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The elasticity of polymer networks, formed by cross-linking high molecular mass polymers in the melt state and then swollen by a solvent, involves contributions from both the presence of cross-link network junctions and the interchain interactions associated with the combined effect of excluded volume interactions and topological constraints that become modified when the network is swollen. We test the capacity of the previously developed localization model of rubber elasticity, a mean field "tube model," to describe changes in elasticity observed in classical experimental studies of the mechanical properties of this type of network. In order to obtain a satisfactory comparison to the experiments, it was found to be necessary to account for the independently observed tendency of the network junctions to become localized in the network with appreciable swelling, as well as the interchain interactions emphasized in previous discussions of the localization model. [ABSTRACT FROM AUTHOR]

This study explores the utilization of bio-polyol, derived from castor oil modified with waste tire rubber (WTR), in the synthesis of rigid polyurethane-polyisocyanurate foams. Two WTR concentrations (10% and 20%) were incorporated, investigating their impact on foaming, cellular structure, and various foam properties. Response surface methodology assessed the influence of polyol/isocyanate ratios and WTR content on thermal, physical, and mechanical responses. Results indicated significant effects of polyol/isocyanate ratios on thermal and density properties, while WTR content exhibited an opposite trend. Mechanical behavior showed a distinct pattern compared to thermal and physical aspects, suggesting no conclusive correlation between compressive stress variability and polyol/ isocyanate ratio or WTR content. Consequently, the application of these foams depends on specific property requirements, highlighting the potential of sustainable bio-polyols and recycled WTR in replacing conventional petroleum-based counterparts in polyurethane foam production. Highlights * Development of rigid polyurethane-polyisocyanurate foams based on castor oil. * Polyurethane-polyisocyanurate foams modified with waste tire rubber. * Increased isocyanate index impacts thermal stability and density. * Response surface methodology showed variability in compressive stress behavior and the polyol/isocyanate ratio. * For application of polyurethane-polyisocyanurate foams will depend on the desired properties. KEYWORDS castor oil, response surface methodology, rigid polyurethane-polyisocyanurate foams, tire rubber waste, 1 | INTRODUCTION Improper disposal of solid waste is one of the main environmental problems currently faced. (1) With the increase in population and consumption, the amount of waste generated [...]

The present study provides a state of the art on methods for evaluating active chain density of rubbers from swelling experiments. This review focuses more particularly on the effects of components that are known to limit the swelling, and which typically results in an overestimation of the active chain density. These components are commonly considered as insoluble. Different corrections dealing with the two principal insoluble components, namely zinc oxide (Zn0) and carbon black (CB) filler, are thoroughly investigated. A comparative study on the same natural rubber (NR), either filled and unfilled, vulcanized with three different vulcanization systems, is performed to evaluate the relevance of each predictive approach. The results obtained highlight their respective limitations. In particular, it is shown that the swelling ratio of unfilled and filled natural rubbers are linearly related, suggesting that fillers have no significant effect on the overall number of cross‐links formed during vulcanization. As a result, we propose a unified approach for correcting the ZnO content for unfilled NR and both the ZnO and CB contents for filled NR. By comparing with results issued from uniaxial tensile tests, it is shown that the use of a mechanical response is a relevant alternative for determining the active chain density. [ABSTRACT FROM AUTHOR]

Bagasse ash (BA) is an agricultural waste obtained from power plants using sugarcane bagasse as an energy source. Although BA is successfully used as a building material, its application in the polymer industry remains challenging due to the lack of surface reactivity. In this study, BA was purified and named PBA before being incorporated into acrylonitrile butadiene rubber (NBR). Tannic acid (TA), a naturally occurring plant polyphenol, was used as a surface‐modifying agent for improved interfacial interaction. The effect of TA content on the properties of PBA‐filled NBR was investigated. The results showed that the presence of TA resulted in cure retardation, i.e., the scorch time, cure time, and activation energy of the vulcanization reaction increased with increasing TA content. However, the increase in TA content enhanced a rubber‐filler interaction, as evidenced by the considerable increase in bound rubber content. Such an enhancement resulted in the improvement of certain mechanical properties, including hardness, modulus, tensile strength, and tear strength. This research showed that tannic acid can be used as a surface‐modifying agent in NBR/PBA composites. [ABSTRACT FROM AUTHOR]

This study explores the contribution of glass phase and rubber phase to polymer failure, and establishes a theoretical model of temperature‐dependent tensile strength (TDTS) considering the effect of two‐phase transition based on the Force‐heat Equivalence Energy Density Principle (FHEEDP). The model achieves good verification by comparison with the TDTS experimental data of various polymer materials, including epoxy‐based shape memory polymer (SMP), PEEK‐based SMP and CdS/PMMA. The results demonstrate that the model can perform an accurate prediction for the tensile strength of polymer at different temperatures by easily obtainable material parameters. In conclusion, the proposed theoretical model deepens the understanding on the two‐phase transition and their effect on the TDTS, as well as supplies a practical predicted method on the TDTS of polymer, which is crucial for polymer applied in extreme condition. [ABSTRACT FROM AUTHOR]

Introduction High-rate non-penetrating blunt impacts to the thorax, such as from impacts to protective equipment, can lead to a wide range of thoracic injuries. These injuries can include rib fractures, lung contusions, and abdominal organ contusions. Ovine animals have been used to study such impacts, in a variety of ways, including in silico. To properly model these impacts in silico, it is imperative that the tissues impacted are properly characterized. The objective of this study is to characterize and validate two tissues impacted that are adjacent to the point of impact—costal cartilage and hide. Heretofore, these materials have not been characterized for use in computational models despite their nearly immediate engagement in the high-rate, non-penetrating loading environment. Materials and Methods Ovine costal cartilage and hide samples were procured from a local abattoir following USDA regulations. Costal cartilage samples were then cut into ASTM D638 Type V tensile coupons and compressive disks for testing. The cartilage tensile coupons were tested at 150 ε/s, and the compressive samples were tested at −150 ε/s. Identical coupons and disks were then simulated in LS-Dyna using a hyperelastic material model based on test data and experimental boundary conditions. Hide samples were shaved and cut into ASTM D638 Type V tensile coupons and validated in silico using identical boundary conditions and an Ogden rubber model based on test data. Results The structural responses of costal cartilage and hide are presented and exhibit typical behavior for biological specimens. The respective model fits in LS-Dyna were a hyperelastic- based "simplified rubber" for the costal cartilage and an Ogden rubber for the hide. The costal cartilage had a mean failure strain of 0.094 ± 0.040 in tension and −0.1755 ± 0.0642 in compression. The costal cartilage was also noted to have an order-of-magnitude difference in the stresses observed experimentally between the tensile and compressive experiments. Hide had a mean failure strain of 0.2358 ± 0.1362. The energies for all three simulations showed material stability. Conclusions Overall, we successfully characterized the mechanical behavior of the hide and costal cartilage in an ovine model. The data are intended for use in computational analogs of the ovine model for testing non-penetrating blunt impact in silico. To improve upon these models, rate sensitivity should be included, which will require additional mechanical testing. [ABSTRACT FROM AUTHOR]

