Heat insulation material based on aerogel

Abstract

A heat insulation material is provided that is produced by drying a fibrous matrix impregnated with a solution of pseudo-peptides of formula (I), wherein: R is a side-chain of a natural or synthetic amino acid, R1 is either a linear or branched (C.sub.1-C.sub.3)alkyl group, or a linear or branched (C.sub.1-C.sub.3)alcoxy group, or an aryl group, or an aryl(C.sub.1-C.sub.3)alkyl group, or an aryloxy group, or a saturated or unsaturated heterocycle, n=1 or 2, and A is an aromatic or heteroaromatic group with at least one cycle.

Claims

1. A thermal insulating material obtained by drying a fibrous matrix impregnated with a solution of pseudopeptides of formula (I), ##STR00007## in which R represents a side chain of a natural amino acid; R.sub.1 represents either a linear or branched (C.sub.1-C.sub.8)alkyl group, or a linear or branched (C.sub.1-C.sub.8)alkoxy group, or an aryl group, or an aryl(C.sub.1-C.sub.4)alkyl group, or an aryloxy group, or a saturated or unsaturated heterocycle, or PhCH.sub.2O or CH.sub.2CHCH.sub.2O, n=1 or 2; and A represents an aromatic or heteroaromatic group with one or more rings, said fibrous matrix having a thermal conductivity of less than 0.05 W/m/K and a density of less than 50 kg/m.sup.3.

2. The thermal insulating material according to claim 1, characterized in that the pseudopeptide of formula (I) is selected from those in which the group ##STR00008## represents either a group ##STR00009## or a group ##STR00010##

3. The thermal insulating material according to claim 1, characterized in that the pseudopeptide of formula (I) is selected from those in which R represents either CH.sub.2Ph, or C(CH.sub.3).sub.3 or CH(CH.sub.3).sub.2 and R.sub.1 represents either PhCH.sub.2O or CH.sub.2CHCH.sub.2O.

4. The thermal insulating material according to claim 1, characterized in that said fibrous matrix is a matrix of plant, animal, mineral origin, of natural or synthetic polymers, or any combination thereof.

5. The thermal insulating material according to claim 4, characterized in that said matrix is selected from the group consisting of a fibreboard, a blanket of wood fibres, a cotton, wool, mineral wool, polystyrene, polyurethane, polyisocyanate and polyisocyanurate matrix.

6. The thermal insulating material according to claim 1, characterized in that said material is obtained by drying a fibreboard impregnated with a solution of pseudopeptide of formula (Ia) or a blanket of wood fibres impregnated with a solution of pseudopeptide of formula (Ia) ##STR00011##

7. A method for preparing a thermal insulating material according to claim 1, wherein said method comprises the following stages: (i) preparing a liquid solution of pseudopeptides of formula (I), in a solvent; (ii) bringing a matrix as described according to claim 1 into contact with the solution obtained in stage (i) until said matrix is completely impregnated with said solution and reaches its maximum capacity for absorbing said solution; (iii) forming an organogel/matrix complex by cooling; and (iv) extracting the solvent contained in said organogel/matrix complex in order to obtain the aforesaid thermal insulating material.

8. A thermal insulating material obtained by the method according to claim 7.

9. The method according to claim 7, wherein step (i) is performed by preparing a liquid solution of pseudopeptide of formula (Ia) ##STR00012##

10. A method for improving the hydrophobicity of a fibrous matrix, said method comprising the following step: applying to said fibrous matrix a solution of pseudopeptides of formula (I): ##STR00013## in which R represents a side chain of a natural amino acid; R.sub.1 represents either a linear or branched (C.sub.1-C.sub.8)alkyl group, or a linear or branched (C.sub.1-C.sub.8)alkoxy group, or an aryl group, or an aryl(C.sub.1-C.sub.4)alkyl group, or an aryloxy group, or a saturated or unsaturated heterocycle, or PhCH.sub.2O or CH.sub.2CHCH.sub.2O, n=1 or 2; and A represents an aromatic or heteroaromatic group with one or more rings, said fibrous matrix having a thermal conductivity of less than 0.05 W/m/K and a density of less than 50 kg/m.sup.3.

