Special Contribution

• CAO Jinfeng,MA Liyuan,SHI Qingxiang,LIU Xilong,LIU Wenjie and XU Ziwei
• Research on Sealing Performance of NBR O-shaped Sealing Ring Under Normal Temperature and High-Pressure Condition

• 2026 Vol. 73(7): 0483-0490

  [Abstract](304)

  [PDF](93)

• Abstract:Taking the nitrile rubber（NBR） O-shaped sealing ring（referred to as O-shaped sealing ring） under normal temperature and high-pressure（80～180 MPa of medium stress） conditions as the research object，a two-dimensional axisymmetric model was established using finite element analysis method to investigate the effects of medium stress，inner fillet radius and sealing clearances on the contact stress of the O-shaped sealing ring.The results indicated that，as the medium stress increased，the maximum contact stress of the O-shaped sealing ring increased linearly and remained consistently higher than the medium stress，ensuring sealing performance met requirements.Altering the inner fillet radius had a minor impact on the contact stress of the O-shaped sealing ring，but when the inner fillet radius was too small，stress concentration occured at the sealing groove of the O-shaped sealing ring，affecting the sealing stability of the O-shaped sealing ring.Increasing the sealing clearance reduced the sealing performance of the O-shaped sealing ring.Changing the inner fillet radius and sealing clearances leaded to a shift in the location of the maximum contact stress. Key words：O-shaped sealing ring；NBR；high-pressure condition；sealing performance；finite element analysisTaking the nitrile rubber（NBR） O-shaped sealing ring（referred to as O-shaped sealing ring） under normal temperature and high-pressure（80～180 MPa of medium stress） conditions as the research object，a two-dimensional axisymmetric model was established using finite element analysis method to investigate the effects of medium stress，inner fillet radius and sealing clearances on the contact stress of the O-shaped sealing ring.The results indicated that，as the medium stress increased，the maximum contact stress of the O-shaped sealing ring increased linearly and remained consistently higher than the medium stress，ensuring sealing performance met requirements.Altering the inner fillet radius had a minor impact on the contact stress of the O-shaped sealing ring，but when the inner fillet radius was too small，stress concentration occured at the sealing groove of the O-shaped sealing ring，affecting the sealing stability of the O-shaped sealing ring.Increasing the sealing clearance reduced the sealing performance of the O-shaped sealing ring.Changing the inner fillet radius and sealing clearances leaded to a shift in the location of the maximum contact stress.

Applied Theory

• LI Chao,MA Gang,SUN Yecheng,LIU Xiayu,LU Yuhe and LIU Junliang
• Investigation on Interfacial Structure Evolution of Silicone Rubber Material for Composite Insulator During Thermal Oxidative Aging Process

• 2026 Vol. 73(7): 0491-0496

  [Abstract](254)

  [PDF](92)

• Abstract:The thermal oxidative aging process of silicone rubber material for composite insulator was studied from the perspective of interfacial structure evolution of the rubber matrix and the filler.The results showed that the silicone rubber material for composite insulator experienced the processes including the degradation of crosslinking structure，the desorption of filler particles and the reconstruction of crosslinking network during the thermal oxidative aging process.As a result，during accelerated aging process，the compatibility between the filler and the silicone matrix deteriorated，showing the separation of the rubber ‘sea’ phase and the inorganic filler ‘island’ phase，and the filler escaped from the encapsulation of the rubber matrix，which made the filler particles desorp from the rubber matrix and form as hole defects towards the rubber matrix.All these accelerated the structure damage and property deterioration of the silicone rubber material.

