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In this study, epoxidized natural rubber (ENR) was mixed using a two-roller mixer. Water hyacinth fiber (WHF) acted as a reinforcing agent in the preparation of the rubber composite at 10 phr (ENRC/WHF). Chlorhexidine gluconate (CHG) was added at different concentrations (1, 5, 10, and 20 phr) as an antimicrobial and coupling agent. The tensile strength increased with a CHG content of 1 phr (4.59 MPa). The ENRC/WHF/CHG20 blend offered high hardness (38) and good morphology owing to the reduction in cavities and fiber pull-out from the rubber matrix. The swelling of the sample blends in oil and toluene decreased as the CHG content increased. Reactions of –NH2/epoxy groups and –NH2/–OH groups occurred during the preparation of the ENRC/WHF/CHG blend. The FTIR spectroscopy peak at 1730 cm−1 confirmed the reaction between the −NH2 groups of CHG and epoxy groups of ENR. The ENRC/WHF/CHG blend at 10 phr and 20 phr exhibited zones of inhibition against three bacterial species (Staphylococcus aureus, Escherichia coli, and Bacillus cereus). CHG simultaneously acted as a crosslinking agent between ENR and WHF and as an antimicrobial additive for the blends. CHG also improved the tensile strength, hardness, swelling, and antimicrobial properties of ENR composites. [ABSTRACT FROM AUTHOR]

Epoxidized natural rubber (ENR) grafted Poly(N-isopropylacrylamide) (ENR-g-PNIPAM) hydrogel was exploited by classic free radical polymerization, which exhibited practical potential for temperature-sensitive material. Free ENR was introduced in the ENR-g-PNIPAM hydrogel to construct a secondary network that will form chain entanglement and further improve the chemical and physical properties of the hydrogel. The renewable ENR and a facile fabrication process make large-scale production of the ENR-g-PNIPAM hydrogel possible and prompt its commercial value. The content of ENR was systematically varied and studied to ensure optimal ratio. Among various compositions examined, the 7:3 weight ratio of ENR/NIPAM in the hydrogel(70ENR) exhibited excellent properties. Additionally, a simple scheme was also designed for fabricating multifunctional ENR-g-PNIPAM/polypyrrole/cotton (EPPC) composites with simultaneous adsorption of Cr (VI) and electrothermal conversion. The EPPC composites demonstrated good adsorption capacity with 127 mg/g at pH = 2 in an aqueous solution containing 100 mg/L Cr (VI), while also functioning as a thermistor with enhanced sensitivity. The adsorption data can be better described by the pseudo-second-order kinetic model and the Freundlich isotherm model, indicating that the adsorption was a chemical and multilayer. Benefiting from these research results, enabling the synthesized hydrogel a crucial role in terms of Cr (VI) treatment and thermal sensor. [ABSTRACT FROM AUTHOR]

Reversible networks of epoxidized natural rubber (ENR) mixed with dicarboxylic acid were studied. ENR is a bio-based polymer, commercially available, and capable of sulphur vulcanisation. In addition, ENR has been already reported to exhibit self-healing characteristics after ionisation by adding ionic groups to the epoxide group. The reversible network structure plays an essential role for self-healing behaviour, which cannot be obtained for elastomers with irreversible sulphur network. In this study, dicarboxylic acid was used to construct the reversible network. The reversible hydrogen bonds were established in such a way that firstly one carboxyl group of di-carboxylic acid (DA) is reacted to ENR and secondary the other carboxyl group of DA interacts with residual carboxyl group to form hydrogen bonds in carboxylic dimer. The self-healing behaviour was evaluated for ENR with DA by tensile tests. This self-healing system provides new insights for sustainable and natural-based materials. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNC) obtained from biomass are increasingly demanding as a candidate for rubber composite reinforcement due to their sustainability and environmentally friendly characteristics. This work explored CNC extracted from oil palm trunks, an agricultural waste, for its reinforcing efficacy for natural rubber (NR) composite. To achieve good compatibility of the hydrophilic CNC in non‐polar NR, the NR was modified in a simple and green epoxidation condition via its latex stage. The epoxidized natural rubbers (ENR) containing 15% and 25% epoxide content, symbolized as 15E and 25E, respectively, were prepared. The ENR/CNC nanocomposites were fabricated by mixing CNC aqueous suspension and ENR latex, followed by co‐coagulation by methanol. A low amount of CNC (0.5–5 phr) was incorporated into the rubber and it was found that the ENR/CNC nanocomposites showed improvement in mechanical properties compared to the NR/CNC nanocomposite. The 25E/CNC nanocomposite with 1 phr of CNC achieved a 22.6% increase in tensile strength while the 25E/CNC nanocomposite with 2 phr of CNC resulted in a 27.1% increase in tear strength. The enhanced performance of the fully bio‐based rubber nanocomposites is attributed to the CNC–rubber interaction and good CNC dispersion in the ENR matrices, evidenced by the results of SEM and crosslink density. Highlights: Cellulose nanocrystal (CNC) was successfully obtained from the oil palm trunk.NR was modified into epoxidized natural rubber (ENR) for increased polarity.ENR/CNC mixing was done in a simple and environmentally friendly latex process.Only 2 phr of CNC resulted in a 27.1% increased tear strength of rubber composite.SEM clearly evidenced improvement of CNC–ENR interaction. [ABSTRACT FROM AUTHOR]

Hybrid nanocomposites, comprising epoxidized natural rubber (ENR) filled with graphene (GP) and carbon nanotubes (CNTs), were prepared via the melt mixing technique. TEM imaging confirmed the development of three-dimensional filler networks, facilitated by the π-π interaction between sp2-hybridized carbon atoms in graphene and carbon nanotubes, alongside Van der Waals forces. Moreover, a notable interaction between polar functional groups on the nanofiller surfaces and the ENR molecules emerged as a significant factor in enhancing properties. This was evidenced by the rise in bound rubber content with increasing CNT loading, amplifying reinforcing efficiency through the establishment of bridge links among rubber chains and filler networks. Temperature scanning stress relaxation (TSSR) results unveiled escalating relaxation forces, moduli, and crosslink density upon nanofiller incorporation and with increasing CNT loading. DMA results indicate elevated storage modulus and glass transition temperature (Tg), coupled with reduced coefficient of reinforcement (C-factor), indicative of an increased degree of reinforcement. [ABSTRACT FROM AUTHOR]

The current challenge of recycling rubber articles beyond the failure time has created an increasingly huge burden on the environment. Therefore, there is a growing focus on enhancing the environmental resistance and reprocessability of rubber materials. In this work, we present a simple way to introduce the fluorinated short-side chains on the molecular chains of epoxidized natural rubber (ENR) via the reaction of epoxy groups and carboxyl groups. The results indicated that the short fluorinated side chains endowed ENR the excellent environmental resistance such as thermal stability, thermal oxygen resistance and solvent resistance. At the same time, the cross-linking network formed by the thermally reversible β-hydroxyl ester bonds enables the rubber to a good reprocessability. The second recycled ENR-DTSA-F had achieved 90.4% of the retention ratio of the tensile strength and reached 69.9% of the retention ratio of the elongation at break compared to the original sample. This work provides a simple method for preparing ENR materials with good environmental resistance and reprocessability. [ABSTRACT FROM AUTHOR]