11. The method of claim 10, wherein the pseudopeptide of formula (I) is selected from those in which the group ##STR00014## represents either a group ##STR00015## or a group ##STR00016##

12. The method of claim 10, characterized in that the pseudopeptide of formula (I) is selected from those in which R represents either CH.sub.2Ph, or C(CH.sub.3).sub.3 or CH(CH.sub.3).sub.2 and R.sub.1 represents either PhCH.sub.2O or CH.sub.2CHCH.sub.2O.

13. The method of claim 10, where the solution of pseudopeptides of formula (I) is a solution of (Ia) ##STR00017##

Description

EXAMPLE 1

Preparation of a Material According to the Invention

DETAILED DESCRIPTION

(1) This example illustrates the preparation of a material of the invention obtained by drying a fibreboard impregnated with a solution of pseudopeptides of formula (Ia).

(2) 1. Materials and Methods

(3) 1.1. Characteristic of the Fibreboard

(4) The fibreboard used in the example has a density of 43 kg/m.sup.3 and is in the form of square samples of 55 cm on each side.

(5) 1.2. Preparation of the Solution of Pseudopeptides of Formula (Ia)

(6) A solution of pseudopeptides of formula (Ia) at 14.9% in 3-pentanol is prepared as follows:

(7) 2.14 g of the compound of formula (Ia) were dissolved hot in 15 mL of 3-pentanol in order to obtain a solution of the compound of formula (Ia) at 14.9% by weight. Solubilization is carried out for 2 minutes under stirring in a flask placed in a microwave oven offering the possibility of open reactor working. The working temperature of the microwave oven is set to 100 C. under a maximum power of 150 Watts. The flask is equipped with a water condensing system in order to condense the solvent vapours and to maintain the concentration of the solution.

(8) The solution is maintained at a temperature greater than the sol-gel transition temperature, i.e. approximately 100 C. for a solution at 14.9%

(9) 1.3. Preparation of the Fibreboard/Organogel Composite

(10) The fibreboard is placed in a stainless steel mould of the same dimension, which has been heated beforehand in order to avoid any thermal shock. The solution of the compound of formula (Ia) in 3-pentanol maintained at 100 C. is then poured onto the fibreboard. The mixture is cooled to ambient temperature until gelation of the gel. The fibreboard/organogel composite obtained is then extracted from the mould.

(11) 1.4. Drying the Fibreboard/Organogel Composite System

(12) The composite obtained is dried according to the supercritical CO.sub.2 drying process described in application WO2010/133798.

(13) Said process is implemented in an autoclave (8 cm high, 100 ml volume) composed of a hollow, double-walled cylinder and two detachable ends composed of sintered metal allowing the passage of fluids.

(14) The fibreboard/organogel composite is placed in an autoclave having a bed of beads covered with 0.5 g of 3-pentanol and maintained at 15 C. After closing the autoclave, the CO.sub.2 previously cooled to 4 C. is introduced into the reactor under a pressure of 50 bar (510.sup.6Pa). The pressure is then raised to 90 bar (910.sup.6Pa) by injecting CO.sub.2 using a diaphragm pump. The pressure of the first separator is set to 50 bar (510.sup.6Pa) and that of the second separator to 20 bar (210.sup.6Pa). The CO.sub.2 flow rate is set to 400 g/h. The temperature of the separation elements is maintained at 20 C. during the entire drying process.

(15) The temperature of the autoclave is then raised to 45 C. so as to cause the CO.sub.2/3-pentanol system to pass to supercritical phase. After 20 minutes, the outlet valves of the autoclave and of the last separator are opened.

(16) The continuous extraction of the 3-pentanol for 4 h with a CO.sub.2 flow rate of 400 g/h makes it possible to obtain the expected fibreboard/aerogel composite.

(17) 2. Characteristics of the Fibreboard/Aerogel Product

(18) The final fibreboard/aerogel product obtained has a density of 183 Kg/m.sup.3.

(19) The thermal conductivity of the final product is measured by the three layers method (Y. Jannot, G. Payet, A. Degiovanni, IJHMT 2009, 52, 1105-1111), finished by a centered hot plate measurement (Y. Jannot, V. Felix, A. Degiovanni, Measurement Science and Technology 2010, 21, No. 35106).

(20) The thermal conductivity of said final product measured at ambient temperature of approximately 25 C. is 0.026 W/m/K.

