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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]

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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. [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]

The influence of thermal treatment on the thermal stability, thermal properties, dielectric properties and intermolecular interaction of binary epoxidized natural rubber (ENR)-salt systems, which may be a candidate for solid polymer electrolytes (SPEs) was investigated. Solubility of salt in ENR enhances, which may be due to the disruption of the lightly-crosslinked microgel under heat treatment. The increase in the ionic conductivities of the thermally treated ENR SPEs at constant salt content is correlated to the higher glass transition temperatures, development of percolation network and higher extent of intermolecular interactions between ENR and charged entities in this study. [ABSTRACT FROM AUTHOR]

In this study, a biocomposite material derived from rice husk filler (RHF) reinforced for polyvinyl chloride (PVC)/epoxidized natural rubber (ENR) blend was developed. RHF particles obtained as a byproduct from the agricultural industry were used as environmentally friendly fillers. ENR was applied as a plasticizer and compatibilizer to improve the compatibilization between PVC matrix and RHF. Regarding the influence of RHF content, RHF particle size, and ENR amount on the properties of such biocomposite, the mechanical and thermal properties were analyzed. The obtained results implied that the combination between PVC, ENR, and RHF in an optimized ratio of 90/10/20 (wt%) can produce a novel biocomposite with enhanced properties, which can offer good advantages for various applications in requirement of environmental protection. [ABSTRACT FROM AUTHOR]

The ring-opening reactions (ROR) of epoxide groups in epoxidized natural rubber/titania (ENR-50/TiO 2) hybrid in potassium hydroxide/isopropanol medium were examined using NMR spectroscopy and supported by the FTIR technique. The thermal behaviour of the hybrid was also studied using TG/DTG and DSC analyses. The 1H NMR results suggested that 16.82% of ROR occurred in the hybrid, while the 13C NMR results exhibited five new peaks at δ 19.5, 71.0, 73.7, 91.7 and 94.4 ppm in the hybrid. 2D NMR, such as HMQC, HMBC and COSY techniques, further scrutinized these assignments. The FTIR spectrum exhibited Ti-O-C characteristics via the peak at 1028 cm−1. The TG/DTG results showed four steps of thermal degradation at 44–148, 219–309, 331–489 and 629–810 °C due to the existence of Ti moieties along with a polymer chain mixture (intact and ring-opened epoxide groups) of ENR-50, which in turn led to an increase in the T g value of the hybrid to 27 °C compared to that of purified ENR-50 at −17.72 °C. [ABSTRACT FROM AUTHOR]

Green biodegradable thermoplastic natural rubber (GB‐TPNR) based on simple blend of natural rubber (NR) and poly(butylene succinate) (PBS) was prepared using three NR alternatives: unmodified NR and epoxidized NR with 25‐ or 50‐mol% epoxide (ie, ENR‐25 or ENR‐50). It was found that ENR‐50/PBS blend showed the best compatibility, which resulted in superior mechanical and thermal properties with the highest crystallinity of the PBS phase, on comparing with the ENR‐25/PBS and NR/PBS blends. This might be attributed to stronger chemical interactions between the epoxide groups in ENR‐50 and the polar functional groups in PBS, which were confirmed by Fourier transform infrared (FTIR). Furthermore, scanning electron microscopy (SEM), atomic force microscopy (AFM), and polarizing optical microscopy (POM) micrographs of ENR‐50/PBS blend revealed phase separation with finer‐grained cocontinuous structure than in ENR‐25/PBS and NR/PBS simple blends. Furthermore, the chemical interactions in ENR‐50/PBS blend enhanced the resistance to accelerated weathering. [ABSTRACT FROM AUTHOR]

Thermal properties and ionic conductivity of epoxidized natural rubber (ENR)-based solid polymer electrolytes (SPEs) are influenced by their sample preparatory pathways. In literature, there are inconsistencies reported on conductivity values in the range of 10−8-10−9 S cm−1 due to different sample preparatory pathways for same systems at constant salt concentration. In this study, simple thermal treatment was adopted on SPE films for regulating the thermal properties of the materials which in turn to govern the conductivity of the materials. ENR (with 25 and 50 mol% epoxidation) and lithium perchlorate salt (0-20 wt.%) were used. The ENR-based SPE films were thermally treated with three different annealing times (i.e. t = 0, ½, 24 h) at 80 °C under nitrogen atmosphere. Differential scanning calorimetry and impedance spectroscopy were utilized to analyze the thermal properties and ionic conductivity at room temperature, respectively. The glass transition parameters such as glass transition temperature, change in heat capacity, width of glass transition and change in enthalpy of endothermic overshoot were elucidated. Higher glass transition temperature values are noted for ENR-based SPEs films with longer annealing time, which may imply higher extent of intermolecular interaction between ENR and salt, thus leading to an increase in ionic conductivity of ∼10−10-10−8 S cm−1 for t = 0 and 24 h, respectively at mass fraction of salt, WS = 0.107. Consequently, it is deemed important to have precise control in the thermal treatment of ENR-based SPEs during their preparatory stage. [ABSTRACT FROM AUTHOR]

