Thermo-oxidative Resistance Research Articles

Investigation of preparation for reactive halloysite loading ZDMA and its thermo-oxidative resistance on the HNBR/FKM composites

Investigation of preparation for reactive halloysite loading ZDMA and its thermo-oxidative resistance on the HNBR/FKM composites

Mechanical and thermo-oxidative resistance properties of natural rubber film reinforced by orange peel-based carbon dots

Bio-based carbon dots (CDs) have a wide range of precursor sources, abundant chemical functional groups, and good free radical scavenging ability. This makes them an excellent candidate for modifying natural rubber (NR). In this work, CDs were synthesized from orange peels using a hydrothermal process and were utilized to reinforce NR latex. The structure and properties of both the CDs (including morphology, functional groups and fluorescence emission spectra) and NR/CDs films (including crosslinking density, morphology, functional groups, and mechanical properties) were comprehensively investigated. The results indicate that the inclusion of CDs led to improvements in tensile and tear strength while maintaining undamaged elongation at break. The tube model results indicate that the Ge (the elastic modulus brought by entangled chains) is significantly higher than the Gc (the elastic modulus contributed by chemical crosslinking) in this system, suggesting that the physical entangled network play a more significant role than chemical cross-linking; and the trend of Gc+Ge with the amount of CDs aligns completely with the cross-linking density measured by swelling method. Additionally, it was observed that CDs exhibited excellent thermo-oxidative resistance properties for NR. After 24 hours of thermal aging, the aging coefficient increased from 20.7% (NR-0) to 65.8% (NR-7). Furthermore, with an increase in thermal aging time, the tensile strength and crosslinking density of NR-0 decreased at a faster rate compared with NR-5. At an aging time of 40 hours, the tensile strength of NR-0 was reduced to 0.53 MPa and almost completely failed; whereas the tensile strength of NR-5 was still maintained at 8.2 MPa. Overall, the addition of CDs dramatically improved the thermo-oxidative resistance and mechanical properties of the NR film. Simultaneously, a novel way involving the utilization of orange peel with high value is being proposed.

Influence of 1,1′-Azobis(cyclohexanezonitrile) on the thermo-oxidative aging performance of diolefin elastomers

Abstract Diolefin elastomers play an important role in production and life, but their unsaturated structure leads to extreme vulnerability to heat and oxygen attack, so research into the aging of diolefin elastomers has been a hot spot in the industry. To overcome this limitation, a strategy based on the thermal decomposition of 1,1′-Azobis(cyclohexanezonitrile) (Azo) is devised, which forms stabilized compounds with imine groups during the heat process and captures radical. The diolefin elastomer was combined with azo, and isoprene rubber (IR) is chosen as a model material. Azo was added to IR to prepare the composite material (IR-Azo), and the thermo-oxidative resistance of the composite was significantly improved. Such as, after being exposed to thermo-oxidative conditions for 24 h, IR-Azo showed a tensile strength of 14.96 MPa with a retention rate of 68.25% which exceeded that of many traditional antioxidants. This study provides new insights into the development of elastomers with excellent thermo-oxidative resistance.

In English

Biopolymer matrices has been synthesized on the basis of ED-20 epoxy resin and soybean oil (SbO) bearing cyclocarbonate and epoxy groups. Mono(cyanoethyl)diethylenetriamine (UP) and tris(2-hydroxyethyl)amine (TEA) were used as hardeners. Chemical structure, mechanical properties, thermo-oxidative resistance of the samples and their changes after contact with distilled water, alkaline or acidic environment were studied. By means of ATR-FTIR the possible formation of H-NIPU (hybrid non-isocyanate polyurethane) fragments between cyclocarbonate groups of SbO and amino groups of the hardener was demonstrated. Influence of the curing mode and the type of hardener on water absorption, chemical and thermal oxidation resistance of the developed biopolymer matrices was thoroughly investigated. UP-based biopolymer matrices showed water and alkali resistance similar to the ones of neat epoxy polymers, while TEA-based biopolymer matrices showed better resistance to the acidic medium. The thermo-oxidative stability of the chosen samples was revealed by the TGA method in an air atmosphere. It was demonstrated that epoxy polymer cured with TEA hardener were more stable than the one cured with UP hardener. The similar dependence is observed for biopolymer matrices based on TEA hardener. At the same time, the curing mode has almost no effect on ultimate tensile strength value of the samples with ED-20/UP composition. However, the addition of functionalized SbO to the epoxy matrix cured with both TEA and UP hardeners increases the ultimate tensile strength values regardless of the type of oil functionalization. As expected, all biopolymer matrices exhibited higher ultimate tensile strength compared with unmodified epoxy polymers, which provides the possibility of their further application to obtain multi-layered bioplastics.

