Search results for "Reaction"
showing 10 items of 6134 documents
Kinetic parameters of a cyanate ester resin catalyzed with different proportions of nonylphenol and cobalt acetylacetonate catalyst
2005
The isothermal cure of a dicyanate ester monomer has been investigated by differential scanning calorimetry (DSC) in the presence of different quantities of a catalyst system formed by nonylphenol (NP) and cobalt (II) acetylacetonate (Co(AcAc)2). Two sets of experiences were studied. Firstly, the NP composition was varied from 0 to 10 per hundred resin (phr) and secondly, the Co(AcAc)2 loadings were changed at 2 phr of NP. It has been observed that the cyanate conversion increases significantly after the first addition of the metal catalyst and, also, at the same time the thermal stability improves. Moreover, the kinetic data have been fitted with a second-order equation respect to the cyan…
Studies on the structure of coumarin-modified dextran nanoparticles by fluorescence spectroscopy.
2012
The photophysical and photochemical characteristics of nano-scaled particles obtained via solvent displacement from coumarin-modified dextrans were studied by means of absorption- and fluorescence-spectroscopy. The environment-dependent fluorescence emission of the pendant 4-methyl-7-alkoxy coumarin groups was exploited as a probe to gain information about the inner structure of the polysaccharide based nanoparticles. Time-resolved fluorescence measurements showed that the particles had two domains of different polarity and it could be confirmed that the core of the nano-assemblies contained water. Moreover, preliminary experiments were carried out demonstrating the possibility to control t…
Multi-olefin containing polyethers and triazolinediones: a powerful alliance
2019
Multi-functional polyethers with ene or diene moieties were prepared via the polymerisation of tailored functional glycidyl ether monomers to create a platform for click chemistry with triazolinediones (TADs). Specifically, two novel monomers (i) 2,4-hexadien-1-yl glycidyl ether (HDEGE) and (ii) citronellyl glycidyl ether (CitroGE), designed to undergo a Diels–Alder or Alder–Ene reaction with TADs, respectively, were synthesized and subsequently transformed into a variety of tailored polyethers, either via the monomer activated method or anionic ring opening polymerisation. Multi-functional copolymers of HDEGE with ethylene oxide, propylene oxide and ethoxy ethyl glycidyl ether as well as A…
Die intramolekulare, radikalische kopf-schwanzbzw. Kopf-Kopf-addition von Phenylen-, Naphthylen- und Biphenylenbis(methacrylat)en
1977
1,2-, 1,3- und 1,4-Phenylenbis(methacrylat) (1a), (1b) und (1c), 2,3- und 1,6-Naphthylenbis(methacrylat) (2a) und (2b) sowie 2,2′-Biphenylenbis(methacrylat) (3) wurden nach einer bekannten Vorschrift dargestellt. Setzt man stark verdunnte Losungen dieser phenolischen Bisester in siedendem Benzol einem grosen Uberschus an 2-Cyano-2-propylradikalen R. (aus AIBN) aus, so entstehen neben wenigen olig-viskosen Produkten hauptsachlich kristallisierbare Verbindungen. Sie entstanden aus der intramolekularen Addition der zwei Methacrylatgruppen und Anlagerung von zwei Radikalen R · je Molekel. 1c gab nur eine derartige Verbindung, die nach den Elementaranlysen, der rel. mol. Masse, spektroskopischen…
Covalently Binding of Bovine Serum Albumin to Unsaturated Poly(Globalide-Co-ε-Caprolactone) Nanoparticles by Thiol-Ene Reactions.