Determination of the thermal characteristics and temperature-dependent rheological properties of the magnetorheological elastomers (MREs) is of paramount importance particularly with regards to MRE applications. Hitherto, a paucity of temperature dependent analysis has been conducted by MRE researchers. In this study, an investigation on the thermal and rheological properties of epoxidized natural rubber (ENR)-based MREs was performed. Various percentages of carbonyl iron particles (CIPs) were blended with the ENR compound using a two roll-mill for the preparation of the ENR-based MRE samples. The morphological, elemental, and thermal analyses were performed before the rheological test. Several characterizations, as well as the effects of the strain amplitude, temperature, and magnetic field on the rheological properties of ENR-based MRE samples, were evaluated. The micrographs and elemental results were well-correlated regarding the CIP and Fe contents, and a uniform distribution of CIPs was achieved. The results of the thermal test indicated that the incorporation of CIPs enhanced the thermal stability of the ENR-based MREs. Based on the rheological analysis, the storage modulus and loss factor were dependent on the CIP content and strain amplitude. The effect of temperature on the rheological properties revealed that the stiffness of the ENR-based MREs was considered stable, and they were appropriate to be employed in the MRE devices exposed to high temperatures above 45 °C.

Herein we endow epoxidized natural rubber with antimicrobial activity by chemical modification. The rubber is firstly ring-opened by bromoacetic acid and then modified by antimicrobial group quaternary phosphonium salt. Using the hydrogen nuclear magnetic resonance spectroscopy (H NMR) and the ICP atomic emission spectrometry (ICP-AES), the degree of epoxidation, the convert ratio of epoxy groups, and the phosphorus content of the products are measured, and then the effects of reaction time on the structure of products are investigated. The possible reaction mechanism and side reactions in ring-opening procedure are discussed through the comparison of data with different reaction time, and the ring-expansion reaction is supposed to be dominated in the side reactions. The thermal properties of modified rubbers and the structural factors behind are also investigated using differential scanning calorimeter and thermogravimetric analyzer. Antimicrobial activities of modified rubbers with different ring-opening reaction time toward Escherichia coli are studied, and the activity may increase with the content of quaternary phosphonium salt groups. This research may have the benefit for optimizing the structure of chemically modified antimicrobial rubbers. [ABSTRACT FROM AUTHOR]

The aim of present study is to develop a toughened polylactic acid/talc composite. Talc and epoxidized natural rubber (ENR-50) were compounded with polylactic acid using counter-rotating twin-screw extruder followed by preparation of samples through injection molding. The effect of silane-treated talc and epoxidized natural rubber on mechanical, thermal, and morphological properties of polylactic acid was investigated. The Young′s and flexural modulus of polylactic acid improved while the impact strength values dropped with increasing talc content (20–30 wt%) indicating that talc increased the stiffness of polylactic acid with a sacrifice in toughness. Subsequently, the blending of epoxidized natural rubber (20 wt%) to polylactic acid/talc (30 wt%) revealed that the impact strength of polylactic acid/talc composites improved 448% with considerable drop in Young’s and flexural modulus. Polylactic acid/talc/epoxidized natural rubber composite contains 60% polylactic acid, 30 wt% talc, and 10 wt% ENR display optimum stiffness and impact strength. Scanning electron micrographs demonstrates that talc agglomerates at higher loadings. Thermogravimetric anlaysis indicated that thermal stability of polylactic acid/talc composite was reduced by the addition of epoxidized natural rubber due to increasing talc agglomeration. [ABSTRACT FROM PUBLISHER]

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. • Taguchi method improves quality of PBSA/ENR/ACW blends by optimizing molding factors. • The size of ENR droplets decreased with decreased mixing temperature, rotor speed and particle size of ACW. • The ACW and ENR phases stimulated degradation of the composites with PBSA matrix. • ANOVA analysis indicated the mixing temperature as the most significant manipulated factor during the preparation of PBSA/ENR/ACW blends. [ABSTRACT FROM AUTHOR]

Thermoplastic natural rubber (NR) of dynamically cured 60/40 NR/polyamide (PA) blends has been prepared by using three types of NR: unmodified air dried sheet NR, epoxidized NR (ENR) with 25 and 50 mol% epoxides. Plasticizer (i.e. dioctyl phthalate (DOP)) and processing oils (i.e. treated distillate aromatic extract and paraffinic oils) were incorporated in the blends. Stress relaxation, rheological, mechanical, and thermal properties of the blends were investigated. It was found that mixing torque, shear viscosity, tensile strength, and hardness of the oil-extended blends exhibited lower values compared with the blends without oil. But higher elongation was observed due to the distribution of oil into PA-12 and rubber phases. Furthermore, an increasing trend of stress relaxation behavior and rubber index was observed in the blends with DOP, which revealed an improvement in elastic properties. It was also found that the incorporation of DOP caused an enhancement in thermal behavior in terms of T10, T50, T90, and integral values, but a reduction in the glass transition temperature (Tg) of NR phase and crystallization temperature (Tc) of PA-12 matrix was also observed. This is attributed to the similar solubility parameter of DOP compared with the blend components. It was also found that the dynamically cured blends showed smaller rubber domains dispersed in PA-12 matrix. However, the addition of DOP resulted in an increase in the size of vulcanized rubber particles. [ABSTRACT FROM PUBLISHER]

