Non-polar Matrix Research Articles

Self-Assembly of Charged Diblock Copolymers with Reduced Backbone Polarity

Charged block copolymers that can self-assemble into a host of nanostructures offer a great opportunity as next-generation battery electrolytes with outstanding ionic conductivity and mechanical robustness. The impact of ions on the self-assembly of charged block copolymers, however, remains to be fully understood. In this article, we report the phase behavior of charged-neutral block copolymers where a relatively nonpolar matrix was employed in the charged block to boost the strength of electrostatic interaction. The phase behavior was established using small-angle X-ray scattering (SAXS). We found that the overall shape of the phase boundary between ordered and disordered states is asymmetric, tilting toward the charged block-lean side of the phase portrait. However, the composition windows of the ordered phases, such as lamellae and hexagonally packed cylinders observed in this study, are comparable to those of neutral diblock copolymers and are not obviously affected by the incorporation of charges. The results obtained in this work provide insight into the impact of ions on the self-assembly of charged block copolymers as well as the design of nanostructured polymer electrolytes.

The Role of Coupling Agents in the Mechanical and Thermal Properties of Polypropylene/Wood Flour Composites

This work is a collaborative effort between academia and industry to promote the development of new sustainable and profitable materials for manufacturing products. Incorporating wood flour particles (WF) in polypropylene (PP) grants environmental advantages in developing products that use renewable resources to manufacture PP/WF composites using the melt intercalation process. However, the interaction between a hydrophilic strengthening phase (wood flour) with a nonpolar polymer matrix (PP) is poor, resulting in deficient mechanical performance. This investigation details the use of graft and masterbatch coupling agents to evaluate their effects on mechanical parameters. The low compatibility between the constituents favors increasing the composites’ thermal properties because the reinforcing phase acts as a nucleating agent. PP showed typical mechanical behavior, with a marked necking and a wide deformation capacity of approximately 180%. The mechanical behavior of the PP/WF composites revealed an elastic region followed by a termination after their yield point, shortening the stress–strain curves and reducing their ductility at strain values of approximately 2–4%. Graft coupling agents have better intermolecular performance with PP than masterbatch coupling agents. The modulus of elasticity of the composites increased to around 82% relative to PP. Processing methods influenced the thermal properties of the composites. The melt-blending process promoted molecular orientation, while injection molding erased the thermomechanical history of the extruded pellets. The melting temperature was similar in the composites, so there was no evidence of thermal degradation. The results showed that the coupling agents favor the crystallinity of the PP over tensile strength. SEM observations showed insufficient adhesion between the WF and PP, which promotes a reduction in stress transfer during tensile testing. The WF particles act as fillers that increase the stiffness and reduce the ductility of composites.

Effect of palm oil as plasticizer for compounding polar and non-polar rubber matrix reinforced carbon black composites

Effect of palm oil as plasticizer for compounding polar and non-polar rubber matrix reinforced carbon black composites

Understanding the aggregation of excitation wavelength independent emission of amphiphilic carbon dots for bioimaging and organic acid sensing

Herein, excitation wavelength-independent, tunable emissive and amphiphilic CDs with high quantum yield were synthesized by a low-temperature oxidation method employing banana peel waste as a carbon source. These CDs showed longer wavelength emissions (green to yellow) independent of the excitation wavelength when dispersed in different polar to non-polar solvents. The quantum yields of the same CDs were 9–32% in different solvent polarities for different emissions. On the other hand, a large stokes-shifted emission (∼9606 cm−1) was observed for CDs in the non-polar and weak polar solvents. The particle size of CDs increases from a hydrophobic to a hydrophilic environment with the change in emission colour from yellow to green. A polar and a non-polar host matrix were used to overcome the limitation of aggregation-caused quenching of CDs in the solid state to obtain bright emissions. These CDs were potentially used for naked-eye detection of trifluoroacetic acid (TFA) by changing the emission colour from yellow to orange under UV 365 nm. Sensing of TFA was also shown reversibly switch emission colour and average lifetime for multiple cycles. Additionally, the highly emissive CDs show negligible cytotoxicity in 3T3 fibroblast cells, indicating possible bioimaging applications in 3T3 cells.