• SUN Yecheng,TIAN Yao,LI Chao,MA Gang,LU Yuhe,TIAN Shaoyang and LIU Junliang
• Effect of Relative Molecular Weights of Silicone Rubber on Aging Properties of Silicone Rubber Materials for Composite Insulators

• 2026 Vol. 73(7): 0497-0502

  [Abstract](251)

  [PDF](101)

• Abstract:The effect of relative molecular weights of methy vinyl silicone rubber（VMQ） on thermal oxygen-high humidity-ultraviolet multi-factor aging properties of VMQ materials for composite insulators was studied.The results showed that in the range of weight average molecular weight of 459 000 to 765 000，the higher molecular weight VMQ material had stronger rubber matrix-filler interaction，the filler was not easily detached after VMQ material aging，and the degradation of surface morphology and the decrease in tensile properties were slower.The aging time for complete pulverization of VMQ material with a weight average relative molecular weight of about 765 000 was delayed about 240 h compared to VMQ material with a weight average relative molecular weight of about 459 000，and after its aging，the performance retention rate of characteristic groups of VMQ molecule was the highest，the performance retention rate of —Si—O—Si— skeleton group was about 43.7%，the performance retention rate of —Si—CH3 hydrophobic side group was at about 21.9%.

• LUO Hengyu,LI Feijie,LI Junyu,LI Liang,LIANG Liqiang and LIU Qi
• Study on Thermal Oxidative Aging Behavior and Life Prediction of FKM and NBR

• 2026 Vol. 73(7): 0503-0508

  [Abstract](318)

  [PDF](88)

• Abstract:The thermal oxidative aging behavior of fluororubber（FKM） and nitrile rubber（NBR） compounds was studied，and the storage and service life were modeled and predictd.The results indicated that the thermal oxidative aging patterns of FKM and NBR compounds were similar，the compression set（CS）of both compounds increased with extended aging time and increased aging temperatures.Compared to FKM compound，the NBR compound was more susceptible to aging at higher temperatures.When the CS reached 10%，the storage critical time for FKM and NBR products at temperatures between 25 ℃ and 30 ℃ was approximately 4.55 and 2.55 a，respectively.For a designated storage life of 5 a for FKM product and 2 a for NBR product，the corresponding critical storage temperatures were 24.07 and 31.71 ℃，respectively.In terms of service life，under a 25 ℃ air atmosphere，the time required for the CS to reach 25% was 38.66 a for FKM product and 27.06 a for NBR product.Furthermore，under the premise of a 20 000 h service life，the critical maximum service temperatures for the CS to reach 50% were 82.58 ℃ for FKM product and 55.74 ℃ for NBR product.

Material · Compounding

• YUE Qianqian,LIU Huiying,HUANG Xianchen,ZHANG Xinlin,ZHU Jianhua,WU Mingjun and WANG Changyin
• Study on Performance of Domestic Oil-Extended NdBR

• 2026 Vol. 73(7): 0509-0515

  [Abstract](275)

  [PDF](92)

• Abstract:The performance of standard formula compounds and winter tire tread compounds using domestic oil-extended neodymium-based butadiene rubber（NdBR） was investigated.The results showed that compared to imported NdBR，the physical and chemical properties of domestic oil-extended NdBR were generally comparable.When domestic oil-extended NdBR was used as an equivalent substitute for imported NdBR，the processability of the standard formula compounds and winter tire tread compounds remained similar，while the wear resistance improved and rolling resistance decreased.

• WANG Hailu,REN Qinghua,LIU Ziguang and DENG Shitao
• Application of Low Rolling Resistance Agent DS-01T in SSBR Compounds

• 2026 Vol. 73(7): 0516-0520

  [Abstract](270)

  [PDF](98)

• Abstract:The application of low rolling resistance agent DS-01T in solution-polymerized styrene-butadiene rubber（SSBR） compounds was investigated.The results showed that，compared to SSBR compound without low rolling resistance agent DS-01T，the Mooney viscosity of SSBR compound with low rolling resistance agent DS-01T increased，the 300% modulus，tensile strength，and rebound resilience of SSBR vulcanizate slightly increased，the rolling resistance was reduced，the wet skid resistance was improved，the carbon black dispersion increased.Overall，the addition of low rolling resistance agent DS-01T improved the performance of ordinary SSBR compounds，it would expected to enhance the cost-effectiveness of tire tread compound to a certain extent.

