Properties Of Rubber Research Articles

Improving the ablative properties of silicone rubber by adding aluminum foil/expanded perlite

In this study, aluminum foil (AF) and expanded perlite (EP) were used as the reinforcing fillers to improve the ablation properties of phenyl methyl vinyl silicone rubber composites. The expansion and caramelization of char layer enhanced the ablation and thermal insulation performance of silicone rubber-based composites. The improved bonding of char layer provided a good basis for enhancing ablative properties. The presence of EP increased the emissivity of the char layer which improved the heat radiation properties during ablation process, and it was advantageous to lower surface temperature and reduce thermal erosion. The graphitic degree of char layer was increased which improved high-temperature and oxidative resistance. SEM observations revealed that the surface and cross-section of the char layer were densified, as characterized by the pore size distribution analysis. The above results indicated that the ablation and anti-erosion resistance as well as thermal insulation behavior of silicone rubbers were significantly improved by implementing the expansion and caramelization strategy, which exhibit promising applications as flexible anti-ablation materials for thermal protection purposes.

Using Thin Ultra-High-Molecular-Weight Polyethylene Coatings to Reduce Friction in Frost-Resistant Rubbers.

Frost-resistant rubbers retain their highly elastic properties over a wide temperature range. They are used in various friction units (e.g., seals), but their high friction coefficient and low wear resistance lead to the need for frequent replacement. In this paper, we propose applying thin (several hundred microns) UHMWPE coatings to formed rubber rings. The application technology depends on the required coating thickness. Friction tests of the coatings and pure UHMWPE were performed using the ball-on-disk (unidirectional sliding) scheme for various loads and velocities. In the experiments, the friction coefficients and temperatures near the contact area were determined. Friction tracks were studied using microscopy methods. The sliding contact of the ball and the two-layer material was modeled to obtain the dependences of the deformation component of friction on the sliding velocity for coatings of different thicknesses. UHMWPE is sensitive to frictional heating, so the thermal problem of determining the temperature in the contact area was also solved. It is shown that the minimum friction coefficient occurs for coatings with a thickness of 600 μm. At the same time, in the case of the 300 μm coating, the surface of the friction track is practically no different from the initial one. Thus, the studied combination of polymers provides antifrictional properties and wear resistance to the surface layer while maintaining the damping properties of rubber.

Synergistic enhancement of magic triangle properties of PC tread stocks modified by amine-capped trans-1,4-poly (butadiene-co-isoprene)

The development of high-performance “green tires” with synergistically improved “magic triangle” properties like lower rolling resistance, higher wet-skid resistance and higher abrasion resistance has always been a hot issue. In this work, an effective strategy for developing high-performance “green tires” with simultaneously improved “magic triangle” properties of solution-polymerized styrene-butadiene rubber (SSBR)/cis-1,4-polybutadiene rubber (BR) nanocomposites modified by amine-capped trans-1,4-poly(butadiene-co-isoprene) copolymers (F-TBIR) was proposed. A series of F-TBIR with 10–60 mol% amine-capped efficiency (CE) and 30-90 × 104 weight-average molecular weight (Mw) were synthesized by using heterogeneous TiCl4/MgCl2–Al(i-Bu)3 Ziegler-Natta catalyst with dicyclohexylamine (DCHA) as chain transfer agent (CTA). With the increase in CE of F-TBIR, the silica-filled SSBR/BR/F-TBIR compounds exhibited improved green strength, modulus at 100 % elongation and bound rubber, and their vulcanizates showed synergistically improved “magic triangle” properties like obviously reduced rolling resistance and abrasion loss, and increased wet-skid resistance. It was found that the incorporation of 10 phr F-TBIR3 with CE of 60 mol% and Mw of 32 × 104 resulted in highly expected properties of the SSBR/BR/F-TBIR3 nanocomposite. The contribution mechanism of F-TBIR3 was discussed based on the improvements of polymer network structures and filler network structures. This work is expected to provide an effective strategy to construct the desired network structures for high-performance rubber composites.

