Synthesis And Modification Of Aromatic Oil-based COPNA Resin For Electric Brush

As a byproduct in petroleum refining,aromatic oil is considered useless and low efficiency.With the continuous expansion of petroleum refining,aromatic oil production capacity has a huge improvement.How to realize the high value-added utilization of aromatic oil becomes a problem that needs to be solved.With short side chain,lower steric hindrance and high reactivity,aromatic oil is a good raw material for the synthesis of condensed poly-nuclear aromatic(COPNA)resin.In this paper,COPNA-B resin and modified COPNA-B resin was synthesized from aromatic oil JSF-47 at relatively low temperature,with 1,4-benzenedimethanol(PXG)as cross-linking agent,with boric acid and molybdic acid as modifying agents and p-toluene sulfuric acid(PTS)as catalyst.Properties of the resulting COPNA resin before and after modification,such as carbon residue,softening point and content of ? resin,were systematically characterized.The possible effects of the different ratio between crosslinking agent and modifying agents to the COPNA resin structure and performance were discussed.To achieve a definitive insight into the reaction mechanism,the critical characteristics of the resulting COPNA resin before and after modification and aromatic oil JSF-47 were purposely explored using by FT-IR,1H-NMR,XRD,and SEM.Structural parameters of aromatic oil JSF-47 and obtained COPNA resin before and after modification were calculated by improved B-L method,and then the average molecular models of aromatic oil JSF-47 and COPNA resin before and after modification were obtained.COPNA resin/graphite electric brushes were made from graphite while COPNA resin and modified resin as binder,and their performances including mechanical property,resistivity,hardness and the heat resistance were investigated.The results show that aromatic oil JSF-47 is a class of polycyclic aromatic substances with no side chains or short side chain structure that is a good raw material for the synthesis of COPNA resin.The synthetic and modified mechanism of COPNA resin from aromatic oil JSF-47 is acid-catalyzed positive ion condensation polymerization.The average molecular weight of COPNA-B resin is 466,and the average condensation degree is about 3.The addition of small amount of boric acid and molybdic acid enhances the average molecular weight of COPNA resin,and significant improves heat resistance of COPNA resin.The optimal technological conditions of resin/graphite composite brush which prepared in laboratory: A certain amount of molybdate modified COPNA-B resin and natural flake graphite powder were wet mixing evenly with proper additives,then hot press molding at 150 oC of molding temperature,30 MPa of molding pressure,20 min of holding time and 300 oC of calcination temperature.The flexural strength,shore hardness and resistivity of resin/graphite composite brush prepared under the process conditions is 24.16 MPa,33.5 and 470 ?? m,respectively.From the comprehensive performance of resin/graphite composite brush,the homemade brush prepared under laboratory conditions has reached the level of similar foreign products.