Blend Matrix Research Articles

Eco-Friendly Approach and Potential Biodegradable Polymer Matrix for WPC Composite Materials in Outdoor Application

Blends based on high-density polyethylene (HDPE) and poly(lactic) acid (PLA) with different ratios of both polymers were produced: a blend with equal amounts of HDPE and PLA, hence 50 wt.% each, proved to be a useful compromise, allowing a high amount of bioderived charge without this being too detrimental for mechanical properties and considering its possibility to biodegradation behaviour in outdoor application. In this way, an optimal blend suitable for producing a composite with cellulosic fillers is proposed. In the selected polymer blend, wood flour (WF) was added as a natural filler in the proportion of 20, 30, and 40 wt.%, considering as 100 the weight of the polymer blend matrix. There are two compatibilizers to modify both HDPE-PLA blend and wood-flour/polymer interfaces, i.e., polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate. The most suitable percentage of compatibilizer for HDPE-PLA blends appears to be 3 wt.%, which was selected also for use with wood flour. In order to evaluate properties of blends and composites tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, and infrared spectroscopy have been performed. Wood flour seems to affect heavy blend behaviour in process production of material suggesting that future studies are needed to reduce defectiveness.

High loading rice husk green composites: Dimensional stability, tensile behavior and prediction, and combustion properties

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.

Development of alginate‐gum acacia‐Ag0 nanocomposites via green process for inactivation of foodborne bacteria and impact on shelf life of black grapes (Vitis vinifera)

ABSTRACTThe main objective of this investigation is to develop sodium alginate‐gum acacia‐silver nanocomposite films (AGA‐Ag0 NC) to inhibit the growth of foodborne and to extend the shelf life of food. The Ag nanoparticles were generated in sodium alginate‐gum acacia (AGA) blend matrix through reduction by basil leaves (Tulasi). The formation of Ag0 was monitored by UV–vis spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), thermogravimetrical analysis (TGA), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The absorption band at 420 nm in UV–vis spectrum and change in the band positions in FTIR spectrum of AGA‐Ag0 NC compared to that of AGA corresponds to the formation of Ag nanoparticles. The XRD profile of AGA‐Ag0 NC exhibits characteristic d‐lines of Ag nanoparticles. The spherical shape of Ag nanoparticles uniformly formed throughout the films was recognized in SEM image with a size of ~ 4 ± 1 nm as observed by TEM. The water uptake and mechanical properties of the films were also studied. The AGA‐Ag0NC films offered excellent antimicrobial activity against various foodborne bacteria and shelf life of food enhanced efficiency of the AGA‐Ag0NC films is also tested on grape fruit (Vitus vinifera). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47331.

Effectively improved ionic conductivity of montmorillonite clay nanoplatelets incorporated nanocomposite solid polymer electrolytes for lithium ion-conducting devices

Synergistic effects of lithium salt concentration and inorganic nanofiller incorporation on the ionic conductivity of polymer blend matrix based nanocomposite solid polymer electrolytes (NSPEs) have been examined. The montmorillonite (MMT) clay nanoplatelets incorporated NSPE films based on poly(ethylene oxide) and poly(methyl methacrylate) blend matrix with lithium tetrafluoroborate (LiBF4) ionic salt have been prepared by the solution-cast method followed by melt-press technique. The 1, 3, and 5 wt% MMT amounts along with 13.3 wt% LiBF4 amount as compared to the weight of polymer blend have been used for the preparation of NSPE films. X-ray diffractometer (XRD) and the Fourier transform infrared (FTIR) spectrometer have been employed for structural characterization of these NSPE films. The complex permittivity and ac electrical conductivity spectra are investigated by using the dielectric relaxation spectroscopy, whereas the electrochemical performance of these materials has been characterized by the electrochemical analyzer. The XRD patterns reveal that the NSPEs are predominantly amorphous and have the intercalated and exfoliated MMT platelets, whereas the relative changes in their FTIR spectra confirm the ion–dipolar–nanofiller interactions between the functional groups of the blended polymers, lithium ions, and the MMT nanoplatelets. The permittivity and conductivity spectra of these materials are analyzed for exploring the dominant contribution of electrode polarization and dipolar polarization in the low and high frequency regions, respectively, and the presence of relaxation processes associated with structural dynamics of the solid-state ion–dipolar complexes. It has been found that the NSPE of relatively fast polymer chain segmental dynamics exhibits higher ionic conductivity. The room temperature ionic conductivity of the 13.3 wt% LiBF4 containing SPE is found more than two times higher as compared to that of the SPE film having 9.7 wt% LiBF4. When the MMT is incorporated, the ionic conductivity of 13.3 wt% LiBF4 containing NSPEs enhances by about one order of magnitude at room temperature. The dc ionic conductivity of the 13.3 wt% LiBF4 containing SPE film is found 1 × 10–5 S/cm at 55 °C, whereas it is 1.65 × 10–5 S/cm at 27 °C for the 5 wt% MMT incorporated NSPE film. The significantly enhanced ionic conductivity with ions transference number close to unity, high electrochemical stability voltage window and good reversibility of these NSPE materials confirm their potential applications as ion conductor/separator for the development of all-solid-state ion conducting devices and the lithium-ion batteries.

