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In this study, the effects of polyaniline (PANI) incorporation (3 wt% of PANI) and graphene nanoplatelets (GNPs) loading (0.1–0.7 wt%) on the mechanical, thermal, and electrical performance of epoxy matrix were investigated. The incorporation of 0.3 wt% GNPs optimally enhanced the bending strength, bending modulus, tensile strength, tensile modulus, and impact strength (90 MPa, 1422 MPa, 63 MPa, 602 MPa, and 8.29 kJm−2, respectively). At 0.3 wt% GNPs, the hybridization effect optimally enhanced the glass transition behaviour of the epoxy nanocomposites. The electrical and thermal conductivities of epoxy were improved upon the inclusion of PANI, and this increase was further augmented when the GNPs content increased to 0.3 wt%. However, higher GNPs contents deteriorated the mechanical performance and electrical and heat conduction. Field emission scanning electron microscopy showed good filler distribution and effective interactions among the GNPs, PANI, and epoxy components with appropriate compositions.

The finished product natural rubber latex gloves consist of latex proteins, which may pose a risk of allergic reactions in some latex-sensitive individuals. The allergic reactions depend on mild exposure to heavy exposure. An alternative solution to allergic users, usage of latex-free gloves are lack of elasticity and less comfort. This study aims to investigate natural rubber films protein reduction via three types of leaching solvent: acetic acid, sodium hydroxide, and ethanol in the leaching process. Then the influence of leaching solvent concentration on the physical properties of natural rubber gloves was analyzed. It was found that the acetic acid performed greater protein reduction effect (30.07%), followed by sodium hydroxide (27.77%), whereas the ethanol was shown to be less significant to protein reduction. All samples were fulfilling the mechanical properties as required in ASTM standard.

In this study, the effect of gamma irradiation on the optical properties of thin films of polymer electrolytes was investigated. The thin films were composed of poly(ethylene oxide) (PEO) doped with different concentrations of potassium iodide (KI) salt. The optical absorption spectrum of each film was measured using a UV–Vis spectrophotometer over a range of 300 to 800 nm. The PEO thin-film samples were subjected to gamma irradiation at two different doses of 100 and 200 Gy generated by a Co-60 source. It was found that the optical properties of the thin films were significantly influenced by the KI dopant concentration and gamma irradiation. Increasing both the KI concentration and the gamma irradiation dose resulted in a reduction in the energy gap and an increase in the absorption coefficient, extinction coefficient, refractive index, and dielectric constant of the PEO electrolyte. These findings have potential applications in the optimization of polymers for use in optical devices and energy storage systems. [ABSTRACT FROM AUTHOR]

Developing a bio‐based polyol polyurethane foam with the desired properties for use as growing media for green vertical walls could be beneficial in the quest to create a more sustainable urban living. In this work, palm kernel oil‐based polyol (PKOP) was mixed with petroleum‐based polyol (PP) at different ratios in synthesizing polyurethane foam. The impacts of PKOP/PP formulation on the density, cell morphology, water absorption, water retention, swelling behavior, and their chemical functional groups were evaluated. It was determined that replacing PP with low levels of PKOP could reduce the water absorption ability due to the introduction of hydrophobic plant‐based fatty acids. On the contrary, polyurethane foam containing more than 30% PKOP has improved the water absorbing ability and retention properties. Fourier‐transform infrared (FTIR) spectrum indicates that the synthesized foams are isocyanate‐free and stable toward pH changes. The trial planting attempt was a success where the plants were grown from seeds using the synthesized foam media. It was proposed that 50% PKOP is most suitable for use as a growing media, based on its water absorbing and retention properties. The findings of this study highlight the potential for the use of bio‐based polyol polyurethane foam for more sustainable growing media in urban gardens. [ABSTRACT FROM AUTHOR]