Highlights Silica is a renewable resource that has become the primary filler for the rubber used in eco‐friendly tires. However, silica tends to agglomerate in the rubber matrix, particularly, micro‐ and nano‐scale silica, which limits its application. When ordinary‐particle‐size silica with low cost and high stacking density is modified using appropriate methods, high dispersion in rubber and good performance can be achieved with common processing equipment, which has significant engineering application value. In this study, silica particles with different sizes (nano‐scale, 19 and 45 μm) were treated with a 3‐mercaptopropyltriethoxysilane coupling agent (KH580). Subsequently, the silica with the ordinary particle size of 300 mesh (45 μm) was coated with natural latex (NL), and the mechanical properties of the modified silica‐filled styrene‐butadiene rubber (SBR)/carbon black (CB) compounds were investigated. The results revealed that the mechanical properties of the NL‐coated 45 μm silica‐filled composite improved significantly, particularly, in the area of tear strength and elongation at break, the composite properties were improved by 17.1% and 118.2%, respectively. Excellent performance over composites filled with coupling agent‐treated micron‐ and nanoscale silica. Enhancing the surface modification of silica through latex coating provides a means to improve the efficiency of industrial production and reduce costs. The low‐fine silica treated with KH580 has good dispersibility. Improved mechanical compatibility of NL‐coated silica with rubber. Improvement in strain performance of composites after NL coated with silica. The effect of silica dispersion on composite properties is greater than the effect of particle size. Industrial silica can be successfully addressed, paving the way for extensive utilization. [ABSTRACT FROM AUTHOR]

In a 1931 report investigating the status of labourers in British colonies, the Colonial Office declared that the system of indenture had been abolished across Malaya. This claim belied the realities of labour practices on the ground. On plantations, mines and in colonial homes, Chinese workers continued to labour under formal indenture and to endure indenture-like practices well into 1930s. This article explores the slow decline of Chinese indenture in Malaya, concentrating on the rubber industry in the Unfederated Malay State of Kelantan during the interwar years. The Chinese migrant workers that were brought to Kelantan in that era signed contracts for one year with the terms of the contract enforced by colonial administrators. These workers endured poor working conditions and high death rates. Those that sought to escape faced criminal conviction and punishments including fines and incarnation. By showing the continuation of indenture in Kelantan, this article challenges the assumption made by historians that Chinese indenture had ended globally by the early 1920s. It also develops new understandings of the fragmentary and complex process of abolition. [ABSTRACT FROM AUTHOR]

The application of warm-mix flame retardant rubber asphalt (WFRA) in tunnel pavement offers a promising solution that enhances both energy conservation and tunnel safety. First, a commercial halogen-free flame retardant (ZK), alumina trihydrate (ATH), and organic montmorillonite compound ATH flame retardant (OMMT/ATH) were melt-blended with warm-mix rubber asphalt (WRA) to prepare different types of WFRAs. Then, the effects of various flame retardants (FRs) on flame retardancy and rheological properties of the WRA were evaluated. Moreover, the functional groups of FR, WRA, and WFRA were investigated. Finally, the synergistic mechanism of FR on the WRA was explored based on the analysis of flame retardancy, rheological properties, and functional groups. Results show that the flame-retardant effect of OMMT/ATH on the WRA is much better than that of single FRs (ZK and ATH), indicating that the OMMT and ATH exhibit synergistic flame-retardant effect. The addition of OMMT/ATH enhances the high-temperature performance but shows little effect on the fatigue performance of the WRA. The synergistic flame-retardant mechanism of OMMT/ATH on the WRA is mainly attributed to the physical barrier effect of OMMT, the cooling and dilution effect of ATH, and the synergistic covering layer effect of OMMT and ATH. [ABSTRACT FROM AUTHOR]

In order to study the effect of water erosion on the adhesion characteristics of warm-mix crumb rubber-modified asphalt (WCR)-steel slag interface, hot-mix crumb rubber-modified asphalt (HCR) was used as the control group. The WCR-aggregate interface adhesion model was established based on the surface energy test. According to the surface energy theory, the adhesion work of WCR-aggregate can be used to calculate their contact angle. Then, the permeability work and spreading coefficient of asphalt-aggregate were obtained. Three processes of asphalt wetting aggregate (adhesion wetting, immersion wetting, and extended wetting) and the compatibility of asphalt-aggregate were analyzed. The interfacial pull-out test and freeze-thaw splitting test were also used to further analyze the adhesion characteristics and water stability of asphalt-aggregate under the action of hydrothermal coupling. Finally, the low-temperature beam bending test of warm/hot-mix crumb rubber-modified asphalt mixture was carried out to verify the experimental results of adhesion characteristics of the asphalt-aggregate interface. The results show that with the erosion of water, the adhesion and water stability of the WCR-steel slag interface and the low-temperature crack resistance of warm/hot-mix crumb rubber-modified asphalt mixture gradually weaken. At the same time, the higher the water bath temperature, the faster the asphalt film destruction, the positive effect of the warm agents on asphalt-aggregate adhesion was weakened, and the WCR-steel slag interface adhesion characteristics were better. The experimental results of low-temperature performance also verify the accuracy of the adhesion characteristics of the asphalt mixture. Finally, the correlation analysis revealed that there was a strong correlation between mechanical indexes (the pull-out strength P, the residual strength ratio, the pull-out strength loss rate η) and water stability index (the freeze-thaw splitting strength ratio). All of them could characterize the water stability of the asphalt-aggregate well. Furthermore, the correlation between η and TSR was the highest, so it is more reliable for evaluating the water stability and adhesion of asphalt and aggregate. [ABSTRACT FROM AUTHOR]

This study investigates the use of an interlocking gap gradation and rubber powder to improve the crack resistance of a cement-stabilized macadam (CSM) mixture. First, a crack-resistant interlocking gap gradation was designed by controlling the percentage of passing of the critical sieve size and the maximum nominal particle diameter. Second, the effect of different addition orders of rubber powder on the crack resistance of the CSM mixture was explored. Finally, the properties and crack resistance of the CSM mixture were analyzed based on the types of gradation and types of rubber powder. The test results show that the crack-resistant interlocking gap gradation not only strengthens the mechanical properties of the CSM mixture but also improves its crack resistance. CSM mixtures with modified rubber powder and cement added simultaneously exhibit the best crack resistance property and mechanical properties. [ABSTRACT FROM AUTHOR]