This study focuses on enhancing the mechanical and thermal properties of thermoplastic starch (TPS) and natural rubber (NR) blends by incorporating polyethylene glycol (PEG2000) and various types of modified natural rubbers, including epoxidized natural rubber (ENR50), poly (methyl methacrylate)-grafted natural rubber (NR-g-PMMA), and poly (butyl methacrylate)-grafted natural rubber (NR-g-PBMA). The influence of the TPS/NR blend ratio, PEG content, and type of modified NR on the properties of the blends was investigated, along with their water absorption and biodegradation. Increased ductile properties were achieved by adding pure and modified NR. Among the series of 90:10 TPS/modified NR blends by weight, the highest toughness (1,628 MJ/m3) was observed when the blend was formulated from ENR50 with 1.0 wt% of PEG. The water absorption of TPS/NR blends was lower than that of TPS but still exhibited a high-water absorption rate compared to the other conventional polymers. Biodegradation tests confirmed the biodegradation capability of TPS/NR blends, and more than 95% of the tested samples were biodegraded in soil within 120 days. These sustainable and eco-friendly TPS/NR blends could be potential materials for single or short-term use products, such as plant nursery pots and other disposable packaging. [ABSTRACT FROM AUTHOR]

This research aimed to utilise coconut shell waste as a raw material to produce compressed coconut shell sheets by using environmentally friendly adhesive from epoxidized natural latex and gelatinized tapioca starch. The coconut shells were cut into 1-mm particles and mixed with the adhesive. The mixture was then compressed in a 30×30×0.5 cm mould using a hydraulic compression machine at 5 MPa and 170°C for 5 minutes to form a compressed coconut shell sheet. The different ratios of adhesive to coconut shell particles (30, 40, and 50 g) per 100 g of coconut shell and the different ratios of gelatinized tapioca starch and epoxidized natural rubber (ranging from 1:0, 1:1, 2:1, 3:1, to 4:1 by weight) were examined. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were employed to analyse the morphology and chemical composition of the coconut shell sheets, respectively. The physical and mechanical properties of the compressed coconut shell sheets were evaluated based on the Thai Industrial Standard (TIS) number 876-2547 for flat pressed particleboards. The results demonstrate successful production of compressed coconut shell sheets from coconut shell waste using the environmentally friendly adhesive. ENR played a role in networking between lignin and cellulose. While GTS improved the strength of the composite using hydrogen bonding. The optimal ratio of adhesive to coconut shell particles was 40 g of the green adhesive per 100 g of coconut shell. The optimal ratio of gelatinized tapioca starch to epoxidized natural rubber was 2:1 by weight. The coconut shell sheets produced from this study were uniform in shape, had unique textures, and met industry standards for wood substitute materials.

In this study, epoxidized natural rubber (ENR) was mixed using a two-roller mixer. Water hyacinth fiber (WHF) acted as a reinforcing agent in the preparation of the rubber composite at 10 phr (ENRC/WHF). Chlorhexidine gluconate (CHG) was added at different concentrations (1, 5, 10, and 20 phr) as an antimicrobial and coupling agent. The tensile strength increased with a CHG content of 1 phr (4.59 MPa). The ENRC/WHF/CHG20 blend offered high hardness (38) and good morphology owing to the reduction in cavities and fiber pull-out from the rubber matrix. The swelling of the sample blends in oil and toluene decreased as the CHG content increased. Reactions of –NH2/epoxy groups and –NH2/–OH groups occurred during the preparation of the ENRC/WHF/CHG blend. The FTIR spectroscopy peak at 1730 cm−1 confirmed the reaction between the −NH2 groups of CHG and epoxy groups of ENR. The ENRC/WHF/CHG blend at 10 phr and 20 phr exhibited zones of inhibition against three bacterial species (Staphylococcus aureus, Escherichia coli, and Bacillus cereus). CHG simultaneously acted as a crosslinking agent between ENR and WHF and as an antimicrobial additive for the blends. CHG also improved the tensile strength, hardness, swelling, and antimicrobial properties of ENR composites.

In this study, cerium oxide nanoparticles (nanoceria, CeNP) were used as a nanofiller in epoxidized natural rubber with varying epoxide levels, including 25% epoxidation (ENR‐25) and 50% epoxidation (ENR‐50). Co‐precipitation methods were employed to synthesize a pure phase of CeNP with an average particle size of 11.4 ± 2.0 nm. CeNP was characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy. The effect of CeNP loading with 0–3 parts per hundreds of rubber (phr) on the properties of rubber nanocomposites was explored. ENR‐25 nanocomposites with 1 phr of CeNP exhibited higher tensile strength and elongation at break compared to ENR‐50 nanocomposites. These findings correspond to a lower Payne effect, improved scorch safety, and better processability. The strongest and most effective CeO2–ENR interactions via silane linkages are expected to outperform sulfur crosslinking in ENR‐25 having 1 phr of CeNP. Microstructural evaluation of an ENR‐25 sample containing 1 phr of CeNP indicated well‐distributed nanofillers in the ENR‐25 matrix, indicating that CeNP and ENR‐25 appeared to be well‐matched. Hardness of all ENR nanocomposites increased with CeNP loading. The cracking resistance, creep properties, and thermal stability of rubber nanocomposites were unaffected by addition of CeNP in the ENR‐25 and ENR‐50 samples. [ABSTRACT FROM AUTHOR]

Water swellable rubber (WSR) was prepared from epoxidized natural rubber (ENR) and sodium acrylate (NaAA) by in‐situ polymerization using sulfur and dicumyl peroxide (DCP) as a vulcanizing agent and an initiator, respectively. The ENR, NaAA, and other additives were mixed in an internal mixer and a two‐roll mill. The effect of the vulcanization system, epoxide, and DCP, and NaAA content on the vulcanization, physical, and mechanical properties of WSR were investigated in this research. As the results, the scorch and curing time of WSR compounded with ENR 25 and vulcanized with a mixture of sulfur‐peroxided or mixed vulcanization system were less than other systems. Furthermore, the scorch and curing time decreased with the increase in DCP content. The WSR with ENR 50 vulcanized with DCP (1.5 phr) in the mixing system provided the highest tensile strength. However, the volume change of WSR with the mixing system (WSR/M) was lower than the WSR cured with peroxide (WSR/P). For WSR/P, the tensile strength, hardness, and volume change in water increased with increasing DCP, and NaAA content, while the elongation at break decreased. These results suggest that WSR has the potential for diverse applications, including waterproofing and sealing solutions in civil construction projects. Highlights: Water swellable rubber (WSR) was prepared from epoxidized natural rubber (ENR) and sodium acrylate (NaAA) by in‐situ polymerization using sulfur and dicumyl peroxide (DCP) as a vulcanizing agent and an initiator.The scorch and curing time of WSR compounded with ENR 25 and vulcanized with a mixed vulcanization system were less than those of other systems.During the vulcanization process, ENR 50 can be generated by the ring‐opening of the adjacent epoxide groups more than ENR 25, and the self‐crosslink of ENR 50 was higher than ENR 25.Water swelling and volume change of WSR tended to decrease with increasing epoxide, and DCP content, whereas those properties increased with increasing NaAA content.Tensile strength, elongation at break, and hardness of WSR with the mixing system (WSR/M) were higher than those of WSR with the peroxide system (WSR/P).Swelling and volume change of WSR/P were higher than those of WSR/M. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the thermoformability of Epoxidized Natural Rubber (ENR)-filled Poly(Lactic Acid) (PLA) films using elevated temperature tensile and ball burst tests. Three different d-Lactide contents of PLA were used to be able to analyze the effect of crystallization and crystallinity. We observed that the ENR acted as a nucleating agent in PLA when the blend was cooled from melt or cold crystallized, but it retarded the drawing-induced crystallization of PLA at elevated temperature tensile testing since ENR droplets acted as obstacles. The effect of NR on PLA crystallization was also found to be dependent on d-Lactide content. In the ball burst test, different behaviors were observed for PLA with the lowest d-Lactide content, which was caused by the complex stress state that even more induced crystallization of PLA and then a single-axis tensile test. [ABSTRACT FROM AUTHOR]