Optimization of Thermoplastic Blend Matrix HDPE/PLA with Different Types and Levels of Coupling Agents.

High-density polyethylene (HDPE) and poly(lactic) acid (PLA) blends with different ratios of both polymers, namely, 30:70, 50:50, and 70:30, were produced. Polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate were also considered as compatibilizers to modify HDPE/PLA optimal blends and were added in the amounts of 1, 3, and 5 wt.%. Different properties of the blends were evaluated by performing tensile tests and scanning electron microscopy to analyze blend and interfaces morphology. Moreover, thermomechanical analysis through differential scanning calorimetry, thermo-gravimetric analysis, and infrared spectroscopy were also performed. The blend containing equal amounts of HDPE and PLA seemed to present a good balance between amount of bio-derived charge and acceptable mechanical properties. This suggests that these blends have a good potential for the production of composites with lingo-cellulosic fillers.

Investigation on Structural and Dielectric Properties of Silica Nanoparticles Incorporated Poly(Ethylene Oxide)/Poly(Vinyl Pyrrolidone) Blend Matrix Based Nanocomposites

Inorganic and organic materials based polymer nanocomposite (PNC) films, comprising silica (SiO2) nanoparticles as inorganic filler and the polymer blend of poly(ethylene oxide) (PEO) and poly(vinyl pyrrolidone) (PVP) as organic matrix (i.e., (PEO–PVP)-x wt% SiO2; x = 0, 1, 3 and 5) have been prepared by the solution-casting method. These PNC films are characterized by employing the scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, and the dielectric relaxation spectroscopy (DRS). The effect of SiO2 nanofiller on the spherulite and porous morphology, miscibility of the polymers, PEO crystallite size, the degree of crystallinity, polymer–polymer and polymer-nanoparticle interactions, and from 20 Hz to 1 MHz range dielectric and electrical dispersion behaviour and also the structural dynamics of these PNC materials have been investigated. The porous morphology, structures of miscible phases, and the PEO crystallite length greatly alter with the incorporation of merely 1 wt% SiO2 in the polymer blend matrix which further changes with the increase of nanofiller concentration up to 5 wt%. The real part of complex permittivity over the radio frequency range (20 kHz–1 MHz) for these PNC films is found about 2 and their dielectric loss tangent values below 0.03, at the room temperature, which are significantly low. The contribution of interfacial polarization effect at lower audio frequencies enhances the complex permittivity of these materials linearly in the range 2 to 4 with the decrease of frequency from 1 kHz to 20 Hz confirming their frequency tunable dielectric behaviour. The dielectric study of 3 wt% SiO2 containing PNC film in the temperature range 30–60 °C reveals its thermally activated dielectric characteristics, and the temperature dependent values of dielectric relaxation time and dc electrical conductivity obey the Arrhenius behaviour with activation energies in the range 0.2–0.3 eV. The dielectric and electrical parameters ascertain the promising applications of these PNC films in the development of novel electroactive functional materials, and also their use as the dielectric substrate and electrical insulating polymeric nanodielectrics for the fabrication of flexible-type naturally degradable organoelectronic devices.

