Search

Obtaining core-sheath fibers by single-spinneret electrospinning is a recent and straightforward approach to prepare composite fibers. Fibers of more complex architecture consisting of poly(ethylene oxide) (PEO) core, inner poly(Llactide) sheath sd and outer beeswax (BW) sheath may also be obtained using this method. In the present study we report its applicability for a large series of (bio)degradable polyesters such as poly(e-caprolactone), poly(D,L-lactide-co-glycolide), poly(butylene succinate), poly(3-hydroxybutyrate), and poly(L-lactideco- D,L-lactide). The fibers have a well-differentiated PEO core, polyester inner sheath and BW outer sheath. The possibility for targeted location of hydrophilic or hydrophobic substances in the core or in the sheaths of the PEO/polyester/BW fibers has been demonstrated using nanosized zinc oxide with unmodified (hydrophilic) or silanized (hydrophobic) surface. PEO/polyester/BW fibrous materials loaded with a model drug (5-nitro-8-hydroxyquinoline) exhibit antimicrobial activity. The obtained results show that single-spinneret electrospinning is a novel and versatile method to prepare core-double sheath composite fibers prospective for various applications such as biomedicine, cosmetics, and food packaging. [ABSTRACT FROM AUTHOR]

For the first time, fibrous polylactide (PLA) materials containing plant extract of Portulaca oleracea obtained using supercritical carbon dioxide were successfully prepared by electrospinning. The effect of the extract concentration on the morphology and properties of the obtained materials was studied. P. oleracea extracts of 0–7.5 wt% in 10 wt% PLA solutions were electrospun. The optimal process conditions for the preparation of defect‐free fibers were found. The newly obtained fibrous materials were fully characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X‐ray diffraction analysis and water contact angle measurements. It was found that the incorporation of the crude extract had a significant effect on the average fiber diameter, thermal characteristics and structure of the obtained materials. Moreover, it was found that the electrospun PLA/P. oleracea materials showed high antioxidant activity. The cytocompatibility of fibrous mats was assessed and it was found that the materials loaded with P. oleracea enhanced the cell viability of mouse BALB/c‐3T3 fibroblasts. Thus the obtained novel materials could be a potential candidate for tissue regeneration and wound healing applications. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

ABSTRACT New microfibrous materials from polylactide and polyvinylpyrrolidone or polyethylene glycol loaded with the natural polyphenolic compound curcumin have been prepared by one-pot electrospinning. The incorporation of curcumin in the fibers contributes to shielding curcumin from photodestruction and to enhancement of the mechanical properties of the fibers. Moreover, the formation of hydrogen bonds between curcumin and polyvinylpyrrolidone or polyethylene glycol facilitates the drug release. Curcumin release provides for the antibacterial and anticoagulant activity of the curcumin-loaded mats and prevents adhesion and aggregation of platelets onto the surface of the mats. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42940. [ABSTRACT FROM AUTHOR]

The effect of pH and the ligand nature over the atom transfer radical polymerization (ATRP) of the anionic monomer sodium 2‐acrylamido‐2‐methylpropanesulfonate (AMPSNa) was investigated in aqueous medium by using ω‐halogenated poly(ethylene oxide) and CuBr, as macroinitiator and catalyst, respectively. The stability of both catalytic complexes and macroinitiator was investigated in function of pH, that is, fixed between 7.5 and 12. UV‐VIS spectroscopy confirmed a good catalytic complex stability in the studied conditions. Hydrolysis of the macroinitiator ester group at pH higher than 7.5 was detected by 1H NMR and GPC, yielding ill‐defined polymer samples when ATRP is performed in alkaline conditions. 2,2′‐Bipyridyl (Bpy), 1,1,4,7,10,10‐hexamethyltriethylenetetramine (HMTETA), and tris(2‐methylaminoethyl)amine (Me6‐TREN)‐based complexes were compared at the optimal pH (pH 7.5). When polymerization was carried out in the presence of CuBr · 2Me6‐TREN complex block copolymers with narrow molecular weight distribution (1.1 ≤ MW/Mn ≤ 1.3), and good agreement between theoretical and experimental molar masses was obtained. Moreover, increasing the PAMPSNa polymerization degrees (n) did not affect the control over the polymerization. Preliminary characterization of the diblock copolymers behavior in aqueous medium revealed a strong polyelectrolyte effect independently of n. Interestingly, occurrence of interactions between the PEO and PAMPSNa‐blocks was also evidenced by differential scanning calorimetry and thermogravimetric analyses. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1108–1119, 2009 [ABSTRACT FROM AUTHOR]