Chloroprene rubber (CR) is an expensive and frequently used material in many industries. Thus, a blend of natural rubber (NR) and CR can be used to balance cost and product performance. In this research, the primary objective is to achieve the ideal blend of CR/NR rubber for automotive industry by simultaneously optimizing various response variables, including hardness, tensile strength (TS), vulcanization index (CRI), torque difference and Tan δ. This optimization process is carried out using response surface methodology (RSM) and desirability functions. The study delves into examining the influence of accelerators, retarders, curatives, and the ratio of NR in the final batch on both curing characteristics and mechanical properties. The investigation is conducted through the application of analysis of variance (ANOVA) and linear/nonlinear regression models with the assistance of Design Expert 11. When the quantities of the fillers, TMTM80, DP80, S80, and CTPI80, are at their optimum levels of 1.08, 1.78, 3.5, and 0.96 PHR, respectively, and the NR ratio in the final masterbatch is around 27%, the estimated values for Tan δ, hardness, and TS are approximately 0.144, 55.183 Shore A, and 21.085 MPa, respectively. The observations from the validation experiments align with the predicted outcomes, as all response variables fall within the 95% prediction interval. It is noteworthy to mention that prior research has not attempted simultaneous optimization for CR/NR blend, incorporating these fillers. [ABSTRACT FROM AUTHOR]

This paper attempts to evaluate the change in the behavior of the acoustic waves associated with flexure cracks developed in rubberized concretes in a subfreezing environment. Seven normal and rubberized concrete mixtures were developed with different compositions. Prism samples from each mixture were tested at two temperatures (25°C and −20°C) under a four-point monotonic flexure test while being monitored via two attached acoustic emission (AE) sensors to collect the emitted AEs till failure. The AE signal characteristics such as signal amplitudes, number of hits, and cumulative signal strength (CSS) were collected and used for three AE parameter-based analyses: b-value, intensity, and rise time–amplitude (RA) analysis. Analyzing the acoustic activity revealed micro- and macrocracks nucleation, which were found to be associated with a noticeable spike in CSS, historic index [H(t)], severity (Sr) values, and a significant dip in the b-values. In addition, cold temperature was found to increase the micro- and macrocracking onset load and time regardless of mixture composition. Besides, mixtures with a lower C/F, less crumb rubber (CR) content, and/or smaller rubber particle size witnessed higher micro- and macrocrack load and time thresholds. Noticeably, the AE signal attenuation effect caused by the high CR content (up to 30%) at 25°C was significantly relieved when samples were tested at −20°C. Three charts were developed to classify the cracking level based on the values of the intensity analysis parameters [H(t) and S] and RA analysis. Practical Applications: Infrastructure failures can cause severe economic losses and fatalities, but luckily they can be avoided through regular inspections with the aid of nondestructive testing and subsequent repairs. Aging structures need more inspections to detect potential deficiencies, whereas newly constructed ones can safely undergo fewer inspections and preserve resources. Data from nondestructive testing programs can optimize inspection schedules. When it comes to hard-to-reach structures in extreme weather, acoustic emission (AE) has the potential to be a more suitable nondestructive testing technique over other conventional methods. Some concerns were raised regarding the effectiveness of the AE technique for applications involving novel construction materials such as rubberized concrete, because rubber particles have noticeable acoustic absorption capacities that may affect the parameters of the AE waves and impact the posttesting analysis. Another concern was the influence of cold temperature on the AE wave characteristics due to the change in concrete microstructure at low temperatures. This study aimed at addressing these concerns by utilizing AE analysis to highlight the onset of micro- or macrocracks in rubberized concrete mixtures exposed to cold temperatures. Three user-friendly charts are presented that can advise on inspection decisions based on whether deterioration has reached a certain level. [ABSTRACT FROM AUTHOR]

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New insights into 3D-oriented strain-induced crystallization of natural rubber/cellulose nanocrystal (NR/CNC) composites have been obtained by 2D wide-angle X-ray diffraction (2D-WAXD). Upon CNC content exceeding 10 wt%, the mechanical behavior of the material exhibits a yield point that resembles those observed in plastics. Taking into account the influence of filler content of CNCs and thickness, the three-dimensional orientation degree of NR crystallites can be quantitatively assessed. The formation of 3D NR crystallites can be established when the CNC content surpasses 10%, and concurrently, the degree of three-dimensional orientation of crystallites increases as thickness decreases. It was found that not only do CNCs enhance the confinement effect, leading to a decrease in the onset strain, but it is also beneficial for the formation of 3D-oriented strain-induced NR crystallites. The current study not only helps in the comprehensive understanding of the mechanism of 3D-oriented strain-induced NR crystallites by the constrained rigid filler network, but also provides the potential application of uniaxial tensile stretching in creating 3D functional materials. [ABSTRACT FROM AUTHOR]

The investigation demonstrates the potential of nano zinc oxide as a substitute for conventional rubber grade zinc oxide in the bead filler compound of passenger car tires, aimed at reducing heat generation while preserving mechanical and reinforcement properties. Experimentation showed that introducing nano zinc oxide increased compound viscosity, indicating enhanced filler networking. Cure rates accelerated due to the higher surface area of nano zinc oxides, while the Payne effect indicated improved dispersion levels in experimental compounds. Notably, the variant with four parts per hundred rubber of nano zinc oxide exhibited mechanical properties akin to the control, alongside a 28% reduction in tan δ and improvements in hysteresis loss ratio and specific heat values. Morphological analysis confirmed superior dispersion in experimental compounds. Finite element analysis demonstrated decreased temperature generation and a reduced percentage contribution of the bead filler to overall heat energy in tires, leading to a 3% drop in rolling resistance. These findings suggest that nano zinc oxide can effectively replace conventional zinc oxide, enhancing fuel economy in tires, thereby offering a green initiative to reduce fuel consumption in passenger car radial tires through improved hysteresis at the bead area via bead filler compound modification. Highlights: Nano zinc oxide replaces rubber grade zinc oxide reducing heat generation.Nano zinc oxide improves compound viscosity, enhancing filler networking.Variant with four parts per hundred rubber of nano zinc oxide matches control's mechanics, with 28% lower tan δ.Morphological analysis confirms dispersion, coupled with aggregation.Simulation shows lower temperature generation and 3% less rolling resistance. [ABSTRACT FROM AUTHOR]

Natural rubber (NR) is a complex material that is often discarded due to its three-dimensional structure. Recycling of rubber is difficult due to its complex structure, and only 1.7 million tonnes of waste, such as tyres and gloves, are considered recyclable. This study aims to develop self-healing rubber, which allows a product to recover without affecting structural reliability. Commercial NR was ionically crosslinked with zinc thiolate, forming an ionic crosslink network between rubber chains and zinc thiolate ions. The ionic crosslinks allow the rearrangement of rubber molecular chains under external heat, providing self-healing capabilities. The highest ionic crosslink density was found in NR with 35 phr zinc thiolate. The self-healing NR can recover 90 % of its initial properties at room temperature for 10 min and can be reprocessed and recycled three times without compromising its properties. It also shows excellent weldability, making it a promising material for repairing existing rubber products in heavy engineering applications. [ABSTRACT FROM AUTHOR]

