Journal of Rubber Research最新文献

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.

There is compelling evidence supporting the benefits of incorporating crumb rubber to enhance the properties of bituminous mixes. The main aim of this paper is to investigate the effect of crumb rubber on the rheological properties of bituminous mixes using the dry method. A comparison was made in terms of linear viscoelastic behaviour, between five mixtures including the control mixture and four mixtures modified with 1% or 2% crumb rubber added and the various bitumen content. This modification was conducted to replace a portion (volume) of the aggregate with an equivalent volume of crumb rubber. Complex modulus tests on cylindrical specimens were carried out for each mixture by the tension–compression method. The complex modulus tests were carried out over a wide range of frequencies (from 0.01 to 10 Hz) and temperatures (− 25 to 45 °C). The specimens are obtained by sawing laboratory specimens in accordance with a gyratory compactor with an air voids content of not more than 1%. The results are modelled and calibrated with the 2S2P1D rheological model. All mixtures have similar rheological behaviour and respect the specification of a BB 0/15, with a modulus values (15 °C, 10 Hz) is greater at 7000 MPa.

The present work focuses on developing a novel composite using a ternary elastomeric blend of epoxidised natural rubber/chloroprene rubber/hydrogenated nitrile-butadiene rubber(ENR/CR/HNBR- ECH) with hybrid fillers in different proportions, aiming to partially replace conventional filler of carbon black with silica as a cheaper alternative to suitable for hard rubber mountings. The work has two parts, the first part deals with determination of optimum blends of ternary elastomers namely ENR, CR and HNBR using a simplex centroid mixture design model. Seven samples are prepared and tested for their mechanical properties using which the optimum combination is determined by adopting Grey Relation Analysis (GRA)-based Response Surface Methodology (RSM) approach and benchmarked using GRA based Kriging-GA surrogate optimisation. The confirmed optimum combination of ECH blend is 33.34/53.33/13.33 phr. Hence in the second part, this optimum blend is taken as the base matrix for developing novel hybrid filled ECH composites by varying the filler contents of CB and silica. Thirteen composites are fabricated following a Face Centered Central Composite (CCF) design and tested for mechanical properties. The optimisation of hybrid filler content is carried out following the same numerical techniques used for optimum blend determination. The optimum filler combination obtained is verified experimentally. Furthermore, these experimental studies are supported with morphological and ATR spectroscopic studies.

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.