In situ UV‐initiated polymerization was performed to prepare solid polymer electrolytes (SPEs) based on epoxidized natural rubber‐graft‐acrylonitrile (ENR‐g‐ACN) by employing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a doping salt. A solid‐state lithium‐ion battery (SSLIB) was fabricated using ENR‐g‐ACN‐LiTFSI as an electrolyte and lithium metal and graphite as electrodes. The SSLIB's performance was evaluated to investigate the electrochemical stability window (ESW), redox behavior, voltage stabilization measurement and electrochemical capacitance response. The ESW of the SPE reached a reasonable value of 5.6 V (vs Li/Li+). The absence of redox peaks on the cyclic voltammetry (CV) curve indicates that the cell behaved more like a capacitor than a battery. At an open‐circuit voltage of 2.78 V, the battery's performance also showed a low capacity due to parasitic (unwanted) reactions, electrolyte degradation or the battery's age. The performance of an electrical double‐layer capacitor (EDLC) was also analyzed by linear sweep voltammetry, CV and galvanostatic charge–discharge. The ESW of the SPE was obtained as 2.7 V. The specific capacitance of the EDLC was found to be 6 F g−1 at 0.005 mA cm−2 and 60 °C. The fabrication of affordable and secure SSLIBs and EDLCs with the use of rubber materials will be successful if this strategy is developed. © 2023 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

The properties of graphene (GP) filled rubber nanocomposites were investigated in functions of rubber type (unmodified natural rubber (NR) and epoxidized natural rubber with 25 mol% epoxides (ENR-25)) and filler content. The Fourier transform infrared spectroscopy (FTIR) spectrum indicated that GP surfaces contain polar hydroxyl and carbonyl functional groups. The ENR-25/GP compound exhibited higher maximum torque, torque difference, storage modulus, initial relaxation modulus, bound rubber, and degree of reinforcement with smaller GP aggregates dispersed in the rubber matrix than the NR/GP composites. Additionally, an increasing trend of tensile strength was observed in the ENR-25/GP composite, but the contrary trend was obviously seen in the NR/GP composites due to the interaction between polar functional groups in ENR-25 and GP surfaces. Furthermore, a higher Payne effect (filler-filler interaction) was found in the NR/GP composites, corresponding to larger GP agglomerates and voids dispersed in the NR matrix. Moreover, the ENR-25/GP composite had higher electrical conductivity and dielectric constant than the NR/GP composite due to the higher polarity of the ENR with the dipoles, leading to increasing orientation polarization and interfacial polarization.

Epoxidized natural rubber (ENR) bio‐composites filled with hemp hurd were fabricated via reactive batch‐mixing and vulcanization. The effect of the ENR‐hemp hurd grafting, silane modification, sulfur vulcanization, and the built‐up crosslinking networks on the thermomechanical and physical properties were analyzed. It was observed that the reactive mixing of ENR and hemp hurd caused epoxy ring opening followed by ether bonding of ENR onto the hemp hurd. There was evidence showing that the hemp fillers were also involved in the sulfur vulcanization. The sulfur vulcanized ENR bio‐composites displayed a low swelling index, homogeneous filler dispersion, and superior thermomechanical properties. The vulcanized bio‐composites with silane‐modified hemp hurd showed slightly less grafting but substantially reduced water absorption. The hardness, tensile strength, and modulus of the optimized formulation displayed a 300%, 1030%, and 960% enhancement as compared to the ENR baseline, respectively. Highlights: ENR bio‐composites with hemp hurd were fabricated.Crosslinking networks were built‐up within the ENR/hemp bio‐composites.SiHemp show similar reinforcement but more water repellence.The synthesized composites had enhanced thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a new type of nanocomposite material by reinforcing epoxidized natural rubber (ENR) through the integration of mercapto‐functionalized nanozirconia (SH‐ZrO2 NPs) synthesized using a ring‐opening reaction. The ENR was prepared through the epoxidation of natural rubber (NR) using in situ generated performic acid from formic acid and hydrogen peroxide. The SH‐ZrO2 NPs were pretreated and systematically embedded into the ENR matrix via a latex‐casting process, resulting in ENR/SH‐ZrO2 nanocomposites with enhanced properties. To prevent the accumulation of nanofillers in the ENR matrix, the surface of the nanozirconia was treated with 3‐(mercaptopropyl)trimethoxysilane (MTS) to create mercapto‐terminated ZrO2 NPs (SH‐ZrO2 NPs) that were covalently attached to the ENR chains. The presence of MTS on the surface of the nanozirconia was confirmed by FTIR and thermogravimetric analysis (TGA) analyses. Structural and morphological characterization of the resulting nanocomposites was performed using standard techniques such as x‐ray diffraction (XRD), scanning electron microscopy (SEM), and TGA. The morphological studies indicated a uniform distribution of SH‐ZrO2 NPs throughout the ENR matrix. Furthermore, TGA analysis revealed that the thermal stability of the nanocomposites was improved, as evidenced by a shift in the decomposition temperature to a higher value compared to neat ENR. Overall, this work demonstrates the potential of SH‐ZrO2 NPs as an effective reinforcing agent in ENR‐based nanocomposites, with improved thermal stability and homogeneity. Highlights: Enhanced nanocomposite properties: Integration of mercapto‐functionalized nanozirconia improves the performance of epoxidized natural rubber (ENR) materials.Innovative synthesis approach: SH‐ZrO2 NPs synthesized via ring‐opening reaction offer a novel method for reinforcing ENR matrices.Improved thermal stability: ENR/SH‐ZrO2 nanocomposites exhibit higher decomposition temperatures, indicating enhanced thermal stability.Uniform dispersion: Morphological studies confirm the uniform distribution of SH‐ZrO2 NPs throughout the ENR matrix.Promising reinforcing agent: SH‐ZrO2 NPs demonstrate their potential as an effective filler for ENR‐based nanocomposites, enhancing homogeneity and performance. [ABSTRACT FROM AUTHOR]

Epoxidized Natural Rubber (ENR) is a specialty rubber produced by modification of natural rubber (NR) latex. In this study, the effects of vulcanisation temperature on the vulcanisation characteristics and vulcanisation kinetics of ENR compounds were studied. A Monsanto Moving Die Rheometer (MDR2000) was used, with vulcanisation temperatures ranging from 140 to 180 °C considered. Unfilled ENR and NR compounds were compared to filled compounds, in which carbon black and silica fillers were used. All compounds' optimal vulcanisation time (t95), curing rate index (CRI), percentage of reversal (R300) and vulcanisation kinetics were investigated. It can be shown that for both filled and unfilled compounds, ENR has a shorter t95, a higher CRI, and a higher R300 than NR. Furthermore, higher vulcanisation temperatures decreased the t95, with increased CRI and enhanced R300 for all compounds. It was observed that ENR tended to have lower activation energy, Ea than NR for both filled and unfilled compounds and among the compounds examined, silica-filled ENR showed the highest activation energy value. [ABSTRACT FROM AUTHOR]

