Search results for "Derivative"
showing 10 items of 1074 documents
Tailoring the stealth properties of biocompatible polysaccharide nanocontainers.
2014
Fundamental development of a biocompatible and degradable nanocarrier platform based on hydroxyethyl starch (HES) is reported. HES is a derivative of starch and possesses both high biocompatibility and improved stability against enzymatic degradation; it is used to prepare nanocapsules via the polyaddition reaction at the interface of water nanodroplets dispersed in an organic miniemulsion. The synthesized hollow nanocapsules can be loaded with hydrophilic guests in its aqueous core, tuned in size, chemically functionalized in various pathways, and show high shelf life stability. The surface of the HES nanocapsules is further functionalized with poly(ethylene glycol) via different chemistri…
Construction and evaluation of sponge scaffolds from hyaluronic acid derivatives for potential cartilage regeneration
2020
A two or one pot synthesis has been used for the reaction of hyaluronic acid (HA) with octadecylamine (C-18) and hydrazine (Hy). In both cases, the chemical derivatization involved primary hydroxyl groups of hyaluronic acid and not its carboxyl groups, whose presence is important for receptor interaction. In this way, Hy-HA-C-18 derivatives have been obtained with appropriate hydrophobic and hydrophilic character. Their ability to form homogeneous physical hydrogels has been evaluated as well as the possibility to obtain porous sponges through salt leaching technology. Sponges showing the highest porosity, potentially compatible with cell entrapment, have been characterized with regard to t…
11B-MAS NMR approach to the boron adsorption mechanism on a glucose-functionalised mesoporous silica matrix
2018
[EN] Boron chemistry has raised much interest because, despite the difference between necessities and toxicity being very narrow, it is still widely used in industrial processes. In a previous work we reported an adsorbent for boron extraction from water by the functionalisation of a UVM-7 mesoporous silica matrix with gluconamide moieties. The ability of this material to adsorb boron is based on its well-known affinity for coordinating the cis-diols present in attached saccharide. Although much research on the formation of boron esters with sugars and sugar derivatives in solution has been done, very few reports have dealt with the adsorption mechanism of boron onto functionalised material…
Performance of Multilayered Particles: Influence of a Thin Cushioning Layer
2005
Nowadays, oral dosage forms with controlled release kinetics have known an increasing interest. The polymer coating of drug-loaded particles is one of the most common methods used for controlling drug delivery. Such multilayered particles could be either filled into capsules or compressed into tablets for their oral administration. However, many studies have noticed that coating films are damaged during the compression process, leading to significant changes in drug release profiles. The aims of this study were to investigate the effects of a thin cushioning layer [made of HydroxyPropylMethyl Cellulose (HPMC)] applied on coated theophylline particles upon particle characteristics, tablet pr…
Electrosynthesis and properties of poly(3,4-ethylenedioxythiophene) films functionalized with titanocene dichloride complex
2006
Synthesis of a titanocene dichloride derivative functionalized with 3,4-etylenedioxythiophene group, Tc1EDOT (Cl 2TiCpC5H4(CH2) (3,4ethylenedioxythiophene)) has been described. Redox behavior of the monomer in tetrahydrofuran (THF), dichloromethane (DCM) and acetonitrile (AN) at different scan rates has been discussed in terms of different ability of these solvents to coordination with the reduced titanocene (Tc) complex and the solvation of Cl − anions. Electrooxidation of Tc1EDOT to get a conducting polymer film with immobilized titanocene dichloride centers and electrochemical properties of its polymer matrix in background acetonitrile solution have been compared with those of non-substi…
A combined computational and experimental study on the mild steel corrosion inhibition in hydrochloric acid by new multifunctional phosphonic acid co…
2020
Two triazole derivatives with phosphonic acid as pendent group, namely [3-(4-phenyl-[1–3]triazol-1-yl)-propyl]-phosphonicaciddiethylester (PTP) and [3-[4-(4-dimethylamino-phenyl)-[1–3]triazol-1-yl]-propyl]-phosphonic acid diethylester (DMPTP) were synthesized and fully characterized using NMR spectroscopy, Mass spectrometry, Infra-Red (FT-IR) spectroscopy and elemental analysis. The synthesized multifunctional heterocycles were investigated to inhibit the corrosion of mild steel in acidic solution HCl (1 M) by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) and weight loss measurements. The results of the different corrosion measurement techniques are in goo…
Effect of Hydrothermal Treatment on Adsorption Properties of Silica Gel
2011
It has been proven by coupling near infared spectroscopy to second derivative processing of the spectra that the free and hydrogen bonded silanol groups attached to water molecules absorb at 5314 a...
Surface Functionality and Water Adsorption Studies of α-Aluminium (III) Oxide Nanoparticles by near Infrared Spectroscopy
2019
The adsorption of water on aluminium (III) oxide nanoparticle surface was studied by near infrared (NIR) spectroscopy. The comparison of NIR spectra at 40% and 60% humidity were reported in this work and were analyzed using second derivative techniques. The second derivative spectra were used to understand the chemistry of adsorption of water molecules. Small amounts of samples were dried under vacuum at 230 °C before the analysis. The analysis of the spectra confirms the presence of three different hydroxyl groups on aluminium (III) oxide surface. The spectra acquired during the adsorption of water molecules show the characteristic peaks in the range of 5400-5100 cm-1 corresponding to the …
Preparation of cholesteric particles from cellulose derivatives in a microfluidic setup
2011
A microfluidic setup was used to process lyotropic cholesteric liquid crystalline mixtures of cellulose derivatives into spherical particles in the micrometre scale. By the method of co-flowing injection, monodisperse droplets of the liquid crystal, dispersed in an aqueous carrier fluid, were prepared. Polymerization of the acrylic solvent with UV-light fixed the orientation obtained by the flowing motion. The resulting particles were characterized by polarizing optical microscopy.
Mesomorphic and electrooptical properties of viologens based on non-symmetric alkyl/polyfluoroalkyl functionalization and on an oxadiazolyl-extended …
2019
Two different sets of ionic liquid crystals based on bistriflimide salts of non-symmetrically substituted polyfluorinated bipyridinium (viologens) and bent symmetrically substituted dialkyl-oxadiazolyl-bipyridinium have been synthesized, in order to study the effect on the mesomorphic and electrooptical properties of the non-symmetric functionalization (alkyl chain and fluoroalkyl chains of different lengths) on the two pyridinium rings and additionally the effect of a bent conjugated spacer among the two pyridinium units of the viologen. POM and DSC characterization show that the synthesized salts have a mesomorphic and, in some cases, polymesomorphic behaviour in a wide thermal range, als…