Hybridization of graphene-reinforced two polymer nanocomposites

This article focuses on the hybridization of thermoplastic polymer matrices with conducting polymers and graphene derivatives.Polypropylene(PP),polymethylmethacrylate(PMMA)and polyox-ymethylene(POM)were used as primary polymer matrices and polypyrrole(PPY)and polyaniline(PANI)as secondary conducting polymers.Highly conductive-reduced graphene oxide(rGO)and graphene(G)have been used as reinforcements.A Taguchi analy-sis has been performed for the blends to find the optimal combi-nation of the blends with respect to electrical conductivity(σ)and mechanical properties.Both electrical and mechanical properties were improved by the hybridization process.The maximum elec-trical conductivity of 0.85 S.cm^(−1) has been acquired with POM/PPY/G blend with 3 wt.%and 5 wt.%of PPY and graphene load-ing,respectively.The mechanical properties have been found to improve with all the blends but,PP/PPY/G blend with 3 wt.%and 6 wt.%of PPY and graphene loading displays overall better prop-erties in comparison with other blends.

Mechanical characterization of functional graphene nanoplatelets coated natural and synthetic fiber yarns using polymeric binders

Fabrication of electrically conductive yarns(glass,flax and polypropylene fibers)coated with graphene nanoparticles(GNP)were characterized for their mechanical properties and compared with their electrical properties.The composites were produced with the use of polymeric binders(epoxy resin and thermoplastic starch)and two different dipcoating methodologies were developed to create the coating layers.Technique-1 involved coating of binder and then GNP layer whereas Technique-2 had a mixture of binder and GNP in the predetermined ratio,which was coated on the yarns.The mechanism of adhesion varies or influences on a number of factors such as the nature of the fiber surface,coating method and effective binder.Tensile properties of the yarns were measured by an appropriate standard,and the highest tensile strength was noticed with epoxy-based glass fiber samples as 222 MPa followed by flax fiber samples as 206 MPa.The composites of starch-based showed poor mechanical performance compared to those of epoxy ones.This was due to poor adhesion between the surface and starch layer(interphase)where the Van der Wall’s force was quite low.Electrical conductivity,glass fiber yarns with epoxy binder were identified to have the highest electrical conductivity of 0.1 S.cm−1 among other samples.

Electrical conductivity of the graphene nanoplatelets coated natural and synthetic fibres using electrophoretic deposition technique

Herein,electrically conductive natural and synthetic yarns through electrophoretic deposition(EPD)technique were fabricated.A parametric study on the conductivity enhancement of the yarns is carried out by Taguchi method.Using this method,the desirable conditions are determined by studying the effects of important parameters on the electrical conductivity of the yarns in the EPD coating process.Based on the L18 design of experiments table,the preferred combination of factors to obtain the highest electrical conductivity of the yarns is found by Taguchi analysis.In addition,the Pareto ANOVA analysis is conducted to identify the major contributing factors on the electrical conductivity of the yarns.Characterisation techniques,such as scanning electron microscopy(SEM),Fourier transformed infrared spectroscopy(FTIR)in attenuated total reflectance(ATR)mode,and thermogravimetric analysis(TGA)are utilised for better understanding the microstructure and physical properties.When powered by only 3 V,the maximum temperature of a Joule heated conductive sample based on natural fibre yarns reached 102°C in less than 25 s.

Study of thermal, flammability and mechanical properties of intumescent flame retardant PP/kenaf nanocomposites

Detrimental physical and mechanical properties are common pro-blems for composites when their flame retardancy is improved through filler additions.An increased interest of the synergistic nanoparticle addition to improve the flame retardancy of natural fiber composites is the aim of this work.The paper investigates the synergistic effect of two different nanoparticles(halloysite nano-tubes(HNTs)and montmorillonite(MMT)nanoclay)on the flame and mechanical properties in an intumescent ammonium poly-phosphate(APP)-based polypropylene(PP)/kenaf composite sys-tem.First,the nature of nanoparticle dispersion in PP through X-ray diffraction(XRD)and transmission electron microscopy(TEM)reveals that under twin screw compounding process,the partial exfoliation and intercalation have taken place within the nano-composites.An increase in the decomposition temperature was observed under thermogravimetric analysis(TGA),with the pre-sence of HNT.However,MMT tends to lower the maximum decomposition temperature under inert atmosphere.The flamm-ability analysis in an intumescent flame retardant(IFR)system shows that the suitable amount of high aspect ratio nanoparticles with their exfoliation characteristics effectively helps to reduce the sustained combustion.Even though,improved stiffness properties can be observed with the presence of increased filler content,particle agglomeration tends to reduce the mechanical strengths of these composites due to low compatibilization and crack propagation.