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Reclaimed rubber (RR) from waste tires was introduced as a wood adhesive by blending with epoxidized natural rubber (ENR). To improve the polarity of RR and compatibility with ENR, maleic anhydride (MA) was grafted onto RR chains. Influences of RR and RR-g-MA (maleic anhydride grafted reclaimed rubber) on the adhesion of wood adhesive along with their properties such as crosslinking, mechanical properties, thermal stability, and wettability were studied. It was found that RR and RR-g-MA affect the vulcanization of ENR by increasing crosslink density. Especially, in the case of using RR-g-MA generates a new form of an ester linkage. The higher crosslink density together with the formation of ester linkages results in superior thermal stability by the addition of RR-g-MA. In addition, the incorporation of RR exhibited an increase in the lap shear strength when compared with the pure ENR. This improvement is due to the increased crosslink density because the presence of RR resulted in the enhanced cohesive strength of rubber adhesive. Additionally, the incorporation of RR-g-MA showed higher efficiency to improve the adhesion of rubber adhesive. The addition of RR-g-MA has not only enhanced the cohesive strength of rubber adhesive, but also increased the adhesive strength from the interaction between the hydroxy group in cellulose on the wood surface and the polar functional group (i.e., oxirane rings of ENR, maleic group of RR-g-MA and ester group of ester linkage) of rubber adhesive. Therefore, the cohesive fracture was observed in ENR/RR-g-MA adhesive. [ABSTRACT FROM AUTHOR]

The formation of covalently cross-linked 3D network makes it difficult to recycle conventional vulcanized rubbers. Introducing dynamic covalent bonds such as reversible ester bonds into the rubber network is a feasible method to solve this issue. However, the low mechanical properties of rubber with only reversible ester bonds make it unsuitable for most practical applications. This work reports a strengthened biobased epoxidized natural rubber/adipic acid/cellulose nanocrystal (ENR/AA/CNC) composite in which biobased AA covalently cross-links ENR to form a network with exchangeable β-hydroxyl ester bonds. This network is able to rearrange its topology at high temperatures, causing the ENR/AA/CNC composite to exhibit certain reprocessing capabilities. Meanwhile, the CNCs form a mass of hydrogen bonds between their hydroxyl groups and the hydrophilic groups of ENR chains, giving the ENR/AA/CNC composite an enhanced mechanical performance. [ABSTRACT FROM AUTHOR]

Sensor of monitor of temperature and pressure changes are garnering constant attention due to their wide applications. It is a challenge to synthesize dual‐functional material with the well‐balanced performance to temperature response and pressure changes. In this work, we have proposed a facile way to fabricate tough, flexible, and self‐healing composite with dually synergistic networks for pressure and temperature sensors, which are composed of polyacrylamide (PAM) and elastic epoxidized natural rubber (ENR). PAM networks are crosslinked by N,N‐methylenebisacrylamide (MBA) and physical crosslinking of hydrophilic hexagonal boron nitride (h‐BN) nanosheets, ENR network is further interlocked and PAM by physical entanglements, hydrogen bonds. It is found that the ternary PAM/ENR/h‐BN (PEB) composite is highly sensitive to temperature, making it can be exploited as a thermistor. This thermistor possesses high flexibility and appealing mechanical performance, with the sensitivity as high as 1.87%/°C at temperature range of −13 to 90°C. Furtherly, the PEB composite also can work as a flexible pressure sensor at operating range of ~80% strain and ~540 KPa. Our research work provides a guideline for the preparation of temperature monitor, piezoresistive pressure sensors, as well as flexible electronic products. [ABSTRACT FROM AUTHOR]

The aim of this work was to enhance the performance of a wood pulp/polylactic acid (PLA) biocomposite using epoxidized natural rubber (ENR)–grafted-modified microfibrillated cellulose (MFC) as a novel compatibilizer. MFC was modified by two different methods of silanization:one with 3-(trimethoxysilyl) propyl methacrylate and the other with 3-aminopropyltriethoxyl silane. The two types of modified MFC were grafted onto ENR via a solution-casting method. Compared with the uncompatibilized biocomposite, the flexural strength and impact resistance of the biocomposite compatibilized with ENR-amino silanized MFC were increased by 168% and 261%, respectively. SEM images and DMTA analysis confirmed the compatibility among the three phases of pulp, PLA, and ENR. Meanwhile, the use of ENR-methacrylate silanized MFC as a compatibilizer in the biocomposite also demonstrated the improvement of compatibility compared with non-MFC and MFC systems. The durability of the biocomposites was assessed in an accelerated weathering test. The pulp/PLA/ENR-methacrylate silanized MFC showed the lowest degradation rate, due to the methacrylate group of silane acted as a chromophore to mitigate UV absorption. [ABSTRACT FROM AUTHOR]

In this work, the crosslinking reaction of epoxidized natural rubber (50 mol% epoxy, ENR-50) by metal ion namely ferric ion (Fe3+, FeCl3, ferric chloride) was studied. It was found that a direct interaction of the ferric ion with the epoxy group as well as internal polymerization enable the ENR to be efficiently cured. The vulcanizing ENR-FeCl3 compound was then reinforced by carbon nanotubes (CNTs). The FTIR spectra of ENR-FeCl3 compounds without and with CNTs show the absorption peak at the wavenumber 470 cm–1, which represents the –O–Fe–O– linkages from a reaction of FeCl3 and opened oxirane ring products of ENR molecules. Furthermore, the ENR-FeCl3 compounds show a typical marching curing curve with a steady increase in torque as increasing of the testing time; especially the effect is more pronounced in CNTs filled system. Furthermore, an increase in the concentration of CNTs causes increasing in torque difference and enhancement of the mechanical properties (i.e., 100% moduli and tensile strength). The SEM micrograph shows good compatibility between CNTs and the rubber matrix in the ENR-FeCl3 compounds. Also, the electrical conductivities of ENR-FeCl3/CNTs nanocomposite increases with the increase of CNTs loading. It is also observed that the degradation temperature (Td) of ENR-FeCl3/CNTs is shifted toward a higher temperature range with the increase of the CNTs loadings.

The present work highlights the preparation of the epoxidized natural rubber conjugated spent coffee biocomposites (ENR‐g‐SC) via one‐pot synthesis to control petroleum oil spills. The structural determination of the spent coffee grafted epoxidized natural rubber (ENR‐g‐SC) was confirmed through FTIR and 1H‐NMR spectroscopic analyses. The thermal performance, tensile tests, and morphological properties of the synthesized (ENR‐g‐SC) biocomposites were performed. The data revealed that ENR‐g‐SC biocomposite with 20 phr of spent coffee (SC) exhibited the highest tensile properties due to maximal chemical linkages of spent coffee and epoxide groups in ENR. The epoxidized natural rubber conjugated spent coffee copolymers were evaluated as oil sorbers for oil absorbency applications in chloroform, toluene, and 10% crude petroleum diluted with toluene. The data revealed that the oil absorbency increased slightly with chloroform or toluene instead of 10% crude oil diluted with toluene. Furthermore, swelling and network parameters including the maximum oil absorbency (Qmax), swelling rate constant (k), polymer‐solvent interaction (χ), effective crosslink density (ύe), equilibrium modulus of elasticity (GT), and average molecular weight between crosslinks (Mc) and theoretical crosslink density (ύt) were determined, and correlated to the efficiency of the synthesized epoxidized natural rubber conjugated spent coffee. [ABSTRACT FROM AUTHOR]

