Journal of Rubber Research最新文献

Rubber packers play a crucial role in extracting unconventional oil and gas reserves using hydraulic fracturing methods. This article conducts finite element modelling and analysis of one typical rubber packer, predicts its sealing performance and optimises its structural parameters. The key structure parameters of the rubber packer are regarded as design variables and the optimisation is carried out using the design of experiment (DOE) analysis and the full factorial design methods through Isight software. This study investigates the influence of major structure parameters on sealing performance. The optimal structure parameters for achieving the best sealing effect are attained, which are chamfer angle at the rubber sleeve end of 47.5°, rubber sleeve thickness of 22 mm, rubber sleeve height of 75 mm and rubber sleeve end width of 11 mm, respectively.

This study investigates a novel method to produce ZnO nanoparticles with different aspect ratios by controlling the stirring time. As the synthesis scale increases, the size of the reaction mixture influences the particle morphology. This study further examines the impact of ZnO nanoparticles, specifically when coated with Si-69, on natural rubber (NR) composites’ mechanical and electrical properties. Characterisation through FTIR, PXRD and SEM reveals successful synthesis of ZnO nanoparticles with varying morphologies. Aspect ratio analysis indicates that reaction kinetics and temperature influence nanoparticle morphology. Si-69 surface modification is confirmed through FTIR, PXRD and SEM. Incorporation of the synthesised nanoparticles into rubber composites demonstrates enhanced electrical and thermal properties. Electrical resistivity decreases with ZnO np concentration and aspect ratio, highlighting tunable electrical conductivity without compromising mechanical performance. Si-69 capped ZnO nps consistently exhibits superior thermal conductivity across concentrations. Furthermore, compared to commercial ZnO, it exhibits improved mechanical properties and cross-linking density. Tensile and tear strength exhibit significant relationships with type and concentration of ZnO nps. Interestingly, aspect ratio has a minimal influence on mechanical properties of rubber composites. TGA shows similar breakdown patterns, with inorganic residues suggesting that ZnO and carbon black may have been present after 650 °C. The findings offer insights into tailoring ZnO-reinforced rubber composites for diverse rubber-based applications.

This study investigates the effect of natural hemp fibre and alkali modification on the properties of rubber compounds. The effect of adding hemp fibre from alkali modified natural fibres to three different rubber compounds was studied. The results revealed a decrease in curing times with the addition of fibres, a decrease that was further increased by alkali modification, shifting the environment to a basic environment. As the fibre content increased, the cross-link density and compound hardness also increased. Alkali modification reduced fibre hardness, resulting in lower compound hardness and viscosity compared to untreated fibre. Tensile strength showed improvement with fibre reinforcement among different rubber types. We observed an increase in tensile strength of up to 70%. The presence of fibres significantly increased the tear resistance. Nitrile butadiene rubber showed an improvement of 137% with untreated fibre and 209% with treated fibre. In contrast, epoxy modified natural rubber showed an improvement of 165% with treated fibre. These findings are promising for the improvement of mechanical properties of rubber compounds through natural fibre reinforcement, especially with alkali modification. However, deformation properties deteriorate after 10% strain, highlighting the need for further optimisation of fibre/polymer interactions for improved performance.

Due to its ease of processing and excellent thermal and chemical stability, silicone rubber (SR) has become the preferred material for prosthetic socket liners. However, its inherent mechanical weaknesses and low surface free energy challenge durability and adhesion strength. This study aims to improve the mechanical strength, hydrophilic characteristics, and antibacterial effectiveness of silicone rubber used for prosthetic socket liners by optimising the composite formulation that incorporates hydroxyapatite (HA), zinc oxide (ZnO) nanoparticles, and chlorophyll into a silicone rubber matrix. Significant improvements in silicone rubber’s hydrophilicity are attained by incorporating chlorophyll, thus enhancing water absorption capacity. Adding nano-ZnO and nano-HA influences mechanical properties, with aggregation affecting tensile and tear strength. Optimum chlorophyll content is established at 10%, balancing mechanical robustness and water absorption for high-performance denture linings. The composite’s crystalline structure is confirmed by XRD analysis, revealing the presence of ZnO and HA nanoparticles dispersed within the matrix. Antibacterial tests demonstrate significant inhibition against Staphylococcus aureus and Escherichia coli after 24 h of contact. The study successfully formulates a multifunctional nanocomposite with improved performance over conventional silicone, offering the potential for enhanced prosthetic socket viability and infection prevention.