Characterization of Microalgae Biomass-Based Composites Obtained through Rotational Molding.

The wide range of applications and the numerous advantages of plastics have led to their excessive use, with subsequent damage to ecosystems. As an environmentally friendly alternative, biocomposites have gained much attention, and microalgae have become a potential source for their production. In this study, the use of washed and unwashed Spirulina in polyethylene-based composites has been evaluated as a way to prevent the thermooxidation of polyethylene, while at the same time, reducing the amount of virgin plastic used. Biocomposites were produced by rotomolding, testing different biomass contents and determining their mechanical and thermal performances as well as their water uptake level. Composites with up to 15% of biomass (by weight), a particularly high ratio for rotomolding, were satisfactorily produced. Using 5% of both biomasses did not significantly modify the behavior when compared with the neat PE samples' properties. For higher loadings, the use of non-washed biomass allowed us to obtain better properties, with added benefits related to using an unwashed biomass (less water consumption, lower costs and fewer environmental impacts). On the other hand, this study showed a promising beneficial effect on the thermooxidative resistance of composites, as the oxidation induction times were notably increased with biomass addition.

Effect of lignin on the structure-property behavior of metal-coordinated and chemically crosslinked ethylene-propylene-diene-monomer composites

The efficient development and utilization of green biomass-based macromolecule engineering materials are essential for the sustainable development of human civilization. In this study, lignin-based ethylene-propylene-diene-monomer (EPDM) composites with excellent mechanical performance were fabricated using a simple method. The effects of water-insoluble enzymatically hydrolyzed lignin (EL) and alkali lignin (KL) on the mechanical performance of the composites were investigated separately. The results showed that the tensile strength of EPDM reinforced with KL and EL increased to 24.5 MPa and 22.1 MPa, respectively, surpassing that of the carbon black (CB)-reinforced EPDM. After 72 h of thermo-oxidative aging, the retention rates of the tensile strength and elongation at break in the lignin-reinforced EPDM were much better than those formed with pure CB, indicating that lignin significantly improved the thermo-oxidative aging resistance of the composites. In summary, the Zn2+ coordination bonds formed between the interface of EPDM and lignin in lignin/CB/EPDM ternary composites effectively improved the mechanical performance and aging resistance of the composites. This study has significant implications for enhancing the utilization of lignin and green functional polymer materials.

Aging Resistance Evaluation of an Asphalt Mixture Modified with Zinc Oxide

The phenomenon of the oxidation and aging of asphalt binders affects the strength and durability of asphalt mixtures in pavements. Several studies are trying to improve the resistance to this phenomenon by modifying the properties of the binders with nano-particles. One material that shows promise in this field is zinc oxide (ZnO), especially in improving ultraviolet (UV) aging resistance. Few studies have evaluated the effect of these nano-particles on the thermo-oxidative resistance of asphalt binders, and, on hot-mix asphalt (HMA), studies are even more scarce and limited. Therefore, in the present study, the resistance to thermo-oxidative aging of an HMA manufactured with an asphalt binder modified with ZnO was evaluated. An asphalt cement (AC 60–70) was initially modified with 0, 1, 3, 5, 7.5, and 10% ZnO (percentage by weight of asphalt binder; ZnO/AC in wt%), and then exposed to aging in Rolling Thin-Film Oven tests (RTFOT) and a Pressure Aging Vessel (PAV). Penetration, viscosity, and softening point tests were performed on these binders, and aging indices were calculated and evaluated. Samples of HMAs were then manufactured using these binders and designed by the Marshall method, determining the optimum asphalt binder content (OAC) and the optimum ZnO/AC ratio. Control (unmodified) and modified HMA were subjected to short-term oven aging (STOA) and long-term oven aging (LTOA) procedures. Marshall, Indirect Tensile Strength (ITS), and resilient modulus (RM) tests were performed on these mixtures. LTOA/STOA results of the parameters measured in these tests were used as aging indices. In this study, ZnO was shown to increase the thermo-oxidative aging resistance of the asphalt binder and HMA. It also contributed to an increase in the resistance under monotonic loading in the Marshall and ITS tests, and under repeated loading in RM test. Likewise, it contributed to a slightly increasing resistance to moisture damage. The best performance is achieved using ZnO/AC = 5 wt%.