Hydrophobization of nanodiamond for polypropylene nanocomposites

Purified and de-aggregated nanodiamonds (ND) synthesized by detonation of explosives provide high surface to volume ratio and unique modification opportunities of their surface groups. In general, ND possesses polar groups, therefore, easily forms agglomerates in non-polar polymer matrix. In this study, the effects of hydrophobization of ND on the structure and the properties of polypropylene (PP) nanocomposites were investigated. Long alkyl chains of octadecyl amine (ODA) were introduced on the surface of ND with the substitution ratio of 68 %. The structural study showed that the dispersibility of ND was remarkably improved by the hydrophobization so that the PP/ND-ODA nanocomposites showed higher transparency than that of the PP/ND nanocomposites. The increased crystallinity of PP in the nanocomposites indicates that ND and ND-ODA acted as crystallization nuclei in the nanocomposites. As for the mechanical properties, the increased Young's modulus of PP/ND nanocomposites was further increased by the addition of ND-ODA. The Young's modulus of the nanocomposites with 0.5 wt% ND-ODA was 64 % higher than that of PP. The strong reinforcement effects also appeared as high heat resistances of the nanocomposites.

Superconductivity enhancement in polar metal regions of Sr0.95Ba0.05TiO3 and Sr0.985Ca0.015TiO3 revealed by systematic Nb doping

Two different ferroelectric materials, Sr0.95Ba0.05TiO3 and Sr0.985Ca0.015TiO3, can be turned into polar metals with broken centrosymmetry via electron doping. Systematic substitution of Nb5+ for Ti4+ has revealed that these polar metals both commonly show a simple superconducting dome with a single convex shape. Interestingly, the superconducting transition temperature Tc is enhanced more strongly in these polar metals when compared with the nonpolar matrix Sr(Ti, Nb)O3. The maximum Tc reaches 0.75 K, which is the highest reported value among the SrTiO3-based families to date. However, the Tc enhancement is unexpectedly lower within the vicinity of the putative ferroelectric quantum critical point. The enhancement then becomes much more prominent at locations further inside the dilute carrier-density region, where the screening is less effective. These results suggest that centrosymmetry breaking, i.e., the ferroelectric nature, does not kill the superconductivity. Instead, it enhances the superconductivity directly, despite the absence of strong quantum fluctuations.

Tunable Van der Waals interfacial interaction for ultrahigh-damping rubber bends

High-damping rubber materials are of crucial significance for realizing high-performance green tire due to their contributions in noise and vibration reduction, auto-braking, and service life. However, the polarity difference and mismatched surface energy significantly reduce the interfacial interaction and compatibility between non-polar tread rubber materials and polar polymers. Herein, we fabricated a multi-functionalization high vinyl polybutadiene rubber (MFHVBR)/ethylene-vinyl acetate rubber (EVM) blend by simple mechanical blending. The incorporation of polar functional groups could increase the surface energy of MFHVBR, which was beneficial for regulating the interfacial compatibility and van der Waals interaction between non-polar rubber matrix and polar polymer matrix. A quantitative correspondence between van der Waals interaction and damping properties was determined. The optimized MFHVBR/EVM blends showed ultrahigh damping properties with an effective damping temperature range of −12.4–62.6 °C, which totally covered the service temperature of tires. The effective damping temperature range width of 75 °C was among the highest value of reported high-damping rubber materials. Meanwhile, the vulcanization efficiencies and physical mechanical properties were obviously improved. Collectively, the developed strategy herein and the proposed surface energy-performance relationship suggest a feasible pathway toward low-cost and high-performance green tire tread rubber materials.

Ferroelectric-Relaxor Crossover and Energy Storage Properties in Sr2NaNb5O15-Based Tungsten Bronze Ceramics.

Filled and unfilled Sr2NaNb5O15-based tungsten bronze ceramics based on Gd doping were prepared using a traditional solid-state reaction method. Relaxor behaviors of the two different systems were analyzed, and the corresponding energy storage performance was also characterized. With the support of weakly coupled polar nanoregions and a non-polar matrix, an energy storage density of 2.37 J/cm3 and an efficiency of 94.4% were obtained in the Sr1.82Gd0.12NaNb5O15 ceramic. A discharge energy density of 2.51 J/cm3 and a power density of 59.1 MW/cm3 further proved its prospect for practical applications. In addition, the thermal stability and fatigue resistance of the ceramic were also evaluated. At the same time, under the theoretical framework of a perovskite and tungsten bronze, the contribution of vacancies to the local structure and relaxor behavior was briefly discussed. Because the currently used ceramics do not contain easily reducible metal oxides, this work lays the foundation for the development of multilayer ceramic capacitors that use base metals as internal electrodes.