In this study, pineapple leaf fiber and polyethylene terephthalate electrospun nanofibers were produced via electrospinning process. Six ratios of pineapple leaf fiber/polyethylene terephthalate, namely 1/10; 1/7,5; 1/5; 1/1 and 1,3/1 were prepared and their wetting, structural and thermal properties were characterised. Wetting properties of this sample were studied using contact angle measurement. X27 Ray Diffraction, differential scanning calorimetry and thermogravimetric analysis were conducted to get better understanding on the structural and its thermal properties, respectively. The results revealed that increasing the pineapple leaf fiber content simultaneously increased the ability of nanofibers to adsorb water as shown by lower contact angle degree with 81,6° and adsorption time of 15 seconds. An increase in pineapple leaf fiber ratio did not change the peak position in X-Ray Diffraction and no new peaks observed for any sample. However, the peak at 23° for samples with ratio 1/1 and ratio 1,3/1 exhibited higher intensity compared to that of pure polyethylene terephthalate. Thermal properties obtained from thermogravimetric analysis results suggested that thermal properties were not influenced by the pineapple leaf fiber ratio. Overall, pineapple leaf fiber/polyethylene terephthalate electrospun nanofibers produced at the ratio of 1/1 displayed the optimum performance. [ABSTRACT FROM AUTHOR]

Conventional polymer blending has a shortcoming in conductivity characteristic. This research addresses the preparation of conductive thermoplastic natural rubber (TPNR) blends with graphene nanoplates (GNPs)/polyaniline (PANI) through melt blending using an internal mixer. The effect of PANI content (10, 20, 30, and 40 wt %) on the mechanical and thermal properties, thermal and electrical conductivities, and morphology observation of the TPNR/GNPs/PANI nanocomposites was investigated. The results showed that the tensile and impact properties as well as thermal conductivity of nanocomposite had improved with the incorporation of 3 wt % of GNPs and 20 wt % of PANI as compared to neat TPNR and reduced with further increase of the PANI content. It was observed that the GNPs and PANI acted as a critical component to improve the thermal stability and electrical conductivity of the TPNR/GNPs/PANI nanocomposites. The most improved conductivity of 5.22 E‐5 S/cm was observed at 3 wt % GNPs and 40 wt % PANI. Variable‐pressure scanning electron microscopy micrograph revealed the good interaction and distribution of GNPs and PANI within TPNR matrix at PANI loadings lower than 30 wt %. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48873. [ABSTRACT FROM AUTHOR]

High-fiber loading green composites were prepared from recycled high-density polyethylene (rHDPE)/recycled polyethylene terephthalate (rPET) blend matrix and rice husk (RH) as filler (from 40 wt% up to 80 wt%) via corotating twin-screw extruder and compression molding. The water absorption (WA) upon immersion in sea water, mechanical behavior, and combustion enthalpy of green composites were examined. The WA mechanisms obeyed the Fickian diffusion. The computed diffusion coefficient (D), thermodynamic solubility (S), permeability (P), and orthotropic swelling were generally increased as a function of RH filler. The increment of tensile strength and modulus of composites were maximized up to 16% and 121%, respectively, which was achieved at 70 wt% RH filler. The theoretical prediction of tensile strength and Young's modulus from micromechanical models for random oriented RH fiber/blend composites were compared with the experimental results. As the RH weight fraction increased, the combustion enthalpy decreased (by approximately 30–48%) and thereby the enhancing the fire retardancy of green composite. [ABSTRACT FROM AUTHOR]

Waveguide bends are essential structures for designing an integrated optical waveguide modulator (IOWM). However, reducing bending loss for strip and slot waveguide bends and obtaining a small increment of footprint size by bending the radius are challenging issues. We aim to evaluate whether using strip waveguides with an adiabatic bend reduces the bending loss and to obtain a specific length suitable for a V-shaped mode converter with a small increment of footprint size in the IOWM. Furthermore, a new 180-deg-bend structure for slot waveguides, to reduce bending loss, is investigated. The results of reducing bending radius (R) with a large coverage angle (ac) for strip waveguide bends revealed a low bending loss and simultaneously a reduction of the footprint size in the IOWM. For the 180-deg slot waveguide bend, both the bending and coupling losses were reduced by optimizing the taper and distance offset, which enhanced transmission power efficiency. We validated the feasibility and efficiency of the proposed bending strip and slot structures in IOWM, which is important for integrated optical applications. [ABSTRACT FROM AUTHOR]

