Rajeev Nayan Gupta

In this study, high‐density polyethylene (HDPE) was reinforced with waste glass powder (WGP) to fabricate a composite, which was subsequently analyzed for its thermal, physical, and tribo‐mechanical properties. Differential scanning calorimetry (DSC) analysis revealed that the incorporation of WGP increased the melting temperature due to restricted polymer chain mobility, while both crystallinity and fusion enthalpy decreased with increasing WGP content. Water absorption increased slightly with WGP content, from 0.01% (neat HDPE) to 0.018% at 20 wt.%, remaining low overall, while shrinkage reduced notably beyond 5 wt.%, reaching 5.8% at 20 wt.%. Higher WGP loadings increased the surface roughness due to particle agglomeration. Shore D hardness and tribological performance improved with WGP content. The optimal coefficient of friction (COF) and specific wear rate (SWR) were achieved at 10 wt.% WGP with a corresponding reduction of 26.67% and 38.28%, respectively. Field emission scanning electron microscopy (FESEM) analysis of the worn‐out surfaces confirmed that WGP reinforcement reduced surface deformation; however, particle agglomeration at higher loadings introduced defects. The HDPE/WGP composite exhibited optimal performance at 10 wt.% WGP, highlighting its suitability for low to moderate load wear‐resistant components (e.g., copier/printer gears, bearings in paper mill rollers, outdoor enclosures), where dimensional stability, hardness, and wear resistance are the dominant design criteria.

This study investigates the development and characterization of polyethylene terephthalate glycol (PETG) composites reinforced with waste glass powder (WGP) for 3D printing applications. The incorporation of WGP aims to enhance sustainability by reducing glass waste while evaluating its impact on the material's chemical, thermal, and mechanical properties. PETG/WGP composites with varying compositions (0–20 wt.% WGP) were fabricated using a single-screw extruder to produce filaments, which were subsequently 3D-printed into test specimens of tensile, flexural, and Shore D hardness tests according to ASTM standards D638-IV, D790, and D-2240, respectively. Comprehensive characterization techniques, including FTIR, XRD, TGA, tensile, flexural, and Shore D hardness tests, were performed to assess material performance. The results indicate that the inclusion of WGP slightly improves the thermal stability and significantly enhances hardness by 22.58% at 10 wt.% WGP. However, at higher filler content (20 wt.% WGP), a 34.37% reduction in ultimate tensile strength and a 43.89% decrease in flexural strength are observed compared to neat PETG. This decline is attributed to inadequate interfacial bonding between the polymer matrix and WGP, stress concentrations caused by the irregular morphology of the WGP particles, along with increased brittleness of the composite. While the study focused on the potential of WGP as a sustainable reinforcement, further optimization is required to improve its mechanical properties for practical applications.

The current study systematically investigated the tribo-mechanical properties of magnesium-based hybrid nanocomposites. To fabricate magnesium alloy (AZ91) based composite by reinforcing nano-sized titanium carbide (nano-TiC), with weight percentages (wt.%) varying from 0.5% to 2% while maintaining a constant 0.5 wt.% of nano-reduced graphene oxide (rGO) throughout the experiments. The hybrid magnesium metal matrix nanocomposites (HMMMNCs) were prepared via the powder metallurgy procedure. The addition of hybrid reinforcements into the AZ91 matrix has a significant impact on its physical, mechanical, and tribological properties. The microhardness of the composite samples exhibited a significant enhancement, with an increase of ∼45.9% compared to the matrix material. This improvement in strength is attributed to the synergistic reinforcement effect of both nano-TiC and rGO. Additionally, at the optimal nano-TiC concentration of 1.5 wt.%, the wear rate and coefficient of friction (COF) of the HMMMNCs were decreased by ∼40.7% and ∼49.33%, respectively. This reduction is primarily due to the formation of a hardened ceramic phase in the contact region, which mitigates heat-induced softening. Also, different analytical tools, like XRD, SEM, and surface roughness profilometer, were employed to characterize the developed composite materials and analyze the worn surfaces.

Development of composites containing both self-lubricating and self-healing (SLSH) characteristics is a nascent area of research for applications where direct lubrication is discouraged such as marine, textile, and food processing industries. For instance, SLSH composites may enhance the longevity of propeller shafts, bearings, and other dynamic components in such applications. The present work focuses on the synthesis of microcapsules with molybdenum disulfide (MoS ₂ ) as a core and polysulfone as a shell material, using the solvent evaporation method. The composites were fabricated by blending synthesized microcapsules in ultra-high molecular weight polyethylene (UHMWPE) matrix via injection moulding technique. Aluminum oxide (Al ₂ O ₃ ) nanoparticles (3–12 wt.%) and glass fibres (10 wt.%) were also used as reinforcements. Flexural and tensile tests of the fabricated composites were conducted to evaluate their mechanical properties. Tribological behaviour was also investigated using a pin-on-disc tribometer. The polymer composites with a constant dose of 10 wt.% glass fibre and 5 wt.% microcapsules along with 6 wt.% Al ₂ O ₃ exhibit the best performance. The maximum reductions in wear rate and coefficient of friction (COF) are 45.28% and 54.47%, respectively, as compared to the base matrix. Moreover, flexural and tensile strength increased by 43.55% and 39.77%, respectively. The worn surfaces exhibited fractured microcapsules which acted as SLSH agents, due to the high thermal stability of the polysulfone shell and release of the solid core. Various analytical tools, including optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), are employed in this study.