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The present work studies the influence of zinc borate (ZB), magnesium hydroxide (MH) and ammonium polyphosphate (APP) as flame retardants on the curing, mechanical, thermal and flammability performances of Kevlar fibre (KF)-reinforced ethylene propylene diene monomer (EPDM) rubber composites. The flame retardant EPDM/KF composites were prepared with variable ratio of ZB, MH and APP. Thereafter, physicomechanical and thermal properties of the fire retardant EPDM/KF composites were analysed with density analysis, tensile testing, TGA analysis, SEM and cone calorimeter tests. The TGA analysis and cone calorimeter tests showed the enhancement in the flame retardant properties of the EPDM/KF composites with the addition of combined fillers with respect to the virgin counterparts. The synergistic effect of ZB and APP containing flame retardant-incorporated composites exhibited a prominence in the thermal stability and fire retardancy. Heat release rate (HRR) and total heat release rate (THR) of the ZB and APP combined fire retardant-incorporated composites were lower than the virgin EPDM.

In the current study, the effect of flyash (FA) on the physic-mechanical, electrical, thermal and morphological behavior of nylon-66 (PA) was investigated. PA/FA composites were prepared by melt mixing via twin screw extruder, with varying weight percent (5 wt %, 10 wt %, 15 wt % and 20 wt %) of flyash. The results of composites were optimized and compared with virgin nylon-66. Mechanical and electrical properties of composites improved up to 10 wt% of FA loading without compromising the properties. The flyash filled nylon-66 composites showed a low abrasive wear rate. Increase the heat distortion temperature of composites with an increase in weight percent of flyash while opposing the melt flow rate. Flyash filler enhances the stiffness of plastics but significantly reduces the impact properties. Dispersion of flyash was examined by impact fracture surface of composites using a scanning electron microscope.

Purpose The purpose of this study is to reduce the application of petroleum in automobile paint industry by replacing it with bio-based castor oil along with nano fillers to synthesize automobile base coat (BC). Design/methodology/approach Bio-based polyurethane (PU) coating applicable in automobile BC was synthesized by using modified castor oil incorporated with nano silica (NS) and titanium-based pigment particles. The influential characteristics of the coating was studied by carrying out cross-cut tape test, abrasion resistance, pencil hardness, lap-shear, thermo gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and acid, alkali and oil resistance tests. Findings Incorporation of NS particles, along with titanium-based pigment particles in optimized ratio into the paint matrix, increases the mechanical, chemical and oil resistance properties and hydrophobicity of the BC, and the findings are compared with the petro-based commercial BC. Research limitations/implications There is no significant improvement in thermal properties of the paint matrix, and it is less thermally stable than the commercial BC. Practical implications The paint developed through this study provides a simple and practical solution to reduce the petro-based feed-stock in automobile paint industry. Originality/value The current work which reports the use of ecofriendly PU BC for automobile paint applications is novel and findings of this study are original.

Polypropylene (PP)/sisal fibre (SF)/carbon fibre (CF) hybrid composites were prepared by melt blending process at a variable weight percentage (wt%) of carbon: sisal fibre loading (20:10, 15:15, 10:20, and 5:25). MA-g-PP (MgP) as a compatibiliser was used to improve the dispersion of the fibres within the PP matrix. The composites were subjected to mechanical tests to optimize the fibre content of CF: SF. Incorporation of 20 wt% of CF and 10 wt% of SF with 5 wt% MgP resulted in higher mechanical performance of about 67.02 and 112% over that of PP/SF composite. Similarly, the impact strength was found to be optimum which enhanced to the tune of 39.62% as compared with PP/SF composites. Halpin Tsai model was used to compare the theoretical tensile modulus of PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites with experimental evaluated values. Fracture toughness parameters such as K IC (critical stress intensity factor) and G IC (critical strain energy release rate) are determined for PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites and compared by using single edge notch test. DSC study showed higher melting temperature (T m ) of PP/SF/CF/MgP composites as compared to PP revealing the enhancement in thermal stability. TGA/DTG study revealed the synergistic effect of the hybrid composite thus confirming the hybridisation effect of the system. DMA study showed that the hybridisation of CF and SF within the matrix polymer contributes to an increase in the storage modulus (Eʹ). Morphological observation by SEM confirmed that the carbon fibres and sisal fibres are well uniformly dispersed within the PP matrix, in the presence of MgP.