Carbon black (CB) and silica are conventional fillers used extensively in the tyre industry worldwide. Due to its affordability and sustainability, feldspar can be utilised as an alternative to traditional fillers in the production of tyres. Styrene-butadiene rubber (SBR) filled with feldspar and CB (SBR/CB-Feldspar) has been used in this study to assess feldspar's potential as a reinforcement filler in tyre tread applications. CB:Silica was compared to CB:Feldspar at a similar ratio to determine the ideal hybrid filler system. For both control and hybrid compounds, this work observed the impacts of different sulphur vulcanisation systems, including conventional vulcanisation (CV), efficient vulcanisation (EV), and semi-efficient vulcanisation (semi-EV). The control compound, which contains 40 parts per hundred rubber (phr) of CB, is based on the composition of hybrid compounds, which have CB:Feldspar filler ratios of 30:10, 20:20, and 10:30. The findings demonstrate that the semi-EV system reduces the SBR-Feldspar compound’s scorch and cure times. The hybrid compound's curing characteristics and physical properties, such as tensile strength, hardness, rebound resilience, and abrasion resistance, have been enhanced using SBR/CB-Feldspar with the maximum CB content (30 phr). Moreover, further research on optimised hybrid CB:Feldspar composition with various rubbers has been conducted to examine the effects on curing characteristics and mechanical properties of hybrid fillers with the rubbers, including Natural rubber (NR), Ethylene Propylene Diene Rubber (EPDM), Chloroprene Rubber (CR), and Nitrile Rubber (NBR). These results conclusively establish the potential value of feldspar, which can function as a softener, extender, and can be considered a semi-reinforcing filler for various rubber applications.

Previous research has shown that the impact of different particles on the mechanical and thermal properties of silicone rubber (SR) can vary greatly. Some researchers believe that these particles have positive effects, while others hold a different view. However, there is still uncertainty surrounding the specific effect of graphene on the mechanical behaviour of silicone rubber. To address this gap in the literature, the authors aim to investigate the role of graphene particles on the mechanical properties of room temperature vulcanised (RTV) silicone rubber. In this research, graphene nanosheets were used as reinforcement for silicone rubber. Different weight percentages of 0, 0.25, 0.5, and 1 were utilised. The mechanical behaviour of the prepared composites was examined through tension and compression tests. Additionally, the fracture surface of the tensile samples was analysed using a scanning electron microscope (SEM) Cambridge Streo Scan model. Results indicate that the inclusion of 0.25 wt% graphene leads to a 10% increase in tensile strength and a 31% increase in elastic modulus compared to the pure state of silicone rubber. Furthermore, the presence of graphene nanosheets enhances the compressive strength from 3.21 MPa in pure silicone to 5.49 MPa at a weight percentage of 0.5%, while also reducing the compression rate of the silicone rubber.

The automotive industry, the highest consumer of carbon black, has established specific targets to integrate effective alternative materials such as pyrolytic carbon black. The purpose of this study is to explore the role of pyrolytic carbon black as a potential alternative filler in the rubber industry, focusing on its effects on processing, rheological, mechanical and dynamic properties. Four compounds were prepared using two pyrolytic carbon blacks with different surface areas and two conventional carbon blacks that are N330 and N550. The results indicated that the use of pyrolytic carbon black increases scorch and optimum cure times and decreases maximum and minimum torque. Tensile strength, elongation at break, modulus at 100% elongation and hardness of the compounds before and after aging were obtained and discussed. In addition, dynamic properties were obtained and it was observed that pyrolytic carbon black decreases tan delta. Pyrolytic carbon black also significantly decreases compound viscosity, enhancing processability. The thermal conductivity of compounds containing pyrolytic carbon blacks and conventional carbon blacks were also analyzed. Based on these findings, pyrolytic carbon black can be used as an alternative filler for specific applications.

