Synthesis of fully acrylic thermoplastic elastomers by atom transfer radical polymerization (ATRP), 2a effect of the catalyst on the molecular control and the rheological properties of the triblock copolymers

in Macromolecular Chemistry and Physics (2000), 201(11), 1108-1114

The ATRP of MMA was initiated by α,ω-dibromo poly(n-butyl acrylate) in the presence of NiBr2(PPh3)2 leading to poly(MMA)-b-poly(nBuA)-b-poly(MMA) triblock copolymers (MnBM). The initiation of the MMA ... [more ▼]

The ATRP of MMA was initiated by α,ω-dibromo poly(n-butyl acrylate) in the presence of NiBr2(PPh3)2 leading to poly(MMA)-b-poly(nBuA)-b-poly(MMA) triblock copolymers (MnBM). The initiation of the MMA polymerization is slow compared to the chain propagation, which results in PMMA blocks of broad molecular weight distribution (MWD). In order to improve this situation, several experimental parameters were varied. CuBr/dNBipy was first substituted for NiBr2(PPh3)2, the results being, however, even worse. Then, the halide exchange was considered by substituting CuCl for CuBr. The CuCl/dNBipy catalyst proved superiority over the originally used NiBr2(PPh3)2 system. Finally, the addition of an excess of CuCl2 (deactivator) to the CuCl/dNBipy catalyst was very beneficial in decreasing the MWD of the PMMA blocks. Indeed, the SEC chromatograms are monomodal and narrow from the very beginning of the polymerization. The rheological analysis of the MnBM triblocks synthesized in the presence of each of the aforementioned catalytic systems confirmed differences in the molecular control of the copolymeriza-tion reaction. [less ▲]

Synthesis of functional amphiphilic copolymers for the elaboration of third generation drug nanocarriers

Poster (2007, May 24)

Synthesis of functional amphiphilic polyesters for the preparation, labeling and targeting of drug nanocarriers

Conference (2006, October)

Synthesis of functional nanoparticles by inverse microemulsion polymerization for diagnostic application

Poster (2001, December 13)

Synthesis of functionalized polyesters by the "click" copper-catalyzed alkyne-azide cycloaddition

in Khosravi, Ezat; Yagci, Yusuf; Savelyev, Yuri (Eds.) New smart materials via metal mediated macromolecular engineering (2009)

The functionalization of aliphatic polyesters by the copper-mediated azide–alkyne Huisgen’s cycloaddition is very efficient under mild conditions, which prevents degradation from occurring. The ... [more ▼]

The functionalization of aliphatic polyesters by the copper-mediated azide–alkyne Huisgen’s cycloaddition is very efficient under mild conditions, which prevents degradation from occurring. The implementation of this reaction requires the synthesis of aliphatic polyesters bearing pendant alkynes and azides, which can be carried out either by polycondensation or by ring-opening polymerization. [less ▲]

Synthesis of growth hormone by bacteria

in Nature (1978), 276(5690), 795-8

A hybrid gene was constructed between the beta-lactamase gene of plasmid pBR322 and the cloned coding sequence for rat growth hormone. This gene is expressed in bacteria and growth hormone sequences are ... [more ▼]

A hybrid gene was constructed between the beta-lactamase gene of plasmid pBR322 and the cloned coding sequence for rat growth hormone. This gene is expressed in bacteria and growth hormone sequences are detectable by immunological methods. [less ▲]

Synthesis of high-relaxivity contrast agents for magnetic resonance imaging by "click" chemistry

Poster (2007, August 31)

Synthesis of highly functionalized poly(alkyl cyanoacrylate) nanoparticles by means of click chemistry

in Macromolecules (2008), 41(22), 8418-8428

A general methodology was proposed to prepare highly functionalized poly(alkyl cyanoacrylate) nanoparticles by means of Huisgen 1,3-dipolar cyclo-addition, the so-called click chemistry. To achieve this ... [more ▼]