The comparative study of biodegradation of various blown films obtained from Poly (lactic) acid (PLA) has been studied via soil burial method. A total of 3-different types of films prepared from neat PLA and the reactive blends containing poly butylenes succinate-co-adipate (PBSA), and thermoplasticized starch (TPS); namely VPLA, PLA/PBSA, PLA/TPS respectively were the subjects of investigation. Several analytical techniques including weight loss method and analysis of mechanical properties were performed in each seven days interval until ninety days to elucidate the biodegradation in soil. The tensile modulus of VPLA and PLA/PBSA blown films were deteriorated to the tune of 60.32% and 71.28% respectively within 28 days, while PLA/TPS blown films recorded a significant reduction of 75.31% in the modulus value within 21 days of soil exposure compared to unexposed blown film samples. Similarly, blown films of PLA/TPS reported the highest rate of weight loss in the order of 40.06% in 90 days of soil burial with an estimated half-life of 103 days in soil environment compared to its counterparts. The depletion in both mechanical properties and weight of the film samples suggesting the occurrence of biodegradation in the real soil environment. Scanning electron microscopy (SEM) revealed the formation of coarse morphology for all three types of soil buried samples which trace of microbial action appeared on PLA/TPS films. Fourier transform infrared microscope (FTIR) showed the decrease in carbonyl index and variation in the intensities of carbonyl and hydroxyl peaks irrespective of the film samples after 90 days of soil exposure. Gel permeation chromatography (GPC) documented reduction in molecular weight and variation in polydispersity index (PDI) of post-exposed soil samples. The elemental analysis exhibited that the percentage of organic carbon and hydrogen content of all the films decreased while the oxygen percentage increased after soil burial due to the biodegradation of film specimens. Both Differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD) reported increase in crystallinity for soil exposed samples indicating the initiation of degradation kinetics preferably at the amorphous region of film composition. It has also been inferred that the biodegradation mechanism of VPLA and PLA/PBSA blown films predominantly driven by hydrolysis of ester bond. Contrastingly, the biodegradation kinetics in case of PLA/TPS film has been proceeded with microbial assimilation of TPS component which further thrived on hydrolysis of PLA component of the blown film system.

The major roadblock for recycling of waste electrical and electronic equipments (WEEE) depends on the viability of sorting process, which is a complex task, involving various techniques such as sink float, froth flotation, optical separation and manual separation, etc. This makes the sorting process highly time consuming and expensive. The primary aim of this investigation is to study the properties of polymeric blends formulated from computer keyboards, by avoiding high end sorting procedure to avoid manpower and instrumental cost. The major polymers recovered from waste keyboards were identified as acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS) and polystyrene (PS), using fourier transform infrared (FTIR) spectroscopy. These polymers were subjected to mechanical recycling by employing melt blending technique, followed by injection moulding. A ternary blend was prepared utilizing various percentages of ABS, HIPS and PS. The mechanical test of the blends revealed an optimum tensile strength of 35 ± 3 MPa, flexural strength of 65 ± 3 MPa, and impact strength of 45 ± 3 J/m. The homogeneity of the blends was determined through thermal analysis and morphological analysis of impact fractured specimens. The thermogravimetry analysis (TGA) showed a narrow peak with degradation of 98% of the blends at 700 °C. It was observed that, the properties of blends were similar to each other, which allows to eliminate multiple sorting process reducing cost aspect with improve performance characteristics.

Hybrid nanocomposites have been evolving as promising materials that can be utilized for various applications. The present work deals with the fabrication of nanosilica reinforced EPDM/Kevlar fiber hybrid nanocomposites. Tensile strength, elongation-at-break, density of the developed EPDM/KF hybrid nanocomposites were evaluated and compared. The ability of the hybrid nanocomposite to resist the temperature conduction has been probed with thermal conductivity measurement and their stability in thermal atmosphere was studied with thermogravimetric analysis. The results demonstrated that nanosilica reinforced EPDM has shown significant enhancement for the tensile strength (upto109%) and modulus. And the thermal conductivity of EPDM has been further lowered with the silica nanoparticles addition, maintaining a lower density. The strategic methodology adopted in our study utilizes a low consumption of nanomaterial which can evocatively communicate the thermal insulation system.