(21) Said final product has a better mechanical strength compared to the organic aerogel alone described in application WO2010/133798 and to the fibreboard.

(22) The density of the final product, which is approximately 183 kg/m.sup.3, is clearly greater than that of the organic aerogel alone described in application WO2010/133798 (2.83 kg/m.sup.3) and that of the fibreboard (43 kg/m.sup.3).

(23) Moreover, said product has a better hydrophobicity than the fibreboard and close to that of the aerogel described in application WO2010/133798.

EXAMPLE 2

Preparation of a Material According to the Invention

(24) This example illustrates the preparation of a material according to the invention obtained by drying a fibreboard impregnated with a solution of pseudopeptides of formula (Ia).

(25) 1. Materials and Methods

(26) 1.1. Characteristic of the Fibreboard

(27) The fibreboard used in the example has a density of 43 kg/m.sup.3 and is in the form of square samples of 55 cm on each side.

(28) 1.2. Preparation of the Solution of Pseudopeptides of Formula (Ia)

(29) A solution of pseudopeptides of formula (Ia) at 14.9% in 3-pentanol is prepared as follows:

(30) 2.14 g of the compound of formula (Ia) were dissolved hot in 15 mL of 3-pentanol in order to obtain a solution of the compound of formula (Ia) at 14.9% by weight. Solubilization is carried out for 2 minutes under stirring in a flask placed in a microwave oven offering the possibility of working in an open reactor. The working temperature of the microwave oven is set to 100 C. under a maximum power of 150 Watts. The flask is equipped with a water condensing system in order to condense the solvent vapours and to maintain the concentration of the solution.

(31) The solution is maintained at a temperature greater than the sol-gel transition temperature, i.e. approximately 100 C. for a solution at 14.9%.

(32) 1.3. Preparation of the Fibreboard/Organogel Composite

(33) The fibreboard is placed in a stainless steel mould of the same dimension, which has been heated beforehand in order to avoid any thermal shock. The solution of the compound of formula (Ia) in 3-pentanol maintained at 100 C. is then poured onto the fibreboard. The mixture is cooled to ambient temperature until gelation of the gel. The fibreboard/organogel composite obtained is then extracted from the mould.

(34) 1.4. Drying the Fibreboard/Organogel Composite System

(35) The composite obtained is dried according to the supercritical CO.sub.2 drying process described in application WO2010/133798.

(36) Said process is implemented in an autoclave (8 cm high, 100 ml volume) composed of a hollow, double-walled cylinder and two detachable ends composed of sintered metal allowing the passage of fluids.

(37) The fibreboard/organogel composite is placed in an autoclave having a bed of beads covered with 3.5 g of 3-pentanol and maintained at 15 C. After closing the autoclave, the CO.sub.2 previously cooled to 4 C. is introduced into the reactor under a pressure of 50 bar (510.sup.6Pa). The pressure is then raised to 90 bar (910.sup.6Pa) by injecting CO.sub.2 using a diaphragm pump. The pressure of the first separator is set to 50 bar (510.sup.6Pa) and that of the second separator to 20 bar (210.sup.6Pa). The CO.sub.2 flow rate is set to 400 g/h. The temperature of the separation elements is maintained at 20 C. during the entire drying process.

(38) The temperature of the autoclave is then raised to 45 C. so as to cause the CO.sub.2/3-pentanol system to pass to supercritical phase. After 20 minutes, the outlet valves of the autoclave and of the last separator are opened.

(39) The continuous extraction of the 3-pentanol for 4 h with a CO.sub.2 flow rate of 400 g/h makes it possible to obtain the expected fibreboard/aerogel composite.

(40) 2. Characteristics of the Fibreboard/Aerogel Product

(41) The final fibreboard/aerogel product obtained has a density of 183 Kg/m.sup.3.

(42) The thermal conductivity of the final product is measured by the three layers method (Y. Jannot, G. Payet, A. Degiovanni, IJHMT 2009, 52, 1105-1111), finished by a centred hot plate measurement (Y. Jannot, V. Felix, A. Degiovanni, Measurement Science and Technology 2010, 21, No. 35106).

(43) The thermal conductivity of said final product measured at ambient temperature of approximately 25 C. is 0.026 W/m/K.

