Applied Theory

• GUAN Chen, XUE Fengxian, WANG Zepeng, YANG Jian, HAN Xiaoying
• Correlation between Wear Resistance and Wear Debris Fractal Dimensions of NR/BR Blends

• 2024 Vol. 71(3): 0171-0177

  [Abstract](225)

  [PDF](216)

• Abstract:The Akron abrasion test was carried out on natural rubber（NR）/cis-1，4-polybutadiene rubber（BR） blends with different blending ratios，and the wear debris fractal dimensions of NR/BR blends were characterized and calculated to explore the relationship between wear resistance and wear debris fractal dimensions of NR/BR blends.The results showed that，with the increase of NR/BR blend ratios，the Akron wear amounts of NR/BR blends decreased first and then increased，and the Akron wear amounts of NR/BR blend was the smallest when NR/BR blend ratio was 60/40.The wear debris fractal dimensions of NR/BR blend increased first and then decreased，and the wear debris fractal dimension of NR/BR blend was the largest when NR/BR blend ratio was 60/40，the changing trend of the wear debris fractal dimensions of NR/BR blends was contrary to that of the Akron wears.The higher the degree of agglomeration of the wear debris of NR/BR blend was，the greater the wear debris group fractal dimension was.

• Tian Youfeng, KE Yuchao, LianG Yifan, Gao Shuiquan, XIA Yingsong
• Simulation Analysis on spatial Magnetic Field Distribution of Multipole Magnetic Rubber Encoder

• 2024 Vol. 71(3): 0178-0182

  [Abstract](186)

  [PDF](365)

• Abstract:Simulation analysis and experimental research on the spatial magnetic field distribution of the multipole magnetic rubber encoder were carried out based on the spatial magnetic field distribution theory.The variation rule of magnetic induction intensity in the air gap height direction and radial direction was obtained，which proved the accuracy of the simulation analysis.The simulation results of the influence of the magnetic pole pairs，the thickness and the width of the magnetic rubber layer on the magnetic induction intensity of the multipole magnetic rubber encoder could provide guidance for the design of multipole magnetic rubber encoders.

• ZHU Xinxin, XUAN Lujia, CUI Kaiwen, GUI Hongxing, WANG Hongzhen
• Preparation and Properties of NR/TPI Blends

• 2024 Vol. 71(3): 0183-0190

  [Abstract](161)

  [PDF](167)

• Abstract:The shock-absorbing product using natural rubber（NR）/trans-1，4-polyisoprene（TPI） blends were prepared，and the effects of natural TPI（Eucommia ulmoides rubber and Guttapo rubber） and synthetic TPI （grades TPI-28，TPI-58，TPI-80） on the properties of NR/TPI blends were studied.The results showed that the crystallinities of synthesized TPI were higher than those of natural TPI.The impacts of both synthetic TPI and natural TPI on the processing safety and vulcanization rates of NR/TPI compounds were minimal.Compared with NR vulcanizate，NR/TPI vulcanizates had higher Shore A hardnesses and moduli at 100% elongation，increased rebound values，reduced compression sets，improved damping performance，decreased dynamic heat generation，perfected heat resistance to air aging，significantly improved fatigue resistance，especially the number of times of six level flexural cracking fatigue and tensile fatigue of NR/TPI-28 vulcanizate were over one million and nearly two million respectively.NR/TPI-28 blend could significantly prolong the service life of shock-absorbing products.

• ZHAI Mingrong, SONG Meiqin, YU Chenglong, ZHUANG Lei, ZHEN Qiang, XU Chao
• Influence of Belt Angle and Warp Density on Dynamic Performance of Passenger Car Radial Tire

• 2024 Vol. 71(3): 0191-0196

  [Abstract](192)

  [PDF](166)

• Abstract:Under the premise of high correlation between finite element simulation results and experimental results，the single variable method was used to explore the influence of belt angle and warp density on the steady-state rolling resistance（referred to as rolling resistance） and cornering characteristics of passenger car radial tire（referred to as the tire）.The results showed that compared to the belt warp density，the belt angle variation had a greater impact on the dynamic performance of the tire.The belt angle variation had a significant impact on the cornering stiffness and return stiffness of the tire，but had a smaller impact on the rolling resistance.The above changes in the dynamic performance of the tire were related to its specification.