Studying the Effect of Reinforcement with Random Short Fibers and Temperature on the Impact Strength of an Epoxy/Polyurethane Blend Matrix

A polymeric blend consisting of epoxy resin and polyurethane was prepared as a matrix material with (88%) of epoxy and (12%) of polyurethane by weight fraction. It was reinforced with a random short whisker fibre of polypropylene (PP) and fibreglass (FG) with fractional volumes of 4, 8, and 12%. The impact strength before and after the reinforcement was done with temperatures of 25, 50, and 75 °C. The results showed that the reinforcement of matrix material with fibre has increased the impact strength from 3.4 kJ/m2 to 16.9 kJ/m2 at 12% vol. of the composite material of both fibre polypropylene with glass fibre and followed by the composite material with polypropylene fibre, and finally by the composite material of glass fibre. Also, the increase in temperature led to a rise in the impact strength, except for the polypropylene fibre-reinforced polymer mixture, as the increasing in temperature led to a decrease in the values of impact strength from 14.2 KJ /m2 at 25 °C to 11.5 kJ/m2 at 75° C.

Functional film of ethylene vinyl acetate and co‐polyamide compound containing “Nisin” active substance

This study deals with flexible films incorporating nisin for antibacterial active packaging purposes. A novel approach was used to gain control over nisin release profile from a thermoplastic film in order to enhance its antibacterial efficiency. This approach involves polymer blends of ethylene vinyl acetate copolymer and co‐polyamide at various ratios. It was shown that the release profile of an antibacterial substance from active packaging to foodstuff is a key factor concerning the antibacterial efficiency. Samples of 400[μm] were produced by using a laboratory twin screw compounder and a laboratory hot press. Samples were characterized for their migration kinetics, molecular interactions, mechanical properties, and water swelling properties. Antibacterial activity tests show that nisin incorporated films reduced bacterial count by different extents. Listeria ATCC 33090 was used as target bacteria (data not shown). Nisin migration profile to water medium was determined by Lowry's protocol. Scanning electron microscopy images and thermal analysis indicated that no significant molecular interactions occurred. Furthermore, droplet and co‐continues like morphology were seen at different polymer blend ratios. Osmotic pressure driven release mechanism appears to be the dominant migration mechanism, and diffusion kinetics was dominant. Results show that morphology of the polymer blend matrix alters the diffusion coefficient. In addition, water swelling characterization of different samples was done in order to reveal the relations with the diffusion coefficient. It seems that there is an inverse resemblance between water swelling and the diffusion coefficient trends.

Nano zinc ferrite filler incorporated polyindole/poly(vinyl alcohol) blend: Preparation, characterization, and investigation of electrical properties

AbstractThe present work deals with the reinforcement and the resulting property enhancement of polyindole (PIN)/poly(vinyl alcohol) (PVA) blend using zinc ferrite (ZnFe2O4) nanoparticles. The polymer blend nanocomposite samples have been prepared using a simple in situ polymerization method. The structural changes in the polymer blend resulting from its interaction with ZnFe2O4 have been identified by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) studies. The FTIR spectra of blend nanocomposite showed the presence of ZnFe2O4 nanoparticles at 580 cm−1. The chemical interactions between the polymer and ZnFe2O4 have been confirmed by the shift in the position of FTIR peaks. The XRD results indicate the increase in the crystalline nature of the polymer blend with the incorporation of ZnFe2O4 nanoparticles into the blend. Scanning electron microscopy photographs of the nanocomposites show the dispersion of nanoparticles in PIN/PVA blend, while transmission electron microscopy images reveal the presence of spherically shaped nanoparticles in the polymer blend with an average size of 15 nm. The glass transition temperature of polymer blend composite has been shifted to a higher value, and thermal stability of the polymer blend improved with the addition of ZnFe2O4 nanoparticles. The incorporation of ZnFe2O4 nanoparticles in the PIN/PVA blend matrix leads to a significant improvement in overall mechanical properties, AC and DC conductivity. The dielectric properties are found to be higher for ZnFe2O4‐reinforced blend systems than the pure blend system due to polarization exerted by the incorporation of nanoparticles.