A detailed analysis of the rubber composites is necessary for the designing and fabrication of advanced rubber products. In this study, composite materials are synthesized by adding different nanofillers of carbon black nanoparticles into epoxidized natural rubber (ENR). The specific characteristics of carbon black (CB) affect the crosslinking density between CB and polymeric chains in ENR. The effects of particle size, structure, thermal conductivity, and functionality of CB on rheology and mechanical properties of filled reinforced ENR are examined. The composite materials are thoroughly characterized for their abrasion, rheology, tensile, hardness, elongation, resilience, and compression behavior. The results revealed that various properties of composite materials depend on the characteristics of the reinforcing CB fillers. It was found that lower particle size and ordered structure provide good tensile strength, tear strength, abrasion, and aging resistance. In contrast, larger particle size and a lower ordered structure provide high flow rate, low hardness, excellent re-bounce, and good compression set characteristics. [ABSTRACT FROM AUTHOR]

The effects of epoxide content on the microstructure and characteristics of epoxidized natural rubber (ENR) were examined. Self-crosslinking between epoxide groups possibly occurred during the vulcanization, with C–O–C linkages in the ENR. Depending on the epoxide level, the self-crosslinking in ENR improved the maximum torque, overall crosslink density (CD) and stability at elevated temperature of the rubber. With increasing epoxide content, the moduli and tensile strengthes of the ENR also increased. The highest tensile strength was achieved at 25 mol% epoxide, exceeding that of crosslinked NR by 46%. The self-crosslinking also facilitated strain-induced crystallization (SIC), reducing the onset strain of crystallization and increasing the degree of crystallinity. Even though increased epoxide content in the NR made the crosslink network distribution less homogeneous, the CD increased so much that the thermomechanical and mechanical characteristics of ENR were improved. The C–O–C linkages from ENR self-crosslinking were also sufficient to boost the thermal stability, complementing the conventional sulfide links. [ABSTRACT FROM AUTHOR]

Epoxidized natural rubbers (ENR)are potential to be an alternative of natural rubber as matrix of magnetorheological elastomers (MREs). These ENR-based MREs offer various advantages such as excellent mechanical properties and damping characteristics that are well-suited for applications in vibration control and noise reduction devices. However, there is a paucity information in regard to the effect of different epoxidation levels on rheological properties of MRE. Therefore, the main aim of this study is to explore the influence of epoxidation level on rheological properties of MRE using commercialized ENR corresponding to ENR 25 and ENR 50. ENR-based MREs were created by blending with carbonyl iron particles (CIPs) and other additives, followed by curing at 150 °C for 30 min. The study involved producing ten MRE samples with various weight percentages of CIP (0,10,30,50 and 70 wt%). The storage modulus of ENR 50 exhibited a significant increment from 0.73 MPa to 1.04 MPa as compared to ENR 25 which caused the storage modulus to increase from 0.77 to 0.88 MPa. This showed that ENR 50-based MRE are stiffer in comparison to ENR 25-based MRE. Initial loss modulus value for ENR 50 (0.098 MPa) was lower than that of ENR 25 (0.112 MPa), consequently less energy is dissipated to surrounding for ENR 50-based MRE compare ENR 25-based MRE. The loss factor that represents damping properties showed that ENR 50 reached higher values (0.120 MPa) compared to ENR 25 (0.106 MPa). The increasing of CIPs content from 0 to 70 wt% contributed to increasing of magnetorheological effect for both ENR-based MRE where ENR 25 produced slightly higher with increment of 1.88 % to 22.6 % than ENR 50-based MRE with increment of 2.47 % to 18.18 % due to rise of magnetic forces generated from interaction of magnetic moments in magnetic domains of each CIPs. The results and analysis indicate that different levels of epoxidation in ENR have a marginal impact on the rheological properties of ENR-based MREs. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a biopolymer with brittleness and no antibacterial efficiency, which can be solved by the combination with epoxidized natural rubber (ENR) due to polar-polar interaction and with modified zinc oxide nanoparticles (ZnO) regarding the releasing of zinc ions (Zn2+) and reactive oxygen species (ROS). To minimize self-interaction in each PLA and ENR molecular chain, ENR with different % epoxidation was modified (mENR) by grafting with sebacic acid (SA). The addition of mENR with 50 % mol to PLA significantly improved the properties of pure PLA in terms of mechanical and impact properties, toughness, and also provided disinfectant ability. Regarding antibacterial properties, the efficiency against Staphylococcus aureus and Escherichia coli was significantly improved by adding ZnO to the blends. Combination of mENR to PLA matrix during mixing operation increases improved ZnO dispersion and distribution in PLA/mENR blends. Thus, antibacterial efficiency had been enhanced using proper mENR:ZnO concentration ratios in the PLA matrix, relative to other modified ZnO types. Also, incorporation of mENR:ZnO enhanced impact strength and retarded biodegradability of the blends due to hydrophobicity of ENR in PLA matrix. The findings of the blends' properties suggest potential for new functional applications, especially in disinfectant sheet lamination products where strength and protection against bacterial growth together with proper degradation period are required. [Display omitted] • Modification of ENR with 50 %mol epoxide enhanced mechanical properties of PLA. • Addition of modified ZnO causes antibacterial properties of PLA and PLA/ENR blends. • With modified ZnO and ENR, impact strength of PLA had increased for 3 times. • Combination with ENR, biodegradability of PLA had retarded, usability was increased. • Blending both bio-based materials causes potential for disinfectant product applying. [ABSTRACT FROM AUTHOR]

Epoxidized natural rubber (ENR) is a modified natural rubber (NR) prepared by the epoxidation of NR. Dispersion of silica in the ENR nanocomposite is crucial for the performance, but there is not a definite relationship among ENR and silane coupling agent bis(γ-triethoxysilylpropyl) tetrasulfide (TESPT) and silica. In this work, ENR/silica with different amounts of TESPT nanocomposites (ENR/silica- x T) were prepared, and the structure and critical properties of ENR/silica- x T for tire tread applications were investigated and compared with NR/silica-TESPT nanocomposite. There is a competitive relationship between TESPT and epoxy groups on the rubber molecular chain in improving silica dispersion. Epoxy groups produce stronger filler-rubber interaction while TESPT provides more chemical crosslinking density. Accordingly, as the amount of TESPT increases, the tear strength, tensile strength, wet-skid resistance, abrasion resistance, as well as rolling resistance performance of ENR/silica- x T improves. The ENR/silica-6T demonstrates significant improvements compared to NR/silica-6T, with a 207 % enhancement in wet-skid resistance, a 29 % increase in abrasion resistance, and a 29 % reduction in rolling resistance. This work will be of significance in guiding the preparation of green tire tread. [Display omitted] • TESPT and epoxy group have a competitive relationship in silica dispersion. • Epoxy groups produce stronger filler-rubber interaction. • TESPT provides more chemical crosslinking density. • The silanization reaction is easier to occur than ring-opening reaction. • The ENR/silica-TESPT demonstrates better performance than NR/silica-TESPT. [ABSTRACT FROM AUTHOR]

