Muhammad Shahid

High density polyethylene (HDPE) is a flexible, chemically resistant, and translucent thermoplastic, commonly used in the manufacturing of piping, plastic bottles, containers, toys, grocery bags, and many household items. However, its poor weathering property, non‐biodegradability, and high flammability have restricted its use in modern advanced engineering applications. In this research, ceramic‐based lyophilized sepiolite clay has been used as a functional filler to improve the mechanical and thermal properties of HDPE. The incorporation of only 4 wt.% loading of modified sepiolite clay in HDPE has successfully decreased the burning rate up to 35.41%, while increasing the tensile strength up to 30%. Structural elucidation of neat HDPE and fabricated nanocomposite samples was carried out using FTIR analysis. Morphological investigations were carried out using SEM, which depicted the successful exfoliation and the uniform dispersion of the modified sepiolite clay in HDPE with the help of twin screw extruder. The filler was successfully embedded in the polymer matrix using the solvent‐free, melt extrusion process followed by hot pressing, which resultantly improved thermal stability, mechanical, and physiochemical properties of the fabricated nanocomposites, as demonstrated in SEM, TGA, DSC, tensile strength, and DMA results.

The zeolitic imidazolate framework-67 (ZIF-67) adsorbent and its composites are known to effectively remove organic dyes from aqueous environments. Here, we report a unique crystalline MoS₂@ZIF-67 nanocomposite adsorbent for the efficient removal of methyl orange (MO) dye from an aqueous medium. In situ synthetic techniques were used to fabricate a well-crystalline MoS₂@ZIF-67 nanocomposite, which was then discovered to be a superior adsorbent to its constituents. The successful synthesis of the nanocomposite was confirmed using XRD, EDX, FTIR, and SEM. The MoS₂@ZIF-67 nanocomposite exhibited faster adsorption kinetics and higher dye removal efficiency compared with its constituents. The adsorption kinetic data matched well with the pseudo-second-order model, which signifies that the MO adsorption on the nanocomposite is a chemically driven process. The Langmuir model successfully illustrated the MO dye adsorption on the nanocomposite through comparing the real data with adsorption isotherm models. However, it appears that the Freundlich adsorption isotherm model was also in competition with the Langmuir model. According to the acquired thermodynamics parameters, the adsorption of MO on the MoS₂@ZIF-67 nanocomposite surface was determined to be spontaneous and exothermic. The findings of this research open an avenue for using the MoS₂@ZIF-67 nanocomposite to efficiently remove organic dyes from wastewater efflux.

Flame retardancy is the property that is highly demanded when it comes to deal with plastics in different industries. In this research general purpose polystyrene (GPPS) and modified sepiolite clay are melt blended together to fabricate flame retardant nanocomposites. Structural analysis were performed with the help of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. Morphological analysis of the fabricated nanocomposites were carried out using scanning electron microscope (SEM). As a result of better clay dispersion in polymer matrix and intermolecular interactions, mechanical properties are also improved. The standard procedure (ASTM D4986-20) was followed for observing the flame retardancy of the fabricated nanocomposites. Tangible decrease is noted upto 48% in burning rate of the optimum sample which reflects improvement in flame retardancy.

Thermal conductivity (TC) and thermal stability are the basic requirements and highly desirable properties in thermal management, heat storage and heat transfer applications. This work is regarding the fabrication of polystyrene/boron nitride composites and melt extruded to produce good thermal stability, increased thermal conductivity and enhanced mechanical properties. Our strategy is potentially applicable to produce thermally conductive composites of low cost over large scale. Boron nitride powder is bath sonicated in 10% NH₃ solution to avoid its agglomeration and tendency toward entanglement in a polymer matrix. An approximately 67.43% increase in thermal conductivity and 69.37% increase in tensile strength as well as 56 multiple increases in thermal stability of the optimum samples were achieved. The developed polymeric composites are potentially applicable in the electronic industry, especially in electronic devices used for 5G, heat sink and several other aviation applications.

Textiles-fibres, yarns and fabrics are omnipresent in our daily lives, with unique mechanical properties that fit the design specifications for the tasks for which they are designed. The development of yarns and fabrics with negative Poisson’s ratio (NPR) is an area of current research interest due to their potential for use in high performance textiles (e.g., military, sports, etc.). The unique braiding technology of interlacement for preparation of braided helically wrapped yarns with NPR effect with later development of auxetic woven fabric made it possible to avoid the slippage of the wrapped component from the core. The applied geometrical configuration and NPR behaviour of the braided helical yarn structure with seven different angles comprising of monofilament elastomeric polyurethane (PU) core with two wrap materials that include multifilament ultra-high molecular weight polyethylene (UHMWPE) and polyethylene terephthalate (PET) fibres were investigated and analysed. The mechanically stable 2D woven textile auxetic fabrics (AF) with various weave patterns such as 2/2 matt and 3/1 twill were developed from the auxetic yarn with PU elastomer core having maximum NPR effect of −1.70 using lower wrapped angle of 9° to study and compare their mechanical responses. The auxetic yarn was used in weft direction and multifilament UHMWPE yarn in warp direction, using semi-automatic loom. Auxeticity of AF was analysed and its various mechanical properties such tensile strength, impact energy absorption, in-plane, and out-of-plane auxeticity, and puncture resistance were studied. Higher energy absorption of 84 Nm for matt fabric was seen compared to twill fabric having an energy of 65 Nm. The puncture resistance capability of matt fabric was better than twill fabric. While twill fabric exhibited better auxetic effect in both in-plane and out-of-plane mode compared to matt fabric. In short, both the twill and matt design AF’s showed unique characteristics which are beneficial in making various protective textiles such as protective helmets, bullet proof shields, cut resistance gloves, blast resistant curtains, and puncture tolerant elastomeric composites.