Production of eco composites based on natural rubber and recycled sugarcane bagasse waste to be utilised as a type of food contact

Natural fibres are abundant, renewable, and biodegradable, which has inspired numerous academics worldwide to investigate their possible applications in various industrial fields. The food packaging sector is seeking bio-based and biodegradable substitutes to increase sustainability. In this study, new composites were prepared from natural rubber (NR) and sugarcane bagasse fibres (SCB) with different concentrations of SCB (0, 2.5, 5, 10 &20 phr). The effect of SCB on the properties of natural rubber was studied before and after the alkaline treatment of the fibres. The biocomposites are characterized using Fourier transmission infrared spectroscopy, thermogravimetric analysis, scanning electron microscope, transmission electron microscope, and dielectric measurements in addition to rheological and mechanical analysis. The overall migration test for biocomposites loaded with 20phr SCB was performed to assess the biocomposite’s safety as food contact materials. The study’s results indicated that, adding SCB improved the conductivity, tensile strength, and elongation at break of natural rubber. Alkaline treatment strengthened the bonding between the filler and matrix and improved biocomposites’ thermal dielectric and mechanical properties. The overall migration test indicated that the alkaline treatment increased the overall migration to simulants. Accordingly, alkaline-treated NR-SCB biocomposites are effective eco-friendly food packaging candidates for certain types of food such as aqueous non-acidic products.

Advanced and sustainable EMI shielding composites: Natural rubber-nitrile rubber blends enhanced with hydrothermally synthesized Polyaniline Nanofibers and spinel strontium ferrites

Conductive fillers, such as metals and carbon compounds, often exhibit lower compatibility with polymer matrices, leading to agglomeration phenomena that negatively impact the processing and performance of composites. Polyaniline (PANI) nanofibers, with their high conductivity, rapidly create conductive pathways upon contact, reducing current leakage and dielectric loss in composites. To address the compatibility challenges between fillers and matrices, this study adopts a simple, cost-effective approach for synthesizing highly efficient EMI shielding composites. Specifically, we employ hydrothermal synthesis to enhance the properties of PANI nanofibers and spinel strontium ferrites, significantly improving their performance as filler particles. By modifying the morphology of the conductive fillers and incorporating magnetic particles wrapped with an insulating polymer layer, we enhance filler-matrix compatibility. Notably, the synthesized system is a composite made of natural rubber, highlighting its relevance and importance in the current era. This approach not only improves compatibility but also leverages the sustainable properties of natural rubber, making it a significant advancement in the field of EMI shielding materials. In this paper, we report a flexible EMI shielding composite with efficient EM wave absorption, prepared using a natural rubber-nitrile rubber blend as the matrix, and hydrothermally synthesized improves polyaniline nanofibers and spinel strontium ferrite as functional fillers. The shielding efficiency (SET) increases up to 36 dB with different PANI-SrFe2O4wt percentages. This demonstrates the potential of composite for high-performance applications.

Synergic effects of physio‐mechanical performances on sliding‐rolling tribological and abrasion behaviors of polyisoprene based aviation tire treads

AbstractAbrasion and tribological properties of tread rubber play a crucial role in governing the service life of aviation tires and the safety of aircrafts. Polyisoprene (IR) with the same chemical structure as natural rubber shows great potential for application in aviation tires. Herein, the abrasion and tribological behaviors of IR based composites under sliding‐rolling conditions were investigated in relation to the carbon black (CB N234) content, sliding‐rolling ratio, ambient temperature, and counterparts in order to provide guidance for the development of high‐performance aviation tire treads. Moreover, the relationship between wear performances and physical–mechanical properties was discussed to establish a prediction model. The results revealed that physical and mechanical properties affected wear performances in a synergetic manner, which could be described as a negative linear correlation of the folding wear with the product of hardness and rebound resilience (H4R) and the ratio between rebound resilience and tensile strength ((1‐R)/σ) even at elevated temperature and sliding‐rolling ratio regardless of the counterpart. The increase in CB N234 content and sliding‐rolling (s‐r) ratio resulted in a transition of the wear mechanism from folding to abrasion due to the formation of soft rubber particles with a certain fluidity and a lubricating transfer film that was located at the friction interface and was generated by the thermal‐mechanical degradation of the IR matrix when it was rubbed against steel counterparts, which marred the aforementioned negative linear relationship.Highlights The increase in temperature improved the abrasion resistance of tire treads. The folding wear was negatively and linearly related to H4R and (1‐R)/σ. Increasing CB N234 content and s‐r ratio made a transition of wear mechanism.

