Shahryar Pashaei

Preparation of novel multi-walled carbon nanotubes nanocomposite adsorbent via RAFT technique for the adsorption of toxic copper ions

In the present work, polymer-coated multiwalled carbon nanotube (MWCNT) was prepared via RAFT method. First, a novel trithiocarbonate-based RAFT agent was prepared attached chemically into the surface of MWCNT. In addition, the RAFT co-polymerization of acrylic acid and acrylamide monomers was conducted through the prepared RAFT agent. In the next age, the surface morphology and chemical properties of the prepared components were fully examined by using FTIR, 1HNMR, SEM, TEM, XRD and TGA/DTG techniques. Finally, the modified MWCNT composite was employed as an excellent adsorbent for the adsorption of copper (II) ions. The results indicated that ion adsorption basically relies on adsorbing time, solution pH, initial copper concentration, and adsorbent dosage. Further, the adsorption kinetics and isotherm analysis demonstrated that the adsorption mode was fitted with the pseudo-second-order and Langmuir isotherm models, respectively. Based on the results of thermodynamic study, the ion adsorption process was endothermic and spontaneous. Finally, based on the experimental results, the surface functionalized MWCNT with hydrophilic groups could be successfully used as a promising selective adsorbent material in wastewater treatment.

Synthesis of magnetic functionalized MWCNT nanocomposite through surface RAFT co-polymerization of acrylic acid and N-isopropyl acrylamide for removal of cationic dyes from aqueous solutions

In this study, magnetic multi-walled carbon nanotube (MMWCNT) composites were prepared via surface reversible addition fragmentation chain transfer (RAFT) co-polymerization of acrylic acid (AA) and N-isopropyl acrylamide (NIPAM) in the presence of Fe3O4 nanoparticles. First, a novel RAFT agent (RA) was prepared and then immobilized onto the surface of MWCNT to fabricate RA-g-MWCNT. Then, Fe3O4 nanoparticles were attached onto the surface of RA-g-MWCNT. Finally, RAFT co-polymerization of AA and NIPAM monomers was carried out via Fe3O4-g-RA-g-MWCNT RAFT agent. The structure and morphology of the prepared polymer-coated MWCNT was examined by FTIR, SEM, TEM, XRD, VSM, and TGA. The adsorption behaviours of the cationic dyes were studied. The equilibrium isotherm and kinetics of cationic dyes were investigated. Thermodynamics investigations also depicted that the adsorptions of cationic dyes were spontaneous and endothermic in nature. The synthesized dye adsorbent with high adsorption capacities, reusability, and easy recovery makes it as a good candidate for wastewater treatment.

Modification in physical properties of organo clay filled polyurethane nanocomposites

Polyurethane (PU) have been prepared by using polyether polyol (jagropol oil) and 1,6-hexamethylene diisocyanate (HMDI) as a cross-linker. The organically modified montmorillonite clay (o-MMT) is well dispersed into urethane matrix by in-situ polymerization method. A series of PU/o-MMT nanocomposites have been prepared by varying amounts viz., 1, 3, 5 and 6 wt % of nanoclay. The mechanical properties such as tensile strength, percentage elongation at break and tensile modulus of the composites were experimentally determined. The swelling behavior of the composites has been studied in different organic solvents. It was noticed that the swelling data of the composites significantly depends on the solubility parameters of the solvents. Microcrystalline parameters such as, lattice strain (g in %), average number of unit cells (〈N〉) in direction perpendicular to Bragg plane, surface weighted crystal size (Ds) and interplanar distance (dhkl), were calculated from X-ray patterns. These parameters were computed using Exponential asymmetric column length distribution functions. Morphological features of cryofractured PU/o-MMT composites were also analyzed using scanning electron microscopy (SEM).

Synthesis of stimuli-responsive chitosan nanocomposites via RAFT copolymerization for doxorubicin delivery

In this study, a unique stimuli-responsive hydrogel nanocomposite was prepared via surface reversible addition fragmentation chain transfer (RAFT) copolymerization of acrylic acid and N‑isopropyl acrylamide onto chitosan and subsequent in situ synthesis of magnetic Fe3O4 nanoparticles. In the next age, the structure and morphology of synthetic magnetic nanocomposite were characterized by FTIR, XRD, VSM, SEM, and TEM techniques. The modified hydrogel nanocomposite was employed as an excellent carrier for controlled releasing of anticancer drug doxorubicin (DOX). The results indicated that the maximum of DOX loading efficiency of nanocomposite was 89%. Notably, in vitro drug release studies showed that DOX was released in a sustained-release manner for the nanocomposites. From the results of in vitro release studies, dual temperature and pH responsiveness of the nanocomposite was demonstrated, and 82% of total DOX was released from the hydrogel within 2 days. Due to the unique structures and properties, the chitosan-based nanocomposite may be utilized as a promising drug carrier for controlled and sustained release of anticancer drugs.

Investigation on Physico-Mechanical, Thermal and Morphological of Dipodal Silane-Modified Walnut Shell Powder Filled Polyurethane Green Composites and their Application for Removal of Heavy Metal Ions from Water

ABSTRACT Dipodal silane-modified walnut shell powder polyurethane green composites have been prepared with different weight fractions of walnut shell powder viz., 0, 3, 6, and 10 wt% with surface-modified dipodal silane. The properties of dipodal silane-modified walnut shell powder-filled polyurethane green composites was investigated by tensile testing, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The polyurethane/dipodal silane-modified walnut shell powder has been fabricated based on 3-aminopropyltriethoxysilane and γ-glycidoxypropyl trimethoxysilane. The green composites were analyzed by ultraviolet–visible in two different water solutions with Ni2+ and Pd2+ ions concentrations. GRAPHICAL ABSTRACT

Rapid production of monodisperse cross-linked red blood corpuscle-like particles via scalable one-pot dispersion polymerization

Cross-linked polystyrene (PS) particles having red blood corpuscle (RBC)-like shape were synthesized by one-pot dispersion polymerization of styrene with ethanol/water mixture and ethylene glycol dimethacrylate (EGDMA) as the reaction medium and cross-linker, respectively. Monitoring of the reaction showed that RBC-like shape forms due to asymmetric shrinkage of a cross-linked network during the phase separation. In addition, three dimensional phase diagram was generated based on the yielded data that showed that the formation of such unique shape extremely depends on the polarity of the medium and injection time of the cross-linker. In situ synthesis of RBC-like particles, as promising biomaterials in targeted drug delivery and a model for the understanding of the cell behavior, via such fast and high solid content approach makes it to be conducive to subsequent scale up, i.e. potential commercial adoption.