The investigation of Corrosion inhibition behavior of synthesized amino acid-based Schiff base inhibitor [(E)-5-nitro-N1-((E)-3-phenylallylidene) benzene-1,2-diamine] was carried out. Its adsorption in two types of (5%) soil solutions was studied at room temperature, using potentiodynamic polarization and gravimetric techniques. The inhibition efficiency obtained at the optimum inhibitor concentration (300ppm), were 23% in acidic and 70% in neutral electrolyte. Results illustrated that the inhibitor worked well in less acidic environment in one of the soil solutions which was relatively acidic than the other. Experimental data of potentiodynamic study also indicated that the inhibitor was more inclined to adsorb on the anodic sites of the carbon steel sample, thus the inhibitor can be categorized as the anodic inhibitor due to suppression of more anodic reaction on the carbon steel sample.

Polystyrene (PS)/sepiolite clay nanocomposites were prepared via the melt extrusion technique using vinyl tri-ethoxy silane (VTES) as the compatibilizer and cross-linking agent. Mechanical, thermal, and flame-retardant properties of the newly developed polystyrene-based nanocomposites were determined. Surface morphology was investigated using scanning electron microscopy (SEM), examining the distribution of the filler in various compositions of fabricated composites. Structural analysis of the samples was carried out using the Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. Thermal stability was determined by thermal gravimetric analysis (TGA), showing a maximum 30.2 wt.% increase in residue by adding sepiolite clay. The results obtained from the dynamic mechanical analyzer (DMA) in terms of the storage modulus, loss modulus and damping factor exhibited better stress transfer rate and effective interfacial adhesion between the filler and the matrix. The higher filler loaded sample showed greater flame retardancy by decreasing the burning rate up to 48%.

Fibers and textiles are ubiquitous in our daily lives, with mechanical properties that match the design specifications for the task for which they are intended; the development of yarns with a negative Poisson’s ratio (NPR) is a hot topic of current research, owing to their potential for use in high-performance textiles (e.g., military, sports, etc.). This study described a simple approach to constructing braided, helically interlaced yarns. When a torque is applied, the yarns prevent the wrapped component from dislodging from the core. The geometry and auxetic behavior of the braided helical structure was analyzed for two different combinations of core materials with similar wrap materials and different braiding angles. Two elastomeric materials (polyurethane (PU) and polyester) served as monofilament cores, while two stiffer multifilament wrap yarns (ultrahigh molecular weight polyethylene (UHMWPE) and polyethylene terephthalate (PET)) served as wrap yarns. In addition, the behavior of yarns braided at seven different angles was investigated to determine the materials’ response to the applied braided configuration’s NPR. The NPR was influenced by the core and wrap materials used and the braiding angle. The NPR value was greater for a core comprising more excellent elasticity (e.g., PU versus polyester); a smaller wrap angle and a slower braiding speed also led to a higher NPR value. The maximum NPR value of −1.70 was obtained using a PU core wrapped at a 9° angle and a strain value of 0.5.

The aim of the present work was to synthesize magnetite (Fe₃O₄) nano hollow spheres (NHS) via simple, one-pot, template-free, hydrothermal method. The structural, morphological, and surface analysis of Fe₃O₄ NHS were studied by scanning electron microscopy (SEM), x-ray diffraction technique (XRD), Fourier transform infrared spectroscopy FTIR and burner-Emmett-teller (BET). The as obtained magnetic (Fe₃O₄) NHS were used as an adsorbent for treating industrial trinitrotoluene (TNT) wastewater to reduce its Chemical Oxygen Demand (COD) values. Adsorption capacity (Qe) of the NHS obtained is 70 mg/g, confirming the attractive forces present between adsorbent (Fe₃O₄ NHS) and adsorbate (TNT wastewater). COD value of TNT wastewater was reduced to >92% in 2 h at room temperature. The adsorption capacity of Fe₃O₄ NHS was observed as a function of time, initial concentration, pH, and temperature. The applied Fe₃O₄ NHS was recovered for reuse by simply manipulating its magnetic properties with slight shift in pH of the solution. A modest decrease in Qe (5.0–15.1%) was observed after each cycle. The novel Fe₃O₄ NHS could be an excellent candidate for treating wastewater generated by the intermediate processes during cyclonite, cyclotetramethylene-tetranitramine (HMX), nitroglycerin (NG) production and other various environmental pollutants/species.

High entropy alloys (HEAs) are multi-elemental alloy systems that exhibit a combination of exceptional mechanical and physical properties, and nowadays are validating their potential in the form of thermal sprayed coatings. In the present study, a novel synthesis method is presented to form high entropy alloy coatings. For this purpose, thermal sprayed coatings were deposited on Stainless Steel 316L substrates using atmospheric plasma spraying technique with subsequent annealing, at 1000 °C for 4 h, to assist alloy formation by thermal diffusion. The coatings in as-coated samples as well as in annealed forms were extensively studied by SEM for microstructure and cross-sectional analysis. Phase identification was performed by X-ray diffraction studies. The annealed coatings revealed a mixed BCC and FCC based HEA structure. Potentiodynamic corrosion behavior of SS316L sprayed as well as annealed coatings were also carried out in 3.5% NaCl solution and it was found that the HEA-based annealed coatings displayed the best corrosion resistance 0.83 (mpy), as compared to coated/non-annealed and SS 316 L that showed corrosion resistance of 7.60 (mpy) and 3.04 (mpy), respectively.