Preparation and characterization of HNTs@ZIF enhanced intrinsic flame retardant RTV silicone rubber

Phenylphosphonyl dichloride (BPOD) and 3-aminopropyltriethoxysilane (APTES) were used to prepare phosphorus-nitrogen hexaethoxysilane (BPTES). BPTES was then used for cross-linking and curing hydroxyl-terminated room-temperature vulcanized (RTV) silicone rubber, providing intrinsic flame retardancy. In addition, halloysite (HNTs) is a kind of tubular silicate, taking advantage of its large aspect ratio, HNTs were used as a template to load ZIF67 on the surface of halloysite to obtain HNTs@ZIF tubular filler. It was added to the above system as a reinforcing and flame-retardant filler by physical blending, and the RTV elastomer with excellent performance was prepared. The successful preparation of phosphorus-containing crosslinkers (BPTES) was demonstrated by FT-IR. After the introduction of the new crosslinker, RTV not only has improved flame retardant performance, but also improved mechanical properties. The tensile strength and elongation at break of RTV with 20 wt.% BPTES are increased by 151% and 211%, respectively. The peak heat release rate (pHRR) and the peak of smoke production rate (pSPR) are reduced by 55.9% and 48.6%, respectively, and the thermal stability is also improved. In addition, the successful preparation of HNTs@ZIF was confirmed by FT-IR, XRD, XPS, and TEM. By introducing 2 wt.% HNTs@ZIF into 20 wt.% BPTES cured RTV, the intrinsically flame-retardant RTVs with enhanced performance were prepared. It is worth noting that when 2 wt.% HNTs@ZIF is added, the flame retardant and smoke suppression properties of phosphorus-containing silicone rubber are further improved. Because the ZIF contains cobalt metal ions that can be catalyzed into carbon. The pHRR and pSPR decrease by 18.3% and 16.3%, respectively, and the total heat release (THR) and total smoke production (TSP) decrease by 23.6% and 24.4%, respectively. This work will provide enlightenment for the study of intrinsic flame-retardant RTVs enhanced by modified halloysite.

Tensile and Elastocaloric Properties of Natural/Devulcanized Waste Rubber Blends.

The need for eco-friendly cooling materials and material recycling are two urgent challenges to address. In this paper, the role of the ground tyre rubber treatment (cryo-grinding and devulcanization) is investigated on the tensile and elastocaloric properties of Natural rubber (NR)/ ground tyre rubber (GTR). The GTR particles that are sieved (<63µm) and devulcanized by microwave irradiation (1 min at 800Watts) exhibit a low network chain density (0.53 × 10-4mol.cm-3) resulting from crosslinks breakage and rubber chains scission, as supported by FTIR showing a decrease of S─S, C─S, and C─C bonds. The NR/GTR blends show a high elastocaloric effect as compared to the pristine NR, which can be ascribed to the high content of carbon black in the GTR (52wt.%) and also the high level of devulcanization of the GTR. NR/GTR blends reach a heating of +8°C and a cooling of >-6°C, resulting in a material's coefficient of performance COPmat = 2.8-3 compared to 2.6 for the pristine NR. The concomitant effect of cryogrinding and microwave devulcanization is proposed as a way to improve the tensile and elastocaloric properties of natural rubber/waste rubber blends for their possible integration into elastocaloric devices for heating/cooling applications.

Enhancing the damping and mechanical properties of phenyl silicone rubber by introducing phenyl MQ silicone resins as molecular fillers

Silicone rubber features excellent thermal stability, outstanding low-temperature performance, and superb processability, however, the poor damping property and low mechanical strength limit its applications. In this work, we synthesized two types of phenyl MQ resins as molecular fillers and incorporated them into phenyl silicone rubber to prepare damping composites. The effects of both the phenyl MQ resin structures and contents on the damping properties and mechanical performances were investigated. The results showed that phenyl MQ resins exhibit multiscale damping effects with temperature rising, and phenyl MQ resins are distributed in silicone rubber with a "sea-island" structure, which strengthen the mechanical property. The composite exhibit optimal performance with incorporating 30phr diphenyl MQ resins: the damping factor at 150 °C increased from 0.1 to 0.18, the temperature range for tan δ > 0.3 expanded by 115.2 %, and maintained a tensile strength of 6.3 MPa. This study paves a new path to design and prepare silicone rubber composite that balance high damping performances with better mechanical strength.

Control by the curing time of the strain induced crystallization and elastocaloric properties in natural rubber and natural/waste rubber blends

This study provides a systematic investigation of the influence of the curing time on strain-induced crystallization (SIC) and elastocaloric (eC) effect in peroxide-cured natural rubber (NR) and NR/ground tyre rubber (GTR) blends. To do so, materials were prepared with three distinct curing times (t10, t50, and t90). Results reveal that extended curing times correlate with increased network hardness and elastic modulus, promoting the number of elastically active chains. GTR fillers accelerate vulcanization but reduce final network chain density due to their partially devulcanized state and their contribution to the vulcanization of the blends. Both SIC and eC effects improve with curing time, with properties at t50 closely matching those at t90, indicating an optimal crosslink density at such times. The temperature span during mechanical cycling increases linearly with curing time, largely unaffected by GTR presence. The material's coefficient of performance (COP) peaks at t50, suggesting this curing time offers the best balance between mechanical energy dissipation and temperature change, highlighting its potential for eco-friendly heating/cooling applications.

