US-12624182-B2 - Functionalized cellular elastomer foam, and a use of a cellular elastomer foam as a catalyst substrate

US12624182B2US 12624182 B2US12624182 B2US 12624182B2US-12624182-B2

Abstract

A functionalized cellular elastomer foam, and a use of a cellular elastomer foam as a catalyst substrate. The cellular elastomer foam is formed by supplying a porous cellular elastomer foam with an apparent porosity and having a mean equivalent diameter of the opening of the pores comprised between 100 μm and 5,000 μm. The porous cellular elastomer foam is then placed in contact with at least one compound including at least one catechol unit, and polymerizing the compound including at least one catechol unit on the surface of said porous cellular elastomer foam, thereby obtaining a mechanically flexible catalyst substrate that includes the cellular elastomer foam having on its surface an intermediate phase formed from the at least one compound including at least one catechol unit.

Inventors

David Edouard
Vincent Ritleng
Loïc JIERRY
Nguyet Trang Thanh CHAU DALENCON

Assignees

UNIVERSITE DE STRASBOURG
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
UNIVERSITE CLAUDE BERNARD LYON 1

Dates

Publication Date: 20260512
Application Date: 20220124
Priority Date: 20140722

Claims (18)

1 . A functionalized cellular elastomer able to be obtained by a method comprising: supplying a porous cellular elastomer foam with apparent porosity and having a mean equivalent diameter of an opening of the pores comprised between 100 μm and 5,000 μm; and placing said porous cellular elastomer foam in contact with at least one compound including at least one catechol unit, and polymerizing said compound including at least one catechol unit on the surface of said porous cellular elastomer foam, thereby obtaining a mechanically flexible substrate comprising said porous cellular elastomer foam having on its surface an intermediate phase formed from the polymerisation of said at least one compound including at least one catechol unit, wherein placing said porous cellular elastomer foam in contact with the at least one compound including at least one catechol unit, and polymerizing said compound including the at least one catechol unit on the surface of said porous cellular elastomer foam, comprises forming a polydopamine layer on a surface of said porous cellular elastomer foam.
2 . The functionalized cellular elastomer of claim 1 , wherein said compound including at least one catechol unit is a catechol monoamine.
3 . The functionalized cellular elastomer of claim 2 , wherein said compound including at least one catechol unit is 4-(2-aminoethyl) benzene-1,2-diol or a derivative thereof.
4 . The functionalized cellular elastomer of claim 1 , wherein said compound including at least one catechol unit is chosen from the group consisting of: caffeic acid, hydroxyhydroquinone, catechol, pyrogallol, morin (2′,3,4′,5′7-pentahydroxyflavone), epigallocatechin, epigallocatechin gallate, catechin and its stereoisomers, tannic acid.
5 . The functionalized cellular elastomer of claim 1 , wherein said porous cellular polymer foam comprises cells with a mean size comprised between 500 μm and 5,000 μm.
6 . The functionalized cellular elastomer of claim 1 , wherein the method further comprises functionalizing said porous cellular polymer foam by depositing a phase of at least one catalytically active material or at least one catalytically active phase precursor.
7 . The functionalized cellular elastomer of claim 6 , wherein the functionalized cellular elastomer is a catalyst substrate.
8 . The functionalized cellular elastomer of claim 6 , wherein said at least one catalytically active material is selected from the group consisting of: metal complexes including at least one group capable of forming covalent bonds with the intermediate phase formed from said compound including at least one catechol unit; organic molecules which are configured to catalyze a reaction, including at least one group to form covalent bonds with the intermediate phase formed from said compound including at least one catechol unit; and metal nanoparticles chosen from among Ag, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Au, Ce, or mixed oxides associated with these elements, or any combination(s) thereof.
9 . The functionalized cellular elastomer of claim 8 , wherein the metal nanoparticles have a mean particle size comprised between 0.5 and 100 nm.
10 . A functionalized cellular elastomer, comprising: a mechanically flexible porous cellular elastomer foam having an apparent porosity and a mean equivalent diameter of an opening of the pores comprised between 100 μm and 5,000 μm; and an intermediate phase, on the surface of said mechanically flexible porous cellular elastomer foam, formed from a polymerisation of at least one compound including at least one catechol unit, wherein said intermediate phase comprises a polydopamine layer.
11 . The functionalized cellular elastomer of claim 10 , wherein said compound including at least one catechol unit is a catecholmonoamine.
12 . The functionalized cellular elastomer of claim 11 , wherein said compound including at least one catechol unit is 4-(2-aminoethyl) benzene-1,2-diol or a derivative thereof.
13 . The functionalized cellular elastomer of claim 10 , wherein said compound including at least one catechol unit is chosen from the group consisting of caffeic acid, hydroxyhydroquinone, catechol, pyrogallol, morin (2′,3,4′,5′7-pentahydroxyflavone), epigallocatechin, epigallocatechin gallate, catechin and its stereoisomers, tannic acid.
14 . The functionalized cellular elastomer of claim 10 , wherein said mechanically flexible porous cellular polymer foam comprises cells with a mean size comprised between 500 μm and 5,000 μm.
15 . The functionalized cellular elastomer of claim 10 , further comprising at least one catalytically active material or at least one catalytically active phase precursor, deposited on the surface of the functionalized cellular elastomer.