The thermal conductivity and mechanical performance of a hybrid multi‐walled carbon nanotubes/silicon carbide (MWCNTs/SiC)‐reinforced thermoplastic natural rubber (TPNR) nanocomposite were investigated. TPNR was fabricated from polypropylene, natural rubber (NR) and liquid NR at a volume ratio of 70:20:10, respectively. The Young's modulus, the tensile strength, and the storage and loss modulus of the nanocomposites with a single filler of MWCNTs or SiC were enhanced compared with those of neat TPNR. The greatest improvements in these properties were achieved at a composition of 1.5 wt% SiC‐1.5 wt% MWCNTs‐reinforced nanocomposite. In addition, the thermal conductivity and specific heat capacity of the nanocomposites, determined using a laser flash technique, were improved in the 3 wt% SiC‐reinforced nanocomposite sample relative to those of the pure sample and the other reinforced nanocomposites. Based on these findings, MWCNTs and SiC could serve as suitable percolated networks of hybrid reinforcement fillers to achieve optimal thermal and mechanical properties in the TPNR matrix. POLYM. COMPOS., 40:E695–E703, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this work, thin films of solid polymer electrolyte made of pure poly (ethylene oxide) doped with cesium iodide (CsI) were prepared using casting method. The films contain different (CsI) concentrations: 0 %, 1 %, 4 %, 8 %, 12 %, and 16 % by weight. The optical properties such as the absorption coefficient, energy gap, refractive index, extinction coefficient, and dielectric constants have been determined in the wavelength range (300 – 800) nm. The results obtained showed that the optical constants change with increase of cesium iodide concentration. The absorption spectra of thin films at different CsI concentrations showed changes in the wavelength range. The optical dispersion parameters have been analyzed by the single oscillator model. The value of Eo and Ed were found and the other parameters have been determined by Wemple-DiDomenico method. [ABSTRACT FROM AUTHOR]

Integrated electric-field (E-field) sensors are commonly used devices in E-field sensing. However, distortion in the modulated signal due to high half-voltage (Vπ) and obtaining a low-frequency response are challenging issues in low-frequency AC E-field sensors. The aim of this study is to investigate a modification by adding a Si layer beneath a segmented slot waveguide (SSW) and optimizing the hybrid SSW as the core of a sensor to determine the sensor features in terms of the frequency response and sensitivity. The results of reducing the Si-layer thickness and segment width with high periodicity revealed a high modulation efficiency for very low-frequency AC E-field sensors and simultaneously expanded the minimum limit of detection by incorporating sensors in very small AC E-fields. This study validated the feasibility and efficiency of using a hybrid SSW as the core of highly sensitive low-frequency AC E-field sensors. [ABSTRACT FROM AUTHOR]

This article studies the enhancement in the properties of thermoplastic natural rubber (TPNR) reinforced by graphene oxide (GnO) and multiwalled carbon nanotubes (MWCNTs). TPNR is a blend of polypropylene and liquid natural rubber (NR), which is used as a compatibilizer and NR at a percentage of volume ratio 70:10:20, respectively. Using TPNR as the host matrix, a number of TPNR/carbon nanotubes (CNTs), TPNR/GnO, and hybrid TPNR/GnO/CNTs nanocomposites are processed and their mechanical, thermal, and electrical properties are characterized. The results extracted from tensile and impact test showed that tensile strength, Young’s modulus, and storage modulus of TPNR/GnO/MWCNTs hybrid nanocomposite increased as compared with TPNR composite and TPNR/GnO nanocomposite but lower than TPNR/MWCNTs nanocomposite. On the other hand, the elongation at break considerably decreased with increasing the content of both types of nanoparticles. Based on the experimental results, the thermal, electrical conductivity of a 0.5 wt% MWCNTs-reinforced sample increased as compared with a pure TPNR and other MWCNTs/GnO-reinforced composites. The improved dispersion properties of the nanocomposites can be due to altered interparticle interactions. MWCNTs, GnO, and MWCNTs–GnO networks are well combined to generate a synergistic effect that is shown by scanning electron microscopy micrographs. With the existence of this network, the mechanical, thermal, and electrical properties of the nanocomposite were improved significantly. [ABSTRACT FROM AUTHOR]