The bead is the key part of the radial tire, which plays the role of supporting the cord layer and fixing the tire on the rim. The good adhesion of the bead wire and rubber is the key factor to ensure the performance of the bead. In this work, for the purpose of improving the adhesion properties of Cu/Sn-plated bead wire and rubber, chlorinated natural rubber (CNR), epoxidized natural rubber (ENR), two kinds of modified alkyl phenolic resin (KPA、HY-2006) were used to coat the surface of the wire, and the effects of type and content of organic coating on the adhesion between bead wire and rubber after vulcanization were studied. The pull-out force (POF) and rubber coverage were used to evaluate the adhesion effects. The microstructure and the element analysis of the vulcanized interface between bead wire and rubber were observed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. Raman spectrometer, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to determine the chemical composition of the vulcanized interface, and the interfacial thickness was studied by XPS depth profiling. The results showed that the POF of the blank coated bead wire-rubber composite is 579.1 N, and the rubber coverage is 63 %. 0.41%CNR60 solution has the best effect on promoting the adhesion between bead wire and rubber (816.3 N, 93 %). The 1.23%KPA solution (703 N, 69 %) and 0.83%ENR solution (657.2 N, 80 %) also play a good role. The interfaces between vulcanized rubber and wires coated with blank, 0.41%CNR60, 0.41%KPA, 0.41%ENR and 0.41%HY-2006 solutions are composed of CuS, Cu 1·8 S, Cu 2 S, SnS 2 and SnO 2 etc., and the proportion of Cu x S is different. The Cu x S layer of the interface coated with 0.41%CNR60 solution is the thickest, followed by ENR, blank, KPA and HY-2006 solutions. This work not only obtains an organic coating formula that could effectively improve the adhesion properties of Cu/Sn-plated bead wire and rubber, but also explored the composition of the interface layer, which provided the necessary information for elucidated the adhesion mechanism between Cu/Sn-plated bead wire and rubber. [ABSTRACT FROM AUTHOR]

The sustainable material—thermoplastic potato starch (TPS)—was blended with modified natural rubber–epoxidized natural rubber (ENR). The poor mechanical properties of the ENR/TPS blends limited the application. Sulfur vulcanization is a common and economical method to improve the mechanical properties in the rubber industry. To fully understand the relationship between vulcanization systems and ENR/TPS blends and the sustainability of the developed material, the effects of a vulcanization accelerator (N-cyclohexylbenzothiazole-2-sulphenamide (CBS), 2-mercaptobenzothiazole (MBT), N-tert-butylbenzothiazole-2-sulphenamide (TBBS)) and a system type (conventional vulcanization (CV), semi-efficient vulcanization (SEV) and efficient vulcanization (EV)) on curing characteristics, mechanical and thermal properties, water absorption and biodegradability were systematically evaluated. The results indicate that vulcanization significantly improves the mechanical properties of ENR/TPS blends. The performance optimization of the CBS-CV vulcanization system is the best for improving the mechanical properties and reducing the water absorption. The CBS-CV curing system makes ENR/TPS less biodegradable (12–56% of mass loss) than other accelerators and systems. TBBS-CV makes the material more biodegradable (18–66% of mass loss). The low rubber content enables the rapid biodegradation of the vulcanized blend. This has implications for research on sustainable materials. The material can be applied for eco-friendly packaging and agricultural films, etc. The investigation on performance by using common accelerators and systems provides ideas for industries and research. [ABSTRACT FROM AUTHOR]

Modifiers such as fibers, fillers, natural and synthetic polymer extenders, oxidants and anti-oxidants, and anti-stripping agents are added to produce modified asphalt. However, polymers are the most widely utilized modifiers to enhance the function of asphalt mixtures. The objective of this research was to evaluate the mechanical properties and durability of epoxidized natural rubber (ENR)-modified asphalt mix under short- and long-term aging conditions. The physical and rheological characteristics of the base asphalt and ENR-modified asphalt (ENRMA) were tested. In order to evaluate the mechanical properties and durability of the modified mixtures, the resilient modulus of the ENR–asphalt mixtures under unaged, and short- and long-term aging conditions at various temperatures and frequencies was obtained. Furthermore, the resistance to moisture damage of asphalt mixtures was investigated. The findings showed that the stiffness of the ENR–asphalt mixes increased because of the mutual influence of short- and long-term aging on the mixes. In addition, ENR reduced the susceptibility to moisture damage. The stiffness of the mixes was influenced by the temperature and frequencies. By using mathematical modelling via the multivariable power least squares method, it was found that temperature was the dominant factor among all other factors. The results suggested that the durability of asphalt pavements is improved by using ENR. [ABSTRACT FROM AUTHOR]

New bio-thermoplastic elastomer composites with self-healing capacities based on epoxidized natural rubber and polycaprolactone blends reinforced with alginates were developed. This group of salts act as natural reinforcing fillers, increasing the tensile strength of the unfilled rubber from 5.6 MPa to 11.5 MPa without affecting the elongation at break (~1000% strain). In addition, the presence of ionic interactions and hydrogen bonds between the components provides the material with a thermally assisted self-healing capacity, as it is able to restore its catastrophic damages and recover diverse mechanical properties up to ~100%. With the results of this research, an important and definitive step is planned toward the circularity of elastomeric materials. [ABSTRACT FROM AUTHOR]

The study presented in this paper focuses upon the preparation, characterization, and properties of novel epoxidized natural rubber/functionalized SiO2 nanocomposites (ENR/f-SiO2 NCs) through the incorporation of surface-functionalized silica nanoparticles (f-SiO2 NPs). Initially, ENR latex (epoxide content of 38%) as a matrix modifier was produced by epoxidation of natural rubber using in situ formed performic acid by mixing formic acid with hydrogen peroxide at 40°C for 24 hours. In order to prevent accumulation and obtain homogeneous dispersion of SiO2 NPs into the ENR latex, 3‐aminopropyltriethoxysilane (APS) was grafted onto the silica surface to form f-SiO2 nanoparticles. Then, f-SiO2 nanoparticles with various contents (0, 5, 10, 15, 20, and 25 wt.%) were embedded into the ENR matrix by ultrasonication technique for the fabrication of ENR/f-SiO2 NCs. The effect of f-SiO2 on the structural, morphological, and thermal properties of ENR was studied by infrared spectroscopy (IR), scanning electron microscopy (SEM), thermo-gravimetric analyses (TGA), x-ray diffraction (XRD). [ABSTRACT FROM AUTHOR]

A new biocomposite was prepared from epoxidized natural rubber (ENR) reinforced with chitosan (CHI) and cellulose nanocrystals (CNCs) without using conventional crosslinking agents. The existence of strong hydrogen bonds in the biocomposite induced a supramolecular network or crosslinks. In this study, CNCs were isolated from Napier grass stems and treated with amino-triethoxysilane, called A-CNCs, prior to being incorporated into the biocomposite at various contents. Mechanical properties, self-healing behavior, and triboelectric nanogenerator (TENG) performance of the ENR/CHI/A-CNC biocomposites were subsequently evaluated. The results showed that modulus and hardness increased continuously as A-CNC content increased, whereas tensile strength was found to be maximum at 1 phr of A-CNCs. Similarly, the self-healing efficiency was notably improved with increasing A-CNC content up to 2 phr. The impaired self-healing property at higher A-CNC content is attributed to the reduction in interdiffusion and poor filler dispersion. Self-healing efficiency was also enhanced with increasing healing time and temperature (up to 80 °C). The TENG performance was found to be maximum at 1 phr of A-CNCs with an output voltage and current of 107.7 V and 10.6 µA, respectively. The highest power density of 156 mW/m2 was obtained when an external load resistance of 9 MΩ was applied. Clearly, the biocomposites containing approximately 1–2 phr of A-CNCs possess the optimum combination of strength, self-healing, and TENG performance. [ABSTRACT FROM AUTHOR]