(44) Said final product has a better mechanical strength compared to the organic aerogel alone described in application WO2010/133798 and to the fibreboard.

(45) The density of the final product, which is approximately 183 kg/m.sup.3, is clearly greater than that of the organic aerogel alone described in application WO2010/133798 (2.83 kg/m.sup.3) and that of the fibreboard (43 kg/m.sup.3). Moreover, said product has a better hydrophobicity than the fibreboard and close to that of the aerogel described in application WO2010/133798.

EXAMPLE 3

Preparation of a Material According to the Invention

(46) This example illustrates the preparation of a material of the invention obtained by drying a blanket of untreated wood fibres impregnated with a solution of pseudopeptides of formula (Ia).

(47) 1. Materials and Methods

(48) 1.1. Characteristic of the Untreated Wood Fibres

(49) The wood fibres used in the example are fine and untreated from the industrial defibration of wood.

(50) 1.2. Preparation of the Solution of Pseudopeptides of Formula (Ia)

(51) A solution of pseudopeptides of formula (Ia) at 13% in 3-pentanol is prepared as follows:

(52) 1.23 g of the compound of formula (Ia) were dissolved hot in 10 mL of 3-pentanol in order to obtain a solution of the compound of formula (Ia) at 13% by weight. Solubilization is carried out for 2 minutes under stirring in a flask placed in a microwave oven offering the possibility of working in an open reactor. The working temperature of the microwave oven is set to 100 C. under a maximum power of 150 Watts. The flask is equipped with a water condensing system in order to condense the solvent vapours and to maintain the concentration of the solution.

(53) The solution is maintained at a temperature greater than the sol-gel transition temperature, i.e. approximately 100 C. for a solution at 13%.

(54) 1.3. Preparation of the Blanket of Wood Fibres/Organogel Composite

(55) The untreated wood fibres are placed and packed into an aluminium mould of dimensions 45 mm45 mm5 mm, which has been heated beforehand in order to avoid any thermal shock. The solution of the compound of formula (Ia) in 3-pentanol maintained at 100 C. is then injected into the mould, thus impregnating the blanket of wood fibres. The mixture is cooled to ambient temperature until gelation of the system. The blanket of wood fibres/organogel composite obtained is then extracted from the mould.

(56) 1.4. Drying the Blanket of Wood Fibres/Organogel Composite System

(57) The composite obtained is dried according to the supercritical CO.sub.2 drying process described in application WO2010/133798.

(58) Said process is implemented in an autoclave (8 cm high, 100 ml volume) composed of a hollow, double-walled cylinder and two detachable ends composed of sintered metal allowing the passage of fluids.

(59) The blanket of wood fibres/organogel composite is placed in an autoclave having a bed of beads covered with 3.5 g of 3-pentanol and maintained at 15 C. After closing the autoclave, the CO.sub.2 previously cooled to 4 C. is introduced into the reactor under a pressure of 50 bar (510.sup.6Pa). The pressure is then raised to 90 bar (910.sup.6Pa) by injecting CO.sub.2 using a diaphragm pump. The pressure of the first separator is set to 50 bar (510.sup.6Pa) and that of the second separator to 20 bar (210.sup.6Pa). The CO.sub.2 flow rate is set to 400 g/h. The temperature of the separation elements is maintained at 20 C. during the entire drying process.

(60) The temperature of the autoclave is then raised to 45 C. so as to cause the CO.sub.2/3-pentanol system to pass to supercritical phase. After 20 minutes, the outlet valves of the autoclave and of the last separator are opened.

(61) The continuous extraction of the 3-pentanol for 4 h with a CO.sub.2 flow rate of 400 g/h makes it possible to obtain the expected blanket of wood fibres/aerogel composite.

(62) 2. Characteristics of the Blanket of Wood Fibres/Aerogel Product

(63) The final blanket of wood fibres/aerogel product obtained has a density of 143 Kg/m.sup.3.

(64) The thermal conductivity of the final product is measured by the centred hot plate method (Y. Jannot, V. Felix, A. Degiovanni, Measurement Science and Technology 2010, 21, No. 35106).

(65) The thermal conductivity of said final product measured at ambient temperature of approximately 25 C. is 0.025 W/m/K.