Reactive porous materials

The research topics developed by our team are mainly related with the synthesis of porous polymer materials and their applications in all domains of sustainable development (heterogeneous catalysis, biosensors, particles filters, cleaning up, green chemistry, etc.).

Keywords :

Porous polymers, supported chemistry, heterogeneous catalysis, concentrated emulsions, microcellular materials, green chemistry, renewable materials, ionic liquids

1.1. Generation of Porosity by Phase Separation

The first theme involves the preparation of functionalized polymeric materials by phase separation and their use in supported multi-step organic chemistry or liquid-solid selective extraction. This approach to generate a micro and mesoporosity in a polymeric network has been applied to different systems, from them, we will detail briefly the followings :

- functional organosilylated molecules have been grafted on polymeric supports to realize solid-phase multi-step syntheses. In our methodology, the silicon atom plays a double role. It serves as an anchoring site for the substrate onto the support, and it constitutes a hidden hydroxyl group as, when the target molecule is freed from the support, it is possible to introduce a hydroxyl function by oxidation of the silyl group.

- a method to reduce the binding power of sweet white wines has been developed using a selective liquid-solid extraction method. The objective was to anticipate the predictable tightening of the regulation on the quantities of sulfur dioxide allowed in wines. The process is patented. M. Blasi, the Ph-D student in charge of the project, was an award-winner of the "2006 Concours national d’aide à la création d’entreprises de technologies innovantes".
This work is still in progress in order to improve the processin view of industrial concern.

- a polymer-supported catalyst has been developed, in collaboration with a French industrial group, with the objective to replace an homogeneous industrial process currently in use by its heterogeneous counterpart preferentially under continuous flow conditions. The very promising results already obtained convinced the society to patent the process.

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SEM micrograph of a porous polystyrene-co-divinylbenzene bead obtained by radical polymerization of the continuous phase of an inverse concentrated emulsion (total porosity : 90%)

1.2. Porosity Generation via Concentrated Emulsions

Our second area of interest concerns the preparation of porous polymeric materials with hierarchical porosity by polymerization of the continuous phase of a concentrated emulsion. This approach allows the straightforward preparation of porous microcellular monolithic materials having an original interconnected open-cell morphology. These materials, known as polyHIPEs, are finding various applications in numerous fields.

Some of our most recent results obtained in this field are briefly described below :

- the in situ growth of metallic nanoparticles onto interconnected microcellular polymeric materials synthesized in the laboratory has been studied. The hybrid materials obtained have been tested as supported catalysts in reactions such as hydrogenations or carbon-carbon bond formations.

- aerosol filters made of microcellular foams were prepared from reverse concentrated emulsions. They possess an alveolar connected structure very different from that of fibrous or granular filters currently used. This work revealed the interest of such materials in the domain of filtration of particles.

- new polydimethylsiloxane-based (PDMS) porous absorbent phases having high specific surface area prepared by the method of reverse concentrated emulsions have been synthesized. These materials are intended to be used to detect directly aromatic hydrocarbons in air (BTX).

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© CNRS Photothèque/ISM/Deleuze Hervé, Birot Marc
SEM micrograph of a porous poly(alkyl)siloxane monolith obtained by hydrosilylation of the continuous phase of a concentrated emulsion
(total porosity : 85%)

- the synthesis and the characterization of microcellular organic-inorganic hybrids materials based on sol-gel processes with applications in the domain of catalysis has been developed. The macroporosity, generated from a direct concentrated emulsion, is combined with some micro and mesoporosity in the cell walls coming from the use of micelles precursors. The results are patented and applications of these materials in the domain of catalysis are in progress.

1.3 Development of Biomass in Porous Material Chemistry

The substitution of polymers issued from fossil resources by raw materials issued from sustainable resources, especially from plants, represents a major issue of the chemistry of the 21st century. In this context, we have undertaken to extend the techniques of generation of porosity, previously developed with synthetic polymers, to the development of by- products of paper-making industry.

Thus, spherical beads of Kraft lignin have been obtained by suspension polymerisation. These materials could represent an alternative to polystyrene resins that are actually widely used in various domains.

The generation of macroporosity from concentrated emulsions (the polyHIPE technique) is under development as well from low-value paper mill by-products (black liquor). Possible applications are macro-microporous monolithic carbon for energy storage or catalytic supports.

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Industrial Kraft lignin beads (Ø =0.5-1 mm)

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SEM micrograph of a porous monolith obtained by crosslinking the black liquor continuous phase of a concentrated emulsion (total porosity : 65%)


Contacts :
Hervé Deleuze
Marie-Anne Dourges
Anne Thienpont

Toutes les versions de cet article : [English] [français]


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