A review on the enhancement of composite’s interface properties through biological treatment of natural fibre/lignocellulosic material

Natural fibre or lignocellulosic fibres have aroused the attention of scientists in the polymer industry, given their eco-friendly, low density, and biodegradability. Nevertheless, the major obstacle to wide commercial applications is the incompatibility between polar natural plant fibres with non-polar polymer matrix due to different chemical constitutions. Therefore, surface treatment of natural fibres before they are implemented to prepare fibre-reinforced composites is considered. Chemical and physical treatments are not preferred as it involves hazardous chemicals and high energy consumption. This review article provides an overview of various environmentally friendly approaches, such as introducing bacterial nanocellulose, pre-treatment with bacterial cellulase, fungal treatment, and enzymatic treatments aimed to treat natural fibres. The implications of working mechanisms on the characteristics of fibre itself and polymer composites with reinforcement are reviewed. The application of treated fibres reinforced composites and comparison of biological treatment with other treatments are discussed in this article. It is evidenced that fibre that undergoes biological modifications facilitates better fibre-matrix interfacial adhesion, has stronger mechanical bonding with the matrix, along with the reduction of water uptake of the composites.

The Effect of Varying the Amount of Short Hemp Fibers on Mechanical and Thermal Properties of Wood-Plastic Composites from Biobased Polyethylene Processed by Injection Molding.

Biobased HDPE (bioHDPE) was melt-compounded with different percentages (2.5 to 40.0 wt.%) of short hemp fibers (HF) as a natural reinforcement to obtain environmentally friendly wood plastic composites (WPC). These WPC were melt-compounded using a twin-screw extrusion and shaped into standard samples by injection molding. To improve the poor compatibility between the high non-polar BioHDPE matrix and the highly hydrophilic lignocellulosic fibers, a malleated copolymer, namely, polyethylene-graft-maleic anhydride (PE-g-MA), was used. The addition of short hemp fibers provided a remarkable increase in the stiffness that, in combination with PE-g-MA, led to good mechanical performance. In particular, 40 wt.% HF drastically increased the Young’s modulus and impact strength of BioHDPE, reaching values of 5275 MPa and 3.6 kJ/m2, respectively, which are very interesting values compared to neat bioHDPE of 826 MPa and 2.0 kJ/m2. These results were corroborated by dynamic mechanical thermal analysis (DMTA) results, which revealed a clear increasing tendency on stiffness with increasing the fiber loading over the whole temperature range. The crystal structure was not altered by the introduction of the natural fibers as could be seen in the XRD patterns in which mainly the heights of the main peaks changed, and only small peaks associated with the presence of the fiber appeared. Analysis of the thermal properties of the composites showed that no differences in melting temperature occurred and the non-isothermal crystallization process was satisfactorily described from the combined Avrami and Ozawa model. As for the thermal degradation, the introduction of HF resulted in the polymer degradation taking place at a higher temperature. As for the change in color of the injected samples, it was observed that the increase in fiber generated a clear modification in the final shades of the pieces, reaching colors very similar to dark woods for percentages higher than 20% HF. Finally, the incorporation of an increasing percentage of fibers also increased water absorption due to its lignocellulosic nature in a linear way, which drastically improved the polarity of the composite.

Comparing C2=O and C2=S Barbiturates: Different Hydrogen-Bonding Patterns of Thiobarbiturates in Solution and the Solid State.

Carbonyl-centered hydrogen bonds with various strength and geometries are often exploited in materials to embed dynamic and adaptive properties, with the use of thiocarbonyl groups as hydrogen-bonding acceptors remaining only scarcely investigated. We herein report a comparative study of C2=O and C2=S barbiturates in view of their differing hydrogen bonds, using the 5,5-disubstituted barbiturate B and the thiobarbiturate TB as model compounds. Owing to the different hydrogen-bonding strength and geometries of C2=O vs. C2=S, we postulate the formation of different hydrogen-bonding patterns in C2=S in comparison to the C2=O in conventional barbiturates. To study differences in their association in solution, we conducted concentration- and temperature-dependent NMR experiments to compare their association constants, Gibbs free energy of association ∆Gassn., and the coalescence behavior of the N-H‧‧‧S=C bonded assemblies. In Langmuir films, the introduction of C2=S suppressed 2D crystallization when comparing B and TB using Brewster angle microscopy, also revealing a significant deviation in morphology. When embedded into a hydrophobic polymer such as polyisobutylene, a largely different rheological behavior was observed for the barbiturate-bearing PB compared to the thiobarbiturate-bearing PTB polymers, indicative of a stronger hydrogen bonding in the thioanalogue PTB. We therefore prove that H-bonds, when affixed to a polymer, here the thiobarbiturate moieties in PTB, can reinforce the nonpolar PIB matrix even better, thus indicating the formation of stronger H-bonds among the thiobarbiturates in polymers in contrast to the effects observed in solution.