Real‐time detection of different physiological characteristics is crucial for human physical and mental health. A detection system with multimodal sensing capability, high sensitivity, excellent mechanical properties, and environmental stability is highly desirable, but it is still a great challenge. Inspired by the structural gradient of biological tissues, a multifunctional sensor based on carboxylic styrene butadiene rubber (XSBR) and sodium polyacrylate (PAANa) non‐covalently modified MXenes is prepared in this study, in which the MXenes exhibit a gradient distribution and simultaneously formed an orientation arrangement at the bottom of the matrix through the formation of hydrogen bonding interactions with PAANa. The material shows a considerable stretchability of 244% and strength of 7.67 MPa, high electrical conductivity of 55.40 S m‒1, low percolation threshold of 2.48 wt%, and excellent response to strain (gauge factor of 906.7 within 98% strain) and humidity (relative resistance change of 530% within 11–93% relative humidity). Based on the superior performances of the XSBR/PAANa/MXene composite, an integrated detection system is designed to accurately detect respiration and body movements at various scales. This work provides a new perspective for the development of a novel biomimetic functional material for sensor applications. [ABSTRACT FROM AUTHOR]

AbstractSelf-healing materials have garnered significant attention for their potential to heal damage when it occurs. Elastomers, particularly natural rubber, have been a focal point of extensive research in the realm of self-healing materials. The ability of self-healing in natural rubber not only promises to extend the service life of rubber-based products but also offers new avenues for recyclability and reprocessability, contributing to environmental protection efforts. A key challenge in the self-healing of natural rubber has been to enhance its self-healing capabilities without compromising its mechanical properties. As a result, various self-healing mechanisms such as hydrogen bond, Diels–Alder (D-A) reaction, disulfide bond, imine bond, and ionic bond have been thoroughly investigated. Among these mechanisms, reversible ionic bonds or ionic interactions have emerged as particularly influential in facilitating the self-healing of natural rubber. This mechanism is easily incorporated into the structure of natural rubber due to its high stability, enabling natural rubber to exhibit promising self-healing properties. This review delves into a comprehensive statistical analysis of numerous published articles and focuses on the exploration of the ionic bonding mechanism in the context of self-healing in natural rubber. Additionally, it provides a succinct introduction to specialized tests designed to assess the self-healing in natural rubber focusing on related methods for ionic bonds mechanism evaluation, namely swelling test and healing efficiency test. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide(MoS2) has a special structure and excellent mechanical properties, making it a promising reinforcing filler for polymers. Carbon dots (CDs) have good antioxidant properties, and the addition of CDs during the synthesis of MoS2 can affect its morphology and size. In this work, a new one-step hydrothermal synthesis process was employed to prepare CDs/MoS2 hybrid particles. Thiourea, sodium molybdate, and glucose were employed as sources of sulfur, molybdenum, and carbon, respectively. The structure and morphology of MoS2 and CDs/MoS2 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), mapping surface scanning (SEM–EDS), and Fourier transform infrared spectroscopy (FTIR). The results show that the prepared 2H-MoS2 is stacked into flower-like spheres with size around 2–10 μm; with the formation of CDs, the size of MoS2 rapidly decreases to less than 1 μm and the CDs are evenly distributed on its surface with mass ratio of 40.2% (CDs in CDs/MoS2). Subsequently, the CDs/MoS2 were used as reinforcing fillers for natural rubber (NR) latex. The results of mechanical properties show that tear strength, tensile strength, modulus, and elongation at break are increased by the addition of CDs/MoS2 in a very lower loading, and the maximum increment ratio is 45.6% and 12.1% when compared to NR-0; the dynamic mechanical analysis and cross-link density results indicated that the CDs/MoS2 can simultaneously improve rigidity and elasticity of NR. The thermal stability results suggest that the CDs/MoS2 shows positive effects on thermal stability of NR. [ABSTRACT FROM AUTHOR]

The rheological properties of polymers before and after mixing are of primary concern because of the damage to the original molecular weight of polymers during processing. In order to reveal the correlation between mixing speed, rheological properties of polymer melts, and their molecular weight parameters, different grades of polybutadiene rubber (BR) at different mixing speeds were prepared in this study. Furthermore, the selected samples were subjected to the dynamic melt viscoelasticity test using a rubber process analyzer (RPA). The molecular weight changes of BR after mixing were observed on a rheological basis to analyze the effects of mechanical shear and thermo-oxidative aging on the molecular weight and distribution of the rubber. The measured values were directly compared with those obtained from gel permeation chromatography (GPC). The results showed that lower mixing speeds did not significantly affect the number-mean molecular weight (Mn), while the Z-mean molecular weight (Mz) and the weight-mean molecular weight (Mw) were increased, and the molecular weight distribution (MWD) was expanded. In addition, a transition state between thermo-oxidative aging and mechanical shear was further demonstrated. The behavior of the rubber was further elucidated and validated through large-amplitude oscillatory shear (LAOS) tests and thermal stability tests, demonstrating that the gel is a manifestation of the molecular weight coalescence of rubber and associating it with the mixing process of BR. According to the results of the RPA tests, melt rheology characterization is an environmentally friendly and fast way to provide information about the molecular structure of the BR. [ABSTRACT FROM AUTHOR]

Hierarchical BiVO 4 /Ti 3 C 2 microcapsules report enhanced solar-driven water evaporation and photothermal-catalytic H 2 evolution activity. The flexible aerogel endows efficient evaporation rates (2.01 kg m−2 h−1) under 1kW m−2 solar irradiation, and the complementary heterostructures present photocatalytic H 2 production evolved after 4 h of reaction is 9.39 μmol. [Display omitted] Desalination processes frequently require a lot of energy to generate freshwater and energy, which depletes resources. Their reliance on each other creates tension between these two vital resources. Herein, hierarchical MXene nanosheets and bismuth vanadate (Ti 3 C 2 /BiVO 4)-derived microcapsules were synthesized for a photothermal-induced photoredox reaction for twofold applications, namely, solar-driven water evaporation and hydrogen (H 2) production. For this purpose, flexible aerogels were fabricated by introducing Ti 3 C 2 /BiVO 4 microcapsules in the polymeric network of natural rubber latex (NRL-Ti 3 C 2 /BiVO 4), and a high evaporation rate of 2.01 kg m−2 h−1 was achieved under 1-kW m−2 solar intensity. The excellent performance is attributed to the presence of Ti 3 C 2 /BiVO 4 microcapsules in the polymeric network, which provides balanced hydrophilicity and broadband sun absorption (96 %) and is aimed at plasmonic heating with microscale thermal confinement tailored by heat transfer simulations. Notably, localized plasmonic heating at the catalyst active sites of the Ti 3 C 2 /BiVO 4 heterostructure promotes enhanced photocatalytic H 2 production evolved after 4 h of reaction is 9.39 μmol, which is highly efficient than pure BiVO 4 and Ti 3 C 2. This method turns the issue of water–fuel crisis into a collaborative connection, presenting avenues to collectively address the anticipated demand rather than fostering competition. [ABSTRACT FROM AUTHOR]