N-[(1RS)-Camphan-2-ylidene]-4-ethoxyaniline and its reduction product as stabilizers of nitrile butadiene rubbers

Objectives. To investigate the protective efficacy of unreduced and reduced forms of the condensation product of D,L-camphor and p-ethoxyaniline in nitrile butadiene rubber formulations when compared with the conventional stabilizer N-isopropyl-N′-phenyl- p-phenylenediamine aged under laboratory and in situ climatic conditions in the tropics.Methods. The thermostabilizing effect of the condensation product of D,L-camphor and p-ethoxyaniline was evaluated by means of infrared spectroscopy using the dynamics of changes in the absorption bands of carbonyl and hydroxyl groups. The features of rubber vulcanization were studied by means of rotorless rheometry. Changes in the physical and mechanical properties of rubbers and degree of cross-linking were evaluated after thermo-oxidative aging in laboratory conditions. They also took into account the results of longterm exposure of samples in undeformed and deformed state in a tropical climate, taking into account meteorological data of the Can Gio climatic testing station.Results. It was found for the first time that condensation products of D,L-camphor and p-ethoxyaniline exhibit a stabilizing effect in formulations of rubbers based on polar nitrile butadiene rubber.Conclusions. According to the results of laboratory and in situ tests, the study established that the use of N-[(1RS,2RS)-camphan-2-yl]- 4-ethoxyaniline (reduced form) as an antifatigue agent is preferable. This is due to the presence of a mobile hydrogen atom at the nitrogen atom. The protective effect is manifested in terms of the better preservation of elastic-strength properties of rubbers with less change in hardness.

Blends of polydimethylsiloxane-based polyurethane and poly (propylene glycol)-based polyurethane with co-continuous structures: Morphology evolution, synergistic effects and application in strain sensors

Blending is an effective way to improve properties of rubbers and develop new materials, so more than 75 % of the rubber consumption in the world is rubber blend. However, blending of thermoplastic elastomers has not yet been emphasized, and few successful examples have been reported. The main challenge for blend systems is compatibility of two components. Herein, a series of (polydimethylsiloxane-based PU)-g-(poly (propylene glycol)-based PU) ((PDMS-PU)-g-(PPG-PU)) graft copolymers with different graft chain lengths and hard segment contents (HSC) were synthesized and utilized as compatibilizers of PDMS-PU/PPG-PU blends. The influence of the structure of compatibilizers on the morphology of blends was investigated, and the compatibilization mechanism was proposed. With the solubilization, the phase structure of blends transforms from “droplet-in-matrix” morphologies to co-continuous ones, and the average size of PPG-PU dispersed phase decreases from 3.5 ± 0.45 μm to 230 ± 60 nm. This is the first time that thermoplastic PDMS-PU/PPG-PU blends with co-continuous structures have been successfully prepared. The properties of blends exhibit synergistic effects. For example, they show high tensile strength of PPG-PU in mechanical properties and unique properties of PDMS in dynamic mechanical properties, weather resistance, water resistance and biocompatibility. In addition, strain sensors were fabricated by introducing carbon nanotubes (CNTs) into the blends, which demonstrated remarkable sensing capability for diverse human body motions.