Synergistic Effect of Fe2O3/NC-Gdl Interlayer and Partially Exfoliated Carbon Nanotubes/Sulfur Cathode for Efficient Polysulphide Confinement in High Performance Lithium–Sulfur Batteries

Lithium sulfur batteries have gained considerable research interest for electric vehicles and portable electronic devices due to their high theoretical energy density (2600 Wh/Kg) compared to existing metal ion batteries. In addition, the low cost, high abundance and high theoretical specific capacity (1675 mAh/g) of sulfur have made Li-S batteries to be the potential replacement for lithium ion batteries. However, the low electrical conductivity of sulfur (5 × 10−30 S/cm), Li2S, low sulfur loading (<70%) at the composite cathode, large volume expansion during S to Li2S conversion and multistep reduction of sulfur to lithium polysulphides (LPS) act as the prohibitor for the commercialization. Elemental sulfur undergoes a various structural variation during the charge–discharge and forms soluble higher order lithium polysulfides Li2S n (8 ≤ n ≤ 3) and lower order insoluble sulfides Li2S2/Li2S in liquid. The poor conductivity of the intermediates formed and their structural changes result in high polarization. Also, the consecutive shuttling of the soluble polysulfides between the anode and cathode results in reoxidation at the cathode and further leads to capacity fading of the Li-S battery. To mitigate these, researchers have developed several types of conducting carbon matrix i.e., acetylene black, super P, carbon nanotubes, graphene, carbon paper etc. However, due to poor interaction of polar polysulfides with non-polar carbon matrix, polysulfide migrates into the electrolyte and increases the shuttle effect. Metal oxides (TiO2, Fe2O3 , MgO, Co3O4, SiO2) based interlayer though offer abundant polar active sites for polysulfides adsorption, but suffers from low electrical conductivity and high binding energy between oxides and sulphides, which results degradation in the electrochemical performance. Hence optimization of oxide interlayers are necessary to increase the performance of Li-S batteries.So, in our work, further to minimize the LPS confinement and conversion, we have proposed an efficient cathode where partially exfoliated carbon nanotubes are used as sulfur host. Due to the high surface area, and high electrical conductivity, it serves as an efficient cathode material with high sulfur loading (>75%) and results in high sulfur utilization. In addition, we have also considered the effect of polar sites and designed Fe2O3/NC nanoparticles coated on the polytetrafluoroethylene ethylene coated carbon paper (GDL paper) as interlayer between separator and cathode, which can efficiently adsorb the polysulphides and effectively mitigates the shuttling effect due to the active polar sites and oxygen vacancy. From our electrochemical studies, we have observed with PECNT/S cathode without interlayer initial discharge capacity of 900 mAh/g can be obtained at 0.1 C rate. However, with only GDL interlayer this capacity increases to ~1400 mAh/g. Further, on coating of Fe2O3/NC nanoparticles on GDL paper the capacity can further be enhanced and reached to 1610 mAh/g. For GDL-Fe2O3/NC interlayer better reversibility and faster charge transfer kinetics are confirmed from the CV curves. Cyclic stability of 500 cycles is carried out for PECNT/S, PECNT/S/GDL and PECNT/S/GDL- Fe2O3/NC at 0.5 C rate. ~80% of initial capacity retention can be obtained even after 500 cycles. This substantiate that with PECNT/S and GDL-Fe2O3/NC as cathode and interlayer respectively can synergistically result in a high capacity and stable lithium-sulfur batteries.

Improving LC-MS analysis of human milk B-vitamins by lactose removal

Our previously reported, first validated, UPLC-MS/MS-based simultaneous analysis of five human milk B-vitamins revealed severe matrix effects. High levels of endogenous lactose fouled the electrospray ionization source affecting the analysis. We evaluated solid-phase extraction (SPE), liquid–solid extraction (LSE), protein precipitation (PPT), and liquid chromatography effluent diversion for lactose-removal. SPE failed to separate lactose from vitamins; LSE using 2-propanol reduced lactose and vitamin recoveries. PPT-solvent, milk volume, and reconstitution solvent influenced flavin adenine dinucleotide, pyridoxal and nicotinamide recoveries. Using an optimized LC-gradient enabled chromatographic separation of lactose from vitamins and its removal using a post-column switch-valve. Only 40 µL milk was subjected to methanol-PPT and non-polar matrix removal by methyl tert-butyl ether. B-vitamin recoveries were established (81.9–118.6%; CV ≤ 11.9%; precision: 4.9–13.7%) with greatly reduced matrix effects, and improved process efficiency, and recovery.

