Search

Considering its promising antimicrobial and metal removal capabilities, water filtration systems have not yet widely used ionic polymer membranes. A textile structure made of Nafion polymer reinforced with Teflon (TFRN) was coated with non-precious metals copper and silver using a chemical decomposition technique. Scanning electron microscopy makes it quite evident that a surface coating was formed with evenly distributed metal particles. Water and moisture uptake capacity for Silver (Ag)-Copper (Cu) coated membrane was reduced by 80 and 67 % respectively compared to pure membrane. Inaddition, Ag–Cu coated membrane showed best performance against Escherichia coli (ATCC25922), and Staphylococcus aureus (ATCC 25923) with 2.04 and 1.7 CFU/ml respectively, by considering below level of Quantification as 1.6 CFU/ml. Pure Nafion membrane at pH 6.5, was used to perform the adsorption studies of transition metal ions like Copper, Nickel, Chromium, Barium, Tin and Arsenic at room temperature. The maximum metal ion removal was about 35 % for Copper followed by Nickel (31 %) and the least adsorption was observed for Barium (13.5 %) from multi-heavy metals solution. The study revealed that the potential of TFRN membrane for water purification in terms of metal and microbial removal process.

In the present study, an unconventional approach in compression molding is chosen to fabricate Ultra High Molecular Weight Polyethylene (UHMWPE) sandwich composites with Graphene (Gr) and Nano-diamond (ND) as fillers. A unique comparison is done between the surface and bulk properties of UHMWPE nano-composites and UHMWPE sandwich composites. Influence of gamma irradiation at doses of 50, 100 kGy doses and vitamin E (vit-E) on crystal structure, mechanical, thermal and tribological characteristics of UHMWPE composites were studied through x-ray diffraction (XRD), raman spectroscopy, dynamic mechanical analysis (DMA), rheology, differential scanning calorimetry (DSC), tensile, nano-indentation and wear characterization techniques. Fracture regions and surface wear of the samples were analysed through scanning electron microscopy (SEM) to understand the dispersion behavior of fillers in matrix. The concentration of vit-E content in UHMWPE greatly influenced the crosslinks and surface properties in gamma irradiated composites. Gamma irradiation have shown significant improvement in crystallinity, viscous behavior and bulk properties of UHMWPE composites. Irradiated UHMWPE nano-composites have shown better tensile results when compared with sandwich composites, with 22 % increase in young's modulus and 16 % increase in yield stress. Wear rate has been reduced by 25 % for irradiated sandwich UHMWPE composites when compared with UHMWPE nano-composites.

Shape memory polymer is widely used in bio-medical applications such as stents, sutures, drug delivery etc., However, the shape recovery behavior and mechanical properties in these applications are crucial and may be affected during shelf storage. The present research, therefore explores the effect of shelf life on mechanical, thermal and shape recovery performance of polyurethane (PU) based shape memory polymer (SMP). Experimental samples S1, S3, S5 and S10 were prepared from polymer pellets that were stored for 1,3,5 and 10-year time duration respectively. FTIR analysis revealed that samples underwent degradation due to chain scissions influencing their performance. The results indicated that tensile and flexural strength decreased by 35.16 % and 29.3 % respectively, from S1 to S10. Fracture surfaces were examined under Scanning Electron Microscopy to identify the failure features. In addition, Differential scanning calorimetry (DSC)exhibited a decrease in glass transition temperature (Tg) from S1 to S10, resulting in a corresponding reduction in the rate of shape restoration. An in-depth analysis is conducted to investigate the relationship between polymer aging and the shape recovery behavior. Finally, the shape recovery motion curves in terms of displacement, velocity and acceleration concerning the time for all the specimens were also discussed in this study.

This work focus on solving the problems of fabricating inadequate prosthetic joint from mechanical perspective in total joint replacement. Ultra high molecular weight polyethylene (UHMWPE) composites with different weight fractions of Graphene (Gr) and Nanodiamond (ND) nanoparticles (0.2–0.5 wt %) were prepared by high pressure compression molding. The effect of vitamin E (vit E) and gamma irradiation at 50 kGy and 100 kGy doses on the structural and thermal properties of UHMWPE composites were investigated through swell ratio test, fourier transformation infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The mechanical properties including tensile, flexural, impact test, nanoindentation and micro scratch were studied and the fractured surfaces were analyzed under scanning electron microscope (SEM). Influence of gamma irradiation on UHMWPE composites shows better crosslinks and crystallinity in the polymer matrix. The nano-composites shows significant improvements in various mechanical properties compared to the 0.5 wt % vitamin-E + UHMWPE composite, with a 23 % increase in Young's modulus, a 21 % increase in flexural strength, a 24 % increase in hardness, and a 17 % increase in impact strength. The results shows that 100 kGy gamma irradiated composites exhibited better results. Composite with 0.5 wt % vit E + 0.3 wt % Gr + 0.5 wt % ND shown significant improvement in structural, thermal and mechanical properties.