Hybrid organic-inorganic nanocomposites employ metal oxides to improve the charge transport properties and stability of the conjugated polymer. They are considered one of the most interesting candidates for optoelectronic applications. This article presents a detailed investigation on the influence of defective electronic states of MgO nanoparticles on the photophysical properties and photostability of a conjugated polymer, poly[2-methoxy-5-(2-ethylhyxyloxy)-1,4-phenylene vinylene] (MEH-PPV). Since MgO is an insulator (

In this review, we survey the state of the art on polymeric foams incorporating nano-scale fillers. Particular focus of the review is on foams from polyolefinic nanocomposite formulations incorporating a wide variety of fillers. The nano-scale additives can influence the foam structure and properties in two ways: Firstly, they can act as composite reinforcement to enhance the mechanical properties and functionality of the matrix polymer; and secondly, they can act as foaming-processing aids through modification of the rheological, thermal and crystallization properties of the matrix as well as serving as heterogeneous nucleation sites. Through a combination of these influences, and using advanced processing techniques it is possible to achieve nanocomposite foams that have higher cell density, and more uniform cell size or controlled cell-size distribution. Such controlled foam morphologies, in turn, can yield better specific mechanical properties resulting in more effective light-weighting solutions. Further, the nano-scale additives can impart additional desired functionality resulting in multi-functional foams. In this article, we provide an overview of the mechanical, thermal and a few other relevant functional properties – such as piezoelectric sensitivity, acoustics, and filtration efficiency – of foams prepared using nanocomposite formulations, along with the processing considerations for achieving high quality foams using such materials.

Poly(lactic acid) (PLA) is an important biomaterial with its easy availability and wide spread acceptability in biomedical field. The most appreciable characteristic nature of PLA is its versatilit...

In this work, we have reported the systematic preparation of flexible and transparent PVDF films, through multi-step processing techniques including solvent casting followed by thermal compression and mechanical stretching. Variation in the structural, morphological and dielectric behaviour of each film with respect to each processing condition are analysed through FTIR, XRD, DSC, FESEM, AFM and impedance spectroscopy. The structural characterisation revealed the deep influence of thermal compression and mechanical stretching process on the electroactive s-phase structure of solvent-casted PVDF films while the morphological analysis confirmed the formation of microfibrillar morphology after three successive processing methods. A significant increment in the dielectric constant value from 10.7 (for solvent-casted PVDF film) to 24 (for solvent-casted followed by thermal compression followed by mechanical stretched PVDF film) and dielectric loss of 0.015 to 0.0018 has achieved for PVDF film after multi-step processing techniques. Such improvements in structural and dielectric behaviour are attributed to the thermo and mechanical dependent changes in the crystalline structure which helps in the rotation of polar –CH2-CF2 group.

Fabrication of noble metal-free semiconductor heterojunction composed of transition metal dichalcogenides (TMDs) and CdS is observed to be an efficient and economical photostable system for hydroge...

Using machine learning (ML) approach, we unearthed a new III–V semiconducting material having an optimal bandgap for high-efficient photovoltaics with the chemical composition of Gallium–Boron–Phosphide ( $$\hbox {GaBP}_{2}$$ , space group: $$\hbox {Pna2}_{1}$$ ). ML predictions are further validated by state-of-the-art ab initio density functional theory simulations. The stoichiometric Heyd–Scuseria–Ernzerhof bandgap of $$\hbox {GaBP}_{2}$$ is noted to be 1.65 eV, a close ideal value (1.4–1.5 eV) to reach the theoretical Queisser–Shockley limit. The calculated electron mobility is similar to that of silicon. Unlike perovskites, the newly discovered material is thermally, dynamically and mechanically stable. Above all the chemical composition of $$\hbox {GaBP}_{2}$$ is non-toxic and relatively earth abundant, making it a new generation of PV material. Using ML, we showed that with a minimal set of features, the bandgap of III–III–V and II–IV–V semiconductor can be predicted up to an RMSE of less than 0.4 eV. We have presented a set of scaling laws, which can be used to estimate the bandgap of new III–III–V and II–IV–V semiconductor, with three different crystal phases, within an RMSE of $$\approx $$ 0.4 eV.

