7% of ethyl silicate was added into PF/FA, the final strength of resin sand increased from 0.94MPa to 1.51MPa. When 0.2% of silane coupling agent and 5% of ethyl silicate were added into PF/FA, the final strength of resin sand is 1.58MPa.