Journal of Rubber Research最新文献

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.

Rubber composites based on vegetable oils are being increasingly developed as these materials significantly reduce the use of petroleum-based carcinogenic oils as plasticisers in rubber products. Apart from renewability, vegetable oils have some functional groups such as polar group, double bond and long alkyl chain, which could make rubber performance more comprehensive, making processing oil from petroleum-based “one agent for one function” to bio-based “one agent for multiple functions”. In this work, we selected one bio-based vegetable oil (FN-B17) as green processing aid for nature rubber (NR) composites and petroleum-based oils (PB-1,2,3,4,5) were also chosen to be investigated for comparison. The plasticisation effects of FN-B17 and other plasticisers on composites were systematically studied. In specific, Mooney viscosity, processing properties and cross-linking characteristics of composites with various kinds of oils were characterised while the mechanical properties and RPA dynamic behaviors were also evaluated. The results indicated that the performance of bio-based oil on processing and mechanical properties of NR composites are similar or even better than that of petroleum-based oils, whereas bio-based oil is renewable with lower cost, which would be cost-effective green processing oil that could replace petroleum-based oil for NR composites. Soon, the trend of utilising bio-based oil may bring considerable advancements in the performance of filled rubber composites in an environmentally acceptable and sustainable manner.

Graphical Abstract

Reusing industrial wastes is one of the cutting-edge tactics used to counteract solid waste disposal for environmental protection. The rigid polyurethane waste (PW) produced while manufacturing shoe soles in the footwear industry contributes to major environmental problems due to its uncontrolled landfill. In the current work, PW and clay were used as fillers in natural rubber (NR) and the fabricated compound’s mechanical, thermal, and sorption properties were looked at. Various analytical techniques were employed to characterise the NR-PW-clay compounds produced by the two-roll mill mixing process. In contrast to NR, the tensile strength and tear resistance of NR compound with 5 phr (parts per hundred rubber) PW and 10 phr clay was improved by 20% and 7%, respectively, and abrasion loss was significantly reduced. The mechanical characteristics of the compounds showed a decreasing trend beyond 10 phr clay due to the PW and clay particle’s aggregation. The thermal stability of NR-PW-clay compounds was slightly increased upon adding clay, as demonstrated by thermogravimetric analysis (TGA). As clay loading increased, the crosslink density and swelling index measurements revealed improved solvent absorption resistance. The fabricated compounds have the potential to provide high-performance, inexpensive NR compounds for a variety of industrial applications.

The development of a corrosion-resistance surface on a desired industrial coating is a challenge in several industries. In the aerospace industry, it is necessary to modify the corrosion-resistant coating to address the susceptibility of damage during flight for aviation applications. The present study tested three types of commercially available corrosion-resistant coatings for aviation, and the coating with the best overall performance was modified to enhance its mechanical properties to prevent coating damage due to impacts from raindrops and sand during flight. Silica (SiO₂) nanoparticles with an approximate particle size of 50 nm were prepared by the sol-gel method using tetraethyl orthosilicate (TEOS). The KH560 silane coupling agent, as the neck layer and the M2070 polyether amine as the crown layer, were covalently bonded and then grafted onto the surface of the nano-SiO₂ core to obtain a core-shell structure of the SiO₂ solvent-free nanofluid (SiO₂@KH560-M2070). The tensile property of the polyurethane coating was improved when a small amount of the SiO₂ solvent-free nanofluid was incorporated into the coating. The present study has theoretical and practical guiding significance for the selection and spraying of existing aircraft radome coatings.

