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A modified coaxial electrospinning process is developed for producing medicated nanofiber membranes of shellac. With pure ethanol as a sheath fluid, high quality borneol-loaded shellac nanofibers have been successfully fabricated using the modified coaxial process. Electron scanning microscopic observations demonstrated that the nanofibers had better quality than those fabricated using a single fluid electrospinning in terms of nanofiber diameters and their distributions. The former had an average diameter of 570 ± 80 nm under a sheath-to-core flow rate ratio of 0.25, whereas the later was 940 ± 230 nm. X-ray diffraction results verified that borneol existed in the shellac matrix in an amorphous state. The medicated nanofiber membranes could significantly improved the physical stability of borneol due to the favorable hydrogen bonding between the drug and the polymer matrix, as demonstrated by the weight loss experiments. The modified coaxial electrospinning process described here expands the capability of electrospinning process in generating high quality functional membranes.

The present study investigates the preparation of sustained release drug-loaded nanofibers using a modified coaxial electrospinning process where only solvent is exploited as sheath fluid. Drug-loaded ethyl cellulose (EC) nanofibers are successfully generated smoothly and continuously without any clogging through the coaxial process, in which ethanol is used as sheath fluid and EC and ketoprofen (KET) are taken as the filament-forming matrix and active pharmaceutical ingredient, respectively. Field-emission scanning electron microscopic observations demonstrated that the nanofibers diameter can be manipulated through the sheath fluid flow rate. The composite nanofibers are in essential a molecular solid dispersion of EC and KET based on the hydrogen bonding between them, as verified by XRD and ATR-FTIR results. In vitro dissolution tests show that KET in the nanofibers has a fine sustained release profile via a typical Fickian diffusion mechanism. The modified coaxial electrospinning with solvent as sheath fluid can be a useful tool for developing novel sustained release drug delivery nanofibers.

Targeting at the brittleness of cured epoxy (EP), functionalized CNTs were integrated into the thermoset to make high-performance CNTs/EP nano-composites.In this investigation, polymaleic acid modified CNTs with a high surface grafting ratio (PMA-CNTs)was prepared through the plasma induced grafting technique , then further functionalized with amino groups to yield A-PMA-CNTs, which were then incorporated into epoxy matrix. Characterization of mechanical properties and heat resistance of the A-PMA-CNTs/EP nanocomposites indicates that A-PMA-CNTs can significantly strengthen and toughen the epoxy resin, with an increased glass transition temperature.