Ultrasonic assisted synthesis of nanocomposite materials based on resole resin and surface modified nano CeO2: Chemical and morphological aspects

Ring Opening Polymerization Used for the Production of VOC Free High-Performance Ecofriendly Novel PBZ/PDA/CeO2 Nanocomposites

This study analyzed the fabrication and characterization of polybenzoxazine/polydopamine/ceria as tertiary nanocomposites. To this end, a new benzoxazine monomer (MBZ) was fabricated based on the well-known Mannich reaction of naphthalene-1-amine, 2-tert-butylbenzene-1,4-diol and formaldehyde under ultrasonic-assisted process. Polydopamine (PDA) was used as dispersing polymer nanoparticles and surface modifier for CeO2 by in-situ polymerization of dopamine with the assistance of ultrasonic waves. Then, nanocomposites (NC)s were manufactured by in-situ route under thermal conditions. The FT-IR and 1H-NMR spectra confirmed the preparation of the designed MBZ monomer. The FE-SEM and TEM results showed the morphological aspects of prepared NCs and illustrated the distribution of CeO2 NPs in the polymer matrix. The XRD patterns of NCs showed the presence of crystalline phases of nanoscale CeO2 in an amorphous matrix. The TGA results reveal that the prepared NCs are classified as thermally stable materials.

Simultaneous improvements in antibacterial and flame retardant properties of PET by use of bio-nanotechnology for fabrication of high performance PET bionanocomposites

Recently, attentions to the applications of biotechnology and nanotechnology in the polymer industries have been greater than before. Hybrid nanocomposites containing multi-type of nano structures are widely established, but application of biotechnology for in-situ embedment of nanoparticles in polymer matrix is rarely reported. In this study, poly (ethylene terephthalate) (PET) based ternary bionanocomposites containing modified chitosan (phosphorylated chitosan) and nanosilver particles were prepared by simple eco-friendly method. Chitosan was selected as a biopolymer with respect to the biological activity and compatibility with PET. Phosphorylation of chitosan was achieved in order to introduce the phosphorus moieties as a flame retardant agent in PET matrix by using chemical approach. Also a cost-effective and environmentally friendly method was used for the in-situ fabrication and decoration of silver nanoparticles on to phosphorylated chitosan in PET matrix. Effects of the hybrid system (phosphorylated chitosan and silver nanoparticles) on the morphology, thermal behavior and antibacterial properties of the PET samples were investigated by different methods. The microstructure and homogeneity of the samples were analyzed by studying of dispersion of nanoparticles in PET via scanning electron microscopy. The antibacterial properties of PET nanocomposites can be improved by insertion of silver nanoparticles into the bulk of polymer matrix. Obtained results indicated that the PET/phosphorylated chitosan/silver nanocomposites showed a significantly higher growth inhibition rate compared with the PET and PET/phosphorylated chitosan blend. Also the flame retardant properties of PET nanocomposites were drastically enhanced.

Casein nanoparticles as oral delivery carriers of mequindox for the improved bioavailability

Mequindox (Meq) is a promising broad-spectrum antibacterial agent, but the clinical application of Meq has been hampered by its low oral bioavailability. Casein (Cas) can bind to a variety of poorly water-soluble drugs to improve their water solubility through a micellar solubilization mechanism. Here, a low-cost and convenient method was introduced to prepare mequindox-loaded casein nanoparticles (Meq-Cas). Meq-Cas was characterized by several methods including differential scanning calorimetry (DSC), X-ray diffraction (XRD), and fourier transform infrared (FTIR) to illuminate the mutual effect between the drug and carriers. Meq-Cas presented nearly spherical nanoparticles with smooth surfaces and its mean particle size was lower than untreated Cas. Meq-Cas showed a nearly complete release of Meq, which displayed a biphasic drug release pattern in both phosphate-buffered solution (PBS) and simulated gastric fluid (SGF). The relative oral bioavailability of Meq-Cas was found to be about 1.20 times higher than that of the animals treated with Meq suspension (control). These results suggest that Cas is a good candidate to load in Meq for pharmaceutical purposes.

Ultrasonic synthesis of CeO2@organic dye nanohybrid: Environmentally benign rabid electrochemical sensing platform for carcinogenic pollutant in water samples

A novel organic-inorganic nile-blue - CeO₂ (CeO₂/NB) nanohybrid has been synthesized by environmentally benign ultrasonic irradiation method for the selective determination of the environmental pollutant, carcinogenic hydrazine (HZ) in environmental water samples. Hydrophobic dyes have generally been as redox mediators in electrochemical sensors fabrication due to strong electron transfer capacity and they would allow the oxidation and reduction of the analytes at lower potentials. The CeO₂ nanoparticles were initially synthesized by the ultrasonic irradiation of Ce(NO₃)₂, NH₄OH and ethylene glycol mixture for 6 h using probe sonicator (20 kHz, 100 W) followed by calcination. The organic-dye NB was then added and ultrasonicated further 30 min for the formation of CeO₂/NB nanohybrid material. Various spectroscopic and microscopic tools such as UV-vis and FT-IR spectroscopy, XRD, SEM and high-solution TEM and surface analysis tool Brunauer-Emmett-Teller (BET) confirm the formation of the nanohybrid. HR-TEM images showed the well-covered CeO₂ on NB molecules and the average size of the nanohybrid is ~35 nm. For the fabrication of environmental pollutant electrochemical sensor, the prepared CeO₂/NB nanohybrid was drop-casted on the electrode surface and utilized for the determination of HZ. The nanohybrid modified electrode exhibits higher electrocatalytic activity by showing enhanced oxidation current and less positive potential shift towards HZ oxidation than the bare and individual CeO₂ and NB modified electrodes. The fabricated sensor with excellent reproducibility, repeatability, long-term storage stability and cyclic stability exhibited the sensational sensitivity (484.86 µA mM^-1 cm^-2) and specificity in the presence of 50-fold possible interfering agents with the lowest limit of detection of 57 nM (S/N = 3) against HZ. Utilization of the present sensor in environmental samples with excellent recovery proves it practicability in the determination of HZ in real-time application.

