| The main chain structure of chloroprene rubber(CR)is unsaturated,and the molecular chain contains a large number of electrically absorbing chlorine atoms.The molecular chain has high regularity and is easy to crystallize.It has excellent comprehensive mechanical properties,fatigue resistance,oil resistance,aging resistance,excellent flame retardancy and electrical insulation.It is widely used in shock-absorbing products,but there are still problems such as easy scorch during processing and poor adhesion during molding and bonding.Therefore,this topic mainly starts from the perspective of formula design.The effects of matrix material selection,vulcanization system,plasticizing system,anti-aging system and tackifying system on the processing safety,adhesion performance and dynamic performance of CR-based damping composites were studied.The influence mechanism of interface structure on adhesion performance was further explored by means of design evaluation of adhesive strength of vulcanizate.The main contents are as follows :Firstly,sulfur-regulated CR,thiol-regulated CR and xanthate-regulated CR were selected as the matrix,and the effects of microstructure on the properties were compared.The results showed that the sulfur-regulated Baypren510 compound was easy to burn,and the adhesive strength of the compound was high.The processing safety of thiol-regulated WRT S-40 V and xanthate-regulated Baypren116 compound was improved,and it had better damping effect.In addition,the thiol-regulated S-40 V exhibits good high-temperature compression permanent deformation and cold resistance.Using thiol-regulated chloroprene rubber S-40 V as matrix,zinc oxide(Zn O)/magnesium oxide(Mg O)/ tetramethyl thiourea(Te MTU)/ N-cyclohexyl2-benzothiazole sulfonamide(CZ)as curing system,with the increase of Te MTU content,the Mooney viscosity of CR compound decreased slightly,the Mooney scorch time shortened,the crosslinking density increased,the adhesion strength of CR vulcanizate bonded sample increased,but the fatigue resistance of lap bonded sample decreased continuously.When the amount of accelerator Te MTU was 1.5 phr,the effects of different types of antioxidants and their combination on the properties of CR-based composites were investigated.The results showed that the introduction of antioxidant reduced the Mooney viscosity,minimum torque(ML)and crosslinking density of CR compound to varying degrees.The influence of antioxidant on scorch time was as follows(from large to small): OD > blank sample,microcrystalline wax > 264,antioxidant A >antioxidant 4020,antioxidant 3100,264 / 4020 / OD,OD / A / 3100.In addition,the addition of antioxidant improved the dynamic and static stiffness ratio of CR vulcanizate and the tensile fatigue resistance of the bonding interface to varying degrees.The combination of antioxidant 264 / 4020 / OD and OD / A / 3100 can effectively improve the bonding strength of the bonding interface of CR vulcanizate.With the increase of the amount of plasticizer dioctyl terephthalate(DOTP),the scorch time and optimum curing time of CR compound were prolonged,and the Mooney viscosity,ML and crosslinking density were gradually reduced.The bonding strength of the vulcanized rubber bonded sample showed a trend of increasing first and then slowly increasing,and the tensile fatigue resistance of the lapped sample reached the highest when the amount of DOTP was 20 phr.The addition or combination of four tackifying resins,such as petroleum resin A-90,octyl phenolic tackifying resin 203,coumarone resin and condensation Koresin resin of butyl phenol and acetylene,will reduce the Mooney viscosity of CR compound,and the Mooney scorch time t5 will be prolonged.Although the scorch time is shortened to varying degrees,it still shows the improvement of CR interface adhesion,among which coumarone resin increases most obviously,followed by A-90;it was also found that the combination of coumarone / Koresin can significantly improve the tensile fatigue resistance of lapped specimens. |
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