Untreated pyrolytic tire char was used in natural rubber (STR20) composites as single filler at loadings of 30–70 phr and co‐filler with carbon black (N330) at a total loading of 50 phr. The results were compared with rubbers filled with N330 and crumb rubber at 30 phr. The effects of fillers on cure characteristic, crosslink density, filler dispersion in natural rubber vulcanizates and their mechanical properties were investigated. The slight reversions were seen for the cure characteristics of 70 phr‐char‐filled and all co‐filler samples because the sulfur amount in the char together with the added sulfur could shift the vulcanization system from EV to SEV, whereas plateau cure curves were seen for the rest. While the highest tensile strength of char‐filled sample was obtained at 50 phr loading, whose tensile strength was about 88% of the N330 sample at 30 phr, 70‐phr‐char filled sample was superior in surface hardness, abrasion resistance and tear strength to N330 sample at 30 phr. For rubber with co‐fillers, the mechanical properties depended on the mass ratio of N330 to pyrolytic tire char. Therefore, it is possible to use untreated char as reinforcing filler for suitable applications according to their properties. [ABSTRACT FROM AUTHOR]

In the modern rubber industry, the major problem is the use of petroleum-derived chemical reinforcements that exploit conventional sources of energy. In this review article, we have discussed the importance of some cellulose-based reinforcements as an alternative to harmful chemicals in rubber composites. The employment of natural cellulosic fillers not only improves the biodegradability of rubber latex but also enhances its mechanical and thermal properties. Such reinforced rubber composites can be used effectively in various sectors, i.e. food packaging, footwear, water purification and sensors. In the last, the current outlook and future perspectives of smart rubber composites in commercial areas are also discussed. [ABSTRACT FROM AUTHOR]

The radiation shielding effectiveness of multifunctional thermoplastic biodegradable polymer incorporated with different loadings of graphene nanoplatelets (GNPs) was investigated. The bio-nanocomposite, fabricated using an ultrasonication-assisted melt compounding technique, was composed of polylactide, liquid natural rubber, polyaniline, and various amounts of GNPs. The inclusion of GNPs has enhanced the crystallinity and thermal stability of the nanocomposites. Fourier transform infrared results confirmed the presence of all characteristic peaks of nanocomposites' components, yet with no interfacial interaction between GNPs and the neat matrix. Microstructural and mechanical testing showed optimum properties are linked to 0.4 wt% of GNPs. The addition of low-content GNPs revealed a slight variation in shielding features. Despite this result, the 0.8 wt% filled nanocomposite (PLPG4) sample recorded the highest linear attenuation coefficient and lowest half-value layer, while the neat polymer matrix (PLPG0) showed superior mass stopping power against proton and alpha particles at all energies. The dose rate and total macroscopic cross sections for neutrons, which were determined by the Monte Carlo N-Particle eXtended program code, showed negligible change upon adding GNPs. The fast neutron removal cross section (ΣR) was the same (0.093 cm−1) for all nanocomposites. These results indicate the potential capability of current bio-nanocomposites for neutron and proton shielding applications. [ABSTRACT FROM AUTHOR]

A comparative study was conducted to investigate the gamma and neutron radiation shielding properties of composites made from iron metal (micro and nano) dispersed within natural rubber (NR). The aim was to attenuate neutron and γ‐rays. The study utilized the gamma spectroscopy technique and the Monte Carlo FLUKA code. To assess the gamma ray shielding, a 3×3 Nal (Tl) detector and radioactive point sources were employed. Two comparative studies were carried out, one using Fe loaded NR (Fe/NR) composites in microsize and the other using Fe/NR composites in nanosize. The objective was to determine the impact of iron nanoparticles on the shielding ability of the composites. The findings revealed that the Fe/NR composites in nanosize exhibited superior gamma radiation shielding ability compared with the Fe/NR composites in microsize. These results were supported by the FLUKA Monte Carlo code, which demonstrated good agreement with both the experimental and theoretical XCOM data. [ABSTRACT FROM AUTHOR]

Rubber tire mold fouling is a severe problem leading to mold surface corrosion, tire defects, and extra energy consumption. Traditional mechanical and chemical cleaning is inefficient and induces mold surface damage. Low surface energy organic coating displays antiadhesive behavior but is susceptible to wear. Here, we develop a bioinspired Co-CeO2/MoS2 coating with effective mechanical robustness, corrosion resistance, and antifouling behavior by leveraging a slippery liquid-infused surface (SLIPS) strategy. The micro-nanostructure of the coating serves as mechanical stability and anticorrosion skeleton with the infused lubricant acting as a slippery antifouling surface. The variation of microstructure, mechanical strength, corrosion resistance, and antifouling behavior of the coating with individual and synergistic addition of CeO2 and MoS2 is systematically characterized. The slippery Co-CeO2/MoS2 coating shows excellent mechanical stiffness, corrosion resistance, and antifouling performances in rubber vulcanization conditions. [ABSTRACT FROM AUTHOR]

This study examines the use of waste and recyclable polyethylene terephthalate (rPET) along with micro-sized ground tire rubber (GTR) to produce a polymer matrix composite (PMC) material. The PMC materials are made in a Twin-screw extruder, with different ratios of rPET to GTR ranging from 90:10 to 50:50. In order to assess the performance of the newly created rPET-GTR matrix composite materials, the physical, mechanical properties are empirically observed. The thermal properties and crystallinity (Xc) of PMC materials are analysed using DSC. SEM and microscopic imaging are used to determine the characteristics of rPET-GTR composite materials, including elemental compositions like carbon, oxygen, and silicon. The functional group and chemical structure are confirmed through IR spectra analysis using FTIR techniques. The inclusion of micro-sized GTR has shown a significant effect on the physical (density = 1.306 - 1.208 g/cm3, water absorption = 1.76%–10.74%, and melt flow index = 8.12 - 12.79 gm/10 min), mechanical (tensile strength = 52.78 – 73.58 MPa, impact strength = 110.64 - 138.44 J/m, hardness = 56.14 - 76.37, and flexural modulus = 66.23 - 106.32 MPa), and thermal (melting temperature = 220.25°C–192.57°C, Xc = 20.30 to 30.58%) properties of rPET. These studies all work together to improve the performance of waste rPET and GTR materials by repurposing them. It helps to promote sustainability, cost-effectiveness, and expands the range of applications (automotive parts, building materials, sports equipment, electrical insulation and prosthetics) for rPET-based composites with potential uses in the polymer industries. [ABSTRACT FROM AUTHOR]

Hierarchical self‐assembly has been recently employed in the construction of anion‐coordination‐driven gel materials. However, the post‐assembly modification strategy, which may be a highly efficient strategy to realize the functionalization of discrete 'aniono' supramolecular architectures, has not been employed yet. Herein we report the first example of anion‐coordination‐driven gel material cross‐linked by well‐defined 'aniono' triple helicate through post‐assembly polymerization. The obtained gel shows self‐healing property and excellent compatibility with various surfaces, including glass, rubber, leaf, PP, and metal. The viscoelastic gel constructed through the post‐assembly modification strategy enriches the method to construct the anion‐coordination‐driven smart materials. [ABSTRACT FROM AUTHOR]

