Study And Application Of Structure-activity Factors Affecting The Vulcanization Rate Of NBR

As the most widely used special synthetic rubber in the world,NBR is an indispensable polymer material in transportation,petrochemical,coal mine,copying and other fields.It is widely used in rubber products such as rubber pipes,cable glue,wear-resistant seals,etc.Generally,NBR is widely used in industrial production.If it is not vulcanized,the comprehensive properties of NBR raw rubber can not meet the requirements of production,such as high hardness,poor physical and mechanical properties.At present,the low vulcanization rate is common in NBR market,which leads to the increase of production time and energy consumption;in addition,the vulcanization rate of NBR foam materials will directly affect the bubble structure and properties of the foam,so it is important to improve the vulcanization rate of NBR for the development of NBR.Because the requirement of NBR in industrial production is not only rapid vulcanization,but also excellent comprehensive performance,this paper will combine NBR with various performance,starting from two parts of NBR microstructure and vulcanization system,to study the internal and external factors affecting the vulcanization performance of NBR,and select the most widely used wear-resistant material when it is selected as chemical safety material In the field of sealing,further experimental research on the formulation and performance of high hardness NBR wear-resistant sealing materials is carried out,which aims to provide new ideas and breakthrough for the continuous production of NBR materials at high vulcanization rate,and provide the basis for the development of safety technology and improvement of quality and efficiency in the elastomer material industry.The following is the research content and main conclusions of this paper:（1）Seven kinds of NBR with medium high acrylonitrile content（about 33%）and high acrylonitrile content（about 41%）were selected,which were CKH3365 and CKH4065 of Sibur company,N21,3305 and 3308 of Lanhua company,1052 and 4155of Nandi company.First,the microstructure of the microstructure was characterized by ¹H NMR,gel and microgel content,Mooney viscosity,molecular weight and its distribution and glass transition temperature.Compared with the vulcanization,physical and mechanical properties and compression permanent deformation,the difference between the structure and properties of different brands of NBR was found,and the NBR vulcanization was analyzed from the microscopic perspective.Performance and various performance factors.The results show that the glass transition temperature of NBR has some corresponding regularity with acrylonitrile content and number average molecular weight.The lower the acrylonitrile content or number average molecular weight,the lower the Tg of NBR and the stronger the cold resistance.When the content of acrylonitrile in NBR is low,the content of acrylonitrile is the main factor affecting the vulcanization rate.With the increase of the content of acrylonitrile,the vulcanization rate is accelerated.When the content of acrylonitrile in NBR is high,the content of olefin is the main factor affecting the vulcanization rate.The higher the content of olefin is,the faster the vulcanization rate is The higher the content of acrylonitrile in NBR,the lower the content of olefin.That is to say,with the increase of acrylonitrile content,the vulcanization rate of NBR first increases and then decreases.The hardness of NBR is directly proportional to the content of acrylonitrile,because the rigidity of acrylonitrile structure is higher than that of butadiene structure;the branching degree of NBR molecular chain with high content of 1,2-vinyl group is higher,which helps to improve the tensile strength and constant elongation stress of NBR;the branching degree of NBR molecular chain with high content of1,4-addition-polybutadiene is lower,which helps to improve the elongation at break of NBR.The content of olefin structure in NBR molecule affects its compression set.With the increase of olefin structure content,the lower the compression set,the stronger the ability to recover the deformation.（2）The effects of sulfur curing system,peroxide curing system and peroxide/auxiliary curing agent composite curing system on the curing properties and physical and mechanical properties of NBR Lanhua 3305 were studied.The results showed that:in the sulfur curing system,the effective curing ev（1）system with high promotion and low sulfur combination had higher processing safety,and the curing rate of NBR could be increased by this system.Compared with sulfur curing system,peroxide curing system can improve the curing rate of NBR better,and the positive curing time T₉₀can be shortened by 60～120s;within a certain range,the more DCP content,the faster the curing rate of NBR,and the tensile properties of NBR vulcanizates are also proportional to the amount of DCP.Compared with DCP,curing agent 3 m has more significant effect on increasing the curing rate of NBR in peroxide/auxiliary curing system,and both TMPTMA and HVA–2 can significantly increase the curing rate of NBR.（3）The formula and performance of NBR wear-resistant seal were studied.The effects of different conditions on the vulcanization performance,physical and mechanical properties,wear resistance,oil resistance and Mooney viscosity of NBR Nandi 4155 were studied from three aspects of reinforcement system,operating system additives and vulcanization system.The results show that:The results showed that the reinforcing effect,vulcanization performance and wear resistance of NBR were the best when carbon black N220,N234,N326 and N330 were used as reinforcing materials.With the increase of N220 dosage,the processing safety of NBR was worse,and the vulcanization rate,physical and mechanical properties,wear resistance and oil resistance increased first and then decreased.When N220 dosage was 80 phr,the comprehensive performance of NBR was the best.The operating system additives were coumarone resin,C₅petroleum resin and phenolic resin.When phenolic resin was used,the hardness,tensile strength,constant elongation stress of vulcanizate were the highest and the wear resistance was the best.The plasticizing effect of coumarone resin was the best,and it was conducive to improve the curing rate of NBR.With the increase of coumarone resin,the curing rate of NBR was accelerated,and the mechanical properties and wear resistance were improved The wear pattern changes from abrasive wear to adhesive wear.The results showed that NBR had good processing safety,fast curing rate and good wear resistance under semi effective curing sev system with different sulfur curing systems;the tensile strength and constant elongation stress of vulcanizate under common curing CV system were the largest and the oil resistance was the best.