Selective location and migration of poly(methyl methacrylate)- grafted clay nanosheets with low grafting density in poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends

The location and migration of poly (methyl methacrylate)-grafted clay (clay-g-PMMA) nanosheets with low grafting density in a phase-separated polymer blend of poly (methyl methacrylate)/poly (styrene-co-acrylonitrile) (PMMA/SAN) was investigated. The grafting density and molecular weight for grafted PMMA chains on the surface of clay nanosheets was about 0.04 chains/nm2 and 7.8 × 104, respectively, indicating that the grafted chains might exhibit the mushroom-like distribution. With phase separation of PMMA/SAN blend matrix, the well-dispersed clay-g-PMMA nanosheets in the blend matrix were first located in the SAN-rich phase and then gradually migrated to the interface between PMMA and SAN. The first abnormal location of modified clay in the blend matrix might be attributed to the favorable interaction between clay-g-PMMA and SAN induced by the miscibility of grafted PMMA/surrounding SAN chains and the unfavorable interaction between clay-g-PMMA and PMMA without any interpenetration of grafted and matrix chains. The enhanced miscibility between grafted PMMA and surrounding SAN just began to be destroyed after being annealed for a long time, resulting in the final migration of clay-g-PMMA to the interface of PMMA/SAN (thermodynamic equilibrium state).

Multifunctional polymer materials with enhanced mechanical, thermal and gamma radiation shielding properties from dicyanate ester of bisphenol-A/bisphenol-A based benzoxazine resin and short kevlar/basalt hybrid fibers

In execution of obtaining outstanding functional materials that possess the features of advanced mechanical behaviour, high thermal resistance and enhanced gamma radiation shielding properties, this present article aimed to boost qualitatively and quantitatively the desired performances of dicyanate ester of bisphenol-A/bisphenol-A based benzoxazine resin using hybrid fibers consisting of kevlar fibers and basalt fibers. To achieve this, the desired amounts of the hybrid fibers were initially surface treated using the silane coupling agent technique and then incorporated within the blend matrix with a total weight selected to be 40 wt%. According to the mechanical results, a noteworthy increase in the flexural and impact strength properties of the reinforced hybrid composites was chiefly observed as compared to the unfilled samples’ properties. Based on the thermal stability studies, the reinforced hybrid composites also showed excellent thermal resistances. The hybrid composites’ shielding properties, which were evaluated using a Cobalt-60 (60Co) as an irradiation source, revealed outstanding gamma-radiation shielding enhancements. The scanning electron microscope confirmed that the improvements in the investigated properties were essentially ascribed to the good dispersion and interfacial adhesion of the two high-performance hybrid fibers within the blend matrix with respect to their advanced properties. Therefore, the enhanced mechanical, thermal and nuclear shielding properties promote the use of the as-developed hybrid composites in domestic and industrial applications.

Structure, morphology and dielectric properties of hexagonal boron nitride nanoparticles reinforced biopolymer nanocomposites

ABSTRACTHexagonal boron nitride nanoparticles (h-BNNPs)/Chitosan (CS)/Hydroxypropyl methylcellulose (HPMC) based ternary nanocomposites were prepared using solution casting method and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analyses (TGA), Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The dielectric properties of CS/HPMC/h-BNNP nanocomposite films were also investigated as a function of frequency and temperature and a maximum dielectric constant of ~1200 was achieved at 5 wt % of h-BNNP loading in CS/HPMC blend matrix. The results from the structural, morphological and thermal studies revealed good interactions between h-BNNPs, CS and HPMC.

Mechanical, morphological, and thermal properties of poly(vinyl chloride)/low‐density polyethylene composites filled with date palm leaf fiber

This article investigates the mechanical, morphological, and thermal properties of poly(vinyl chloride) (PVC) and low‐density polyethylene (LDPE) blends, at three different concentrations: 20, 50, and 80 wt% of LDPE. Besides, composite samples that were prepared from PVC/LDPE blend reinforced with different date palm leaf fiber (DPLF) content, 10, 20, and 30 wt%, were also studied. The sample in which PVC/LDPE (20 wt%/80 wt%) had the greatest tensile strength, elongation at break, and modulus. The good thermal stability of this sample can be seen that T10% and T20% occurred at higher temperatures compared to others blends. DPLF slightly improved the tensile strength of the polymer blend matrix at 10 wt% (C10). The modulus of the composites increased significantly with increasing filler content. Ageing conditions at 80°C for 168 h slightly improved the mechanical properties of composites. Scanning electron microscopic micrographs showed that morphological properties of tensile fracture surface are in accordance with the tensile properties of these blends and composites. Thermogravimetric analysis and derivative thermogravimetry show that the thermal degradation of PVC/LDPE (20 wt%/80 wt%) blend and PVC/LDPE/DPLF (10 and 30 wt%) composites took place in two steps: in the first step, the blend was more stable than the composites. In the second step, the composites showed a slightly better stability than the PVC/LDPE (20 wt%/80 wt%) blend. Based on the above investigation, these new green composites (PVC/LDPE/DPLF) can be used in several applications. J. VINYL ADDIT. TECHNOL., 25:E88–E93, 2019. © 2018 Society of Plastics Engineers