The effect of Closite C93A nanoclay on the mechanical, thermal properties of diglycidyl ether bisphenol A (DGEBA) epoxy resin and epoxidized soybean oil (ESO) bioepoxy blend at various wt.% (10, 20...

Polypropylene (PP)/sisal fiber (SiF)/cellulose nanocrystals (CNC) hybrid composites were prepared at a variable weight percentage of SiF/CNC loading (29:1, 27:3, 25:5, and 23:7) using melt-blending technique followed by injection molding. The dispersion of the CNCs and SiFs within the nonpolar PP matrix was enhanced by using maleic anhydride grafted PP (MAPP) as a compatibilizer. Furthermore, the mechanical properties like tensile, flexural, and impact properties of the hybrid composites were evaluated. High tensile strength and modulus of 47.02 MPa and 2820.26 MPa, respectively, were observed for the hybrid composite with the incorporation of SiF/CNC (27:3 wt%) in the presence of 5 wt% MAPP. Additionally, an increment of 30.87% and 14.81% was observed for corresponding flexural strength and modulus as compared to their counterparts without MAPP. The elastic moduli obtained experimentally were compared with the theoretical elastic moduli using Cox–Krenchel and Ouali model in combination with the Halpin–Tsai model. Surface morphology by field emission scanning electron microscopy observed that the CNCs and SiFs were well dispersed within the PP matrix in the presence of MAPP. Differential scanning calorimetry thermograms showed no measurable changes in the melting temperature (Tm) of PP in PP hybrid composites; however, an increment in the crystallization temperature (Tc) was observed. The thermogravimetric analysis confirmed the enhancement in the thermal stability of PP hybrid composites due to the synergistic effect of hybridization within the PP matrix. Partial substitution of CNCs along with SiFs within the matrix polymer shows an increment in the stiffness of the hybrid composites as evident by dynamic mechanical analysis.

Liver regeneration is a highly organized tissue regrowth process and is the most important reaction of the injured liver. The present study endeavors towards the preparation and characterization of nanoporous Sodium Alginate (SA)/ Poly Vinyl Alcohol (PVA) composite, nanofibrous scaffolds coated with silver (Ag) nanoparticles for hepatocellular regeneration. Chitosan based Silver nanoparticles possess high antibacterial activity has been preferred in the scaffold preparation to improve the antibacterial properties. The structural characterization of Ag Nanoparticles revealed the amorphous nature with an average particle size of 300 nm. Nanofibres (Scaffolds) were prepared by electrospinning SA/PVA solution at a voltage of 18-25 kV and Ag NPs were coated on it for antibacterial activity. Invitro studies denoted the growth of nitro compounds, amides and collagen which are the major constituents of liver tissue.

Homologous series of alkyl lactate and alkyl lactate acrylates starting from hexyl to dodecyl were synthesized and then polymerized by solution polymerization using AIBN as the free radical initiat...

The focus of this study was on the preparation of porous bio-based matrix with a view to fabricating the environment-friendly supercapacitors from two sustainable materials, cellulose acetate (CA) and chitosan (CS). The strategy used is, first preparing a tri-hybrid of rGO/NiO/Fe3O4 (rNF) particles followed by mixing it into CA/CS (CC), as prepared CC/rNF was then dipped into aniline. After the impregnation by aniline, the polymerization proceeded to get a CA/CS/PANI/rNF (CCPRNF) electrode. The prepared electrode shows excellent properties such as high conductivity (7.1 × 10–2 S/cm), an areal capacitance of 16.61 mF/cm2 at a scan rate of 5 mV/s and 88% capacitance retention after 1000 cycles. The symmetric device fabricated from 15% CCPRNF achieved areal capacitance of 5.5 mF/cm2 (scan rate 20 mV/s). Herein, we suggest a new approach for the construction of environment-friendly, flexible, conducting, 3D scaffold-like porous electrodes for supercapacitors using CA/CS through simple “phase inversion and in-situ polymerization method”. These slides can be retrieved under Electronic Supplementary Material.

