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A new, low-cost, and direct green synthesis strategy was developed for the preparation of polymer composites composed of silver nanoparticles (AgNPs) decorated on a shape memory polymer blend using Rubus caesius L. leaves. X-ray powder diffraction, ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS) elemental composition were applied to characterize the crystal size, morphology, and elemental composition of Ag-NPs. UV-vis spectra detected the characteristic absorbance signal of AgNPs at about 430 nm, and the average crystal size of nanoparticles was calculated as about 12.60 nm. When nanocomposite films were characterized by attenuated total reflectance infrared spectroscopy, characteristic polylactic acid, and poly ethylene glycol (PEG) signals were determined. From the thermogravimetric analysis curves, it was determined that the amount of residue of nanocomposites increased as the amount of AgNP increased. It was seen that AgNPs did not affect the [T.sub.g] temperature of the nanocomposite films, while it was also a proof that the polymer blend was immiscible. It was observed that the shape recovery properties of nanocomposite films were better with increasing AgNPs content. Finally, both green synthesized AgNPs and nanocomposites prepared with shape memory polymers showed very good antibacterial activity against Gram-positive and Gram- negative bacteria. Highlights * Green synthesis of silver nanoparticles (AgNPs) was carried out with Rubus caesius L. leaves. * The synthesized AgNPs were characterized by ultraviolet visible spectroscopy and x-ray powder diffraction. * Composite films were prepared with poly lactic acid/poly [epsilon]- caprolactone blend by solvent casting method. * The amount of residue of nanocomposites increased with increasing AgNPs percentage. * The nanocomposite film containing 10% AgNPs has good activity. KEYWORDS antibacterial, green synthesis silver nanoparticles, nanocomposite, poly [epsilon]-caprolactone, poly lactic acid, shape memory effect, 1 | INTRODUCTION Nanoscale materials ranging from 1 to 100 nm are thought to provide solutions to environmental and technological challenges in medicine and water treatment. (1,2) This increasing demand [...]

CdFe₂O₄ NPs show promise in addressing antimicrobial development and microbial resistance, highlighting the need for further research to fully harness their biological potential. This study aims to investigate the effects of calcination temperature and the incorporation of dopant elements (Cu and Sr) into CdFe₂O₄ nanoparticles (NPs) on their antimicrobial activity against extensively drug-resistant (XDR) bacteria and biofilms. The biological performance of the nanoparticles is analyzed by correlating their physical and chemical properties with antimicrobial efficacy. X-ray diffraction (XRD) analysis revealed that the NPs' formation and crystal structure strongly depends on the calcination temperatures. Thermogravimetric analysis (TG) indicated that higher calcination temperatures reduced mass loss, suggesting stronger chemical bonding and a decrease in the surface-to-volume ratio, enhancing nanoparticle stability. Antimicrobial testing against Pseudomonas aeruginosa XDR strains showed that calcination temperature significantly influenced antibacterial activity. Samples calcined at 500 °C and 700 °C exhibited inhibition zones, with 90% inhibition (MIC90) at 100 µg/mL for the 700 °C-calcined samples. The minimum bactericidal concentration (MBC) for all active samples was 200 µg/mL. Regarding antibiofilm activity, all samples reduced biofilm formation by over 50%, with the undopped sample calcined at 700 °C showing the highest efficacy, achieving 100% biofilm reduction at 60 µg/mL. In conclusion, the NPs calcined at 700 °C exhibit enhanced antibacterial and antibiofilm properties, likely due to their optimized surface characteristics and crystalline structure, making them promising candidates for combating XDR bacterial infections. Their improved physicochemical properties, including crystallinity and surface characteristics, contribute to their effectiveness in disrupting bacterial biofilms and inhibiting bacterial growth. [ABSTRACT FROM AUTHOR]

In recent years, the focus has been on the use of calcium carbonate-based seashell wastes in the production of new thermoplastic and thermoset polymer materials, paving the way for their use as biofillers in polymeric composites. In this study, it is aimed to obtain a new polymeric composite material by doping Chamelea gallina shells, on polylactic acid (PLA)/polyethylene glycol (PEG) blend. Structural characterization of the obtained PLA/PEG blend/C. gallina composite films was performed with attenuated total reflection infrared spectroscopy (ATR-IR). When the thermal properties of composite materials were examined by thermogravimetric analysis (TGA), it was determined that the thermal stability of polymeric composites increased with the addition of C. gallina. SEM images showed that the polymer blend films, which appeared to have a porous structure, filled the pores with increasing C. gallina ratio. It was observed that the biodegradability of PLA/PEG blend composite films decreased with increasing C. gallina shells addition. However, C. gallina had a positive effect on the swelling and water absorption capacities of polymeric composites. The increase in tensile strength and elongation at break values of PLA/PEG blend/C. gallina composite films with increasing C. gallina means that the mechanical properties of the polymer are improved. [ABSTRACT FROM AUTHOR]

In this work, bisphenol A propoxylate diglycidyl ether–piperazine copolymer functionalized MWCNTs (oxidized MWCNT + aminated MWCNT) composites were prepared and structurally characterized using FTIR and NMR spectroscopy. The composites were investigated in terms of their electrical and thermal properties. The surface morphology of the composites was examined by SEM. It was observed that thermal stability decreased while the ac conductivity and dielectric constant (relative permittivity) increased with increasing functionalized MWCNT content (2, 5, 10 and 15 mass %) of the composites. The electrical conductivity increased with increasing temperature and the activation energy of ac conductivity was determined and discussed.