Enhancement of spectroscopic, thermal, electrical and morphological properties of polyethylene oxide/carboxymethyl cellulose blends: Combined FT-IR/DFT

Different ratios between polyethylene oxide (PEO) and carboxymethyl cellulose (CMC) blends were prepared through the solution casting technique. The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), dielectric spectroscopy and scanning electron microscopy (SEM) were used to investigate the blends. The XRD results confirmed the semicrystalline nature of PEO and amorphous nature of CMC, respectively. The intensity of XRD was changed with varying ratios in the blends. The FT-IR spectra of PEO/CMC blends exhibited all characteristic vibrational spectral bands with variations in their intensities depicting interaction attributed to hydrogen bond in the polymers. Density Function Theory (DFT) was utilized to study the theoretical interaction process for PEO/CMC and indicated that the prepared blends had unique hydrogen bonding. TGA curves indicated that the thermal stability of prepared blends was changed. The Coats-Refern's model was used to calculate the thermal activation energy. The AC electrical conductivity and the dielectric behaviors in these blends were studied using the dielectric relaxation at different frequencies. Argand plots showed half semicircle which depicts the Debye-type relaxation process. The morphology from the scanning electron microscope (SEM) reveals that the degree of miscibility significantly improves as CMC content increases within the PEO/CMC blend matrix.

Development of Novel Nano-ZnO Enhanced Polymeric Membranes for Water Purification

ZnO nanoparticles (NPs) were treated using three different polymers: polysulfone (PSF), polyvinylpyrrolidone (PVP), and polyvinylidene fluoride (PVDF). 10 wt% of ZnO NPs and ternary polymer-blended membrane were prepared by a simple and effective method based on ultrasonication. A highly-dispersed and stable polymeric membrane based on ZnO NPs was obtained. This polymer blended based nanocomposite (NC) has proven to have important industrial applications. The thermal stability of the pure polymer blends and ternary polymer blends/ZnO NPs was analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry. The morphology and the structural analysis of the resultant NCs were then evaluated by scanning electron microscopy, X-ray diffraction and Fourier transform-infrared spectroscopy. Molecular weight cut-off test was applied to study the rejection behavior of the membranes. The best results were achieved by PSF@PVP@PVDF–ZnO NP-incorporated membrane when the durability test was performed; it was observed that the samples were not swollen for 45 days when kept at pH 7. The experimental results showed that ZnO NPs were dispersed homogeneously in the ternary polymer blend matrix in nanoscale and enhanced the chemical and thermal stability of the membranes. Fabrication of PSF/PVP/PVDF–ZnO NP-blende membrane on glass plate using a film casting knife.

Electrospun conductive mats from PANi-ionic liquid blends

The study is focused on the production of conductive mats from polyaniline - ionic liquid (IL) blends by electrospinning. PAN was used as a binding matrix in blends. The effect of adding 3 to 40 wt.% of polyaniline salt to PAN blend was investigated on the electrical and mechanical properties of the mats. 10 wt.% of IL was used in PAN blends for improving the dispersion of PANi particles. IL increased the conductivity of the material three times, comparing with the materials without IL. The optimum concentration of polyaniline in blend was 10–12.5 wt.% to produce mechanically strong mats.

Tailoring the desired properties of dicyanate ester of bisphenol-A/bisphenol-A based benzoxazine resin by silane-modified acacia catechu particles

In this present work, silane modified acacia catechu particles (MACPs) filled dicyanate ester of bisphenol-A/bisphenol-A based benzoxazine (DCBA/BA-a) blend composites were successfully prepared by a simple and environmentally friendly solution blending method. The main focus of this study was to investigate the influence of the modified particles on the overall morphological, mechanical and thermal properties of the blend composites using various tests. The FTIR analysis confirmed the surface modification of the acacia catechu particles. Besides, it showed the nature of the chemical interactions taking place between the modified particles the resin blend. According to the mechanical results, a remarkable increase in the tensile, impact strength and microhardness properties of the reinforced blend composites was chiefly observed as compared to the unfilled samples' properties. Based on the thermal stability studies, the filled blend composites showed much enhanced thermal resistance properties. The scanning electron microscope confirmed that the improvements in the investigated properties were essentially ascribed to the good dispersion and interfacial adhesion of the modified particles within the blend matrix with respect to their advanced properties. Therefore, we supposed herein that these eco-friendly acacia catechu particles have enough potential to be utilized as alternative fillers for producing naturally friendly blend composites with tailored properties.

