| The rapid development of the automotive industry puts higher requirements on the filter industry,and the performance requirements of the reinforced resins used in air filter paper,oil filter paper,and fuel filter paper(referred to as three filter paper)are also increasing.At present,air filter paper is reinforced with styrene-acrylic emulsion,which has the disadvantages of insufficient water resistance,hot sticky and cold brittleness,short service life especially in the coastal hot and humid environment,and the water-soluble phenolic resin commonly used in oil filter paper to enhance the processing and molding,the oil filter paper has the disadvantages of large brittleness,insufficient toughness,and poor processing performance.Therefore,this article uses the method of polymer blend modification.Silicone resins are generally insoluble in most polar solvents and water due to their hydrophobic character,oleophobic character.In order to increase the dispersion of silicone resin in water,it is necessary to introduce a hydrophilic chemical structure on the silicone main chain to prepare a water-soluble or water-dispersible silicone resin,and the styrene-acrylic emulsion and the water-soluble phenolic resin were further blended and modified,to improve the comprehensive performance of the filter paper after impregnating the resin.First,consideringthehydrosilylationreactionofmethacrylicacidand hydrogen-containing silicone oil,the carboxyl group and Si-H bond are prone to side reactions,therefore,methyl methacrylate is used to graft-modify the silicone oil,and the optimal preparation conditions are determined:the temperature is 130?.,the time is 4 hrs,the catalyst content is 30ug/g(the amount of platinum is based on the total mass of the reactants),the polymerization inhibitor is 2%(mass percentage of methyl methacrylate),and the molar ratio is n(C=C):n(Si-H)=1.2:1.In addition,a series of methacrylic methacrylate grafted silicone oil were prepared by gradient hydrolysis method,and the hydrolysis conditions of the soluble graft-modified silicone oil were determined.When the temperature was 60?,the hydrolysis time was 6hr,at this point,the acid value is 15.68mgKOH/g to obtain water solubility.And its structure was confirmed by FT-IR and ~1H-NMR.The modified silicone oil was blended with a styrene-acrylic emulsion and Differential Scanning(DSC)was used to characterize the compatibility of the two blends.Result display,as the degree of hydrolysis deepens,the endothermic peaks of styrene-acrylic emulsion and modified silicone oil gradually converge,combining the blend's centrifugal stability with high temperature stability indicates good compatibility.Secondly,using allyl glycidyl ether(ether)and allyl polyoxyethylene ether(polyether)as raw materials,hydrosilylation reaction is used to introduce hydrophilic polyoxyethylene ether side chains on the silicone molecular chains,to impart dispersibility to the modified silicone oil in water.At the same time,introduction of reactive epoxy groups,through the post-crosslinking technology,at the stage of the oil filter solidification process,the modified silicone oil and the phenolic methylol reactive group of the phenolic resin are copolymerized to achieve the defect that the toughness of the phenolic curing paper is insufficient.The factors such as reaction temperature,reaction time,amount of catalyst,mole ratio of unsaturated bond to silicon-hydrogen bond,and molar ratio of ether to polyether were examined.The results show,the best preparation conditions for the ether and polyether cograft silicone oil:the temperature is 85?,the time is 4hrs,the catalyst content was 30ug/g,and the molar ratio is n(C=C):n(Si-H)=1.2:1.At the same time,ether and polyether was co-grafted with silicone oil(the molar ratio of ether to polyether is 1:1).This modified silicone oil is water-soluble and can be blended with aqueous phenolic resin.The FT-IR and~1H-NMR spectra were used to characterize the structure,and the DSC was used to characterize the compatibility of the aqueous phenolic and modified silicone oils.At last,the blending system of methacrylic acid(methyl ester)side-chain modified silicone oil and styrene-acrylic emulsion was investigated to enhance the performance of air filter paper,the blending system of ether and polyether side chain modified organic silicone oil and water-based phenolic was investigated to enhance the performance of oil filter paper,and studied the water resistance of air filter paper and the oil resistance of oil filter paper.The results show,when the system blend mass ratio is 7:3(styrene-acrylic emulsion:modified silicone oil),air filter paper has the best comprehensive properties such as burst resistance,tensile strength,elongation at break,stiffness,and work of fracture.Compared with the pure styrene-acrylic emulsion system,its performance is maintained or slightly improved,but the water resistance is greatly improved.The bursting degree retention rate was 33.7%,and the burst strength was almost undetectable after immersion in pure styrene-acrylic emulsion-impregnated filter paper.When the phenolic resin was introduced into the ether and polyether cograft silicone oil,the mechanical properties of the prepared oil filter paper were improved.The fracture work and elongation at break,which characterize toughness,increased by 60%and 50%respectively.The oil resistance test of the oil filter paper showed that:the tensile strength,bursting resistance,fracture work,and elongation of the oil filter paper are greatly maintained,among them,the tensile strength has increased to some extent. |
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