As a conductive material for snow melting on bridge decks, the interfacial shear strength of carbon fiber/rubber conductive composites is a prerequisite for engineering applications. The interfacial shear strength of the carbon fiber/rubber conductive composite was determined. The microstructure after the shear test was analyzed by scanning electron microscope (SEM). The interfacial stability was evaluated base on the extreme temperature on bridge decks. Finally, the interface durability was analyzed through 100 low-temperature cycles, 240 h high temperature and 50 electrification tests. The results show that the interfacial shear strength is 4.32 MPa. SEM results show that the shear force at the interface comes from three aspects. The interfacial shear strength is 13.45% higher than normal at −20°C, and 17.33% lower than normal at 60°C. The interfacial shear strength decreases by 7.48% after 15 cycles of low temperature and then stabilized. The effect of continuous high temperature and multiple energizations on the interfacial shear strength is small. SEM results confirm that low-temperature cycling reduces the internal bonding of rubber. The carbon fiber/rubber composite has good interfacial stability and durability. This study provides a mechanical foundation for the active snow melting of carbon fiber/rubber conductive composites on bridge decks. [ABSTRACT FROM AUTHOR]

The incompatible thermoplastic poly lactic acid/carboxylated acrylonitrile butadiene rubber (PLA/XNBR) was prepared, and the effect of graphene oxide (GO) as a reinforcement and glycidyl methacrylate (GMA)-grafted XNBR (XNBR-g-GMA) as a compatibilizer on the properties of PLA/XNBR blend was investigated in this research. The microstructure, mechanical behavior, thermal, rheology, and dynamic mechanical properties of PLA/XNBR composites were investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), tensile test, and dynamic mechanical thermal analysis (DMTA). The incorporation of XNBR-g-GMA improved the compatibility of the PLA/XNBR blend phases, as confirmed by microstructure and DMTA analysis. The results of the mechanical properties showed that with an increase in GO content in the PLA/XNBR/XNBR-g-GMA matrix, there was a significant improvement in tensile strength, Young's modulus, hardness, and impact strength. In order to validate the experimental mechanical and rheological results, various theoretical models were applied and a good agreement was observed between the theoretical and experimental data. [ABSTRACT FROM AUTHOR]

The goal of this work was to develop acrylonitrile–butadiene (NBR) elastomer composites filled with hydroxyapatite (HAP) characterized by improved cure characteristics and resistance to burning. Silane, i.e., (3-aminopropyl)-triethoxysilane, ionic liquid, i.e., 1-decyl-3-methylimidazolium bromide and surfactant, i.e., cetyltrimethylammonium bromide, were used to improve the filler's dispersibility in the elastomer matrix and to reduce the time and temperature of vulcanization. The effects of HAP and dispersants on the cure characteristics, crosslink density and physico–chemical properties of NBR composites were explored. The additives used, especially the ionic liquid and surfactant, effectively improved the dispersion of HAP in the NBR matrix. The amount of HAP and the dispersant used strongly affected the cure characteristics and crosslink density of NBR. The optimal vulcanization time significantly increased with HAP content and was pronouncedly reduced when ionic liquid and surfactant were applied. In addition, ionic liquid and surfactant significantly lowered the onset vulcanization temperature and improved the crosslink density and hardness of the vulcanizates while impairing their elasticity. HAP and dispersants did not significantly affect the damping properties or chemical resistance of NBR vulcanizates. Above all, application of HAP considerably enhanced the resistance of vulcanizates to thermo-oxidative aging and reduced their flammability compared with the unfilled NBR. [ABSTRACT FROM AUTHOR]

Soil improvement is a significant aspect of geotechnical engineering that requires periodic assessment and modification. This study aims to see how glass powder (GP) and rubber particles (RP) affect the shear strength and bearing capacity of clay soil collectively and separately. The soil samples were subjected to direct shear testing and California Bearing Ratio (CBR) tests at various glass powder and rubber particle contents. The CBR test was conducted under soaked and unsoaked conditions. Clay-rubber, clay-glass powder, and clay-rubber-glass powder mixtures were prepared for the tests. It was discovered that adding glass powder and rubber particles improved the soil's shear strength parameters and bearing capacity. A comparative analysis was conducted on the clay-rubber mixtures and clay-glass powder mixtures. The results indicated much improvement by the rubber particles than the waste glass powder in the direct shear test. In contrast, the glass powder had a better impact than the rubber particles in the CBR test. Furthermore, a correlation analysis was conducted to ascertain the relationship between the CBR values and the shear strength of the soil samples using a single Linear Regression Analysis (SRLA) model. The correlation yielded satisfactory coefficients (R2), indicating a strong link between the engineering properties. [ABSTRACT FROM AUTHOR]

A compact and versatile tensile apparatus for polymer materials is designed and fabricated. Three distinct stretching modes are developed: constant speed, cyclic, and sinusoidal, with adjustable speeds ranging from 0.001 to 120 mm/s. To capture the true strain of the central region, a high-speed camera has been integrated into the apparatus. The temperature of the sample chamber is controlled by flowing air, enabling a homogeneous temperature in the range of RT ∼200 °C. The apparatus is particularly suitable for a synchrotron beamline. The structural evolution of natural rubber during sinusoidal stretching is investigated by in situ wide-angle x-ray scattering. Scattering patterns, force, clamp position, and sample images are saved simultaneously during stretching. Notably, the results reveal a sinusoidal variation in the crystallinity of crosslinked natural rubber when a sinusoidal strain was applied to the sample. The integration of advanced measurement techniques and controlled experimental conditions ensures the acquisition of reliable and accurate data, providing valuable insights into the structural evolution of materials under dynamic deformation conditions. [ABSTRACT FROM AUTHOR]

This paper describes the effects of incorporating the commercially available phenylurea-based antimicrobial agent S89 to pre-vulcanised natural rubber latex (NRL). The physical properties of the dipped film derived from the S89 incorporated into pre-vulcanised NRL such as antimicrobial efficacy, wettability properties, surface characteristics, surface morphology and tensile strength were further evaluated. The antibacterial activity of S89 in NRL films was tested using the agar disc diffusion method and S89 had been demonstrated to suppress and prevent bacterial growth even at low loading levels. Moreover, the minimum inhibitory concentration (MIC) of S89 was obtained by fitting the inhibition zone diameter and loading of S89 using two mathematical diffusion models, free and dissipative models. In this work, the dissipative model is shown to be the best-described diffusion model for S89. The leaching behaviour of S89 in an artificial sweat was investigated where the leachate of S89 is observed after 20 min of immersion at a very low concentration (0.039 ug/mL). Interestingly, NRL films incorporated with S89 displayed better wettability properties on air facing (AF) surface indicating that the AF surface of the film had been altered to be more hydrophilic. Nonetheless, there were no changes observed to the former facing (FF) surface. In addition, the polarity of the surface was also reduced which corresponds to the contact angle results. Further analysis of the Field Emission Scanning Electron Microscopy (FESEM) surface morphology on the NRL film incorporated with S89 exhibited sufficient miscibility and homogeneity during latex compounding with no agglomeration observed on both surfaces (air and former) and at the cross-sectional surface. Meanwhile, comparative tensile strength (of more than 20Mpa) of NRL films incorporated with S89 was observed for low dosage at 1 phr and 3 phr. In conclusion, antimicrobial natural rubber (NR) films for glove application with satisfactory tensile properties, adequate wettability properties, non-agglomerated surface morphology and good antimicrobial properties were achieved by employing a low loading of S89 in the NRL. [ABSTRACT FROM AUTHOR]