Thermal properties and morphologies of different thermoplastic polymers blended with an elastomer are discussed. Poly(ethylene terephthalate) (PET), poly(3-hydroxybutyrate- co-3-hydroxyvalerate) with 12%mole of hydroxyvalerate content (PHBV) and poly(ethylene oxide) (PEO) were blended with epoxidized natural rubber (ENR). These blends turn out to be immiscible. Degree of crystallinity after isothermal crystallization and equilibrium melting point of the crystallizable constituents stay constant to a good approximation in blends with ENR. Exponential decay of rate of crystallization could be observed for both neat polymers and blends. Morphology formation was observed under condition of constant rate of crystallization, which is concomitantly related to different distances to equilibrium. It turns out that morphology development in the blends reflects both aspects. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Epoxidized natural rubber (ENR) samples of various epoxidation degrees were synthesized from natural rubber (NR) latex, and 25 mole% epoxide of ENR was used to prepare ENR room temperature-curable films for coating applications. The films were prepared from rubber solutions. Trimethylolpropane tris(2-mercaptoacetate) (TMP-SH) was used as a curing agent. The effect of the thiol additive on the tensile and thermal properties of epoxidized natural rubber (ENR) was investigated. For the sake of comparison, NR and TMP-SH-containing formulations were also prepared. It was observed that the addition of TMP-SH improved the tensile, thermal and swelling properties of ENR, indicating the formation of crosslinks. On the other hand, the addition of TMP-SH didn't improve the properties of NR, indicating the absence of reaction with TMP-SH. On the basis of data on the properties of the ENR films of this work it is demonstrated that these are appropriate for coating applications. [ABSTRACT FROM AUTHOR]

A series of polymer blends of poly(vinyl chloride) (PVC) and epoxidized liquid natural rubber (ELNR) were prepared and characterized. The aim of the work was to study the plasticizing effect of ELNR on the PVC/ELNR blend systems. Thermal properties of the samples were studied by differential scanning calorimetry (DSC). The glass transition temperature of the samples decreased with both degree of epoxidation and the percentage of composition of the samples. The scanning electron microscope (SEM) studies point to the two phase morphology. Tensile test results for the blend samples have been compared. From tensile tests, it was found that elongation of the materials increased with degree of epoxidation. On the other hand, tensile strength and modulus of the material decreased with the epoxide content. A good plasticization effect was observed for samples of ELNR with wt. 50% of epoxidation. [ABSTRACT FROM AUTHOR]

The effect of epoxidized natural rubber (ENR) or polyethylene acrylic acid (PEA) as a compatibilizer on properties of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends was studied. 5 wt.% of compatibilizer was employed in EVA/SMR L blend and the effect of compatibilizer on tensile properties, thermal properties, swelling resistance, and morphological properties were investigated. Blends were prepared by using a laboratory scale of internal mixer at 120°C with 50 rpm of rotor speed. Tensile properties, thermal properties, thermo-oxidative aging resistance, and oil swell resistance were determined according to related ASTM standards. The compatibility of EVA/SMR L blends with 5 wt.% of compatibilizer addition or without compatibilizing agent was compared. The EVA/SMR L blend with compatibilizer shows substantially improvement in tensile properties compared to the EVA/SMR L blend without compatibilizer. Compatibilization had reduced interfacial tension and domain size of ethylene vinyl acetate (EVA)/natural rubber (SMR L) blends. [ABSTRACT FROM AUTHOR]

Determination of the thermal characteristics and temperature-dependent rheological properties of the magnetorheological elastomers (MREs) is of paramount importance particularly with regards to MRE applications. Hitherto, a paucity of temperature dependent analysis has been conducted by MRE researchers. In this study, an investigation on the thermal and rheological properties of epoxidized natural rubber (ENR)-based MREs was performed. Various percentages of carbonyl iron particles (CIPs) were blended with the ENR compound using a two roll-mill for the preparation of the ENR-based MRE samples. The morphological, elemental, and thermal analyses were performed before the rheological test. Several characterizations, as well as the effects of the strain amplitude, temperature, and magnetic field on the rheological properties of ENR-based MRE samples, were evaluated. The micrographs and elemental results were well-correlated regarding the CIP and Fe contents, and a uniform distribution of CIPs was achieved. The results of the thermal test indicated that the incorporation of CIPs enhanced the thermal stability of the ENR-based MREs. Based on the rheological analysis, the storage modulus and loss factor were dependent on the CIP content and strain amplitude. The effect of temperature on the rheological properties revealed that the stiffness of the ENR-based MREs was considered stable, and they were appropriate to be employed in the MRE devices exposed to high temperatures above 45 °C. [ABSTRACT FROM AUTHOR]