The selective laser melting (SLM) technology, a 3D printing method, has been gaining more attraction recently due to its ability to fabricate highly complex and intricate featured medical, aerospace, automotive components. The extensive use of SLM in recent years has been augmented by readily available processing materials and distinct product features such as enhanced surface properties and improved mechanical strength of the printed products. This paper investigated the effects of support structures, building direction and post-processing on mechanical properties, surface roughness and microscopic analysis of parts printed by SLM. Support structures are required during the SLM printing process. It is desired to optimize the support structures, as this increases printing time and material consumption and reduces surface finish. Finite element analysis has been carried out prior to metal printing to optimize the support structure. It was found that the spider-cone line support shows efficient structure for this study. The mechanical properties of the fabricated specimen were studied, and experimental results were validated and compared with conventionally machined specimen. It was observed that the SLM printed parts have 20% increment in tensile strength as compared with conventionally cast specimen. However, the percent of elongation is low for SLM specimen due to large number of pores and un-melted powder presented in the printed part. In this study, the SLM specimens were subjected to heat treatment at the temperature of 550 °C for 2 h in order to achieve increment or optimal mechanical properties. The heat treatment demonstrated a 2-fold increment in elongation, as compared with the SLM as printed specimen. The present study is also aimed at evaluating the surface roughness of SLM printed specimen. It was observed that the surface roughness of SLM specimen ranged between ~ 0.3 and 3 μm. This demonstrated that SLM process is capable of providing the good surface quality component and considered an alternative process to conventional manufacturing process. The morphological studies have been carried out to support the results derived from the evaluation of mechanical properties and surface roughness. The morphological behaviour clearly shows the large pores and un-melted particles in fractured specimen. The results revealed that the support structure, build direction, orientation, surface finish and post-processing are important parameters to build a part using SLM effectively and efficiently.

The recycling of polyvinyl chloride (PVC) recovered from the plastic insulations in wires and cables is a rising concern in the current situation due to its hazardous behaviour during recycling. Similarly, high-impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS) used in the structural components of electrical and electronic equipment are also generated in large quantities. In the current work, three agendas were fixed: (a) to determine the effect of recycled polymeric material (HIPS and ABS) recovered from different sources on the mechanical property of the polymeric blends; (b) to formulate a high-impact strength blend; and (c) to deduce a mechanism for improved impact strength. The mechanical characterizations were conducted on the entire blends formulated. Among them, the recycled blend composed of recycled PVC (r-PVC) and recycled ABS (r-ABS) (segregated from uninterrupted power supply housing) and recycled HIPS (r-HIPS; collected from television housing) was confined for further physio-mechanical and thermal analysis. Besides, the r-PVC/r-ABS systems had shown better mechanical properties than r-PVC/r-HIPS systems in similar composition. The impact strength of blend r-PVC/r-ABS (70:30) was found to be 250 J/m, which was 200% more than the blend r-PVC/r-ABS (0:100). The compatibility and non-compatibility in PVC/ABS and PVC/HIPS blends respectively were explained with thermal, mechanical and morphological characterizations. Furthermore, a plausible cross-linking mechanism is developed between ABS and PVC, which controls the release of chlorine atoms into the environment.