Synthesis and characterization of a high-temperature polycyanophosphate resin

A phosphorus-containing polymer with very high thermo-oxidative stability was synthesized for the first time by addition of silver nitrate to tricyanophosphine (P(CN)3). By optimizing the reaction time and silver nitrate concentration to a 1:1 molar ratio, a new polycyanophosphate [p(CP)] was formed as the primary phosphorus-containing product over the competing species, P(CN)3. The reactions and products were monitored by FT-IR, ICP-OES, NMR, and XPS spectroscopic techniques, which indicated a complicated oxidation reaction that converted the P(III) precursor species to P(V) polyphosphate species with pendant cyano- and isocyano- moieties. The p(CP) resin was found to contain a high (17.6 at.%) amount of phosphorus by ICP-OES, which contributed to its excellent thermo-oxidative resistance with a high char yield of over 60 wt.% at 1000 °C (1273 K) in air, indicating that the material could be particularly useful for high-temperature applications.

Thermo-oxidative resistance of C-rich SiCN(O) nonwovens influenced by the pretreatment of the silazane

C-rich SiCN(O) ceramic nonwovens with thermo-oxidation resistance up to 600 °C were developed from electrospinning of polyacrylonitrile in combination with different ratios of an oligomeric or polymeric silazane and subsequent pyrolysis. The influence of the selective pre-polymerization of the oligosilazane and the respective amount on the electrospinning, pyrolysis, phase formation and the properties of the resulting C-rich ceramic nonwovens was evaluated. The fiber diameter after pyrolysis at 1000 °C ranges from 0.26 to 0.63 µm. The oligosilazane/PAN-derived ceramic nonwovens contain high oxygen and carbon content because of high reactivity leading to a high ceramic yield due to additional crosslinking. A higher initial oxidation temperature compared to pure carbon was confirmed for all samples. However, the best result was achieved with a sample based on a high proportion of polysilazane in combination with PAN, as a dense passivating layer to protect the free carbon regions was obviously better able to form.

Anti-aging effect of TMQ on EPDM for Various Cure Systems

Ethylene propylene diene rubber (EPDM) is a common raw material for weather resistant rubber products used in lots of areas such as cable, automotive, marine industry and aviation applications. Superior processing behaviour, electrical properties and moderate high temperature resistance also make EPDM an attractive raw material for a wide range of further industrial performance requirements. As well as the other general purpose rubbers, EPDM needs to be protected against thermo-oxidative aging. Short and long term aging behaviour of both sulphur and peroxide cured EPDM has been studied in literature. However, to the authors’ best knowledge, there is not any study in literature systematically evaluating a common rubber antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) for investigating theoretical life-time of EPDM based materials that were vulcanized with different crosslinking systems. In this study, effects of TMQ on the thermo-oxidative resistance of EPDM has been studied for conven-tional and efficient sulphur vulcanization systems as well as peroxide vulcanization system. Aging mechanism for different cases has been investigated by using structural, rheological and mechanical tests. Thermo-oxidative aging has been monitored by carbonyl index and activation energy. Arrhenius based life-time estimation methodology has also been employed to evaluate aging behaviour of the reference and TMQ containing (-T) compounds. TMQ was found to exhibit different levels of protection against thermo-oxidative aging for all the curing systems and at all aging conditions. Higher aging activation energy for -T compounds has been attributed to extended service life of the material in the presence of TMQ.

