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We report here a synthetic study on the formation process of hollow polymeric nanospheres based on a simple, core-template-free route, and the effects of polymerization concentration, shell cross-linking, pH, salt concentration and temperature on the size and stability of hollow polymeric nanospheres. The hollow structure of polymeric nanospheres is spontaneously formed by polymerization of acrylic...
A novel antibacterial coating for cotton fabrics has been developed using core-shell particles that consist of poly(n-butyl acrylate) (PBA) cores and chitosan shells. The spherical particles are prepared via a surfactant-free emulsion copolymerization of n-butyl acrylate in an aqueous chitosan solution induced by a small amount of tert-butyl hydroperoxide. The PBA-chitosan core-shell particles have...
In this work, the synthesis, properties of a thermal/pH-sensitive core-shell copolymer latex were studied and its potential application as a targeting drug carrier was also investigated, where the crosslinked copolymer of N-isopropylacrylamide (NIPAAm) and chitosan was synthesized by soapless dispersion polymerization as the core, and the copolymer of methacrylic acid (MAA) and methyl methacrylate...
Synthesis of poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers is discussed herein. Siloxane prepolymer was first prepared via acid-catalyzed ring-opening polymerization of octamethylcyclotetrasiloxane (D 4 ) to form polydimethylsiloxane (PDMS) prepolymers. It was subsequently functionalized with hydroxy functional groups at both terminals. The hydroxy-terminated PDMS...
A simple strategy for the one-step synthesis of AgCl/polypyrrole core/shell nanostructures with controllable shell thickness in the presence of chitosan and thus hollow polypyrrole nanoparticles was reported. AgCl, as a template, was formed during the initial polymerization by the interaction between metal cations and oxidizing anions and adsorbed with chitosan whereupon to induce the coating of polypyrrole...
New spherically shaped crosslinked IPN hydrogels based on chitosan and poly(vinylpyrrolidone) were prepared. The IPN hydrogels were synthesized in two steps: (1) chitosan (CHT) crosslinked beads were obtained by reaction of chitosan with ethyleneglycol diglycidyl ether (EGDE); (2) absorption of a suitable amount of a solution of vinylpyrrolidone (VP) monomer from the porous CHT beads followed to VP...
The grafting of poly(ethylene glycol) functionalized by ester groups (MeO-PEG-ester) onto chitosan was studied and optimized using different reaction conditions. In a first procedure, the grafting was made from 6-O-triphenylmethyl-chitosan after protection of primary hydroxyl groups and in a second one, it was made directly onto chitosan. NMR spectroscopy was an important tool to study these reactions...
N-Phosphonomethylation of chitosan reaction was studied and optimized using different reaction conditions. NMR spectroscopy was an important tool in this work to study this reaction and the α-aminomethylphosphonic acid function introduced onto chitosan was unequivocally characterized by 31 P and 13 C NMR analyses. But surprisingly, whatever the reaction conditions used, N-phosphonomethylation...
An electrospinning method was used to fabricate chitin nanofibous matrix for wound dressings. Chitin was depolymerized by gamma irradiation to improve its solubility. The electrospinning of chitin was performed with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a spinning solvent. Morphology of as-spun and deacetylated chitin (chitosan) nanofibers was investigated by scanning electron microscopy. Although...
The electrospinning of silk fibroin(SF)/chitosan(CS) blends with different composition ratios was performed with formic acid as a spinning solvent. The SF/CS blends containing up to the CS content of 30% could be electrospun into the continuous fibrous structure, although pure CS was not able to be electrospun into the fibrous structure. As-spun SF/CS blend nanofibers showed smaller diameter and narrower...
Crosslinking on chitosan was conducted with γ-glycidoxypropyltrimethoxysilane (GPTMS) with in situ formation of chitosan–silica hybrid membranes. The formed silica structure was observed with 29 Si NMR, scanning, and transmission electronic microphotograghy. Energy dispersive X-ray Si-mapping analysis demonstrated the homogeneous dispersion of silica in chitosan polymer domains. The formed...
The complexation agent 2[-bis-(pyridylmethyl) aminomethyl]-4-methyl-6-formyl-phenol (HL) was immobilized in chitosan in order to obtain a new adsorbent material to be employed in studies on adsorption and pre-concentration of Cu(II). The chitosan modified by the complexation agent was characterized by infrared spectroscopy, DSC and TGA. The studies were conducted as a function of the pH of the medium...
Homogeneous transparent hybrid films consisting of chitosan (CHI), poly(monomethyl itaconate) (PMMI) and silica were obtained indicating the absence of microphase separation. These ternary hybrid materials are very interesting since materials with high functionality can be obtained presenting different properties from those of the starting materials but with the advantage of preserving the inherent...
A novel chitosan-based polymeric surfactant, DG-chitosan, was prepared via reductive N-alkylation of chitosan with 3-O-dodecyl-d-glucose in acetate buffer (pH 4.3, 0.1 M)-methanol in the presence of sodium cyanoborohydride (NaBH 3 CN). DG-chitosan was swelling in water, partly dissolvable in pyridine and DMF, and completely soluble in 0.1% aqueous acetic acid. 1 H and 13 ...
This study describes a comprehensive approach to the preparation of novel polymer electrolytes comprising (i) oligo(ethylene oxide) solvating chains and conjugated furan chromophores, both grafted onto a film-forming chitosan backbone and (ii) lithium perchlorate as the ionic conductor. The combination of these four elements was conceived in order to optimize both the electrochemical and mechanical...
A novel cytocompatible graft copolymer of chitosan and l-lactic acid (CL) was prepared by grafting l-lactic acid onto the amino groups in chitosan without a catalyst. The structures of the CL graft copolymers were characterized by FTIR, 13 C-NMR and X-ray measurements. Degree of substitution and side-chain length were evaluated from salicylaldehyde and elemental analysis. The tensile strength...
Novel chitosan gel beads were synthesized by a coupled ionic and chemical co-crosslinking mechanism. Tripolyphosphate (TPP) and a naturally occurring crosslinking reagent, genipin, which has been used in herbal medicine, were employed, respectively, as an ionic and a chemical crosslinkers to prepare the chitosan-based networks of gel beads. The competitive crosslinking of chitosan with ionic crosslinker...
A new method for the surface modification of nonporous glass beads (average diameter, 6μm), which characterized by formation of a 1,3-thiazolidine ring between l-cysteine linkers on the glass bead and reducing ends of chitosan, has been developed. γ-Aminopropyltriethoxysilane (APES)-treated glass bead was first subjected to condensation with an l-cysteine derivative, l-4-carboxy-3-formyl-2,2-dimethylthiazolidine...
Macroporous chitosan beads used for the immobilization of an anti-inflammatory drug were prepared by the wet phase-inversion method. There are two stages of phase-inversion observed from the cast of chitosan droplet in tripolyphosphate (TPP) aqueous solution. The first stage of phase-inversion is dominated by liquid-liquid demixing and the morphology of the freeze-dried chitosan bead shows a bundle-like...
The complexation of copper ions by chitosan and its oligomers is investigated using potentiometric and spectrophotometric methods to study the nature of the complexes involved and the role of the degree of polymerisation. Two complexes are demonstrated. Their structure is proposed, the pH range in which they are respectively stable is determined and their stability constants calculated. Finally a...
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