A finite element model for analysing the sealing performance of three types of wellhead rotary blowout preventer rubber ring structures in use on site was established. By using this model, the stress, deformation and contact pressure distribution of the passive rubber ring during pre-tightening conditions were calculated when the inner annulus of the passive rubber ring passed through the 5-inch drill pipe body and the 7-inch joint. The distribution position, length, and magnitude of contact pressure on the contact surface between the three types of rubber rings and the outer wall of the drill string under different pressure penetration loads under rated working conditions were calculated. Overall, the sealing performance of the active rubber ring is the best while the sealing performance of the passive rubber ring is the worst. However, the passive rubber ring has a simple structure and does not require a hydraulic system, which makes it impossible to adjust the sealing strength of the rubber ring in real time based on the actual fluid pressure on site. On the other hand, the I-type rubber ring uses part of the rotating blowout preventer structure as the hydraulic chamber wall, which can thicken the rubber layer in contact with drill pipe. Therefore, passive rubber rings are more suitable for low fluid pressure drilling operations. When the fluid pressure at the lower part of the rubber ring exceeds the rated maximum fluid pressure, it will lead to a sharp decrease in the sealing performance of the rubber ring. Therefore, stricter control of the use of the rubber ring is needed during on-site use, especially in drilling conditions with wellhead fluid pressure. The research methods and achievements in the article provide theoretical guidance for the safety evaluation of rotary blowout preventers used in ultra deep wells unbalanced drilling. [ABSTRACT FROM AUTHOR]

In the current study, samples were taken from the sewage treatment plant to isolate rubber-degrading microbial strains. The sludge samples were screened for rubber degradation microbes and later on, each strain was separately characterised for rubber degradation. Initially, strain BA23 showed half the rubber degradation ratio in mineral salt medium. The isolated microbial strains were identified based on 16SrRNA gene sequence analysis, morphological and biochemical characteristics and named Brucella sp. belonging to the genus Bacillus. Later on, the medium conditions for strain BA23 were optimised based on carbon, nitrogen sources, pH, temperature and incubation period. After optimising various environmental and nutritional conditions, the rubber degradation increased twice when inorganic nitrogen sources (aammonium nitrate) used 1 g/L in the medium at pH 7.5. Furthermore, the structural changes that occurred in the rubber polymer associated with the rubber polymer were analysed through Fourier transform infrared spectroscopy (FTIR) and the breakdown of important functional groups such as aldehyde, ketone ester and carboxylic acid was observed. Finally, the gravimetric weight loss of CO2 during rubber degradation was 42.88 g/L, showing CO2 evolution greatly when the rubber degradation occurred in the mineral salt medium. It was concluded that strain BA23 has a maximum potential for rubber degradation when it is used for future solid waste management of rubber and its products for a long period in the environment. [ABSTRACT FROM AUTHOR]

This study aimed to identify stable and productive genotypes of rubber tree [Hevea brasiliensis (Willd. ex. Adr. de Juss. Müell-Arg.)] in water stress using the linear mixed model approach and to compare genetic parameters estimates of different genotypes groups in different years. The experiment was composed of 58 test clones and control clones (RRIM 600, GT 1 and PB 235) distributed across four trials evaluated in the Centro Avançado de Pesquisa e Desenvolvimento de Seringueira e Sistemas Agroflorestais, Votuporanga, São Paulo, Brazil. Rubber yield was evaluated over four years. The crop water stress index (CWSI) was used to evaluate water conditions over the period. The rubber yield data were analysed by the Restricted Maximum Likelihood model and Best Linear Unbiased Prediction (REML/BLUP) procedure. The plant development conditions were inadequate throughout the period. The effect of genotypes was significant in all analyses, indicating conditions favourable to the selection. The superior clones were V 051, V 006, and V 123 (Trial 1); V 227, V 263, and V 288 (Trial 2); V 744, V 619, and V 582 (Trial 3) and C 311, C 344, and C 33 (Trial 4). These genotypes can be used as parental clones in future breeding cycles. There are clones capable of maintaining yield stability in water deficit periods. The annual genetic variability estimated for rubber yield varies from year to year but is maintained during the breeding cycle. This contributes to the maintenance of the genetic variability among productive genotypes. [ABSTRACT FROM AUTHOR]

It is well known that long-term chemicalised agricultural practices harmfully affect soil health and prevent sustainable management of fertility in crop fields, including that of plantation crops. Accordingly, an investigation was carried out to check how soil fertility characteristics such as soil pH, soil mineral nutrient and organic carbon content are altered in long-term chemicalised rubber plantations of Kerala, located in the ecologically sensitive Western Ghats of South India. Soil fertility status concerning soil types in the Rubber fields (USDA soil orders - suborders) such as Inceptisols - Oxic Dystrudepts (IOD), Ultisols - Ustic Haplohumults (UUH), Ultisols - Typic Kandiustults (UTK) and Mollisols - Pachic Argiustolls (MPA) involving six soil series are critically analysed. A negative impact of long-term chemicalised agriculture was visible in low soil pH and nutrient levels. In general, rubber fields in the region, even in the generally alkaline Mollisols, showed a pH of 6.23. The soils showed reduced nutrient and carbon content and a comparatively poor soil fertility index specific to soil types. The soil available NPK and soil total cations were found to be comparatively low and soil specific. However, rubber fields in Mollisols were significantly higher in STK, STMg, STCa, and STNa while those in Ultisols were significantly higher in SAP and SAK than other soil orders. The Inceptisols were significantly higher in SAN, STP, and soil organic carbon than others. Therefore, balanced fertilizer application concerning soil types per proper soil fertility monitoring has become significant to sustainable soil productivity management in rubber plantations. [ABSTRACT FROM AUTHOR]

A novel accelerator, cerium cysteine (Ce-Cys) was synthesised by double replacement reaction. The complex was characterised by FT-IR analysis, thermal analysis, EDTA titration and elemental analysis, respectively, to determine that the molecular formula of the complex was Ce (Cys)3Cl3·3H2O. Cure characteristics, crosslink density, mechanical properties and thermo-oxidative ageing of NR compounds were investigated. The research revealed that the vulcanisates containing Ce-Cys manifested high scorch time, outstanding mechanical properties, and better thermo-oxidative ageing properties. Furthermore, based on kinetic calculations, it was concluded that as the amount of Ce-Cys increased, the reactivity of the crosslink precursor increased while the activation energy decreased. [ABSTRACT FROM AUTHOR]