• LIU Wanping,ZENG Fanwei,WANG Hongqing,LIN Qiang,ZHANG Bozhi and YU Yunbao
• Effect of Protective Waxes on Insulation Performance of CPE Wires

• 2026 Vol. 73(7): 0521-0526

  [Abstract](296)

  [PDF](81)

• Abstract:Using polyvinyl choride（CPE） insulation materials to prepare wires（referred to CPE wires），the effect of protective waxes on the insulation performance of chlorinated polyethylene （CPE） wires was studied.The results showed that compared with 58^# paraffin，the crystals of protective wax RW287，RW217 and LSB20 were smaller，the formed wax film was denser，so that the resistance of their CPE wires increased，the insulation performance was better.Adding protective wax could significantly increase the resistance of CPE wires.The larger the protective wax dosage amount was，the greater the resistance of CPE wires was，and the better the insulation performance was better.Moreover，the longer the room temperature storage and water immerdion time was，the greater the improvement of insulation performance of CPE wires by protective wax was.The protective wax LSB20 and RW287，which were suitable for a wider temperature range，had better protective effect on CPE wires.The protective wax LSB20 had better protective effect on CPE wires at normal temperature（25 ℃），while the protective wax RW287 had better protective effect on CPE wires under long-term water immersion conditions.

Product · Design

• MA Dongli,LUO Pingchang,LIU Huan,WANG Keyi,LI Liwei,HE Lei and WANG Runguo
• Preparation and Performance Study of Antibacterial Nitrile Latex Gloves Modified with Bio-Based Itaconate Latex

• 2026 Vol. 73(7): 0527-0530

  [Abstract](181)

  [PDF](66)

• Abstract:The antibacterial nitrile latex gloves were prepared by nitrile latex modified with bio-based itaconate latex and their properties were studied.A low-temperature redox emulsion polymerization method combined with a stepwise monomer addition process was employed to produce highly active bio-based itaconate latex，the itaconate latex and nitrile latex were blended in a solid mass ratio of 2/3，and an antibacterial agent consisting of nano-silver ions/cetyltrimethylammonium bromide（mass ratio of 2/1） at 0.8% of the latex solid mass fraction was added.The modified nitrile latex gloves exhibited a tensile strength of 28.6 MPa and an elongation at break of 515%，meeting the national standard requirements for strength performance.The bio-based content of the modified nitrile latex gloves reached 26%，while the antibacterial and anti-allergic properties were excellent，addressing the issues of traditional nitrile latex gloves’ reliance on petrochemical resources and insufficient long-lasting antibacterial performance.

• CAO Yong,ZHANG Jianhua,GAO Junfeng and XU Yongqiang
• Design of 53/80R63 Tubeless Giant All-steel Off-The-Road Radial Tire

• 2026 Vol. 73(7): 0531-0534

  [Abstract](271)

  [PDF](79)

• Abstract:The design of 53/80R63 tubeless giant all-steel off-the-road radial tire was described.In the structure design，the following parameters were taken：overall diameter　3 820 mm，cross sectional width　1 295 mm，width of running surface　1 182 mm，arc height of running surface　82 mm，bead diameter at rim seat　1 588 mm，bead width at rim seat　914.4 mm，maximum width position of cross–section（H₁/H₂）　0.88，the tread using a comprehensive pattern design，pattern depth　110 mm，number of pattern pitches　38，block/total ratio　75%.In the construction design，the following processes were taken：adopting rubber strips to wrap the tread craw and base for building，1^# and 2^# belt using 7×7×0.25＋0.15HT high tenacity steel cord，3^# and 4^# belt using 7×（3＋9＋15×0.245）＋0.245HT high tenacity steel cord，5^# and 6^# belt using 4×6×0.25HE high elongation steel cord，using six drum secondary building machine to build green tire，using steaming pot vulcanization press to vulcanizate tire.The test results showed that，the inflated peripheral dimention and durability of the finished tire met the design and national standard requirements.