Research on Durability and Long-Term Moisture Stability Improvement of Asphalt Mixture Based on Buton Rock Asphalt

Buton rock asphalt (BRA) has been used in asphalt pavement for its contribution to high-temperature stability. However, how BRA affects the durability of a corresponding asphalt mixture requires systemic discussion. This study investigated how BRA affected durability in terms of the fatigue resistance, thermo-oxidative aging resistance, and long-term moisture stability of asphalt mixture. Furthermore, improvement of the long-term moisture stability of asphalt mixture containing BRA modified asphalt (BRAM) was also included. An AC-20C asphalt mixture based on BRA asphalt, neat asphalt, and SBS-modified asphalt were prepared and their high-temperature, low-temperature, and moisture performance were examined. A semi-circular bending cyclic loading test was used to characterize fatigue performance. Thermo-oxidative aging tests in both the short-term and long-term were used to indicate the aging performance. Freeze–thaw cyclic splitting tests were carried out to investigate BRAM’s long-term moisture stability. Finally, the optimization and enhancement of BRAM’s long-term moisture stability was discussed in terms of ceramic, basalt, and polyester fiber, as well as hydrated lime. Results showed that BRA can enhance the high-temperature, low-temperature, and moisture performance of BRAM. The cracking fatigue resistance and thermo-oxidative aging resistance of BRAM were also improved by BRA. The long-term moisture stability of BRAM was lower than that of the asphalt mixture based on SBS and neat asphalt. It was found that the long-term moisture durability of BRAM can be optimally enhanced by replacing mineral filler with 50% hydrated lime by equal volume and using 0.2wt% ceramic fiber as an additive in BRAM.

Investigation on the thermo-oxidative aging resistance of nitrile-butadiene rubber/polyamide elastomer blend and the swelling behaviors in fuels predicted via Hansen solubility parameter method

Temperature-induced degradation of nitrile butadiene rubber (NBR) can negatively affect its mechanical properties. Further improvement in the aging resistance of the elastomer is required in view of the stringent application requirements. Polyamide elastomers (PAE) were used as reinforcing agents of NBR to prepare NBR/PAE blend by physical blending. Interaction between NBR and PAE was investigated using FTIR, DMA, SEM and swelling test. After aging at 110 and 130 °C for 7 days, NBR/PAE blend exhibited the minimum change of tensile strength. The reason why NBR/PAE blend could maintain excellent tensile strength retention during thermo-oxidative aging was investigated. Finally, the swelling behavior of rubbers in biodiesel and IRM 903 was measured and validated in combination with the Hansen solubility parameter (HSP) method. FTIR and swelling mass changes were also used to explain the reduction of the mechanical properties of NBR/PAE blend in biodiesel. This work presents useful guidelines for the development of thermo-oxidative aging resistance rubber products.

EFFECT OF LOW OXIDATION TEMPERATURE ON PROPERTIES AND SERVICE LIFE OF PETROLEUM ROAD BITUMEN

Studies were researched based on the quality and operating properties of oxidized road bitumen at different temperature conditions. The improvement of the quality of road oil bitumen, including the thermooxidative resistance to aging, at the production stage with the reduction of the oxidation temperature has been theoretically and empirically justified. BND 60/90 bitumen samples were taken during the research. The samples taken were analyzed according to the temperatures of 200, 220, 250 and 280 ℃. Here, in order to increase the resistance of bitumen samples taken at 160 ℃ to aging due to thermooxidative effect, softening temperature, fragility temperature, penetration at 25 ℃, mass loss, limiting shear stress, softening temperature in Petri cups and the relationships between them were studied in different regimes. It was determined that the preparation of asphalt-concrete mixtures and road surfaces from bitumen obtained as a result of oxidation of raw materials at a temperature of 220 °C is considered more favorable. It has been studied that bitumen oxidized at a temperature of 220 ℃ allows to extend the service life by 1.3-1.5 times due to its aging resistance. Keywords: bitumen, oxidation temperature, softening temperature, fragility, mass loss, road surfaces, aging resistance, limited shear stress, thermooxidative effect.

Impact of toluene sorption on oligomers and antioxydants migration from HDPE pipes

