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Today, the use of biodegradable polymers has become widespread in a wide range of industries. This research scrutinized the physical, mechanical, and rheological properties of poly (lactic acid)/poly (ethylene oxide)/carbon nanotube (PLA/PEO/CNTs) blend nanocomposites, as a good candidate for usage in the packaging industry. PEG and CNTs were added at various concentrations to improve the flexibility, toughness, gas permeability, thermal stability, and mechanical properties of PLA via solution blending. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Field Emission Scanning Electron Microscope (FESEM), water contact angle (WCA), rheometric mechanical spectrometer (RMS) test, gas permeability, and tensile characterization were performed to characterize the properties of the prepared blends and nanocomposites. The experimental results revealed that the addition of 25 wt% PEO to the PLA matrix made a partially miscible blend with a droplet-matrix morphology. PEO at this concentration increased the elongation at break (from 2.2% to 18%) while reducing the modulus (from 25 to 6 MPa). Also, the experimental results indicated that the miscibility of PLA and PEO was enhanced by the addition of 1 wt% CNTs to the prepared blend, associated with diminished entropy of mixing in the LCST phase diagram. Theoretical calculations predicted that the CNTs would be localized in the PLA phase which increased the total crystallinity of the sample by 28%, considerably reducing the amount of gas permeation into the nanocomposite. In addition, the introduction of the CNTs to the blend increased the elongation at break and tensile strength by 13% compared to pure PLA and lowered the rate of thermal degradation effectively. Also, the final results showed that the COOHCNTs located in the PEO phase caused a decline in the crystallinity and an increase in the gas permeability of the prepared nanocomposite. Highlights * Improvement of physical properties of PLA by blending with PEO and CNTs. * A deep investigation on rheological behavior of the prepared nanocomposite. * Increasing the crystallinity degree of PLA/PEO blend by adding CNTs. * Improvement of the miscibility between PLA and PEO in the presence of CNTs. * Controlling the CNTs localization by surface modification. KEYWORDS carbon nanotube, physical and mechanical properties, poly (ethylene oxide), poly (lactic acid), solution blending, 1 | INTRODUCTION Recent years have been witnessing increased usage of petroleum-based polyolefins in the food packaging industries, which is due to their acceptable mechanical properties, cheapness, excellent processability, and [...]

This study describes the synthesis of a novel meso/magnetic adsorbent based on chitosan nanocomposite hydrogel to remove heavy metal ions from aqueous solutions. The meso/magnetic nanocomposite hydrogel was designed from the blending of chitosan and cellulose bio-polysaccharides in the presence of magnetic Laponite RD (nanoclay) nanoparticles (Fe3O4/La). Fe3O4/La nanoparticles were obtained by the in-situ co-precipitation method. The nanocomposite hydrogel was characterised by FT-IR, XRD, VSM, TGA, TEM, FE-SEM, and BET techniques. Several important parameters influence the adsorption of Cu (II), Hg (II), Co (II), and Ni (II) ions in the aqueous solution such as contact time, pH, temperature, and effect of metal concentration with single and multi-metal systems were investigated systematically by batch experiments. Compared with the adsorption of other ions, adsorption of the Hg (II) ions on the chitosan/cellulose/laponite RD nanocomposite hydrogel was showed high selective and high-efficient. The adsorption process of Hg (II) ions has shown best correlated to the Langmuir isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of Hg (II) ions was 579.8 mg/g. The thermodynamic data showed that the adsorption process was spontaneous, favourable, and endothermic. [ABSTRACT FROM AUTHOR]

In this research, the alginate doped graphene oxide (GO)-Fe3O4-TiO2 photomagnetic nanocomposite was synthesised through a three-step method. For comparison, alginate-GO was also prepared. The synthesised materials were characterised through FTIR, XRD, TGA, SEM, EDX, and TEM techniques. The photomagnetic properties of the resultant nanocomposite were evaluated by VSM. Degradation of Malachite green as a dye pollutant was studied in the presence of alginate (Alg), Alg-GO, and Alg-GO-Fe3O4-TiO2 nanocomposite using a sonophotocatalysis technique. The results showed, that, Alg-GO-Fe3O4-TiO2 nanocomposite has high efficiency in the removal of Malachite green. Recycling experiments displayed that the degradation efficiency dropped only by 12%, after five successive runs. and makes it a promising catalyst for efficient degradation of dye pollutants in the practical applications. [ABSTRACT FROM AUTHOR]

Reversible addition-fragmentation chain transfer (RAFT) polymerization enables the synthesis of controlled architectures for a wide-variety of polymers with defined end and pendant functionalities using mild conditions. A simple synthetic route for the preparation of polystyrene (PS)/ZnO nanocomposite with well-defined structure is demonstrated. ZnO nanoparticles were synthesized by homogeneous precipitation. To reduce the aggregation among ZnO nanoparticles, an effective surface modification method was proposed by grafting polystyrene onto the ZnO particles. The surface of ZnO nanoparticles was firstly treated with a 4-cyano-4-[(4-methoxyphenyl carbon thiol) solfanylvaleric acid] coupling RAFT agent in the presence of THF as a solvent at 65°C. A carboxylic group in raft agent attached to ZnO nanoparticles by the esterification reaction with the hydroxyl groups on the ZnO particle surface. Then, RAFT polymerization of styrene was subsequently conducted to graft PS onto the exterior surface of ZnO nanoparticles by new RAFT agent 4-cyano-4-[(4-methoxyphenyl carbon thiol) solfanylvaleric acid]. The obtained nanocomposite was characterized by Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric (TGA), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). POLYM. ENG. SCI., 56:187-195, 2016. [C] 2015 Society of Plastics Engineers, INTRODUCTION Polymeric nanocomposites consisting of inorganic nanoparticles and organic polymer are a useful class of materials which combine thermal stability, mechanical strength or optical properties with flexibility and the ability [...]

