Existence Of Polyethylene Glycol Research Articles

Controllable crystal growth of Mg(OH)2 hexagonal flakes and their surface modification using graft polymerization

Mg(OH)2 crystals with excellent flame retardance in the application of polymer materials are always in demand. Herein, regular and well-dispersed Mg(OH)2 hexagonal flakes were hydrothermally prepared with the existence of polyethylene glycol (PEG) and then modified by surface grafting-polymerization of methyl methacrylate (MMA) monomers. The results showed that the morphology and dispersity of Mg(OH)2 relied on the precise control of the reaction parameters including hydrothermal conditions, the molecular weight and additive amount of PEG. PEG with a molecular weight of 8000 exhibited an enhanced directing role due to its more appropriate length of molecular chains and intensive interaction with the formed Mg(OH)2 crystallites. The molecular chains of PEG-8000 can be preferentially adsorbed onto the (001) and (101) planes of Mg(OH)2 crystallites and sub-micro hexagonal flakes with low-polarity were consequently assembled. The optimal conditions for preparing Mg(OH)2 hexagonal flakes with higher crystallinity and more regular morphology were determined to be hydrothermal treatment at 120 °C for 12 h with 3 wt% PEG-8000. The dimension and decomposition temperature of the end products were 400 ~ 500 nm and 388 °C, respectively. The surface graft-modified Mg(OH)2 hexagonal flakes exhibited high hydrophobicity with a water contact angle of 148°, indicating an excellent compatibility with polymers.

Structural, optical properties of ZnO doped SnO2 nanocomposites with enhanced photocatalytic performance under UV illumination

ZnO doped SnO2 nanocrystallites are fabricated by the sol-gel technique in the existence of polyethylene glycol as a template and characterized by various techniques for structural, morphological and optical properties. The photocatalytic efficiency of the synthesized photocatalysts is assessed by photodegradation of methylene blue dye under ultraviolet light illumination. The ZnO/SnO2 molar ratios are changed in order to study their effect on the photocatalytic efficiency. The ZnO/SnO2 nanocrystallites are a most efficient photocatalyst with the efficiency of 1.0:1.0 in molar ratio and it is attributed to the existence of heterojunctions between the ZnO and SnO2. This allows increased charge parting of the photogenerated electron/hole pairs due to the energy difference amongst the two oxides.

PEG-assisted hydrothermal synthesis of CoFe2O4 nanoparticles with enhanced selective adsorption properties for different dyes

Cobalt ferrite nanoparticles (CFO NPs) are synthesized by a facile and polyethylene glycol (PEG) assisted hydrothermal method. In the synthesis of cobalt ferrites, PEG is used as a surfactant. The formation of single-phase spinel structure in the samples is confirmed by XRD patterns. TEM images show that the addition of PEG results in the decrease in the size of the CFO NPs. When the amount of PEG is lower than 2.4g, the particle sizes decrease, then, further increasing the concentration of PEG in the solution, the particle sizes begin to increase, for much more PEG will cover onto the surface of the nanoparticles. Here, the existence of PEG on the surface of CFO NPs is confirmed from the characteristic bands of PEG in FTIR spectra. All the samples are ferromagnetic, and their saturation magnetization (Ms) decreases with the increase in PEG concentration. The as-synthesized samples show highly selective adsorption characteristics for organic dyes. Compared with methyl orange (MO) and methyl blue (MB) dyes, good adsorption performance of the PEG/CoFe2O4 nanocomposites for Congo red (CR) dye is presented. Moreover, the addition of PEG greatly enhances their adsorption capacity (qe) for CR. The corresponding adsorption behavior fits well with the pseudo-second-order kinetic model and the Langmuir model. And the adsorption mechanism is investigated. This study suggests that the as-prepared products can be regarded as an excellent selective adsorbent to remove dyes from the wastewater.