Natural rubber with 50 mol % epoxidation (ENR-50) was filled with carbon nanotubes (CNTs) and conductive carbon black (CCB) hybrid fillers with various CCB loadings of 2.5, 5.0, 7.0, 10.0 and 15.0 phr, and the compounds were mixed with ferric ion (Fe3+) as a crosslinking agent. The ENRs filled exclusively with CNTs, and CNT–CCB hybrid fillers exhibited typical curing curves at different CCB loadings, i.e., increasing torque with time and thus crosslinked networks. Furthermore, the incorporation of CNT–CCB hybrid fillers and increasing CCB loadings caused an enhancement of tensile properties (modulus and tensile strength) and crosslink densities, which are indicated by the increasing torque difference and the crosslink densities. The crosslink densities are determined by swelling and temperature scanning stress relaxation (TSSR). Increasing CCB loadings also caused a significant improvement in bound rubber content, filler–rubber interactions, thermal resistance, glass transition temperature (Tg) and electrical conductivity. A combination of 7 phr CNT and CCB with loading higher than 2.5 phr gave superior properties to ENR vulcanizates. Furthermore, the secondary CCB filler contributes to the improvement of CNT dispersion in the ENR matrix by networking the CNT capsules and forming CNT–CCB–CNT pathways and thus strong CNT–CCB networks, indicating the improvement in the tensile properties, bound rubber content and dynamic properties of the ENR composites. Moreover, higher electrical conductivity with a comparatively low percolation threshold of the hybrid composites was found as compared to the ENR filled with CNTs without CCB composite. The superior mechanical and other properties are due to the finer dispersion and even distribution of CNT–CCB hybrid fillers in the ENR matrix. [ABSTRACT FROM AUTHOR]

Novel composite based on rubber and modified bentonite clay (Clay) was investigated. The modified bentonite clay was developed by dispersing in ethanol solutions (Et-OH) using ultrasonic method. The effect of Et-OH on the dispersion of bentonite clay at various mixing temperatures in case of different type of rubber matrix, i.e., natural rubber (NR), epoxidized natural rubber (ENR25, ENR50) on dynamic mechanical rheology, Payne effect, XRD and mechanical properties of rubber composites were studied in detail. The bentonite clay dispersion in Et-OH at a mixing temperature of 80 °C improves the intercalation and exfoliation in rubber chains. Bentonite clay is highly intercalated in ENR 50-Clay composite, which can be confirmed from its superior mechanical properties. The results indicated that sonication of bentonite clay in Et-OH improves the interlayer spacing of bentonite clay by partial intercalation of rubber matrix. [ABSTRACT FROM AUTHOR]

To effectively mitigate carbon emissions and promote sustainability in the polymer field, biological macromolecules have emerged as a prominent strategy for fabricating functional materials. Herein, tannin (TA) was used as a biological curing agent to design fully bio-based polylactic/epoxidized natural rubber thermoplastic vulcanizates (PLA/ENR TPVs) with mechanical robustness and multi-stimuli-responsive shape memory properties. A dual cross-linking network, comprising both covalent bonds and hydrogen bonds, was successfully constructed in the ENR phase. A special co-continuous morphology was concomitantly constructed in the TPVs, which promoted effective stress transfer between the PLA and ENR phases, endowing the TPVs with balanced stiffness-toughness and shape memory properties. Moreover, the photothermal effect of TA also made it respond to near-infrared light and sunlight, which achieved the non-contact multistage shape memory performance, revealing the significant potential of the TPVs in the field of actuators., Competing Interests: Declaration of competing interest We confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Tire development tendency is green, environment‐friendly, and safeguarding life and health. The conventional tires, consisting of solution polymerized styrene‐butadiene rubbers (SSBR), silica, silane coupling agents, and other rubber additives, will not be able to keep up with the demand. SSBR, as a synthetic rubber processed from nonrenewable petroleum resources, creates a large amount of carbon emissions in the production process and the reaction between silica and silane coupling agents generates a large amount of volatile organic compounds (VOCs), which is detrimental to the environment and human health. In this article, epoxidized natural rubber (ENR) with different epoxide degrees was successfully prepared and blended with natural rubber (NR)/silica composites to improve the dispersion of silica and the performance of nanocomposites. The effect of heat treatment temperature on the reaction between ENR and silica and the dynamic and static mechanical properties of ENR/NR/silica nanocomposites was investigated by mechanical properties test, transmission electron microscopy, x‐ray photoelectron spectroscopy, and Fourier transform infrared. The results showed that the epoxy groups on the ENR molecular chain could react with the silanol on the surface of silica to form a strong chemical bond, which improved the dispersion of silica in the rubber matrix and further enhanced the performance of the rubber composites without carbon emission and VOCs. [ABSTRACT FROM AUTHOR]

Fabrication of containing renewable material epoxidized natural rubber (ENR) graft polyacrylamide (PAM) functional composites are promising exploration for the treatment of organic dye and heavy metal. This research developed a hydrogel consisting of epoxidized natural rubber (ENR) and acrylamide (AM) via a one-pot free radical polymerization that can be exploited as an absorbent for organic dye removal. The ungrafted ENR in the ENR grafted polyacrylamide (ENR-g-PAM) hydrogel system through physical chain entanglement can form a secondary network, which is beneficial to improvements of the comprehensive properties of the hydrogel. The resultant hydrogel shows better mechanical properties due to the entanglement structure that is crucial for stress transfer and dissipation. The mass ratio of ENR and AM was varied and explored to ensure a superior ratio. Methylene blue (MB), a cationic dye, is often utilized to determine adsorption behaviors. The ENR/AM weight ratio at 3:2 hydrogel (60ENR) has a better swelling ratio (up to 336%). More importantly, 60ENR exhibited a better adsorption value of 766.4 mg/g for MB. The experimental data can be also better depicted by the pseudo-second-order kinetic and the Freundlich models, revealing adsorption processes were governed by chemical and multilayer mechanisms. In addition, 7% polypyrrole@ENR-g-PAM (7% PPy@ENR-g-PAM) hydrogel fabricated by a simple mixture method can effectively adsorbed Cr (VI) with a high adsorption value of 284.4 mg/g when pH=2 and be also exploited as a pressure sensor with better durability. Based on the above study results, the ENR-g-PAM hydrogel was expected to play a key role in fields such as dye treatment, heavy metal ion adsorption, and pressure sensor. [Display omitted] • A novel and synthetic method using redox initiator, ceric ammonium nitrate. • Epoxidized natural rubber grafted polyacrylamide hydrogels synthesized from epoxidized natural rubber and acrylamide. • Synergy between epoxidized natural rubber and polyacrylamide enhanced the comprehensive properties. • Composites fabricated polyrrole and epoxidized natural rubber grafted polyacrylamide hydrogel. • Methylene blue treatment, Cr (VI) ion adsorption and pressure sensor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biological phytic acid is utilized to vulcanize ENR without any curing additives. • Cuttlefish ink realizes the reinforcement and multi-stimuli-respond of the composite. • All of the raw materials are renewable biomasses and the fabricated composite is recyclable. • A simple method is proposed to design shape memory biobased elastomer with mechanical robustness and recyclable ability. Facilitating the utilization of biomass in the rubber field is a facile strategy to reduce environmental pollution and the carbon emission. Herein, biological phytic acid (PA) was served as an eco-friendly curing agent, and cuttlefish ink (CI) was acted as a photothermal trigger switch to fabricate multi-stimuli-responsive shape memory biobased epoxidized natural rubber (ENR) with mechanical robustness and recyclable ability. ENR was vulcanized by PA via the ring-opening reaction between phosphate groups of PA and epoxy group of ENR, leading to the construction of an impeccable cross-linking network and an adjustable T g gradient, which endowed the elastomers with improved mechanical properties and shape memory effect. Meanwhile, the topology rearrangement occurred at elevated temperatures relied on phosphate transesterification, leading to excellent thermo-activated recyclable ability and reconfigurable shape memory performance of the elastomers. Additionally, CI acted as reinforced filler to enhance the ENR matrix, enabling elastomers to achieve a robust tensile strength of 21.4 MPa and tensile toughness of 30.4 MJ/m3, which was nearly 26.8 times and 11.3 times of the neat ENR, respectively. Exhilaratingly, CI also acted as photothermal trigger switch for the response to near-infrared light and sun, which realized the remotely multistage shape memory performance, demonstrating the potential application of ENR in the field of actuators without environmental pollution. [ABSTRACT FROM AUTHOR]