• SHAN Tilun, GAO Xiaodong, TIAN Xiaolong, BIAN Huiguang, WANG Kongshuo, LI Chaoyang, WANG Chuansheng
• Study on Pyrolysis Mechanism of Waste Tire by Applying Various Kinetic Models

• 2024 Vol. 71(3): 0197-0203

  [Abstract](179)

  [PDF](1290)

• Abstract:The pyrolysis mechanism of waste tire at four heating rates（10，20，30，40 ℃·min^-1） was studied by thermogravimetric（TG） analysis，and the kinetic parameters of waste tire were calculated by model-free method（FWO method，KAS method，Starink method，Friedman method and Kissinger method） and model fitting method（C-R method）.The results showed that，Kissinger method only obtained a single dynamic parameter，while the dynamic parameters obtained by FWO method，KAS method，Starink method and Friedman method were range values，so Kissinger method had the least calculation accuracy.When the kinetic parameters were calculated by the equal conversion method，the pre-exponential factor calculated by the FWO method was significantly larger than that calculated by the KAS method and Starink method.When using the C-R method to determine the most probable mechanism function，with the increase of heating rate，the activation energy increased，and the correlation coefficient had no obvious change rule.The mechanism function model followed in the pyrolysis process of waste tires was diffusion model D₃.The integration of TG analysis and kinetic model establishment could provide theoretical support for the pyrolysis treatment of waste tires.

Material · Compounding

• YANG Dechao, LI Chaoqin
• Effect of Structured Control Agents on Performance of Silicone Rubber

• 2024 Vol. 71(3): 0204-0210

  [Abstract](166)

  [PDF](152)

• Abstract:The effects of structured control agents hydroxy silicone oil，methoxy silicone oil and dimethyl diethoxysilicone oil on the performance of silicone rubber were studied using methyl vinyl silicone rubber as the main material.The results showed that the addition of structured control agent could inhibit the structured phenomenon of silicone rubber，reduce the degree of cross-linking，hardness，modulus at a given elongation，tensile strength，rebound value and compression set of silicone rubber，and increase the elongation at break.Hydroxyl silicone oil had the best inhibitory effect on the structuring of silicone rubber，which could reduce the storage modulus of silicone rubber（pinching compound） and prolong the storage time，while a better effect could be achieved when hydroxyl silicone oil amount was 6 phr.

• LIU Jinpeng, LIU Zhiguo, CAO Jiangyong, ZHANG Xiaolin, DING Qi, SONG Chuanyun
• Development of Low-temperature Resistant Rubber Sealing Material for Braking Device and Its Compatibility with Lubricating Grease

• 2024 Vol. 71(3): 0211-0215

  [Abstract](160)

  [PDF](146)

• Abstract:The failure modes and principles of the rubber sealing part in railway vehicle braking device at low temperature were analyzed，the low-temperature resistant rubber sealing material was developed by optimizing the formula，the compatibility between the low-temperature resistant rubber sealing material and the lubricating grease was studied，and the low-temperature sealing test and fatigue test of the rubber sealing part were conducted to verify the low-temperature resistant rubber sealing material.The results showed that Molykote 55 lubricating grease had little effect on the volume change rate，physical properties，and low-temperature resistance of the low-temperature resistant rubber sealing material，making it suitable as a lubricating grease for the braking device.The rubber sealing part produced could meet the requirements of the low-temperature airtightness and fatigue life at －55 ℃.

Product · Design

• CHANG Hao,LI Yu,LIU Xiangqian,GE Qi and CHENG Haitao
• Development of Lateral Stop for Rail Vehicle

• 2024 Vol. 71(3): 0216-0221

  [Abstract](161)

  [PDF](133)

• Abstract:A lateral stop for rail vehicle was developed based on Abaqus software.The lateral stop was made of metal bottom plate，rubber layer and top wear-resistant plate by vulcanization processing.Corresponding solutions were proposed to the problems encountered during the development process of the lateral stop，and the trial production of the product was completed.The structural reliability of the lateral stop had been verified through type experiments，and the lateral stop had been put into mass production.This study had certain reference value for the research and development of this type of products.

