WO2010081918A1 - Rigid foams of composite type based on biopolymers combined with fibrous clays and method for the preparation thereof - Google Patents

Rigid foams of composite type based on biopolymers combined with fibrous clays and method for the preparation thereof Download PDF

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Publication number
WO2010081918A1
WO2010081918A1 PCT/ES2009/070542 ES2009070542W WO2010081918A1 WO 2010081918 A1 WO2010081918 A1 WO 2010081918A1 ES 2009070542 W ES2009070542 W ES 2009070542W WO 2010081918 A1 WO2010081918 A1 WO 2010081918A1
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composite foam
foam according
composite
clay
preparation process
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PCT/ES2009/070542
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Spanish (es)
French (fr)
Inventor
Eduardo Ruiz Hitzky
Pilar Aranda Gallego
Margarita Darder Colom
Francisco Miguel Moreira Martins Fernandes
Charlene Regina Santos Matos
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Consejo Superior De Investigaciones Científicas (Csic)
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Publication of WO2010081918A1 publication Critical patent/WO2010081918A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0066—Use of inorganic compounding ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/346—Clay
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/048—Elimination of a frozen liquid phase
    • C08J2201/0484—Elimination of a frozen liquid phase the liquid phase being aqueous
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2205/00—Foams characterised by their properties
    • C08J2205/10—Rigid foams