The objective of this work was to investigate the ageing behaviour of filled HDPE samples, immersed into toluene at 60 °C, in terms of migration and extraction of stabilizers and oligomers. Firstly, the high level of solvent solubility (mass uptake of∼13.6 wt%), due to the high toluene/HDPE affinity allowed the oligomers (M < 450 g/mol) to migrate and to finally be extracted (3.5 wt% of the mass sample for an immersion time of 96 h). Secondly, the decrease in OIT values, measured at 200 °C on HDPE samples dried after immersion, also revealed the extraction of antioxydants. On the other hand, the impact of the introduction of spherical (ZnO) or lamellar (graphite and organomodified montmorillonite) fillers up to 15 wt% on toluene sorption and migration phenomena was studied. As a result, the introduction of fillers, whatever the filler type, led to modification of the extraction profile of the oligomers. However, ZnO and MMT fillers had little effect on toluene sorption compared to graphite. Indeed, a significant decrease in the amount of toluene sorbed by the matrix and a significant slowdown in the toluene diffusion rate were demonstrated for amounts of graphite greater than 10 wt%. Interestingly, a reduction in the migration of low molar mass oligomers was evidenced and attributed to possible adsorption on the filler surfaces. Among the fillers used, graphite-type was more effective, reducing the amount of extracted species by a factor of 3.5. Regarding the impact of fillers on the thermo-oxidative behavior, once again, it was shown that graphite, at concentration higher than 10 wt%, allowed to prevent the antioxidant migration and consequently the thermal-oxidative degradation. Finally, and as expected, another way to improve the thermo-oxidative resistance after immersion in toluene was to increase the initial amount of antioxidants by adding Irganox B225 which is an equimassic mixture of Irganox 1010, a primary antioxidant and Irgafos 168, a secondary antioxidant.

Modification of Alkyd with Epoxy and its Application for Paint. Part 2: Durability of Paint Manufactured from this Ester

This article synthesized the epoxy alkyd ester resin by modifying alkyd resin with epoxy resin. The characteristics of synthesized resin was considered through the thermo-oxidation resistance, the chemical resistance (in 5 wt.% HCl, or in 5 wt.% NaCl solution), the UV-thermo-humidity complex stability (30 cycles, each cycle of 8 hours in UV irradiation at 60 °C and followed by 4 hours of humidity condensation at 50 °C), and the thermal shock resistance (7 cycles, each cycle of 10 minutes in refrigerated chamber at - 50 °C and 10 minutes in oven chamber at + 50 °C) The results showed that the thermo-oxidation resistance, the chemical resistance, and the UV-thermo-humiditycomplex stability of the ester epoxy alkyd paint film were higher than that ​​of alkyd paint film, while the thermal shock ability was similar to that of the alkyd paint.

Rheological and Thermo-Oxidative Aging Properties of Asphalt Modified with a Combination of Sasobit and Linear Low-Density Polyethylene

Research of different asphalt modifiers has been necessary for the attempt to construct durable roads with higher standards. Fischer Tropsch-paraffin wax (Sasobit) has recently attracted considerable attention over polymer modification due to its capacity to lower the energy requirements for asphaltic mix construction. In this study, Sasobit was used to recover the performance as well as the workability of 3 wt% linear low-density polyethylene (LLDPE) modified asphalt. A base asphalt binder with a penetration grade of 50/70 was blended with 3 wt% LLDPE and 3 wt% Sasobit separately and then combined with different Sasobit dosages (1–3 wt%). The performance of modified asphalt binders was evaluated using conventional, rheological, and thermal tests. As a result, it was found that loading Sasobit (1–3 wt%) into LLDPE-asphalt mixture steadily decreased the penetration and ductility at 25 °C from 25 to 12 dmm and 31 to 18 cm, respectively, and softening point increased by 20% indicating improved high-temperature performance. The binder workability and mix temperature were improved since the addition of Sasobit reduced the LLDPE-asphalt viscosity from 0.292 to 0.189 Pa.s (22% less). Sasobit improved the thermo-oxidative aging resistance of the binder by showing less weight variation (less than 0.001%) after the Rolling Thin-Film Oven Test (RTFOT) and high ductility retention (65%). Thermogravimetry (TG) and kinetics analysis results indicated that Sasobit-LLDPE delayed the initial and maximum decomposition temperature by 11 °C and hence increased the thermal stability of modified binders. Thus, the proposed binders are a suitable solution for asphalt pavement construction in regions that encounter high-temperature changes.

Construction of Biomass Tea Polyphenol-Functionalized Halloysite Nanotubes Enabling Green and Sustained-Release Antioxidants for Highly Antiaging Elastomers