Reversible addition-fragmentation chain transfer (RAFT) polymerization enables the synthesis of controlled architectures for a wide-variety of polymers with defined end and pendant functionalities using mild conditions. A simple synthetic route for the preparation of polystyrene (PS)/ZnO nanocomposite with well-defined structure is demonstrated. ZnO nanoparticles were synthesized by homogeneous precipitation. To reduce the aggregation among ZnO nanoparticles, an effective surface modification method was proposed by grafting polystyrene onto the ZnO particles. The surface of ZnO nanoparticles was firstly treated with a 4-cyano-4-[(4-methoxyphenyl carbon thiol) solfanylvaleric acid] coupling RAFT agent in the presence of THF as a solvent at 65°C. A carboxylic group in raft agent attached to ZnO nanoparticles by the esterification reaction with the hydroxyl groups on the ZnO particle surface. Then, RAFT polymerization of styrene was subsequently conducted to graft PS onto the exterior surface of ZnO nanoparticles by new RAFT agent 4-cyano-4-[(4-methoxyphenyl carbon thiol) solfanylvaleric acid]. The obtained nanocomposite was characterized by Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric (TGA), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). POLYM. ENG. SCI., 56:187-195, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

A synthetic route for the preparation of a novel solution copolymer derived from styrene (St), pyrrole (Py) and its organoclay nanocomposite with conductive and mechanical properties is demonstrated. The electroactive copolymer of polystyrene-g-polypyrrole (PSt-g-Ppy) nanocomposite was successfully prepared by atom transfer radical polymerisation (ATRP) and chemical polymerisation methods. First, potassium pyrrole was reacted by α-chlorophenyl acetyl chloride to prepare an initiator that can polymerise styrene by ATRP technique. Then, polypyrrole was prepared by chemical polymerisation using FeCl3as an oxidant in dichloromethane,s solvent. Nanocomposites of the copolymer with modified montmorillonite were prepared with a solution intercalation method. The conductivity of the copolymer was measured by the four-point probe method. The structures of the intermediate, copolymer and nanocomposite were investigated by Fourier transform infrared spectroscopy,1H-NMR and X-ray diffraction techniques. The molecular weight of the copolymer was determined by gel permeation chromatography. Their thermal behaviour was examined by differential scanning calorimetry and thermogravimetric analyses. [ABSTRACT FROM AUTHOR]

Due to the strong tendency of nanoparticles such as metal oxides to agglomerate, homogeneous dispersion of these materials in a polymeric matrix is extremely challenging. In order to overcome this problem and to enhance the filler-polymer interaction, this study focused on living polymerization that was initialized from the surface of titanium fillers. A new method for synthesizing TiO2/polymer nanocomposites was found with a good dispersion of the nanofillers by using the RAFT agent, 4-cyano-4-[(phenyl carbon tool) solfanylvaleric acid. This RAFT agent has an available carboxyl group to anchor onto TiO2nanoparticles, and an S = C (C6H5) moiety for subsequent RAFT polymerization of 4-chloromethyl styrene (PCMS) to form n-TiO2/4-chloromethyl styrene nanocomposites. The functionalization of n-TiO2was determined by FTIR and partitioning studies, the livings of the polymerization were verified using GPC, while the dispersion of the inorganic filler in the polymer was studied using electron microscopy, FTIR and thermal analysis. [ABSTRACT FROM AUTHOR]

This work reports the synthesis of novel antibacterial magnetic-/pH-sensitive hydrogel beads based on ionotropic-gelation of alginate biopolymer. Using pomegranate peels extract, green-Ag nanoparticles were synthesized inside a mixture of alginate and Fe 3 O 4 , via in situ method. The alginate beads were investigated by VSM, TEM, XRD, and FE-SEM techniques. The introducing Ag and Fe 3 O 4 nanoparticles in hydrogel beads caused a reduction in the swelling capacity of hydrogel beads. Besides, a pH-dependent swelling behavior was observed for hydrogel beads with a maximum swelling capacity at pH = 7.4. Diclofenac sodium (DS) as a model drug was loaded in hydrogel beads and its release showed a pH-dependent behavior. Drug release studies exhibited significant behaviors on the subject of physiological simulated pHs with a high release rate at pH = 7.4. The alginate beads have shown a prolonged and successive controlled drug release nearly 83% at pH = 7.4 and time 200 min. In addition to the pH, the release of DS from magnetic beads was affected by the external-magnetic-fields. Also, the Ag-incorporated alginate beads showed strong antibacterial activity against S. aureus and E. coli. These results indicated that the hydrogel beads have potentially applicable in drug delivery systems., Competing Interests: Declaration of competing interest We confirm that the manuscript has been read and approved by all named authors., (Copyright © 2020. Published by Elsevier B.V.)