Rare earth elements (RRE), due to their unique magnetic, electrical, and optical properties, are an important group of elements demanded in many application areas from machine technology to the health industry. In this study, new composites were obtained by mixing Erbium oxide (Er2O3), one of the rare earth element oxides, into PCL–PEG blend, which is also an important material group, in different ratios. The characteristic functional groups of the obtained polymer blend/Er2O3 nanocomposites were determined by the ATR-IR, and as the erbium oxide ratio increased, characteristic peaks of the polymers in the blend as well as characteristic signals of the Er–O–Er bond were found. When the thermal behavior of the obtained composites was examined, it was observed that the polymer blend exhibited miscible blend properties and the melting temperature of the polymer blend increased as the Er2O3 ratio increased. In addition, it was determined that the thermal stability of the composite increased significantly. X-ray measurements of composites at room temperature support other measurement results. It was determined that the presence of Er-RRE oxide increased the crystal structure feature in the polymer blend composite. Gamma radiation shielding capabilities of polymer materials containing different erbium ratios were investigated by calculating shielding parameters such as half value layer (HVL), radiation protection efficiency (RPE), and mean free path (MFP). Cs-137 and Co-60 radioactive sources were used as gamma sources. According to the obtained measurement results, Erbium oxide increased the absorption property of the polymer composite material. [ABSTRACT FROM AUTHOR]

This article explores the thermal degradation kinetics of modified Fe3O4 with poly(vinyl chloride) (PVC) using click chemistry. The authors analyze the thermal properties of the modified Fe3O4 and its precursors, as well as the thermal characteristics of the final product through thermogravimetric analysis (TGA). They determine the thermal degradation kinetic parameters using the Flynn-Wall-Ozawa method (FWO) and Kissinger-Akahira-Sinuse method (KAS). The results indicate that the modified polymer exhibits good thermal stability. The study also examines the saturation magnetization of the modified Fe3O4. Overall, this research provides valuable insights into the thermal degradation behavior and thermal stability properties of modified magnetic nanoparticles, which can have potential industrial applications. [Extracted from the article]

This work aimed to investigate the effect of magnetic Fe3O4 nanoparticles (MNP), which are known to have a wide range of applications in recent years, on nanocomposite films prepared with shape memory polymers. Herein, PLA–PEG blend nanocomposite films were prepared by solution casting method using MNP at different ratios. PLA–PEG Blend/MNP nanocomposite films were characterized with Attenuated total reflection infrared spectroscopy (ATR-IR) to determine the –C=O stretching of PLA and Fe–O stretching signals of Fe3O4. The thermal stability, morphology, and magnetic behavior were studied by comparing the results among PLA–PEG blend, PLA–PEG blend/MNP nanocomposite with thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and a vibrating sample magnetometer (VSM), respectively. The effect of MNP on the shape memory properties of PLA/PEG blend was investigated. Moreover, the comparison of antimicrobial activity between PLA/PEG blend and PLA–PEG blend/MNP nanocomposite films were conducted by the disk diffusion method. The results showed that MNP increased the thermal stability of the PLA/PEG blend and the nanocomposites inhibited the growth of C.albicans microorganism. [ABSTRACT FROM AUTHOR]

Recently, there has been a great demand for boron‐containing compounds (BCCs) with unique biological properties. The demand for the use of these compounds not alone but as additives in composite materials is increasing day by day. In this study, the effect of adding B2O3 compound to the blend of PLA and PEG polymers, which is an important biocompatible shape memory polymer, was investigated. In order to examine the effect of increasing B2O3 additive on the thermal properties of PLA‐PEG blend, it was determined by using a Differential Scanning Calorimetry (DSC) and thermogravimetric analyzer (TGA), and it was seen that while the melting temperature of PEG decreased, the melting temperature of PLA increased. In addition, when the thermal stability of the composites was examined, increasing of thermal stability was observed with the addition of B2O3 and a three‐step degradation occurred. It was determined that the B2O3/PLA‐PEG composite was homogeneous by taking X‐ray measurements and SEM measurements. The antimicrobial property of the PLA‐PEG blend improved with the increasing B2O3 contribution were observed from the antimicrobial activity measurements of the composite against 4 different bacteria. However, it was determined that the PLA‐PEG blend preserved its shape memory effect with increasing diboron trioxide contribution. [ABSTRACT FROM AUTHOR]