Effect of Different Accelerators on Some Mechanical Properties of Natural Rubber

Effect of Different Accelerators on Some Mechanical Properties of Natural Rubber

Application of wet carbon black masterbatch in green mining radial tires

AbstractIn the context of environmental protection and energy consumption reduction, reducing the rolling resistance of mining machinery tires is one of the important methods to achieve the goal of green mining. This study probes the effects of wet mixing with a wet carbon black masterbatch on the rolling resistance and grounding performance of wide‐body vehicle tire treads by investigating the cross‐linking structure, rubber–filler (R–F) interaction force, and physicomechanical properties of the wet mixing rubber compounded with a wet carbon black masterbatch. The results indicate decreases in the maximum torque‐minimum torque difference, cross‐link density, and R–F interaction of the wet mixing rubber and increased filler–filler (F–F) interaction and carbon black dispersion. Meanwhile, the tensile elongation of the wet mixing rubber increases, its DIN abrasion property improves, and its Tanδ decreases at 60°C. A numerical method to estimate tire steady‐state rolling resistance is also developed. Finite element simulation analysis reveals that the steady‐state rolling resistance of the wet mixing rubber is reduced by 7.04% at 100% standard load, and its grounding performance is enhanced. By proposing a method to reduce the rolling resistance of tires, this study also provides a reference for the development of wide‐body vehicle tires.Highlights Explored the filler interaction of wet mixing rubber. Explained the low energy loss of wet mixing rubber. Proposed a new finite element method for calculating tire rolling resistance.

Molecular dynamics simulation of interfacial interaction mechanisms between ground tire rubber and styrene-butadiene rubber enhanced by nanomaterial incorporation

The recycling of ground tire rubber (GTR) is an effective method for addressing black pollution. In this study, we investigated and compared the effects of acidic oxidation treatments and different nanomaterial contents on the interfacial properties of styrene-butadiene rubber (SBR) and GTR. Molecular models of GTR modified by acidic oxidation and nanomaterials, as well as SBR, were established. The interfacial interaction mechanisms between SBR and GTR were studied through tensile and shear behaviors. The results indicated that the properties of SBR-GTR interface were enhanced through acidic oxidation and nanomaterial modification, with the latter demonstrating superior advantages in augmenting the interfacial strength. Specifically, the addition of a carbon nanotube and graphene increased the interfacial cohesion strength by 55.12 % and 82.93 %, and the interfacial shear strength by 29.87 % and 43.05 %, respectively. Moreover, graphene exhibited superior performance in enhancing interfacial interactions compared to carbon nanotubes and increasing the nanomaterial content did not positively impact the improvement of interfacial properties. The interfacial properties of SBR and GTR were quantitatively analyzed using molecular dynamic (MD) simulations. This study provides a theoretical foundation for enhancing the mechanical properties of recycled rubber by using nanomaterials, thereby guiding the experimental preparation of recycled rubber.

Novel fillers for wearable technology: Impact of titanium carbide and thinners on room temperature vulcanized silicone rubber composites

Wearable technology has emerged as a robust pathway to achieve smart functionalities in healthcare, sports, fitness, and beyond. This study investigates the mechanical and electromechanical properties of silicone rubber (SR) composites. The SR was reinforced with titanium carbide (TiC) and modified with varying (room-temperature vulcanized) RTV-thinner (silicone oil) concentrations. RTV-SR was utilized, which cures at room temperature to form a flexible, durable, and moldable rubber widely used for sealing, bonding, and making molds. The addition of TiC enhanced tensile strength from 0.5 MPa (control) to 0.59 MPa (5 phr of TiC), and tensile modulus from 0.41 MPa to 0.51 MPa. However, the thinner inclusion reduced tensile properties. For instance, the T10 sample (10 phr thinner) showed a tensile strength of 0.51 MPa and a tensile modulus of 0.29 MPa making the composites soft. Thinner addition also increased ductility, with fracture strains rising from 151 % (control) to 217 % (T10). Compressive strength followed a similar trend, with the control and 5 phr TiC samples exhibiting compressive strengths of 0.18 MPa and 0.17 MPa, respectively, which decreased to 0.12 MPa for the T20 sample. Under cyclic loading, TiC-filled samples showed consistent load patterns, while thinner addition resulted in increased energy dissipation and reduced stiffness. Electromechanical analysis revealed that TiC 5 phr samples exhibited stable piezoelectric responses, with voltage outputs increasing from ±0.1 mV at 15 % strain to ±1.0 mV at 40 % strain. The T5 samples demonstrated significant voltage improvements, generating ±2.5 mV at 15 % strain and ±5 mV at 40 % strain. Long-term cyclic tests confirmed the stability of T5 samples, maintaining voltage outputs of −1.5 mV to 1.5 mV over 50 minutes. Response time analysis indicated faster response times for TiC 5 phr samples, decreasing from 145 ms at 15 % strain to 102 ms at 40 % strain, while thinner addition led to longer response times. Real-time electromechanical tests under mechanical study showed that T5 samples achieved optimal performance with voltage peaks up to ±2.4 mV under thumb pressing. These findings highlight the trade-off between mechanical strength and flexibility, suggesting that an optimal balance of TiC and thinner enhances the properties of silicone rubber composites for applications in wearable technology and sensors.