Technology · Equipment

• SUI Zhihua, HAO Yingjie, SUN Zuodong, QIU Jian, YAN Lizhi, ZHU Donglin, LI Li, WANG Chuansheng, BIAN Huiguang
• Effect of Filter Apertures of Dual Drive Synchronous Rubber Gear Pump Rubber Filter on Properties of Sidewall Compound

• 2024 Vol. 71(3): 0222-0226

  [Abstract](153)

  [PDF](137)

• Abstract:A dual drive synchronous rubber gear pump rubber filter was used to filter the tire sidewall compound，and the effect of the filter apertures on the properties of the sidewall compound was studied.The results showed that the properties of the filtered compound were better than those of the unfiltered compound，and the compound filtered with filter of 0.070 mm aperture（200 mesh） had the best vulcanization characteristics，physical properties and flexibility resistance，the weakest Payne effect，and better dynamic mechanical properties.Compared with unfiltered vulcanizate，the vulcanizate filtered with filter of 0.070 mm aperture had a 33.0% increase in tensile strength，a 33.3% increase in tear strength，and a 3-level decrease in average cracking level.

Testing · Analysis

• WANG Honggang, YANG Xingya, WANG Mingbo, ZHAO Ming′en, LI Zikang
• Analysis of Differences in Domestic and Foreign Standards for Shore A Hardness Testers

• 2024 Vol. 71(3): 0227-0231

  [Abstract](166)

  [PDF](168)

• Abstract:The use，calibration and verification standards of Shore A hardness testers used for rubber materials at domestic and foreign were analyzed，and the technical parameters of each standard，including the diameter of the cone frustum top，the diameter of the pressure foot，the diameter of pressure foot hole，the maximum extension of indentor and the allowable spring force applied to indentor were compared.This provided reference for Shore A hardness tester production and use enterprises，and the calibration and verification institutions.

Comprehensive and Special Review

• YIN Kezhen
• Research Progress in Polymer Multilayer Co-extrusion Technology

• 2024 Vol. 71(3): 0232-0239

  [Abstract](144)

  [PDF](159)

• Abstract:Polymer multilayer co-extrusion technology is a technique that uses a specially designed extrusion die to produce hundreds or thousands of layers of thin films from two different polymer materials.This technology can overcome the limitations of phase separation of traditional composite materials，achieving effective combination of different polymer materials.The nanoscale effect，interface effect and structural effect generated by polymer multilayer co-extrusion technology have broad applicability.Nanoscale effect can effectively control the crystalline phase and orientation of polymer crystals.Interface effect serves as an effective mean to study the interactions between polymer materials and can be used to manufacture novel materials，such as all-interface materials.Structural effect has optical significance，utilizing one-dimensional ordered layered structures to produce one-dimensional photonic crystals and combining the orientation characteristics of polymer materials，resulting in unique effects on the reflection and refraction of light.Polymer multilayer films have significant scientific research and practical applications in various fields.

Special Contribution

• HAN Xiaoying, WANG Zepeng, LI Xinyan
• Molecular Dynamics Simulation of Effect of Nano-SiO₂ with Different Particle Sizes on Properties of EPDM

• 2024 Vol. 71(3): 0163-0170

  [Abstract](185)

  [PDF](1701)

• Abstract:The model of ethylene propylene diene rubber（EPDM） and the models of nano-silica（SiO₂）/EPDM composites with nano-SiO₂ particle sizes of 1.2，1.5，1.8 and 2.0 nm were constructed by using Materials Studio 9.0 software，and the effects of nano-SiO₂ on the microstructures and mechanical properties of nano-SiO₂/EPDM composites under high pressure and low temperature（100 MPa/230 or 240 K） conditions.The results showed that compared with that of EPDM，the glass transition temperature（T_g） of the composites filled with nano-SiO₂ of different particle sizes increased to varying degrees，and the Tg of the composite with nano-SiO₂ particle sizes of 1.2 nm was 5 K higher than that of EPDM.The microstructures of the composites were changed，the mean square displacements and fractional free volumes decreased，and the decrease amplitudes increased with the decrease of nano-SiO₂ particle sizes.The cohesive energy densities were improved，and the increase amplitudes increased with the decrease of nano-SiO₂ particle sizes.But nano-SiO₂ particle sizes had little effect on the all-atom radial distribution functions of the composites.The mechanical properties of the composites were improved，and the improvement amplitudes decreased with the increase of nano-SiO₂ particle sizes.When nano-SiO₂ particle size was 1.2 nm，the bulk modulus of the composite increased by 5.98%，the shear modulus increased by 198.00%，and the elastic modulus increased by 34.65%.