A large number of waste tires are discarded every year. These waste tires will have a great impact on the environment. If they can be recycled, environmental and economic benefits can be obtained. In this paper, rubber powder is added to concrete, and a variety of analytical methods are used to study the effect of rubber powder on the performance of concrete. Experiments show that the slump of concrete decreases with the increase of rubber powder substitution rate, and the rheological performance results show that the friction force increases with the increase of rubber powder substitution rate. The compressive strength of concrete decreases with the increase of substitution rate. The results of ICP show that rubber powder will adsorb cations to affect cement hydration. Nanoindentation shows that the addition of rubber powder leads to the decrease of high-density hydration products. The results of SEM-EDS show that rubber powder will affect the Si/Ca of hydration products. The results of UPV and MIP are similar. The hydrophobicity of rubber powder and the poor compatibility with hydration products are the key factors affecting the durability of concrete. Because the rubber powder only needs to be ground to avoid the related process of cement, it can obtain good economic and environmental benefits. In practical engineering, rubber powder can be added appropriately. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative methodology for evaluating the dry rubber content (DRC) of natural rubber latex (NRL) through the utilisation of transient hot wire (THW) technique. To accomplish this objective, an instrumentation system has been devised and implemented, which operates based on this underlying principle. The proposed approach capitalizes on the significant disparity in thermal conductivity between rubber particles (0.13 W/m-K) and water (0.58 W/m-K). A series of NRL samples obtained from the field were assessed using the developed instrument and their corresponding DRC values determined using conventional weighing-drying technique. The outcomes reveal a strong correlation between measured temperature increments for each sample within a predefined time frame and their respective DRC values. Furthermore, the proposed method offers the advantage of a significantly reduced measurement time, requiring only approximately 10 min to determine the DRC, in contrast to the existing weighing-drying technique, which necessitates around 18 h. Both techniques yield a measurement accuracy of ± 2%. [ABSTRACT FROM AUTHOR]

Methylene blue undergoes decomposition upon the exposure to ultraviolet (UV) light and oxygen to release reactive species such as singlet and triplet oxygen. These reactive species have adequate energy to oxidise and degrade organic materials including natural rubber (NR). In this work, NR latex was exposed to UV in the presence of methylene blue and hydrogen peroxide to produce low molecular weight NR latex. The Mn of NR was reduced from 544 × 103 g/mol to about 6 × 103 g/mol with low gel content. During the photodegradation, the NR chain was cleaved at both C = C and C-C bonds. The molecular structure of LNR was similar to that of the NR but with new functional groups of hydroxyl and carbonyl, resulting from oxidation and chain cleavage. The rubber particles were originally pear-shaped but changed to spherical after the degradation reaction, although their size remained largely similar. [ABSTRACT FROM AUTHOR]

The influence of silver nitrate as an antimicrobial agent on natural rubber (NR) and nitrile butylene rubber (NBR) latex films were investigated. The NR and NBR latex films were prepared using coagulant dipping with an additional dipping procedure was performed prior to wet gel leaching to deposit the silver nitrate solution onto rubber films. Different concentrations of silver nitrate solution were used in the range of 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0 mM, respectively. The degree of microbial inhibition efficiency of the antimicrobial NR and NBR on Staphylococcus aureus (S. aureus) which is a common nosocomial pathogen in combating hospital acquired infections (HAIs) were evaluated. The field emission-scanning electron microscopy (FE-SEM) analyses showed an obvious morphological transition of the silver particle structures were observed as the concentration of silver nitrate increased. On the other hand, the microbial inhibition study using free diffusion and dissipative equations are suggested to determine minimum inhibition concentration (MIC). The antimicrobial study suggested that silver nitrate deposited on the NR and NBR latex films were not influenced by the morphology of silver microstructure which yielded from different concentrations of silver nitrate deposited on latex films surface. Hence, the study effectively demonstrates that antimicrobial inhibition on different antimicrobial latex films results different of MIC values. The tensile strength results of silver nitrate treated NR and NBR latex films also showed no significant reduction on unaged and aged of film's tensile strength, modulus at 300% (M300) and elongation at break (EB). These results indicated that the deposition of silver ion latex films had no negative effect on film's integrity of the NR as well as NBR latex films. [ABSTRACT FROM AUTHOR]

Semi-IPN composites of natural rubber (NR), hydrophilic sodium carboxymethyl cellulose (CMC) and carbon black (CB) with different compositions have been created by solution casting process in an attempt to develop a novel adsorbent under various pH ranges for the cationic dye methylene blue (MB). The produced NR/CMC film can be employed as an adsorbent of MB dye, according to the results, which demonstrate that composites with 2% CMC and 0.2 g CB displayed a maximum adsorption capacity of 1.72 mg/g and a dye removal efficiency of 85.22% at pH 9. The semi-IPNs were characterised using X-ray diffraction, Thermogravimetry, FTIR, and SEM methods. The NR/CMC semi-IPN composites' SEM micrographs showed a continuous, homogenous and porous structure. The films' equilibrium swelling characteristics were examined. For the NR98%CMC2% polymeric composition, containing 2% glutaraldehyde (GA) and 0.02 g CB loading, a maximum tensile strength of 3.3 MPa was achieved. In a 12-month period with 2% CMC, the NR/CMC semi-IPN showed a 70% biodegradation rate, while the pure NR showed only a 20% degradation rate. X-ray diffraction analysis shows that the addition of CMC reduces the crystallinity of natural rubber. [ABSTRACT FROM AUTHOR]

The article focuses on synthesising a new nanocomposite incorporating ZnS filler and investigating its structure, optical properties and specific electrical conductivity. In this study, expanded perlite (EP) and butadiene rubber (BR) underwent simultaneous oxidative chlorophosphorylation and subsequent hydrolysis. ZnS nanoparticles were then grown on the crosslinked/ion-exchange composite (EP-PhBR) using the Successive Ionic Layer Adsorption and Reaction (SILAR) method, resulting in the ZnS/EP-PhBR nanocomposite. The structure of the nanocomposite was characterised through UV-Vis spectroscopy and X-ray diffraction analysis. Embedding ZnS nanoparticles in EP-PhBR caused a reduction in the optical band gap from 3.18 eV to 3.045 eV, signifying increased disorder in ZnS nanoparticles due to alterations in the nanocomposite's intermolecular structure. XRD studies revealed cubic crystal-structured ZnS nanoparticles with an average size of approximately 3 nm in the ZnS/EP-PhBR nanocomposite. The specific electrical conductivity (σ) at ambient temperature demonstrated the enhanced crystallinity of EP-PhBR, attributed to interfacial interactions with ZnS nanoparticles and the developed nanolayers. The ZnS/EP-PhBR nanocomposite exhibited favourable properties, making it a promising material for photocatalysis and solar cell applications. [ABSTRACT FROM AUTHOR]