The use of integrated waveguide modulators is a common technique in electric-field sensing. However, the distortion in the modulated signal caused by high half-voltage Vπ and the difficulty in obtaining low-frequency responses are challenging issues for the use of low-frequency alternating-current (AC) electricfield sensors. This study investigates the use of an optimized segmented slot waveguide as the core of a sensor to determine the sensor features that produce useful frequency responses and sensitivity. The segmented slot waveguide is optimized in terms of periodicity and segment width to produce low Vπ and electrical bandwidth before testing the sensor sensitivity. The results show that reducing the segment width achieves a low Vπ of 0.32 V and a very low electrical bandwidth of 4.3 kHz. Our study provides evidence of the feasibility of using a segmented slot waveguide as the primary element for highly sensitive, low-frequency AC electric-field sensors. [ABSTRACT FROM AUTHOR]

Biocomposites of recycled high-density polyethylene (rHDPE)/recycled polyethylene terephthalate (rPET) matrices with a high loading of rice husk flour (RHF) were fabricated through a two-step extrusion. The use of ethylene-glycidyl methacrylate (E-GMA) copolymer improved the compatibility of the immiscible rHDPE/rPET blend. Maleic anhydride polyethylene (MAPE) was used as a coupling agent to increase the adhesion of the fibre–matrix interface. In this study, the effect of natural fibre loadings on rHDPE/rPET blends was examined. The water absorption process in the RHF-filled composites followed the kinetics and mechanisms of Fickian diffusion. Compared with samples without RHF, the rHDPE/rPET/RHF system had 58–172% higher tensile modulus and 80–305% flexural modulus. The thermal stability of the composites slightly increased with the addition of the RHF filler. The storage modulus of biocomposites was greatly enhanced by RHF. From these results, we can conclude that RHF can work well with rHDPE/rPET for manufacturing high loading biocomposite products. [ABSTRACT FROM AUTHOR]

ABSTRACT Rice husk flour (RHF) biocomposites based on uncompatibilized and compatibilized recycled high density polyethylene/recycled polyethylene terephthalate (rHDPE/rPET) with ethylene-glycidyl methacrylate (E-GMA) copolymer were prepared through a two-step extrusion and hot pressing with fiber loadings of 40, 60, and 80 wt %. Results showed that tensile and flexural properties increased. However, the elongation to break and impact strength decreased as the RHF loading increased. Compatibilizing polymer blend matrices can further enhance the mechanical properties. Water absorption (WA) test were examined in distilled and seawater. It is interesting to note that for composites made from uncompatibilized matrix, the calculated D and KSR were lower in seawater, but for the compatibilized matrix composites, the D and KSR obtained were generally lower in distilled water. However, compatibilization of rHDPE/rPET has been markedly reduced the WA and thickness swelling. Scanning electron microscope analysis of the compatibilized matrix composites confirmed the improved interfacial bonding of matrix-matrix and filler-matrix phases. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41494. [ABSTRACT FROM AUTHOR]

This paper discusses the effect of Gamma irradiation on the mechanical properties of thermoplastic natural rubber (TPNR) reinforced with hybrid nanofiller, multi-walled carbon nanotubes and nanoclay, (MWCNTs-OMMT). The hybrid nanocomposites samples have been subjected to gamma radiation with doses started from 0 to 200 kGy in air at room temperature. SEM micrographs revealed the fillers orientation in the TPNR matrix also promoted strongly to interfacial adhesion between fillers and the matrix which is contributed significantly to the improvement of the mechanical properties at optimum dose also the degradation of samples with high dose. The changes in the mechanical properties of hybrid nanocomposites after irradiation were attributed to the formation of crosslinks via irradiation. [ABSTRACT FROM PUBLISHER]

