Superparamagnetic polymer nanofibers intended for drug delivery and therapy are considered here. Magnetite (Fe3O4) nanoparticles in the diameter range of 5-10 nm were synthesized in aqueous solution. Polymer nanofibers containing magnetite nanoparticles were prepared from commercially available poly(hydroxyethyl methacrylate), PHEMA, and poly-L-lactide (PLLA) by the electrospinning technique. Nanofibers with diameters ranging from 50 to 300 nm were obtained. Nanofibers containing up to 35 wt % magnetite nanoparticles displayed superparamagnetism at room temperature. The blocking temperature was about 50 K for an applied field of 500 Oe, and the saturation magnetization was 3.5 emu g(-1) and 1.1 emu g(-1) for Fe3O4/PHEMA and Fe3O4/PLLA nanofibers, respectively, and depended on the amount of Fe3O4 nanoparticles in the nanocomposites. To test such magnetic nano-objects for applications as drug carriers and drug-release systems we incorporated a fluorescent albumin with dog fluorescein isothiocyanate (ADFI).
Carbon-coated CoS2–MoS2 catalysts
were prepared by a hydrothermal method via the addition of polyvinylpyrrolidone
(PVP). The effects of PVP amount on their structure properties and
hydrodeoxygenation (HDO) activity were studied. The characterization
results showed that carbon coated on the surface of CoS2–MoS2 and that its hydrophobicity was enhanced.
During the HDO of 4-ethylphenol, these catalysts presented high direct
deoxygenation activity, even at high hydrogen pressure. High reaction
temperature and hydrogen pressure were beneficial to increase the
conversion, but had little effect on the product distribution. After
reaction at 250 °C and 4.0 MPa hydrogen pressure for 5 h, the
deoxygenation degree reached 96.1% with a selectivity of 99.3% ethylbenzene.
The high HDO activity of carbon-coated CoS2–MoS2 catalysts mainly resulted from its enhanced hydrophobicity.
Moreover, the reusability tests also showed that these catalysts had
a good stability during the HDO reaction because of the inhibition
of hydrophobic coated carbon to sulfur loss. Therefore, improving
the hydrophobicity of the sulfide catalyst was favored for increasing
its HDO activity and inhibiting the deactivation.
ABSTRACT:A novel liquid crystalline polyester-polyurethane (LCPU) that contains polyester mesogenic units was synthesized in the present work. Through a careful investigation of the structure and morphology of the LCPU, it was found that the home-synthesized LCPU is a highly birefringent thermotropic nematic liquid crystal. After being blended with bisphenol-A epoxy, the liquid crystalline polymer can, simultaneously, improve the impact strength and the glass transition temperature as well as the tensile strength and the tensile modulus of the blends. It was proved to be an efficient toughening agent for epoxy without the expense of other properties.
Hydrophobic reduced graphene oxide supported Ni-B-P-O and Co-B-P-O catalysts were beneficial to disperse in the non-polar solvent, prevent the contact with water, and consequently protected the active phases and exhibited high catalytic activity in the liquid-phase p-cresol HDO reaction.
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