Polymer composites have been a material of choice for lightweight and durable applications in sectors ranging from automobile, packaging, structural components, and electronics to energy harvesting. Their versatility and ability to be tailored to application requirements have made them prospective alternatives for metal enclosures used in communication systems, power electronics, electric motors, and generators. The easy processing and high strength-to-weight ratio provide advantages over traditional materials that involve time- and-labor intensive processes. However, high thermal conductivity (TC) and electromagnetic interference (EMI) shielding are factors limiting their penetration into niche markets, and thus the development of alternatives with high TC and EMI shielding efficiency is critical. Thermally conductive polymer composites and EMI shielding effectiveness (SE) is a current issue in different applications including polymers providing light weight, corrosion resistance, and ease of processing as compared with metal. This paper focuses on improvements in the TC and shielding effectiveness of polymers by incorporating various fillers including carbon-based, mineral-based, and hybrid fillers. The paper reviews the current research worldwide regarding the enhancement of the TC and shielding effectiveness of polymer composites.

The enhancements in the properties of the recycled blends are concerned as the major highlight in the field of polymer recycling and technology. The materials containing polar functional groups are generally employed for enhancing the mechanical and thermal properties of the recycled blends. In this study, epoxidized soybean oil (ESBO), a bio-derived material, was considered as the toughening agent for the modification of the recycled blends made of poly(vinyl chloride) and poly(methyl methacrylate). A series of concentrations (3–12 wt%) of ESBO have been incorporated into the recycled blend matrix via the melt blending method. Further, the formulated recycled blends were analysed for their mechanical, rheological, thermal, flammability and morphological characteristics. Among them, the modified blend with 9% ESBO has been indicated a significant improvement in the fracture toughness parameters. The scanning electron micrographs are clearly indicating the changes in the microstructural properties of the recycled blend after the integration of ESBO. Moreover, dynamic mechanical analysis indicated changes in the glass transition values which resulted from the improved interfacial adhesions and compatibility of the recycled blend matrix.

Herein, we report a novel, low-temperature solvothermal method to grow 3D-Bi2O3 flower-like microspheres on Ti substrates as a binder-free negative electrode for supercapacitor applications. The Bi2O3/Ti electrode showed an areal capacitance of 1.65 F cm-2 at 4 mA cm-2. Moreover, the 3D-NiCo2O4||3D-Bi2O3 hybrid device delivered high energy and power densities of 31.17 μW h cm-2 and 7500 μW cm-2, respectively. The more optimal energy storage performance based on the strong adhesion of the current collector and self-assembled three-dimensional nanostructures permits efficient electron and ion transportation.

The recycled poly(vinyl chloride) (r-PVC) collected from the data cable has been incorporated into the recycled poly(methyl methacrylate) (r-PMMA) matrix in different weight percentage through the melt blending technique. The obtained recycled blends were analysed for mechanical, rheological, thermal and morphological characteristics. Among the various recycled blends formulated, 70:30 wt% of r-PVC/r-PMMA exhibits higher fracture toughness value. The rheological analysis highlights that recycled blends have pseudo-plastic characteristics. Furthermore, the storage and loss modulus values are decreasing with the increment of r-PVC in the recycled blend. The scanning electron microscope (SEM) study reveals the transformation of recycled blend matrix from brittle to the ductile character with the higher concentrations of r-PVC. Similarly, the water absorption, chemical resistance behaviour of the developed blends was depended on the concentration of r-PVC in the recycled blend.

This research article describes the impact of the depressurization rate change on the morphology of microcellular polycarbonate foams (PCMFs) using batch-wise foaming with carbon dioxide as...

Long-term gas separation performance and stability are the predominant factors enabling successful implementation of mixed matrix membranes (MMMs) for large-scale industrial applications. This study highlights the integration of CNT and graphene into Polysulfone (PSf) matrix and studied the synergistic effect on the permeation characteristics of O2/N2 pair. An electrical alignment technique has adopted for the preparation of the MMMs by solution casting method. Also, the parent counterparts, including PSf/CNT and PSf/rGO systems have prepared. FTIR, UV, and EDS established the existence of membrane-forming materials. The electron micrographs confirmed uniform dispersion of the filler phase within the PSf matrix, thereby indicating an effectual increase in the permeation characteristics. The hybrid system exhibited improved mechanical and thermal stability against other tested membranes. The prepared membranes showed excellent O2 permeation with higher selectivity for N2, despite the minimal difference in molecular size. The hybrid system rendered uniform permeation coefficient for 120 h; also displayed excellent hydrothermal and chemical stabilities, thus establishing commercial potential.