This study investigated the sonication effect on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced by multi-walled carbon nanotubes (MWCNTs). The TPNR nanocomposites were prepared using the melt blending method from polypropylene, natural rubber and liquid natural rubber as a compatibilizer, respectively, with 1% of MWCNTs. The results showed that a good dispersion on nanotubes was achieved by sonication. An optimal sonication time of 1 h was found to produce nanocomposites with maximum tensile and impact strength. The Young’s modulus, tensile strength, elongation at break and impact strength increased by almost 11%, 21%, 43% and 50%, respectively as compared with a pristine TPNR sample. The effect of sonication was also confirmed by dynamic mechanical analysis, it showed that the storage modulus E′, loss modulus E″ and glass transition temperature (Tg) also increased for all MWCNTs reinforced samples. Scanning electron micrographs confirm the effect of good dispersion of MWCNTs and their interfacial bonding in TPNR after sonication. [ABSTRACT FROM AUTHOR]

This article discusses the inclusion of MWNTs, nanoclay (OMMT), and hybrid nanofillers (MWNTs–OMMT) as reinforcing agents to improve the mechanical properties of TPNR. TPNR is a blend of PP, LNR as a compatibilizer, and NR at the percentage of volume ratio 70:10:20, respectively. The total reinforcement content is fixed at 4 wt%. The TPNR with 4 wt% OMMT, 4 wt% MWNTs, and hybrid 2 wt% OMMT2 wt% MWNTs was compounded using the internal mixer. The results show that the properties of the composite were improved by using the hybrid nanofillers. The tensile strength and Young's modulus for TPNR −2 wt% MWNTs −2 wt% OMMT hybrid nanofillers are the highest compared with TPNR/4 wt% MWNTs, TPNR/4 wt% OMMT, and TPNR. However, the elongation at break considerably decreased with the hybrid nanofiller. The effect of MWNTs, OMMT, and hybrid MWNTs–OMMT was also confirmed by DMA. This showed that the storage modulus E′, loss modulus E″, and glass transition temperature (Tg) also increased for all samples reinforced with nanofillers. TEM micrographs revealed the interfacial adhesion between the fillers and the matrix, which contributed significantly to the improvement of the properties. [ABSTRACT FROM PUBLISHER]

The main goal of this article was to study the effect of ultrasonic treatment time on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites. The intercalation of TPNR enhancement into layers of clay by increasing d-spacing was found using XRD. TEM micrograph showed a combination of intercalated—exfoliated structure of the TPNR composites with organic clay. The tensile properties of nanocomposites treated with ultrasonic increased as compared with untreated nanocomposites. The optimum ultrasonic treatment time was obtained at 1 h with the addition of a coupling agent (12% PP-g-MA). DMA has shown that the storage modulus E' and loss modulus E'' of TPNR nanocomposites had improved as compared with TPNR, the optimum results with ultrasonic effect achieved at 1 and 3 h. Ultrasonic treatment can promote the dispersion of the clay in TPNR and also improve the compatibility of organoclay filler and the TPNR matrix. [ABSTRACT FROM AUTHOR]

This study investigated the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced by multi-walled carbon nanotubes (MWNTs). The TPNR nanocomposites were prepared using melt blending method from polypropylene, natural rubber, and liquid natural rubber as a compatibilizer, respectively, with 1—7 wt% of MWNTs. The tensile strength and Young’s modulus increased by almost 39% and 30%, respectively, at 3 wt% of MWNTs. The elongation at break decreased with increase in the percentage of MWNTs. The maximum impact strength was recorded at 5 wt% of MWNTs which was increased by 74% as compared with a pristine TPNR sample. The effect of MWNTs was also confirmed by DMA; it showed that the storage modulus E′, loss modulus E′′, and glass transition temperature (Tg) also increased for all MWNT reinforced samples. SEM micrographs confirm the effect of good dispersion of MWNTs and their interfacial bonding in TPNR. [ABSTRACT FROM PUBLISHER]