Basic Study of Extensional Flow Mixing for the Dispersion of Carbon Nanotubes in Polypropylene by Using Capillary Extrusion

Abstract This study evaluated the mixing effect of simple uniaxial extensional flow for the dispersion of multiwalled carbon nanotubes (MWCNTs) into polypropylene (PP) as a nonpolar matrix. An only converging flow allowed for a high strain rate and was suitable for the compounding process. The extensional flow was characterized from the entrance pressure drop (ΔP0) at the converging section. Thus, in this study, capillary extrusion was employed to generate uniaxial extensional flow. Based on the hypothesis that the dispersion of nanofillers depends on the magnitude of flow-induced stress, ΔP0, which related to extensional stress, was measured directly during capillary extrusion by using an orifice die. The influences of the mass flow rate and the hole diameter in the orifice die, which affected ΔP0, on the extrusion of PP nanocomposites with an MWCNT loading of 1.0 wt.% were studied. The extruded samples were collected, and the dispersion state was evaluated based on the melt viscoelastic properties, volume resistivity, and morphological observations by optical microscopy (OM) and transmission electron microscopy (TEM). The agglomeration area of the MWCNTs decreased with higher ΔP0 (higher mass flow rate and smaller hole diameter), which increased the uniformity of the dispersion. Moreover, the influence of the length-to-diameter (L/D) ratio of the hole in the capillary die on the dispersion state of the MWCNTs was investigated. A higher L/D ratio of the capillary die did not improve the dispersion state, although shear and extensional stresses were provided.

NaNbO3‐(Bi0.5Li0.5)TiO3 Lead‐Free Relaxor Ferroelectric Capacitors with Superior Energy‐Storage Performances via Multiple Synergistic Design

AbstractRelaxor ferroelectric (FE) ceramic capacitors have attracted increasing attention for their excellent energy‐storage performance. However, it is extremely difficult to achieve desirable comprehensive energy‐storage features required for industrial applications. In this work, very high recoverable energy density Wrec ≈ 8.73 J cm–3, high efficiency η ≈ 80.1%, ultrafast discharge rate of &lt;85 ns, and temperature‐insensitive high Wrec and η (Wrec ≈ 5.73 ± 4% J cm–3, η ≈ 75 ± 6%, 25–200 °C) are simultaneously obtained in 0.68NaNbO3‐0.32(Bi0.5Li0.5)TiO3 relaxor FE ceramics by introducing various polarization configurations in combination with microstructure modification. The structure mechanism for the excellent energy‐storage performance is disclosed by analyzing in situ structure evolution on multiple scales during loading/unloading by means of transmission electron microscopy and Raman spectroscopy. Both local regions consisting of different‐scale polar nanodomains and a nonpolar matrix, and local orthorhombic symmetry remaining with electric fields ensure a linear‐like polarization response within a wide field and temperature range owing to significantly delayed polarization saturation. The stabilization of orthorhombic FE phases rather than antiferroelectric orthorhombic phases in NaNbO3 after adding (Bi0.5Li0.5)TiO3 is also explored by means of X‐ray diffraction, dielectric properties, and selected area electron diffraction. In comparison with antiferroelectric ceramics, NaNbO3‐based relaxor FE ceramics provide a new solution to successfully design next‐generation pulsed power capacitors.

Development and Characterization of Environmentally Friendly Wood Plastic Composites from Biobased Polyethylene and Short Natural Fibers Processed by Injection Moulding.

Environmentally friendly wood plastic composites (WPC) with biobased high density polyethylene (BioHDPE) as the polymer matrix and hemp, flax and jute short fibers as natural reinforcements, were melt-compounded using twin-screw extrusion and shaped into pieces by injection molding. Polyethylene-graft-maleic anhydride (PE-g-MA) was added at two parts per hundred resin to the WPC during the extrusion process in order to reduce the lack in compatibility between the lignocellulosic fibers and the non-polar polymer matrix. The results revealed a remarkable improvement of the mechanical properties with the combination of natural fibers, along with PE-g-MA, highly improved stiffness and mechanical properties of neat BioHDPE. Particularly, hemp fiber drastically increased the Young’s modulus and impact strength of BioHDPE. Thermal analysis revealed a slight improvement in thermal stability with the addition of the three lignocellulosic fibers, increasing both melting and degradation temperatures. The incorporation of the fibers also increased water absorption due to their lignocellulosic nature, which drastically improved the polarity of the composite. Finally, fire behavior properties were also improved in terms of flame duration, thanks to the ability of the fibers to form char protective barriers that isolate the material from oxygen and volatiles.

