Degree of Cure, Microstructures, and Properties of Carbon/Epoxy Composites Processed via Frontal Polymerization.

The frontal polymerization (FP) of carbon/epoxy (C/Ep) composites is investigated, considering FP as a viable route for the additive manufacturing (AM) of thermoset composites. Neat epoxy (Ep) resin-, short carbon fiber (SCF)-, and continuous carbon fiber (CCF)-reinforced composites are considered in this study. The evolution of the exothermic reaction temperature, polymerization frontal velocity, degree of cure, microstructures, effects of fiber concentration, fracture surface, and thermal and mechanical properties are investigated.

Nanogels based on poly(vinyl acetate) for the preparation of patterned porous films.

The use of poly(vinyl acetate) (PVAc) nanogels for the fabrication of patterned porous surfaces is described. These nanogels were synthesized by controlled radical cross-linking copolymerization (CRCC) involving a xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) mechanism. This synthesis methodology allowed for the preparation of nanogels based on PVAc with a controlled constitutive chain length and average numbers of chains and cross-links.

Environmentally responsive particles: from superhydrophobic particle films to water-dispersible microspheres.

We describe the preparation, by precipitation copolymerization, of multifunctional divinylbenzene-co-pentafluorostyrene microspheres able to produce superhydrophobic surfaces or disperse in aqueous media upon annealing either in air or water, respectively. For that purpose, an amphiphilic block copolymer, polystyrene-b-poly(acrylic acid), was introduced in the initial feed composed of divinylbenzene and 2,3,4,5,6-pentafluorostyrene. As a result, fluorinated particles were obtained in which the diblock copolymer was encapsulated during the polymerization step.

Fabrication and superhydrophobic behavior of fluorinated microspheres.

We describe the preparation of fluorinated microspheres by precipitation polymerization and their use to fabricate superhydrophobic surfaces. For that purpose, two different approaches have been employed. In the first approach, a fluorinated monomer (either 4-fluorostyrene or 2,3,4,5,6-pentafluorostyrene) was added to the initial mixture of monomers constituted by styrene (S) and divinylbenzene (DVB).

Self-organized hierarchical structures in polymer surfaces: self-assembled nanostructures within breath figures.

Herein we report the preparation of hierarchically micro- and nanostructured polymer surfaces in block copolymer/homopolymer blends. The structural order at different length scales was obtained combining two methodologies, e.g.

Design of polypeptide-functionalized polystyrene microspheres.

In this contribution, the principle of spontaneous surface segregation has been applied for the preparation of polypeptide-functionalized polystyrene microspheres. For that purpose, an amphiphilic diblock copolymer was introduced in the mixture styrene/divinylbenzene and polymerized using AIBN as initiator. During the polymerization, cross-linked particles were obtained in which the diblock copolymer was encapsulated.

Structured assemblies of ferromagnetic particles through covalent immobilization on functionalized polymer surfaces obtained by surface segregation.

We report a strategy to immobilize magnetic particles on polymer surfaces in an organized manner. Surface segregation of binary polymer blends provided surfaces with the desired chemical functions (carboxylic functions). These functional groups were demonstrated to be accessible and were thus able to react with magnetic particles functionalized with amine functions.

Amphiphilic diblock copolymers with adhesive properties: I. Structure and swelling with water.

We study asymmetric block copolymers with the simple diblock AB architecture, in the case where the longer block A is both hydrophobic and "soft", whereas the shorter block B is hydrophilic and "hard". Materials with such a particular combination of physico-chemical and mechanical properties have distinctive advantages, in particular for designing water-compatible adhesive materials. The phase diagram is established, combining NMR and SAXS characterisations of the materials.

Scaling properties of contact area of pressure-sensitive adhesives.

Two new devices were developed to provide accurate measurements of both the contact area and the tack strength of pressure-sensitive adhesives (PSAs). The first one is the "mechano-optical tack tester" (MOTT), which was designed to apply controlled contact pressure by means of a quartz prism probe, for determined contact times, onto the surfaces of PSA samples. The contact area is measured by the reflection of light at the quartz probe surface, which is in contact with the adhesive.

Influence of surface and bulk structures of acrylic PSA films onto their tack properties.

PSA films are obtained by coalescence of latices synthesized by free-radical emulsion polymerization of methyl methacrylate (MMA) and 2-ethylhexyl acrylate (EHA). For the same overall 50/50 molar composition, the polymer particles have well-defined structures when the feed composition and the feed mode (using batch or semicontinuous processes) are adjusted. The characterizations of the film structures by surface (tapping mode AFM) and bulk (DSC, rheology) analyses argue for the conservation of the initial particle structure when coalescence occurs.

[Good tolerance and absence of immunologic effects in mice treated with arsenic-rich thermal water].

Three strains of mice were given, per os and ad libitum, a spa water containing 6.8 mg/l arsenic and indicated for the treatment of allergic respiratory diseases or chronic bronchitis. The daily arsenic intake was approximately from 1.