16 . The functionalized cellular elastomer of claim 15 , wherein said at least one catalytically active material is selected from the group consisting of: metal complexes including at least one group capable of forming covalent bonds with the intermediate phase; organic molecules which are configured to catalyze a reaction, including at least one group to form covalent bonds with the intermediate phase; and metal nanoparticles chosen from among Ag, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Au, Ce, or mixed oxides associated with these elements, or any combination(s) thereof.
17 . The functionalized cellular elastomer of claim 16 , wherein the metal nanoparticles have a mean particle size comprised between 0.5 and 100 nm.
18 . The functionalized cellular elastomer of claim 10 , wherein the functionalized cellular elastomer is a catalyst substrate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a divisional of U.S. patent application Ser. No. 15/326,539 (filed Jan. 16, 2017), which is a National Stage Application of PCT International Application No. PCT/FR2015/051903 (filed on Jul. 9, 2015), under 35 U.S.C. § 371, which claims priority to French Patent Application No. 1457055 (filed on Jul. 22, 2014), which are each hereby incorporated by reference in their respective entireties. TECHNICAL FIELD The invention relates to the field of porous solid materials, more particularly cellular polymer foams. It relates to a method for modifying the surface of elastomer cellular foams, in particular foams with apparent porosity, so that they may be used as catalyst substrates. BACKGROUND Many catalysts are known whereof the catalytic phase is present in a porous solid material, and more particularly adsorbed to the surface of a ceramic or metal cellular foam. For example, the most widely used method for producing ceramic foams consists of impregnating a polymer foam, most often a polyurethane or polyester foam, cut to the desired geometry, with a suspension of ceramic particles in an aqueous or organic solvent. The excess suspension is discharged from the polymer foam through the repeated application of compression or by centrifugation, so as to keep only a fine layer of suspension on the strands of the polymer. After one or several impregnations of the polymer foam, the latter is dried so as to evacuate the solvent while preserving the mechanical integrity of the deposited layer of ceramic powder. The foam is next sintered in order to obtain an inorganic foam usable as a catalyst substrate. This fairly complex manufacturing method creates a relatively high manufacturing cost. One of the advantages of ceramic foams is their chemical and thermal strength. However, excellent thermal strength is not always needed. Furthermore, ceramic foams have the drawback of concealing micro-cracks and other microstructural flaws that considerably decrease their mechanical properties. Furthermore, in many cases, recovering the active metal phase (catalyst) requires many chemical treatments. SUMMARY One aim of the present invention is to provide new catalyst substrates that are an alternative to the catalyst substrates made from metal or ceramic foams currently used in the chemical, pharmaceutical and/or cosmetic industry in environments that do not require high thermal strength; are easy to prepare, with a low manufacturing cost; and have similar or advantageous structural characteristics. Another aim of the present invention is to provide new catalysts, for heterogeneous and/or supported homogenous catalysis, with a low pressure loss and having a large specific surface, while having very good chemical inertia, and which are available in all types of geometric shapes (square, planar, cylindrical, etc.) and mechanically flexible. According to the invention, the problem is resolved by chemically modifying the surface of a known cellular material, i.e., a cellular polymer foam (in particular elastomer) with apparent porosity. Cellular polymer foams (also called “honeycomb foams”) are well known and are commercially available for many applications. When they are made up of closed cells, they have excellent mechanical strength and are used as foam wedges, packaging foam, or in mechanical construction. At the same time, these closed cells capture air and thus give the foams excellent heat insulation properties, which are used in the building sector. Also known are polymer foams (in particular elastomers) with apparent porosity (called “open-cell polymer foam”), in which only the edges of the cells are made up of solid polymer. This in particular involves polyurethane foams. They are used as filters, in particular in aquariums. However, these foams are not usable as a catalyst substrate due to the low adherence of the catalysts (or their precursor compounds) on the surface of this polymer. Their use as a catalyst substrate is faced with the difficulty of depositing a catalytically active phase or an active phase precursor phase. Indeed, the surface of the polymer bridges (edges) is smooth, with no micro-pores, and does not have a sufficient adherence to deposit the precursor molecules or active phases thereon typically used in homogenous or heterogeneous catalysis. For this reason, cellular polymer foams with apparent porosity have hardly been considered as candidates to manufacture catalyst substrates. The inventors have found an appropriate surface treatment that prepares the cellular polymer foams (in particular elastomers), and particularly those with apparent porosity, to receive a catalytically active phase (here called “active phase”) or active phase precursor phase deposition. A first object of the present invention is a method for modifying a cellular polymer foam with apparent porosity, preferably made from polyurethane, comprising the following steps: supp