Synthesis and release behavior of methotrexate from Fe3O4/PLA–PEG core/shell nanoparticles with high saturation magnetization

A magnetic targeted drug delivery system with a high Ms value was prepared based on Fe3O4/PLA core/shell nanoparticles for the controlled release methotrexate (MTX). To endow the carrier with hydrophilicity and biocompatibility, an effective surface modification method to graft polyethylene glycol (PEG) was also proposed. The obtained nanocomposites were characterized by TEM, FTIR, XRD, and VSM. The MTX-loading efficiency and drug release behavior of the system were determined by UV–vis spectrometer. The results showed that the MTX displayed a pH-dependent releasing behavior and the existence of PEG would slow down the release rate. Additionally, a cell viability assay was also carried out to evaluate the biocompatibility of Fe3O4/PLA–PEG and the anticancer activities of prepared Fe3O4/PLA–PEG–MTX.

<i>In Situ</i> FTIR Spectroscopy Study on the Crystallization Process of Isotactic Polypropylene in Isotactic Polypropylene/Polyethylene-Glycol Blends

The crystallization of isotactic polypropylene (iPP) and polypropylene/polyethylene-glycol （iPP/PEG） blends were investigated by in situ Fourier transform infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). It was found that the existence of polyethylene-glycol（PEG） does not destroy the helical structure of iPP in the melt, but changes the crystal structure of iPP in the bends. Moreover, the variation tendency of ratios of intensity A998 cm-1/A1460 cm-1 for iPP and iPP/PEG blends showed that the the onset crystallization temperature of iPP is improved by addition of PEG until the PEG content reaches to 5 wt%, and beyond this content, the crystallization point decreases.

Oleanolic acid liposomes with polyethylene glycol modification: promising antitumor drug delivery

Oleanolic acid is a pentacyclic triterpene present in many fruits and vegetables, and has received much attention on account of its biological properties. However, its poor solubility and low bioavailability limit its use. The objective of this study was to encapsulate oleanolic acid into nanoliposomes using the modified ethanol injection method. The liposomes contain a hydrophobic oleanolic acid core, an amphiphilic soybean lecithin monolayer, and a protective hydrophilic polyethylene glycol (PEG) coating. During the preparation process, the formulations described were investigated by designing 3⁴ orthogonal experiments as well as considering the effects of different physical characteristics. The four factors were the ratios of drug to soybean phosphatidylcholine (w/w), cholesterol (w/w), PEG-2000 (w/w), and temperature of phosphate-buffered saline at three different levels. We identified the optimized formulation which showed the most satisfactory lipid stability and particle formation. The morphology of the liposomes obtained was determined by transmission electron microscopy and atomic force microscopy. The existence of PEG in the liposome component was validated by Fourier transform infrared spectrum analysis. The PEGylated liposomes dispersed individually and had diameters of around 110-200 nm. Encapsulation efficiency was more than 85%, as calculated by high-performance liquid chromatography and Sephadex® gel filtration. Furthermore, when compared with native oleanolic acid, the liposomal formulations showed better stability in vitro. Finally, the cytotoxicity of the oleanolic acid liposomes was evaluated using a microtiter tetrazolium assay. These results suggest that PEGylated liposomes would serve as a potent delivery vehicle for oleanolic acid in future cancer therapy.

Large-scale synthesis of antimony nanobelt bundles

The large-scale synthesis of antimony nanobelt bundles has been facilely realized in existence of polyethylene glycol (PEG) by a hydrothermal reduction method using aluminum powder as reducing agent. These nanobelts have width in the range of 200–600 nm and length up to several micrometres, and the width-to-thickness ratio is ca. 10. FESEM images show individual nanobelts have multi-layered structures. The size of nanobelts can be varied by adjusting the molecular weights of PEG. Based on a series of comparative experiments under different reaction conditions, the probable formation mechanism of antimony nanobelt bundles is proposed to be a solid–liquid–solid transformation and surfactant-assisted directional growth process.