Journal of Rubber Research最新文献

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.

Many rubber-based components are required to withstand long-term stress or strain without developing excessive stress relaxation or creep. A model was implemented for simple shear which used the Boltzmann superposition principle (BSP) to predict the stress relaxation following changes in strain and the William–Landel–Ferry transformation to allow for changes in temperature. Stress relaxation was modelled as linear with the logarithmic of time with a Prony series deduced from two independent parameters. By means of small-time increments, the model can be used to model the stress relaxation under arbitrary strain and temperature histories. Stress relaxation measurements were carried out for two types of deformations: simple shear and compression. The samples were made of an unfilled natural rubber and tested under varying strains and temperatures and the results compared to the predictions of the model. The agreement was generally good, and the discrepancies are discussed. The model parameters were also used within the linear viscoelastic model in the commercial finite element analysis package ABAQUS, which enables modelling in deformation modes other than simple shear.

Extensive investigations have been performed on Egyptian rice straw (RS) fibre residues to be employed as a supplementary reinforcement material in polymer composites. In this study, two identical groups based on carbon black (CB) filled styrene butadiene rubber (SBR) vulcanisates were prepared by incorporating different proportions (10–50 phr) of treated and untreated rice straw (TRS/ URS) in the SBR composites to examine their effects on some of the demanded properties in rubber applications. Maleic anhydride (MA), as a coupling agent, was added to improve the interfacial bonding between the hydrophilic RS natural fibre and the hydrophobic SBR matrix. The TRS and URS were selectively grinded through a grinding machine to obtain RS fine powder with a selective grain size distribution ranging from about 20–180 μm. Some important physico-mechanical properties of the rubber vulcanisates were studied. The prepared samples were analysed by using X- ray diffractometer (XRD) and scanning electron microscopy (SEM). The tensile strength (TS), modulus (M100) and hardness values of TRS filled composites were almost superior compared to the URS ones, and 20 phr of TRS was found to be the optimum filling in SBR vulcanisates and this was obviously revealed through all the mechanical properties results as well as in the percentage swelling findings. The SEM analysis indicates that the presence of MA increases the interfacial interaction between SBR, and the alkali treated rice straw fibres, as well it was found to be in complete agreement with the TS findings. The XRD analysis reveals that the alkaline pretreatment of RS fibres was found to yield a higher crystallinity index for the SBR vulcanisates. The results indicate the potential of using TRS as filler in the rubber industry for cost reduction and raising the environmental credentials of the product.

Oil palm trunk biochar (OPTB) serves as a flame-retardant additive aimed at enhancing the thermal stability of natural rubber (NR) latex foam. This study explores whether OPTB affects the physical and mechanical properties of specialty NR (SpNR) latex foam, specifically deproteinised NR (DPNR) latex foam and epoxidised NR (ENR) latex foam. The results indicate that the addition of OPTB up to 8 phr insignificantly increases the density of DPNR and ENR latex foams, but significantly at 16 phr and 24 phr (p < 0.05). Shore F hardness also shows a significant increase with OPTB loading (p < 0.05), while volume shrinkage decreases with higher OPTB loading (p < 0.05), thereby enhancing foam dimensional stability. The study also found that the addition of OPTB reduced the elasticity of both DPNR and ENR latex foams, resulting in higher hysteresis loss ratios as OPTB loading increased from 8 to 16 phr and 24 phr. The highest observed hysteresis loss ratio was 0.32 in DPNR latex foam loaded with 24 phr of OPTB. Additionally, OPTB loading up to 24 phr in DPNR latex foam decreased its rebound resilience from 66 to 55% and increased its vibration-damping ratio from 0.14 to 0.24. This implies that the addition of OPTB to SpNR latex foam alters its physical and mechanical properties, making it ideal for applications requiring good vibration damping and impact absorption, such as seat cushions and headliners for vehicles.

In this study, we investigated the reinforcement of nitrile butadiene rubber (NBR) using talcum powder modified with polybutadiene (M-Talc). To achieve this, a block copolymer of poly (glycidyl methacrylate)- block -polybutadiene- block -poly (glycidyl methacrylate) (PGMA-b-PB-b-PGMA) was synthesised via reversible addition-fragmentation chain transfer (RAFT) polymerisation. The PGMA-b-PB-b-PGMA solution was then sprayed onto talc powder (Talc) and dried, yielding the modified talc (M-Talc). Both M-Talc and Talc were subsequently incorporated into NBR. The results showed that NBR composites with M-Talc exhibited a notably slower vulcanisation rate compared to those with unmodified Talc. Additionally, M-Talc demonstrated improved dispersion within the NBR matrix. The mechanical properties of NBR/M-Talc composites were significantly enhanced, with a 30% increase in tensile strength, a 17% improvement in tear strength, and an impressive 757% boost in elongation at break. Furthermore, there was a substantial 37% reduction in the compression set.