Study on powdering properties of silicone rubber insulating material in a coastal area

Abstract Silicone rubber insulation materials are widely used in energy systems. The powdering of silicone rubber sheds is a newly discovered aging phenomenon in recent years, and there is no specific research. In this paper, the powder composition of the composite insulators in coastal areas was studied, and the powdering process of silicone rubber under a high humidity environment of salt fog was repeated in the laboratory. The results show that the powders can be divided into two types according to particle shape, element composition, and molecule groups: the inorganic filler and its dehydrated product and the small molecule siloxane after polymer aging fracture. The particle size of Type I of powder is 3∼8μm, and the particle size of Type II of small molecule siloxane is 0.3∼1.1μm. The surface hydrophobicity of the powdered sample in a salt-fog environment will deteriorate, and the static contact angle will decrease. However, the hydrophobicity will gradually recover after leaving the harsh environment. Powdering of composite insulator silicone rubber in coastal areas is a complex physical and chemical process caused by the combined action of electricity, heat, and moisture. During this, polymer molecular chains break, and fillers gradually precipitate, forming powders.

Comparative study on rolling resistance force in tire-ice interaction with a variation of tread rubber compound

Abstract The complex phenomenon involved in the tire-ice interaction can be better understood by studying the tire and ice properties. A significant force at the contact patch is the rolling resistance force. To study the effect of tire characteristics on rolling resistance forces, data collected from a free-rolling tire can be used as there is no tractive or braking torque applied to the wheel and thus the data representing the longitudinal forces is only related to resistive forces viz. friction and rolling resistance force. Although a lot of research and literature has been developed for tire-ice interaction over the years, there is a significant lack of work in the subsection of free-rolling tires specifically to study the effect of ice parameters on rolling resistance forces. To fulfill the aim of this study, several sets of experiments for 16 winter tires of 8 different rubber compounds in free-rolling conditions were conducted. The experimental data was compared with predictions of 4 well-known formulations from the literature. Based on the findings and the relative error between the predicted and measured values, it was proposed that the high error percentage could be due to the variation in the viscoelastic properties of the tread rubber. The longitudinal force generated during those tests would thus be a combination of frictional forces due to adhesion between the tread rubber and its viscoelastic nature in addition to the contribution from the remaining sections of the tire. The data collected from the experiments and results from implementing the existing models to obtain frictional force will further help in analyzing the relation between the rolling resistance force with variation in normal load, inflation pressure, and change in camber angle once a generic formulation considering the rubber compound effects is incorporated. Another significant finding of this work is that formulations in literature used for finding the rolling resistance coefficient of radial passenger car tires were found to highly underestimate the coefficient when compared to the equivalent coefficient of friction found from experimental results. The future scope may include the development of a model which will incorporate the viscoelastic properties, especially the loss moduli and loss tangent to evaluate the coefficient of friction and rolling resistance force in the free-rolling condition of a winter tire on ice as the rolling resistance losses are found to be highly correlated to these two properties.

A Study of the Influence of Maleimides on the Properties of Rubber Based on Hydrogenated Nitrile Butadiene Rubber

A Study of the Influence of Maleimides on the Properties of Rubber Based on Hydrogenated Nitrile Butadiene Rubber

Influence mechanisms of ultraviolet irradiation aging on DC surface discharge properties of silicone rubber in dry and humid air

In the modern DC electrical transmission system, high-energy photons interact with silicone rubber (SIR) chains during long-term ultraviolet (UV) irradiation, it degrades the surface properties and triggers surface discharge (flashover) along the SIR-air interface, threatening the secure operation of the advanced electrical equipment. To further comprehend how UV-aging influences the flashover performance, in this work, the chemical bonds, surface charge transport parameters, and flashover performance of UV-aged SIR samples are characterized, and the influence mechanisms of UV-aging on surface discharge in dry and humid air are comprehensively clarified through the investigation from “molecular-mesoscopic-macroscopic” scales. The results indicate both degradation and oxidization reactions occur during UV-aging. The degraded molecular chains dominate the discharge in dry air, while oxidization reactions determine the discharge in humid environment: The degradation reactions reduce the surface trap depth and increase surface conductivity, leading to large surface leakage current and surface charge dissipation rate, causing flashover voltage in dry air increases and decreases as UV-aging time increasing. The oxidization of the chains introduces –OH and –COOH groups into chains, enhancing permittivity and adsorbing H2O molecules, significantly increasing surface leakage current, causing surface discharge voltage in humid air to decrease as UV-aging time increases.