Technology · Equipment

• AI QI,ZHOU Mingyong and LIU Jiani
• Optimisation on Vulcanization Time of V-Shaped Rubber Spring Based on Simulation Analysis

• 2026 Vol. 73(7): 0535-0541

  [Abstract](249)

  [PDF](87)

• Abstract:Aiming at the problem of inconsistent vulcanisation degree caused by uneven temperature distribution in the cavity and sloppy design of vulcanisation time for V-shaped rubber springs, numerical simulation based on vulcanisation heat transfer and vulcanisation kinetic model calculates the temperature field distribution in the cavity of the mould and the vulcanisation degree of the rubber, the strategy of increasing the heating ring in the middle mould and determining the optimal temperature setting were proposed, and the optimal vulcanisation time was determined by considering “thepost-vulcanisation effect”. Finally, the accuracy of the simulation results is proved by the results of swelling and vertical stiffness test.Aiming at the problems of inconsistent vulcanization degree caused by uneven temperature distribution in the mould cavity and improper design of vulcanization time for thick product—the V-shaped rubber spring，by numerical simulation based on vulcanization heat transfer and vulcanization kinetic model，the temperature field distribution in the mould cavity and the vulcanization degree of the core of the V-shaped rubber spring were calculated to propose increasing the heating ring in the middle mould and determine its optimal temperature，and the optimal vulcanisation time of the V-shaped rubber spring was determined by considering the post-vulcanisation effect.The accuracy and reliability of the simulation results for the vulcanization time of the V-shaped rubber spring were proved by swelling inedx and vertical stiffness test.

Testing · Analysis

• SHEN Libin,FAN Junlei,CHEN Jing,ZHANG Yun and WANG Liansheng
• Comparison of Testing Methods for Polymer Contents of EPDM Particles Used in Sport Grounds

• 2026 Vol. 73(7): 0542-0547

  [Abstract](260)

  [PDF](75)

• Abstract:For 10 samples of ethylene propylene diene monomer rubber（EPDM） particle used in sport grounds，the organic contents were tested according to GB/T 14837.1—2014 and GB/T 14837.2—2014 thermogravimetric（TG） methods（referred to as TG1 method and TG2 method respectively），the solvent extraction contents were tested according to GB/T 3516—2006 solvent extraction A method and solvent extraction B method（referred to as extraction A method and B method respectively），and the polymer contents were tested using four combination testing methods.The results showed that compared to TG2 method，TG1 method ensured complete decomposition of EPDM in EPDM particle and effectively avoided interference from other components in EPDM particles.Compared to extraction A method，extraction B method not only demonstrated higher efficiency and thorough extraction，but also had a certain possibility of discovering sample abnormalities.When testing the polymer content of EPDM particles，the combination testing method of TG1 method and extraction B method was found to be the optimal choice.

Comprehensive and Special Review

• GAO　Yu,XIAO　Ping,LUO　Zhu,ZHU Sijia,CHENG Ya''nan and HU Shikai
• Research Progress on Thermal-Oxidative Aging of Rubber Materials

• 2026 Vol. 73(7): 0548-0556

  [Abstract](272)

  [PDF](96)

• Abstract:The mechanism and influencing factors of thermal-oxidative aging of rubber materials were analyzed，and the research status of protective technologies of rubber materials was reviewed.The differential expressions of the free radical chain oxidation reactions in different rubber materials were as follows：natural rubber materials were primarily characterized by competitive reactions of crosslinking and chain breaking of rubber molecules，styrene-butadiene rubber was more prone to secondary crosslinking due to allyl activities of rubber molecules，ethylene-propylene-diene monomer rubber exhibited early degradation characteristics dominated by broken chains due to the saturation of the rubber molecule main chain.Rubber molecular structures and environmental conditions were dual influencing factors of the thermo-oxidative aging of rubber materials，specifically including the chemical bond energy of the rubber molecule main chain and side group characteristics，and temperature，oxygen and ultraviolet actions.Traditional antioxidants effectively delayed the thermo-oxidative aging process of rubber materials through radical quenching and hydroperoxide decomposition mechanisms.While filler modification technologies significantly improved the thermal stability of rubber matrix through multiple mechanisms such as physical barrier，crosslinking network reinforcement and catalytic inhibition.Novel protective technologies include the synergistic mechanism of nano-protective materials and bio-based antioxidants.In future，the research on the thermo-oxidative aging of rubber materials should focus on the combination of multi-scale simulation and experimental verification to develop intelligent material systems that combine high protection efficiency with environmental friendliness.