Cerium oxide doped nanocomposite membranes for reverse osmosis desalination

Cerium oxide (CeO₂) nanoparticles (NPs) have indicated great potentials as nanofiller owing to its high surface area, antioxidant properties and low cost. In this paper, thin film nanocomposite (TFN) RO membranes were proposed to be prepared through incorporation of hydrophilic CeO₂ NPs in polyamide (PA) selective layers via interfacial polymerization (IP). EDX, XPS, SEM, AFM, contact angle and zeta potential were used to examine the property and morphology of the prepared membranes. CeO₂ NPs were successfully embedded in the PA network, which endowed the TFN membranes with rougher surfaces and thinner PA layers. The TFN membranes were fabricated with different CeO₂ NPs contents (0, 50, 100, 150, 200, 400 mg/L). With increasing CeO₂ NPs loading amount, the hydrophilicity improved from 85.4° to 65.7° and the surface charge declined from -19.4 to -34.2 mV. These characteristics contributed to a 50% enhancement in water flux of TFN-CeO₂100 membrane (containing 100 mg/L of CeO₂ NPs) without compromise the NaCl rejection (98%). Moreover, CeO₂ embedded membrane exhibited an enhanced fouling resistance property through preventing the adhesion of hydrophobic foultants. This study demonstrated the desirable applicability of CeO₂ NPs in synthesizing novel TFN membranes for desalination application.

Production of polyimide ceria nanocomposites by development of molecular hook technology in nano-sonochemistry

Poly(amic acid), the precursor of polyimide (PI), was used for the preparation of PI/CeO₂ nanocomposites (NC)s by ultrasonic assisted technique via insertion of the surface modified CeO₂ nanoparticles (NP)s into PI matrix. In the preparation stages, in the first, the modifications of CeO₂ NPs by using hexadecyltrimethoxysilane (HDTMS) as a binder were targeted using ultrasonic waves. In the second step, newly designed PI structure was formed from the sonochemical imidization process as a molecular hook. In this step two different reactions were occurred. The acetic acid elimination reaction in the main chain of macromolecule, and the acetylation reaction in the side chains of poly(amic acid) were accomplished. By acetylation process the hook structure was created for trapping of the modified nanoparticles. In the final step the preparation of PI NCs were achieved by sonochemical process. The structural and thermal properties of pure PI and PI/CeO₂ NCs were studied by several techniques such as fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and thermal analyses. FT-IR and ¹H NMR spectra confirmed the success in preparation of PI matrix. The FE-SEM, TEM, and AFM analyses showed the uniform distribution of CeO₂ NPs in PI matrix. The XRD patterns of NCs show the presence of crystalline CeO₂ NPs in amorphous PI matrix. The thermal analysis results reveal that, with increases in the content of CeO₂ NPs in PI matrix, the thermally stability factors of samples were improved.

Synthesis and characterization of polyester bionanocomposite membrane with ultrasonic irradiation process for gas permeation and antibacterial activity

Optically active bionanocomposite membranes composed of polyester (PE) and cellulose/silica bionanocomposite (BNCs) prepared with simple, green and inexpensive ultrasonic irradiation process. It is a novel method to enhance the gas separation performance. The novel optically active diol containing functional trifluoromethyl groups was prepared in four steps reaction and it was fully characterized by different techniques. Commercially available silica nanoparticles were modified with biodegradable nanocellulose through ultrasonic irradiation technique. Transmission electron microscopy (TEM) analyses showed that the cellulose/silica composites were well dispersed in the polymer matrix on a nanometer scale. The mechanical properties nanocomposite films were improved by the addition of cellulose/silica. Thermo gravimetric analysis (TGA) data indicated an increase thermal stability of the PE/BNCs in compared to the pure polymer. The results obtained from gas permeation experiments showed that adding cellulose/silica to the PE membrane structure increased the permeability of the membranes. The increase in the permeability of the gases was as follows: P_CH4 (38%) <P_N2 (58%) <P_CO2 (88%) <P_O2 (98%) Adding silica nanoparticles into the PE matrix, improved the separation performance of carbon dioxide/methane and carbon dioxide/nitrogen gases. Increasing the cellulose/silica mass fraction in the membrane increased the diffusion coefficients of gases considered in the current study. Further, antimicrobial test against pathogenic bacteria was carried out.

Nanocomposite materials based on poly(vinyl chloride) and bovine serum albumin modified ZnO through ultrasonic irradiation as a green technique: Optical, thermal, mechanical and morphological properties

In this project, physicochemical properties of poly(vinyl chloride) (PVC) reinforced by ZnO nanoparticles (NPs) were studied. Firstly, ZnO NPs were modified with bovine serum albumin (BSA) as an organo-modifier and biocompatible substance through ultrasound irradiation as environmental friendly, low cost and rapid means. Nanocomposite (NC) films were prepared by loadings of various ratios of ZnO/BSA NPs (3, 6 and 9wt%) inside the PVC. Structural morphology and physical properties of the ZnO-BSA NPs and NC films were investigated via Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), transmission electron microscopy and field emission scanning electron microscopy. According to the obtained information from the TGA, an increase in the thermal stability can be clearly observed. Also the results of contact angle analysis indicated with increasing percent of ZnO/BSA NPs into PVC the hydrophilic behaviors of NCs were increased.