Influence of Microwave on the Structure and Properties of Nanomodified Fluoroplastic

Polymers modified with carbon nanomaterials exhibit enhanced electrical conductivity. The modifier, which is qualitatively distributed in the polymer matrix, actively absorbs microwave waves even with an extremely small introduced volume (up to 1.5 mass parts). Photographs obtained by scanning electron microscopy indicate a uniform distribution of carbon nanotubes in the matrix of fluoroplastic 4. The microwave treatment of the obtained composites showed a significant increase in the temperature of the samples with a heating time of up to 100 sec. even with minimal amounts of modifier added. Strength characteristics for a uniaxial plant of modified materials after microwave increase by 40-50%. The obtained modified materials based on a non-polar polymer matrix have enhanced characteristics of absorption of microwave radiation.

INTRODUCING BIOBASED NONPOLAR BOTTLEBRUSH β-MYRCENE SEGMENTS TO IMPROVE SILICA DISPERSION FOR SUSTAINABLE SSBR/SILICA NANOCOMPOSITES

ABSTRACTTo overcome the problem of fossil fuel depletion and associated environmental issues arising from the use of tire tread elastomers, a convenient, environmentally friendly, and highly efficient strategy was developed to prepare high-performance green solution polymerized styrene–butadiene rubber (SSBR)/silica nanocomposites by improving silica dispersion in the nonpolar polymer matrix via the introduction of a biobased nonpolar bottlebrush segment with two double bonds. Various elastomers containing biobased nonpolar bottlebrush β-myrcene segments were synthesized using an industrially robust anionic polymerization method. Results of rubber process analysis, small-angle X-ray scattering, scanning electron microscopy, and transmission electron microscopy revealed that rubber with myrcene could significantly improve silica dispersibility and inhibit the strong filler–filler interactions, which are due to the formation of hydrogen bonding between the double bonds in the myrcene block and silanol groups on the silica surface and possibly to the spreading or infiltrating of myrcene bottlebrush segments onto silica. Furthermore, for the modified rubber, rolling resistance decreased by 41.7%, tear strength increased by 20.78%, and tensile strength increased by 77.8% with the elongation at break remained practically unchanged as compared with the unmodified silica/SSBR composite. On the basis of aforementioned assessment, we believe that silica-reinforced β-myrcene–based styrene–butadiene integrated rubber is a versatile and promising candidate for future tire tread elastomers.

Effect of carbon black and graphene on the performance of EPDM rubber composites: A short review

Ethylene Propylene Diene Monomer (EPDM) rubber is for major used in engineering and many technical works and its application like automobile, constructions, electronic industries, and electric and many more. Industries commonly EPDM use for making the rubber inlet/outlet hoses for car and other vehicle. EPDM rubber properties are like good weather resistance ability as well as heat ozone. The resistance of steam is outstanding. EPDM rubber commonly is used for seals in automobile area. In the present review paper, different hardness of EPDM has been discussed on the basis of mixing or adding different proportion of graphene and carbon black (CB) and other additives. Also discussed how improve the performance of EPDM using silica and graphene and titanium dioxide and other additives and synergistic effect of graphite nanotubes on EPDM nanotubes. Effect of graphene on non-polar and polar rubber matrix also discussed with mechanical behaviour of EPDM.

External electric and magnetic field effects on the polaron in a wurtzite nitride nanowire embedded in a nonpolar matrix

We examine the Frohlich polaron problem in wurtzite nitride cylindrical nanowire embedded in a nonpolar matrix within the framework of the Lee–Low–Pines variational approach. The effects of the external electric and magnetic fields and quantum-size confinement on polaron self-energy and effective mass due to electron interactions with both quasiconfined and interface optical phonons are investigated. The numerical results obtained for wurtzite GaN material are discussed in comparison with the zinc-blende structure cylindrical nanowires. The estimation of contributions of different phonon modes reveal that interface optical phonons are much more important in narrow wires. It is found that the electric field has a relatively pronounced influence on the polaron self-energy and effective mass, while the effect of the magnetic field is small. The obtained results will be of importance in further study of the phonon-assisted electro-optical properties in wurtzite semiconductor low-dimensional structures.