A general methodology was proposed to prepare highly functionalized poly(alkyl cyanoacrylate) nanoparticles by means of Huisgen 1,3-dipolar cyclo-addition, the so-called click chemistry. To achieve this goal, different protocols were investigated to obtain azidopoly(ethylene glycol) cyanoacetate of variable molar mass, followed by a Knoevenagel condensation−Michael addition reaction with hexadecyl cyanoacetate to produce a poly[(hexadecyl cyanoacrylate)-co-azidopoly(ethylene glycol) cyanoacrylate] (P(HDCA-co-N3PEGCA)) copolymer, displaying azide functionalities at the extremity of the PEG chains. As a proof of concept, model alkynes were quantitatively coupled either to the P(HDCA-co-N3PEGCA) copolymers in homogeneous medium followed by self-assembly in aqueous solution or directly at the surface of the preformed P(HDCA-co-N3PEGCA) nanoparticles in aqueous dispersed medium, both yielding highly functionalized nanoparticles. This versatile approach, using alkyl cyanoacrylate derivatives, opened the door to ligand-functionalized and biodegradable nanoparticles with “stealth” properties for biomedical applications. [less ▲]

Synthesis of highly ordered mesoporous compounds with control of morphology using a non-ionic surfactant as template

in Studies in Surface Science and Catalysis (2002), 141

Highly ordered hexagonal mesostructures (CMI-1 compounds) can be obtained under mild acidic conditions by working at low concentrations of non-ionic decaoxyethylene cetyl ether [C16(EO)10]. The present ... [more ▼]

Highly ordered hexagonal mesostructures (CMI-1 compounds) can be obtained under mild acidic conditions by working at low concentrations of non-ionic decaoxyethylene cetyl ether [C16(EO)10]. The present work shows that it is possible to gain control at the nanometer scale over the packing symmetry of the channels, as well as at the micrometer level over the morphology of the particles by varying the surfactant / silica molar ratio and the hydrothermal treatment conditions. Very high loadings of silica precursors typically afford highly ordered hexagonal CMI-1 compounds whereas an increase of the surfactant / silica molar ratio results in materials with a more disordered channel array. In a parallel way, very low molar ratios of surfactant / silica lead to ropes, gyroids and toroids whereas spheres are the most stable shape with the lower quantities of silica. From this point, it appears thus that not only the structure but also the morphologies encountered for MCM-41 type mesoporous silica can be reproduced with a non-ionic templating agent. [less ▲]

Synthesis of large pore disordered MSU-type mesoporous silicas through the assembly of C16(EO)10 surfactant and TMOS silica source: Effect of the hydrothermal treatment and thermal stability of materials

in Journal of Physical Chemistry B (2001), 105(26), 6070-6079

Decaoxyethylene cetyl ether [C 16(EO) 10] has been employed as templating agent for large pore disordered MSU-type mesoporous silicas synthesis. The effect of the hydrothermal treatment (heating time and ... [more ▼]

Decaoxyethylene cetyl ether [C 16(EO) 10] has been employed as templating agent for large pore disordered MSU-type mesoporous silicas synthesis. The effect of the hydrothermal treatment (heating time and temperature) on the textural properties, in particular, pore diameter of materials has been investigated. The obtained materials have been characterized by different techniques such as X-ray diffraction, scanning and transmission electron microscopy and nitrogen adsorption-desorption analysis. The thermal stability of the compounds is also evaluated. Our results show that the pore diameter depends strongly on the heating time and temperature. This is the result of a competition between the stretching of the surfactant chains, which can lead to the breakdown of the walls separating adjacent pores, and the reorganization of micelles with heating time and temperature. At higher temperature or for longer durations, a more extended surfactant molecular conformation can be obtained, which leads to materials with larger pore sizes. A reorganization of the micellar solution during the hydrothermal treatment in autoclave can also simultaneously occur to give materials with smaller pore diameter. It is found that compounds prepared with the nonionic surfactant exhibit an enhanced thermal stability compared to those synthesized with cetyltrimethylammonium bromide (CTMABr) as templating agent. This higher stability is related to the synthesis pathway and the structure of materials. [less ▲]