Effects Of Catalysts On Structure Of Water-soluble Phenolic Resin And Itsapplication On Filter Paper

Lubricating oil filter paper is usually impregnated by thermosetting water-solublephenolic resin catalyzed by inorganic catalysts. This is due to the fact that inorganic catalystsare abundant, cheap, strongly alkaline, efficient and easily to prepare water-soluble phenolicresin. However, water-soluble phenolic resin prepared by inorganic catalysts shows poorstorage stability, brittleness, dark color and bad moisture resistance. On the contrary, phenolicresin prepared by organic catalysts results in an ash-free resin with excellent strengths andmoisture resistance. Moreover, the organic-catalyzed resins present better storage stability.However, the disadvantage is that organic catalysts are easy to vapor away, poisonous,expensive, and weak alkaline. Therefore, it is a good idea to combine the inorganic catalystsand organic catalysts to prepare water-soluble phenolic resin.Firstly, three phenolic resins were prepared using sodium hydroxide, ammonia andN,N-dimethylethanolamine, respectively, as catalyst. The molecular structure and thermalbehavior of the prepared phenolic resin was studied by Fourier transform infraredspectrometer, differential scanning calorimetry and thermal gravimetric analysis. Theperformances of filter paper impregnated with the prepared phenolic were studied by relevantequipments.Secondly, phenolic resins were prepared by binary composite catalysts system. Effects ofcatalyst dosages, ratio of catalysts and reaction duration on the molecular structure andperformance of impregnated filter paper were investigated. The catalysts system wasoptimized system based on the performance of impregnated filter paper.Finally, phenolic resin were prepared by triple composite catalysts system by adding thethird catalyst into the optimized binary composite catalysts system. The results shows that:when using5％sodium hydroxide,5％ammonia and5％N,N-dimethylethanolamine astriple composite catalysts, the impregnated filter paper shows best comprehensiveperformances. The impregnated filter paper’s burst strength and stiffness increases10％and30％, respectively, compared to phenolic resin prepared by inorganic catalyst. What’s more,there is no shrinking and a little growth in thickness. Mean pore diameter and max pore diameter almost stay the same. Oil resistance reaches5d and the peak of exothermic action is160℃.Effect of catalysts on resin and resin on impregnated filter paper is great. Sodiumhydroxide increases the water solubility of resin for it has a lot of hydroxymethyl groups.N,N-dimethylethanolamine causes resin linear resulting in good bending resistance of filterpaper. Ammonia causes benzoxazine structure making resin rigidity and filter paper’s burststrength high.