Search results for "Copolymers"
showing 10 items of 87 documents
Amphiphilic Copolymers Based on Poly[(hydroxyethyl)-d,l-aspartamide]: A Suitable Functional Coating for Biocompatible Gold Nanostars
2013
Novel amphiphilic copolymers have been synthesized based on a biocompatible poly(hydroxyethylaspartamide) (PHEA) backbone, bearing both anchoring groups for gold nanoparticles, such as thiols and disulfide, and conjugable moieties, such as amino groups, the latter as points suitable for appending further functional agents. The strategy was to functionalize α,β-poly[(N-2- hydroxyethyl)-d,l-aspartamide] (PHEA) with PEG2000-NH2 and with ethylenediamine (EDA) obtaining a partially pegylated copolymer with a large number of pendant primary amino groups. A fraction of the latter was conjugated with molecules bearing terminal thiol moieties such as 12-mercaptododecanoic acid (MDA) and disulfide gr…
Effect of the Substituent Position on the Anionic Copolymerization of Styrene Derivatives: Experimental Results and Density Functional Theory Calcula…
2019
In a combined synthetic, kinetic and theoretical study, the living anionic copolymerization of styrene and its ring-methylated derivatives ortho-, meta-, and para-methylstyrene (MS) was examined by real-time 1H NMR spectroscopy in the nonpolar solvents toluene-d8 and cyclohexane-d12 as well as by density functional theory calculations. Based on the NMR kinetics data, reactivity ratios for each comonomer pair were determined by the Kelen–Tudős method and numerical integration of the copolymerization equation (Contour software). The reaction pathway was modeled and followed by density functional theory (DFT) calculations to validate and predict the experimentally derived reactivity ratios. Un…
PEG-based Multifunctional Polyethers with Highly Reactive Vinyl-Ether Side Chains for Click-Type Functionalization
2011
Introduction of highly reactive vinyl ether moieties along a poly(ethylene-glycol) (PEG) backbone has been realized by copolymerization of the novel epoxide monomer ethoxy vinyl glycidyl ether (EVGE) with ethylene oxide (EO). A series of copolymers with varying structure (block and random) as well as EVGE comonomer content (5-100%) with molecular weights in the range of 3,900-13,200 g/mol and narrow molecular weight distributions (M-w/M-n = 1.06-1.20) has been synthesized and characterized with respect to their microstructure and thermal properties. The facile transformation of the vinyl ether side chains in click type reactions was verified by two different post polymerization modification…
in vitro biological evaluation of folate-functionalized block copolymer micelles for selective anti-cancer drug delivery.
2008
The main objective of this study was to evaluate the ability of folic acid-functionalized diblock copolymer micelles to improve the delivery and uptake of two poorly water-soluble anti-tumor drugs, tamoxifen and paclitaxel, to cancer cells through folate receptor targeting. The diblock copolymer used in this study comprised a hydrophilic poly[2-(methacryloyloxy)ethyl phosphorylcholine] (MPC) block, carrying at the chain end the folate targeting moiety, and a pH-sensitive hydrophobic poly[2-(diisopropylamino)ethyl methacrylate] (DPA) block (FA-MPC-DPA). The drug-loading capacities of tamoxifen- and paclitaxel-loaded micelles were determined by high performance liquid chromatography and the m…
When Functionalization of PLA Surfaces Meets Thiol−Yne Photochemistry: Case Study with Antibacterial PolyaspartamideDerivatives
2014
International audience; In this work we wish to report on the covalent functionalization of polylactide (PLA) surfaces by photoradical thiol–yne to yield antibacterial surfaces. At first, hydrophilic and hydrophobic thiol fluorescent probes are synthesized and used to study and optimize the conditions of ligation on alkyne-PLA surfaces. In a second part, a new antibacterial polyaspartamide copolymer is covalently grafted. The covalent surface modification and the density of surface functionalization are evaluated by SEC and XPS analyses. No degradation of PLA chains is observed, whereas covalent grafting is confirmed by the presence of S2p and N1s signals. Antiadherence and antibiofilm acti…
Calorimetric and Volumetric Investigations of the Effect of the Hydrophobicity of the Surfactant on the Binding between (Ethylene oxide)13-(propylene…
2004
The enthalpy and the volume of transfer (DeltaY(t)) of the unassociated (ethylene oxide)(13)-(propylene oxide)(30)-(ethylene oxide)(13) (L64) from water to the aqueous sodium alkanoate solutions as functions of the surfactant concentrations (m(S)) were determined at 298 K. The surfactants studied are sodium hexanoate, sodium heptanoate, sodium octanoate, sodium undecanoate, and sodium dodecanoate. As a general feature, for the short alkyl chain surfactants, DeltaY(t) describes an S-shaped curve in the range of m(S) analyzed whereas for the more hydrophobic surfactants the DeltaY(t) vs m(S) trends exhibit maxima which appear at ms values very close to the critical micellar concentration in w…
Copolymerization of ethylene with 1‐hexene over metallocene catalyst supported on complex of magnesium chloride with tetrahydrofuran
2004
The study of ethylene/1-hexene copolymerization with the zirconocene catalyst, bis(cyclopentadienyl)zirconium dichloride (Cp 2 ZrCl 2 )/methylaluminoxane (MAO), anchored on a MgCl 2 (THF) 2 support was carried out. The influence of 1-hexene concentration in the feed on catalyst productivity and comonomer reactivity as well as other properties was investigated. Additionally, the effect of support modification by the organoaluminum compounds [(MAO, trimethylaluminum (AlMe 3 ), or diethylaluminum chloride (Et 2 AlCl)] on the behavior of the MgCl 2 (THF) 2 /Cp 2 ZrCl/MAO catalyst in the copolymerization process and on the properties of the copolymers was explored. Immobilization of the Cp 2 ZrC…
Synthesis of PP-LCP graft copolymers and their compatibilizing activity for PP/LCP blends
1998
The aim of this work was the synthesis of new graft copolymers consisting of polypropylene (PP) backbones and liquid crystalline polymer (LCP) branches, to be used as compatibilizing agents for PP/LCP blends. The PP-g-LCP copolymers have been prepared by polycondensation of the monomers of a semiflexible liquid crystalline polyester (SBH 1 : 1 : 2), that is, sebacic acid (S), 4,4′-dihydroxybiphenyl (B), and 4-hydroxybenzoic acid (H) in the mole ratio of 1 : 1 : 2, carried out in the presence of appropriate amounts of a commercial acrylic-acid-functionalized polypropylene (PPAA). The polycondensation products, referred to as COPP50 and COPP70, having a calculated PPAA concentration of 50 and…
Acid-base properties and sequestering abilities towards toxic metal ions of cyclodextrin-calixarene co-polymers
Smart materials with stimuli-responsive properties represent an interesting research area considering both their potential applications and the conceptual issues implied. They might be successfully employed in various fields, such as drug carrier/delivery devices to sensors, environment remediation, active packaging [1-2]. In this contest, we have recently synthesized various pH-responsive pre- and post-modified cyclodextrin-calixarene nanosponges (CyCaNSs) with 1,2,3-triazole linker units (ACNSs) able to vary their sequestering abilities towards organic and inorganic compounds. In particular, their adsorption properties were varied changing the molar ratio between the co-monomers, and the …