The preparation of epoxidised natural rubber (ENR) latex-dipped film was successfully carried out. The effects of several parameters, such as sulphur loading, vulcanisation temperature and time, leaching temperature and time, thickness, oil, and chemical resistance, were studied. ENR latex films were successfully prepared by varying the sulphur loading from 0.5 phr to 2.0 phr. Superior tensile properties were observed for the vulcanised temperature at 75 °C with vulcanisation at 30 min. A longer leaching time and higher leaching temperature demonstrated an optimal tensile strength for ENR latex to leach out all undesirable chemicals. The thickness of ENR-dipped film can be varied by selecting an appropriate concentration of latex TSC and coagulant, different dwelling times, and former temperatures. The determination of oil resistances showed that the oil uptake of ENRs in oils was substantially less than that of natural rubber (NR) and was comparable to commercial gloves. Aside from that, ENR demonstrated remarkable chemical resistance to acid and alkaline solutions.

Skim latex can be concentrated using an ultrafiltration process. It is a liquid separation process where water can be removed from latex through a membrane. Vulcanised dipped concentrated skim latex (CSK) films were prepared, and their properties were compared to commercial high ammonia natural rubber (HANR)-dipped films. As expected, HANR-dipped films were stronger as seen from the higher tensile and modulus values. However, the highest tensile strength and modulus values for CSK-dipped films stood at 17 MPa and 620%, respectively. Interestingly, the crosslink density of CSK-dipped films was higher than HANR-dipped films while the average molecular weight of rubber between crosslinks, M_c demonstrated the opposite. Both dipped films showed comparable results in oil and water uptakes, with CSK-dipped films having more water-resistance after prolonged immersion time than HANR-dipped films. The maximum decomposition temperature of CSK, i.e., 373.06 ^oC, and HANR dipped films, i.e., 374.08 ^oC, were almost identical. Interestingly, the TEM images revealed vulcanised CSK particles formed only intra-particle crosslinks, which agreed with the lower tensile strength, elongation at break (EB), crosslink density, and higher M_c. Overall, the non-rubber components and naturally occurring networks, with the influence of molecular weights, vulcanisation degree, and smaller particles, substantially affected the resulting CSK vulcanised dipped films.

The use of catalysts in rubber production industry has drastically altered production processes, increasing efficiency and quality. By solving polymer microstructure and elevating reactions, catalysts enable high-performance rubber improvement while minimising waste and energy consumption. Sustainable best practices, involving biodegradable rubber exploration and eco-friendly catalysts, contribute to long-term industry viability. In this mini literature review, we introduce various types of catalysts currently applied in the rubber industry and recent advancements in catalyst design for the future of rubber production. In the rubber industry, the selection of catalysts is a vital decision, which impact the efficiency of the polymerisation process and the quality of end products. Therefore, by carefully selecting catalysts with desired stereoselectivity and activity, producers can create synthetic rubbers with specific properties tailored to their real applications. By exploring the production of biodegradable rubber, this shift is vital for decreasing the environmental effect of rubber manufacturing and making the industries long-term environmentally friendly and sustainable.

Hevea brasiliensis, or the Para rubber tree, is a major commercial source of natural rubber (NR). The rubber tree is susceptible to various fungal attacks, which affect NR production and Corynespora cassiicola is one of the major pathogens affecting young and mature rubber trees. Corynespora leaf fall disease (CLFD) outbreaks often cause serious loss in latex productivity by adversely affecting tree health. Since fungicidal chemical control is uneconomical and unsustainable, improving host resistance is the most effective strategy for the long-term management of this disease. In this context, 78 Hevea genotypes were screened against two virulent isolates of two races of C. cassiicola (Race 1 and Race 2). The level of host resistance was determined in vitro using detached leaf bioassay and those genotypes that were found to be highly resistant were subjected to further evaluation under greenhouse conditions. Seven genotypes were classified as highly resistant against both races of C. cassicola in vitro, with less than 20% disease intensity. Subsequent assessment under greenhouse conditions identified three genotypes with less than 40% disease severity and corresponding rAUDPC value of less than 0.4 when challenged with both races of C. cassiicola. These resistant genotypes are suitable candidates to be included in breeding programmes aimed at the development of superior clones with durable resistance against Corynespora leaf fall disease.