Toughening Modification Of Phenolic Resin And Its Application In Abrasives

Phenolic resins have an increasing industrial demand due to their excellent adhesion and flame retardancy,especially in the grinding process.However,phenolic resin also has the disadvantages of poor heat resistance and low toughness,which greatly limits the application of phenolic resin.With the development of current industry,the performance requirements of phenolic resin are getting higher and higher,in order to meet the requirements of use,It is especially important to modify the phenolic resin.Improving the heat resistance and toughness is the direction of the development of phenolic resin materials.In view of the shortcomings of low phenolic resin,the phenolic resin is modified by polytetrafluoroethylene,ultrahigh molecular weight polyethylene,nitrile rubber and xylene to improve its toughness and other properties.It was determined by experiments:(1)polytetrafluoroethylene modified phenolic resin.When the reaction temperature was 50℃,the time was 20 h,and the amount of acrylic acid was 6 ml,an acrylic grafted polytetrafluoroethylene copolymer with a graft ratio of 7.49%was obtained.When the reaction temperature was 80℃for 2 h,When the amount of PTFE-g-PAA added is 2 wt%,the PTFE-g-PAA modified phenolic resin has the best comprehensive performance;(2)the ultrahigh molecular weight polyethylene modified phenolic resin.The reaction temperature was 100℃,the reaction time was 4h,and the amount of acrylic acid was 8 ml to obtain an acrylic grafted ultrahigh molecular weight polyethylene copolymer with a graft ratio of 10.8%.When the reaction temperature was 80℃for 2 h,When the amount of UHMWPE-g-PAA added is 1.5wt%,the overall performance of UHMWPE-g-PAA modified phenolic resin is the best;(3)a.Nitrile rubber modified phenolic resin.The carboxylated nitrile rubber solution was directly added.When the reaction temperature was 80℃,the reaction time was 2 h,and the carboxylated nitrile rubber solution was added in 10 parts,the nitrile rubber modified phenolic resin had the best comprehensive performance.b.First synthesize part of the phenolic prepolymer and then add the carboxylated nitrile rubber solution.When the dehydration reaction temperature is 140℃,the reaction time is 3 h,the carboxylated nitrile rubber liquid is added in an amount of 10 parts,and the amount of the phenol and the aldehyde used in the synthesis of the prepolymer is 40%,the performance of the modified phenol resin is optimal.At this time,the modified phenolic resin was 3.37 KJ/m~2,which was increased by 58.2%;the flexural strength was up to 59.62 MPa;and the hardness was 84 HRB.(4)Nitrile rubber/xylene co-modified phenolic resin.After 6 g of xylene formaldehyde resin and phenol were boiled under oxalic acid for 2 h,5 parts of carboxylated nitrile rubber solution and residual phenol and some formaldehyde were reacted at 80℃for 2 h to obtain the product.The comprehensive analysis shows that the toughness of polytetrafluoroethylene modified phenolic resin and ultrahigh molecular weight polyethylene modified phenolic resin is improved,and their impact resistance is 11.1%and 16.5%higher than that of our pure phenolic resin.However,in the case where the compatibility with a reagent such as phenol cannot be improved,the toughness cannot be further improved.The toughness of the nitrile rubber modified phenolic resin increased greatly,and the impact resistance improved by 58.2%to 3.37 KJ/m~2.The heat resistance of the nitrile rubber/xylene co-modified phenolic resin is basically not reduced,and the toughness and water resistance are greatly improved.The impact resistance is improved by 63.5%,reaching 3.48KJ/m~2,which is superior to the commercial phenolic resin.