2019
When nanoparticles (NPs) are introduced to a biological fluid, different proteins (and other biomolecules) rapidly get adsorbed onto their surface, forming a protein corona capable of giving to the NPs a new "identity" and determine their biological fate. Protein-nanoparticle conjugation can be used in order to promote specific interactions between living systems and nanocarriers. Non-covalent conjugates are less stable and more susceptible to desorption in biological media, which makes the development of engineered nanoparticle surfaces by covalent attachment an interesting topic. In this work, the surface of poly(globalide-co-e-caprolactone) (PGlCL) nanoparticles containing double bonds i…
HPMA-Based Nanoparticles for Fast, Bioorthogonal iEDDA Ligation
2019
Contains fulltext : 216143.pdf (Publisher’s version ) (Open Access) Fast and bioorthogonally reacting nanoparticles are attractive tools for biomedical applications such as tumor pretargeting. In this study, we designed an amphiphilic block copolymer system based on HPMA using different strategies to introduce the highly reactive click units 1,2,4,5-tetrazines (Tz) either at the chain end (Tz-CTA) or statistical into the hydrophobic block. This reactive group undergoes a rapid, bioorthogonal inverse electron-demand Diels-Alder reaction (iEDDA) with trans-cyclooctenes (TCO). Subsequently, this polymer platform was used for the preparation of different Tz-covered nanoparticles, such as micell…
Multihydroxy-Functional Polysilanes via an Acetal Protecting Group Strategy
2010
A new acetal-protected monomer for Wurtz-type coupling to polysilanes, dichloro(3-(2,2-dimethyl-1,3-dioxolane-4-yloxy)propyl)methylsilane, referred to as dichloro(isopropylidene glyceryl propyl ether)methylsilane (DCIMS), has been introduced to synthesize a series of protected linear polysilane copolymers, poly[di-n-hexylsilane-co-(isopropylidene glyceryl propyl ether)methylsilane] (P(DHS-co-IMS)) via alkali-mediated reductive Wurtz-type coupling. The acetal protecting group proved stable under the harsh polymerization conditions. Differential scanning calorimetry combined with 1H, 13C, and 29Si NMR measurements confirmed composition and random structure of the obtained copolymers. After se…
In situ forming hydrogels of hyaluronic acid and inulin derivatives for cartilage regeneration.
2014
An in situ forming hydrogel obtained by crosslinking of amino functionalized hyaluronic acid derivatives with divinylsulfone functionalized inulin (INU-DV) has been here designed and characterized. In particular two hyaluronic acid derivatives bearing respectively a pendant ethylenediamino (EDA) portion (HA-EDA) and both EDA and octadecyl pendant groups (HA-EDA-C18) were crosslinked through an azo-Michael reaction with INU-DV. Gelation time and consumption of DV portions have been evaluated on hydrogel obtained using HA-EDA and HA-EDA-C18 derivatives with a concentration of 3% w/v and a ratio 80/20 w/w respect to the crosslinker INU-DV. The presence of pendant C18 chains improves mechanical…
Physicochemical investigation of cobalt?iron cyanide nanoparticles synthesized by a novel solid?solid reaction in confined space
2004
Cobalt–iron cyanide (Cox[Fe(CN)6]) nanoparticles have been synthesized by a novel solid–solid reaction in the confined space of dry sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reversed micelles dispersed in n-heptane. The reaction has been carried out by mixing two dry AOT/n-heptane solutions containing CoCl2 and K4Fe(CN)6 or K3Fe(CN)6 nanoparticles in the micellar core, respectively. By UV-Vis spectroscopy it was ascertained that, after the mixing process, the formation of stable nanoparticles is fast and complete. Microcalorimetric measurements of the thermal effect due to the Cox[Fe(CN)6] nanoparticle formation allowed the determination of the stoichiometric ratio (x) and of the molar e…
A bioinspired metal–organic approach to cross-linked functional 3D nanofibrous hydro- and aero-gels with effective mixture separation of nucleobases …
2020
The direct reaction between Cu(CH3COO)2 and uracil-1-acetic acid in water gives rise to the formation of a hydrogel consisting of entangled nanometric ribbons of a crystalline antiferromagnetic 1D Cu(ii) coordination polymer (CP) decorated with biocompatible uracil nucleobases. This hydrogel is the precursor for the preparation of a meso/macroporous ultralight aerogel that shows a remarkable Young's modulus. As a proof-of-concept of the molecular recognition capability of the terminal uracil moieties anchored at Cu(ii) CP chains, this material has been tested as the selective stationary phase for the separation of nucleobase derivatives in HPLC columns.