Study On Mechanical Properties And Hot Air Aging Mechanism Of Hydrogenated Nitrile Rubber

Rubber aging can cause changes in the physical and chemical properties of rubber products,leading to performance degradation and even failure.This article uses hydrogenated nitrile rubber as the matrix to study the effects of different vulcanization systems,filling and reinforcement materials,and various antioxidants on the properties of hydrogenated nitrile rubber.At the same time,the influence of these factors on the hot air aging performance of hydrogenated nitrile rubber and the thermal aging mechanism of hydrogenated nitrile rubber sealing products were also analyzed.Through the research in this article,we can provide specific theoretical and practical guidance for developing aging-resistant hydrogenated nitrile rubber and strong support for developing high-end equipment in the country.Firstly,this article explores the effects of different vulcanization systems on the properties of hydrogenated nitrile rubber,including sulfur vulcanization and peroxide vulcanization systems.The results showed that the crosslinking degree of HNBR vulcanized with peroxide was higher,and the vulcanization rate was the fastest,but the processing safety was poor.The HNBR tensile strength,100% elongation stress,and compressive permanent deformation resistance of peroxide vulcanized rubber are higher regarding physical and mechanical properties.Under the same strain,the vulcanized rubber has the highest energy storage modulus.In addition,the rubber compound cured with peroxide has the best heat resistance to air aging;in contrast,the amount of curing agent DCP and auxiliary curing agent TAIC significantly impact the HNBR performance.When the DCP dosage is 5 phr,the all-around performance of hydrogenated nitrile rubber is the best;An increase in the amount of auxiliary vulcanizing agent TAIC will also increase the vulcanization rate and crosslinking density of HNBR,thereby improving the tensile strength,100% elongation stress,and compression permanent deformation performance,as well as improving the heat resistance to air aging performance.DSC testing found that the glass transition temperature of HNBR rubber before and after hot air aging is mainly cross-linking reaction.Secondly,the effect of carbon black on the performance of HNBR when mixed with ZDMA and white carbon black was studied.The experimental results indicate that ZDMA can increase the crosslinking density and vulcanization rate of HNBR,but it will shorten the scorching time,which is detrimental to the processing performance.At the same time,ZDMA can improve the tensile strength,elongation,and tear strength of hydrogenated nitrile rubber vulcanizate,but it will reduce its compressive permanent deformation resistance.The addition of white carbon black can promote the vulcanization reaction of the rubber material,and increase the crosslinking density of the rubber material.Still,it can also cause the rubber material to scorch at high temperatures,affecting its processing performance.In addition,adding white carbon black can improve the elongation and tear strength of HNBR vulcanizate,but it will reduce its tensile strength and compressive permanent deformation resistance.To gain a deeper understanding of the effects of different reinforcement materials on HNBR,we conducted DSC tests.We measured the glass transition temperature of HNBR filled with varying reinforcement materials.The results show that the hot air aging process of HNBR rubber mainly involves crosslinking reaction,and the addition of ZDMA can improve the crosslinking reaction during the hot air aging process of HNBR.Finally,this article explores the effects of three types of antioxidants(antioxidant RD,antioxidant 4010 NA,antioxidant 445)and their combinations on the performance of HNBR.Research has found that compared with rubber without antioxidants added,the crosslinking density of rubber with antioxidants added decreases,the vulcanization rate decreases,and the scorching time increases.In terms of mechanical properties,adding different anti-aging agents reduces the tensile strength and constant elongation stress of the rubber compound,increases the elongation and tear strength,and reduces the compressive permanent deformation resistance.In the HNBR system vulcanized by peroxide,it was found that the anti-aging effect of three antioxidants was445>RD>4010NA.The glass transition temperature of HNBR filled with three types of antioxidants before and after hot air aging was tested by DSC.From the trend of glass transition temperature changes,it can be inferred that the cross-linking reaction mainly characterizes the hot air aging process of HNBR rubber.The primary anti-aging mechanism of the antioxidant in the hydrogenated nitrile rubber system was determined to terminate the secondary crosslinking reaction of the rubber compound.