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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 [...]

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]

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]