Facilitating biobased rubber with excellent reprocessability is a facile strategy to save resources and protect the environment evoked by the waste vulcanizates. Herein, a novel worm-like structure of aramid nanofibers (ANFs) was designed and served as both reinforcing agent and crosslinker for the biobased epoxidized natural rubber (ENR). The worm-like ANFs which covered a layer of nanoparticles could significantly hinder the strong orientation under intermolecular hydrogen bonds of the pristine ANFs, meanwhile hybrid interactions were created by forming hydrogen bonds and dynamic di-/polysulfide crosslinking between ANFs and ENR. Therefore, a well dispersed ANFs in the ENR matrix was established by the green aqueous compounding method and achieved advanced stress and modulus as well as the desirable recycling and self-healing ability. This strategy opens up new avenues for the design of rubber composites with enhanced strength, recyclable and repairable properties. [Display omitted] • The tiny and homogeneous nanoparticles on the surface of t-ANFs were fabricated. • Hybrid interactions were created between t-ANFs and ENR. • A well dispersed t-ANFs in the ENR matrix was established by the green aqueous compounding. • The tensile stress showed 1300 % increment by incorporating 10 wt% t-ANFs in ENR. • The ENR/t-ANFs composites showed desirable recycling and self-healing ability. [ABSTRACT FROM AUTHOR]

Silica is a popular filler, but in epoxidized natural rubber, can act as a cross-linking agent. Unfortunately, a high amount of silica is necessary to obtain satisfactory tensile strength. Moreover, a high amount of silica in ENR/silica hybrids is associated with low elongation at break. In our paper, we propose natural phenolic compounds, including quercetin, tannic acid, and gallic acid as natural and safe additional crosslinkers dedicated to ENR/silica hybrids to obtain bio-elastomers with improved mechanical properties. Therefore, toxic crosslinkers, such as peroxides or harmful accelerators can be eliminated. The impact of selected natural phenolic compounds on crosslinking effect, mechanical properties, color, and chemical structure of ENR/silica composite have been analyzed. The obtained results indicated that only 3 phr of selected natural phenolic compounds is able to improve crosslinking effect as well as mechanical properties of ENR/silica hybrids. Moreover, some of the prepared materials tend to regain mechanical properties after reprocessing. Such materials containing only natural and safe ingredients have a chance of becoming novel elastomeric biomaterials dedicated to biomedical applications. [ABSTRACT FROM AUTHOR]

In this paper, biodegradable epoxidized natural rubber containing cyclic carbonate groups (CNR) was prepared by the reaction between epoxidized natural rubber (ENR) and carbon dioxide. Dynamic disulfide bonds and a boronic ester structure were successfully constructed and then the cross-linking network was formed by the thermally initiated "click" reaction between thiol groups of the cross-linker and the residual epoxy groups of ENR. As a result of the exquisite double dynamic covalent structure, the material exhibits high self-healing efficiency. Moreover, by virtue of the cyclic carbonate structure of the CNR, the natural rubber was confirmed to be biodegradable according to the biodegradable measurement. To the best of our knowledge, natural rubber with biodegradable and self-healing characteristics was obtained for the first time. [ABSTRACT FROM AUTHOR]

This study investigates the influence of spent coffee (SC), and potassium hydroxide (KOH) modified spent coffee (ACT-SC) as fillers on the mechanical and thermal properties of epoxidized natural rubber (ENR) biocomposites. The results show the tensile strength, 100% modulus, elongation at break of the ACT-SC rubber biocomposites were enhanced, which was further confirmed by changes in the diffraction pattern for filler filled composite. The SEM micrograph indicates the biocomposite was substantially more homogenous with modified spent coffee. However, FTIR analysis revealed no significant differences between the modified and unmodified samples. In addition, the thermal analysis results show the thermal stability of ENR-ACT-SC is higher than that of ENR-SC but lower than that of ENR. [ABSTRACT FROM AUTHOR]

Herein, acid functionalized carbon nanotubes (FCNTs) reinforced epoxidized natural rubber (ENR 25) composites with 25% epoxidation are studied with particular reference to the effect of FCNTs on microstructural development along with their effect on thermo‐mechanical and gas barrier properties. Excellent improvement in tensile strength, that is, 128% and 118%, was observed with the addition 1 and 2 wt% of FCNTs, respectively, without compromising the elongation at break. A 76% improvement in oxygen impermeability was found for 2 wt% of FCNTs. Chemical interactions among FCNTs and ENR 25 altered the composite morphology and led to good dispersion, both of which contribute to the excellent thermo‐mechanical and gas barrier properties of the composites. The distribution of the filler inside ENR 25 has been characterized with scanning electron microscopy, which unveiled segregated FCNTs. The obtained experimental gas permeability values were correlated with the well‐known Bharadwaj model. The fabricated functional composites could find applications in automobiles, packaging, and other demanding engineering sectors. [ABSTRACT FROM AUTHOR]

Shape memory polymer (SMP) based on thermoplastic natural rubber (TPNR) for soft-touch splint application has been successfully developed. The main aim was to investigate the proper phase combination between thermoplastic (i.e., polycaprolactone (PCL)) and rubbers materials. Different types of rubbers, namely natural rubber (NR) and epoxidized natural rubber (ENR), were used as the rubber phases in the SMP-TPNR. Mechanical properties, shape memorial efficiency, swelling, and morphologies of the resulting material were examined. The tensile strength and hardness of the SMP-TPNR were found to be increased by using polar ENR as the rubber phase. Better compatibility between ENR and PCL molecular chains lead the material to achieve significant improvement in the shape memory behavior compared to the one with unmodified NR. The main advantage of polar rubber is its great opportunity to apply the material for splint fixing applications. On comparing with various commercially available materials (i.e., plaster, fiberglass, aluminum with foam and commercial thermoplastic splint), the developed SMP-TPNR material exhibited better performances in terms of ease of processing, costeffectiveness, comfortability (soft-touch), water resistance and impact resistance.

Fully bio-based poly (butylene succinate-co-adept) (PBSA) and epoxidized natural rubber (ENR) blends filled with agarwood waste (ACW) were prepared according to an experimental design following the Taguchi method. The PBSA/ENR/ACW blends were studied for mixing torque, morphology, thermal and hardness properties, and hydrolytic degradation; and in a soil burial test. The results show that the lowest mixing temperature and highest rotor speed gave the highest mixing torque. The size of ENR droplets (in SEM micrographs) decreased with decreased mixing temperature, rotor speed and particle size of ACW, while the hardness properties increased with mixing temperature. Moreover, the PBSA/ENR/ACW blends prepared at the highest mixing temperature (130 °C) and rotor speed (100 rpm) together with comparatively large sized ACW particles (80-mesh) displayed the most weight loss in soil burial test, as well as from exposure to water or HCl.