PLA/EVA/Teak Wood Flour Biocomposites for Packaging Application: Evaluation of Mechanical Performance and Biodegradation Properties

Mechanical properties such as tensile modulus and strength, elongation-at-break, and impact strength of poly(lactic acid)/ethylene-co-vinyl acetate copolymer (EVA, vinyl acetate content 18 weight %)/Teak wood flour (TWF) composites were evaluated at TWF volume fractions ranging from Φf = 0.1–0.32. Tensile modulus showed an initial increase up to Φf = 0.25 and the parameter decreased marginally at Φf = 0.32, however, remaining much higher than that at Φf = 0. The increase in modulus was attributed to the generation of mechanical restrains by TWF. This mechanical restrains decreased ductility of the composites which also decreased the impact strength. The composite structure was evaluated by comparing the tensile properties with predictive theories, of two-phase models. TWF decreased the thermal stability of the composite, although char yield enhanced due to decomposition of cellulosic bodies in TWF. Differential scanning calorimetry (DSC) studies indicated decrease in the crystallinity of the crystallizable component PLA in the presence of TWF particles in the polymer blend matrix. The biodegradation studies were undertaken to evaluate the biodegradation of the composite under soil burier condition.

Conductivity and free volume studies on bismuth sulfide/PVA:polypyrrole nanocomposites

The polymer composite films of polyvinylalcohol:polypyrrole blend containing different wt% of bismuth sulfide (Bi2S3) particles are prepared through in situ oxidation followed by solution casting method, where the particles are coated with blend matrix. The XRD studies affirm the enhanced crystallinity of the composites. The variation of crystallite size is measured with the Debye–Scherrer method. The DSC studies are used to investigate the glass transition that occurred in the Bi2S3 particles-filled polymer blend matrix. The AFM and SEM studies illustrated the effect of insertion of metallic sulfide particles on the surface morphology. The addition of bismuth sulfide particles results in the increased mechanical properties of the composite matrix. The electrical conductivity is determined by the Cole–Cole plot fitted using equivalent circuit model, and the conductivity is observed to be enhanced with an increase in filler content due to the enhanced conductive pathways. The variation of o-Ps lifetime, o-Ps intensity, average size of the free volume and fraction of free volume is studied using Tao–Eldrup Model. The obtained free volume parameters are correlated with the electrical, microstructural and thermal properties. The increased interfacial width is illustrated in terms of increased free volume size. The enhanced free volume provides more space for mobility of charge carriers, and hence the conductivity is enhanced.

Features of the Structure and Properties of Radiation Vulcanizates Based on Blends of Polybutadiene and Ethylene‐Propylene Diene Rubber

Polybutadiene rubber (BR) was blended with ethylene‐propylene diene (EPDM) rubber on rubber mill with different weight ratios (100/0‐70/30‐50/50‐30/70‐0‐100), then application of gamma rays at different irradiation doses from 25 up to 150 kGy to induce crosslinking. Mechanical, physio‐chemical, and characterization of prepared blends are to be followed up as functions of the blend composition and the radiation absorbed dose. Mechanical properties like tensile strength (TS), elongation at break (Eb), and tensile modulus (M100) were increased with increasing content of EPDM in blend composition. On the other hand, TS and M100 increased with radiation dose, whereas the value of Eb decreased with radiation dose. Physico‐chemical properties like gel fraction and volume fraction of rubber in swollen gel (Vr) increased with increasing the content of EPDM rubber in blend formulation while the swelling ratio and soluble fraction decreased with increasing content of EPDM. On the other hand, the Vr increased with radiation dose, whereas the values of soluble fraction and selling ratio (Q) decreased with radiation dose. Fourier transforms‐infrared measurements confirmed the compatibility between BR and EPDM rubber moieties in the blend matrix. J. VINYL ADDIT. TECHNOL., 25:E64–E72, 2019. © 2018 Society of Plastics Engineers