The white root rot (WRR) disease poses a formidable economic challenge to rubber plantations globally, with Malaysia particularly hard-hit. This disease is attributed to Rigidoporus microporus. This glasshouse experiment investigated the effects of a stored, peat moss-based formulation containing silicon (Si), Glomus mosseae, and Enterobacter sp. UPMSSB7 on combatting WRR and promoting the growth of rubber plants. Compared to the positive control, the experimental bioformulation significantly reduced disease incidence (P < 0.0001), with efficacy comparable to the propiconazole fungicide. Furthermore, the bioformulation and fungicide treatments demonstrated superior disease mitigation compared to the positive control 24 weeks after R. microporus-inoculation. The bioformulation treatment not only reduced disease incidence and mitigated foliar and root rot symptoms, but it also resulted in a lower disease progressive curve and reduced R. microporus colonisation. Additionally, bioformulation significantly increased (P < 0.001) plant growth parameters 24 weeks after R. microporus inoculation. These parameters included stem height, girth size, chlorophyll content, leaf area, root and shoot dry weight, root volume, total root length, and root surface area. These effects surpassed those observed in fungicide and control treatments. The Si content in shoot and root and leaf N, P, and K nutrient contents were also significantly (P < 0.001) increased in the R. microporus-inoculated plants with the tested bioformulation than the fungicide and control. In the case of R. microporus-inoculated plants of bioformulation treatment, there was a significant (P < 0.001) increase in the population density of Enterobacter sp. (1.5 × 10⁸ cfu g^− 1 soil), surpassing the levels observed in non-inoculated plants of bioformulation and inoculants with Si, with or without R. microporus-inoculation. Moreover, bioformulation treatments improved (P < 0.001) root colonisation as well as spore density of G. mosseae after R. microporus-inoculation than control and fungicide. This study suggests that a peat-based bioformulation containing G. mosseae, Enterobacter sp., and Si could be an effective strategy for both enhancing plant growth and mitigating WRR in rubber plants.

The objective of this research was to investigate the impact of silicon nitride (Si₃N₄) on the compression moulding process of potential passenger tyre tread compounds, which include both butadiene rubber (BR) and styrene-butadiene rubber (SBR). Understanding how Si₃N₄ influences the curing process, particularly through temperature monitoring in the mould, is crucial for optimising the vulcanisation and performance characteristics of tyre tread compounds. By examining the kinetic reaction characteristics and thermal properties, this study aims to elucidate the role of Si₃N₄ in enhancing the efficiency and effectiveness of the curing process. The obtained kinetic reaction characteristics demonstrated a decrease in the duration of optimum curing and scorch by ~ 25 and ~ 40%, respectively, by adding silicon nitride. Moreover, the rheometry analysis illustrated an increase of ~ 12% in maximum torque when 6 phr of Si₃N₄ was loaded. The Kamal–Sourour model, employed for the determination of kinetic parameters, revealed that the thermal conductivity of Si₃N₄ played a catalytic role in enhancing the curing reaction by approximately 40%, notably at 6 phr of filler. Temperature monitoring results revealed that the Si₃N₄ particles increase the heat transfer rate and thermal diffusivity by approximately 17 and 98%, respectively, during curing. This increase is also observed in the cured compound, with a notable improvement of around 17%, particularly at 6 phr of Si₃N₄. This phenomenon facilitated a uniform heat distribution within the sample during the moulding process, resulting in an accelerated vulcanisation reaction.