The strategy of using sustainable biomass resources instead of traditional petrochemical products has been established as an environmentally friendly way to achieve the “green rubber” industry. Meanwhile, rubber antioxidants possessing high efficiency, long-lasting protection, migration resistance, and green multifunctional properties have attracted intensive investigation for rubber protection. Herein, a naturally extracted substance of tea polyphenol (TP)-functionalized halloysite nanotubes (HNTs), which generates the slow release of free-radical capturing activity and excellent interfacial interaction in the natural rubber matrix, is fabricated by vacuum-pumping and surface-decorating methods (denoted as HNTs-s-TP). Interestingly, the nontoxic and natural antioxidant HNTs-s-TP exhibited remarkable thermo-oxidative aging resistance and stability in a natural rubber (NR) matrix compared to that of TP directly pumped into the tubes due to the further modification of the chemical anchor TP on the outer surface of HNTs. In addition, we have systematically investigated the mechanism for highly efficient and sustainable antioxidation in the rubber matrix via the natural antioxidant HNTs-s-TP derived from the constructed galloyl structure. We envision that this new natural antioxidant fabrication technology will provide significant insights into the innovation for the construction of green and eco-friendly functionalized rubber additives.

Novel prepared nano potassium methyl siliconate as antioxidant for nitrile rubber

In this work, novel potassium methyl siliconate (PMS) was employed as a new nano-type antioxidant for acrylonitrile-butadiene rubber (NBR). NBR/PMS composites were produced by incorporating various contents of the prepared compound as anti-ageing agents (PMS) to improve the heat resistance of these composites. Potassium methyl siliconate (PMS) was prepared, and its chemical structure was confirmed by different elemental analyses. The curing properties, filler dispersion, thermo-oxidative ageing test, mechanical properties, FTIR, and TGA of the NBR/PMS composites were evaluated. It was detected by TEM images of PMS. The particles had a rhombic shape, and the particle size ranged from 1.23 nm to 7.84 nm. PMS could successfully promote the interfacial interaction between rubber and filler and the uniform dispersion of silica particles into the NBR matrix. As a result, the mechanical characteristics of the NBR/PMS composites were significantly improved, and they were superior to those of the NBR/TMQ composites with similar filler contents. Furthermore, the crosslinking density of the NBR composites was reduced after adding PMS (an antioxidant), which had a great effect on the mechanical properties. The results exhibited that PMS dramatically enhanced the solvent extraction resistance and the thermo-oxidative ageing resistance of NBR/silica composites more efficiently than TMQ. Overall, this work extended the application scope of PMS to develop novel and effective antioxidants for elastomers.

Effect of V-type crystallinity and starch particle structure on the oil loading capacity and anti-oxidation

Starch-based carriers have a great potential in functional oil encapsulation because of their mild preparation conditions, but the oil loading capacity and underlying anti-oxidation mechanism remain unclear. Here V-type starches were applied to fabricate flaxseed oil powder. Particle size analysis and scanning electron microscopy showed a loose aggregation microstructure of normal maize starch (NMS) prepared using the anti-solvent (AS) precipitation method, with an average size of 24.9 μm. Differential scanning calorimetry displayed a good thermo-oxidation resistance of NMS-derived V-type starch prepared via AS precipitation. Principal component analysis revealed that the oil loading capacity, related closely to V-type crystallinity and D50, has a significant positive correlation with the onset oxidation temperature and a negative correlation with the peroxide, thiobarbituric acid, and ρ-anisidine values. Our original study reveals the effects of V-type crystallinity and aggregation microstructure on the oil loading capacity and anti-oxidation, providing theoretical guidance for developing novel, starch-based carriers.

Evolution of crosslinking networks structure and thermo-oxidative aging behavior of unfilled NR/BR blends with TBIR as extra functional compatibilizer

As the most popular rubber blends in rubber industry, the aging behaviors of NR/BR vulcanizates have been a major challenge in science and industry. Our previous work reported the substitution of trans-1,4-poly (isoprene-co-butadiene) (TBIR) for BR in filled NR/BR vulcanizates for improved thermo-oxidative resistance. However, the effect of microstructure, especially the evolution of crosslinking networks structure on aging mechanism of unfilled NR/BR blends with extra TBIR has not been studied cleanly so far. Herein, the relationship between the crosslinking structure and mechanical or dynamic properties for unfilled NR/BR blends with extra TBIR are showed, and the microstructure evolution before and after thermo-oxidative aging also has been discussed. The evolution of crosslinking network, compatibility and phase morphology are systematically investigated. The results show that the polysulfide bond content and density decreased with the increased thermo-oxidative aging time and increased with the TBIR content. The increased polysulfide bonds give NR/BR/TBIR blends excellent fatigue properties. The chemical structure and thermo-oxidative aging mechanism of NR/BR/TBIR vulcanizates are also been discussed.