Definitions

  • the present invention relates to composite materials, also known as composites, of high porosity that are presented as rigid foams and comprising fibrous clays (sepiolite and palygorskite) and biopolymers that can function as acoustic and thermal insulators, protective packaging or packaging. merchandise, support of drugs and biological species, implants for tissue regeneration. Therefore, the invention is within the sector of new materials, while its application is mainly located in the construction, transport, packaging and biomedicine sector.
  • Rigid foams or cellular materials widely applied for insulation and packaging are generally associated with polymers such as polyurethane or polystyrene prepared so that the polymeric material is formed by embedding bubbles of varying size (nanometers to millimeters) of a gas such as air.
  • the rigid foams object of the invention are based on composite materials instead of polymers.
  • Composite materials are called, those constituted by two or more solid phases, the most common being those constituted by an organic polymer that constitutes the continuous phase (matrix) and an inorganic solid as a dispersed phase that acts as a polymer reinforcing agent or filler.
  • said composite materials have substantial improvements in their properties with respect to the starting components due to their synergistic effect.
  • the resulting composite materials are called “nanocomposites”, and present even more notable improvements in many of their properties compared to conventional composites. Said improvements are caused by a more efficient contact between the reinforcing particles and the polymer, which is produced due to a relatively high value of the ratio between the surface area of the particles and their mass.
  • nanocomposites materials as well as their method of preparation (US2008039570, 2008-02-14, N. Bhiwankar Nikhil, A.
  • Weiss Robert "Polymer clay nanocomposites and methods for making the same", University of Connecticut) uses a laminated clay and modified polystyrene to favor the interleaving in the molten phase of the polymer in the interlaminar space of the clay, generating sheets of nanometric thickness that can be dispersed in isolation in the composite material.
  • the generated nanocomposite shows significant improvements in its thermal properties.
  • polystyrene and polyvinylchloride are examples of polymers that have been of great interest to produce nanocomposites.
  • a boom in the use of matrices of biological origin such as polypeptides, lipids and polysaccharides, that is to say naturally occurring polymers (biopolymers) to prepare nanocomposites materials is being recently verified.
  • These materials are constituted by a matrix of biological origin or a biocompatible synthetic polymer, as well as a particulate solid of nanometric dimensions, they are called bionanocomposites (M. Darder, P. Aranda, E. Ruiz-Hitzky, "Bio-nanocomposites : a new concept of ecological, bioinspired and functional hybrid materials "Adv. Mater. 2007, 19, 1309-1319).
  • bionanocomposites M. Darder, P. Aranda, E. Ruiz-Hitzky, "Bio-nanocomposites : a new concept of ecological, bioinspired and functional hybrid materials "Adv. Mater. 2007, 19, 1309-1319).
  • porosity is a textural characteristic of high importance in innumerable applications.
  • the generation of macroporosity (defined according to IUPAC standards as the existence of pores with dimensions greater than 50 nm) in these materials imparts relevant features in different fields of application.
  • a paradigmatic example of the utility of pores in composite materials refers to the generation of bone implants that combine excellent mechanical properties with a structured pore architecture so that the functionality of the organ to be replaced can be promoted (osteogenesis, osteoinduction, etc.). ) (V. Thomas, DR Dean, YK Vohra, "Nanostructured Biomaterials for regenerative medicine", Current Nanoscience, 2006, 2, 155-177).
  • macroporous materials also known as rigid foams or cellular materials, which have low density and good properties as thermal insulators
  • thermal insulators WO2005082993, 2005-09-09, K Woo-Nyon, S. Won-Jin, H. Jae-Sung, "Clay-polyurethane nanocomposite and method for preparing the same", Korea University Industry, K. Woo-Nyon, S. Won-Jin, H. Jae- Sung), and acoustic insulators (JP3247546, 1991-11-05, U. Kazuaki, O. Yuzo, O. Masayuki, K. Yoshitaka, N.
  • lyophilization which consists of the generation of pores by sublimation of ice and supercritical drying, a technique that induces drying of the sample by injection of CO2 or other solvents in the so-called “supercritical conditions”.
  • processed bionanocomposites have been prepared as rigid foams comprising a biopolymer and a clay in which the clay is of the laminar type (montmorillonite) and the polysaccharide is agar, gelatin, starch, sodium alginate or carboxymethyl cellulose (S. Ohta, H. Nakazawa, "Porous clay-organic composites: potential substitutes for polystyrene foam", Appl. Clay Sci. 9 (1995) 425-431).
  • the clay is of the laminar type (montmorillonite) and the polysaccharide is agar, gelatin, starch, sodium alginate or carboxymethyl cellulose
  • fibrous clays in the preparation of bionanocomposites has been described for the development of materials that involve biopolymers such as collagen (N. Olmo, MA Lizarbe, JG Gavilanes, "Biocompatibility and degradability of sepiolite collagen complex” Biomaterials 1987, 8 , 67-69.), Chitosan (M. Darder, M. López-Blanco, P. Aranda, AJ Aznar, J. Bravo, E. Ruiz-Hitzky, "Microfibrous chitosan-sepiolite nanocomposites” Chem. Mater. 2006, 18, 1602-1610) or the jelly (FM Fernandes, AI Ruiz, M. Darder, P.
  • collagen N. Olmo, MA Lizarbe, JG Gavilanes, "Biocompatibility and degradability of sepiolite collagen complex” Biomaterials 1987, 8 , 67-69.
  • Chitosan M. Darder, M. L
  • the present invention is based on three fundamental aspects:
  • a first aspect of the invention is the rigid composite foam comprising a biopolymeric matrix and silicate particles belonging to the family of fibrous clays.
  • a second aspect of the invention is the process of preparing this type of material comprising the steps of mixing a colloidal dispersion of biopolymer with a colloidal dispersion of clay, homogenization of the mixture obtained until obtaining a gel and elimination of water from the prepared gel by lyophilization or supercritical drying techniques.
  • a third aspect of the present invention is the use of this type of foam such as acoustic and thermal insulators, packaging material, solids support with specific properties, as well as drugs and biological species.
  • foam such as acoustic and thermal insulators, packaging material, solids support with specific properties, as well as drugs and biological species.
  • the present invention is based on the preparation by applying lyophilization or supercritical drying techniques of new nanocomposites materials comprising hydrophilic biopolymers (structural proteins and polysaccharides), as a biological base matrix, and micro- or nano- particles of one or more silicates of the type of clays of fibrous morphology, ie sepiolite and palygorskite (the latter also known as attapulgite).
  • hydrophilic biopolymers structural proteins and polysaccharides
  • micro- or nano- particles of one or more silicates of the type of clays of fibrous morphology ie sepiolite and palygorskite (the latter also known as attapulgite).
  • fibrous clays object of the present invention supposes an advantage over the already described use of laminar morphology clays such as montmorillonite and other smectites, since the fibrous clays considered herein contain superficial silanoles groups, which together with their Morphology provide greater efficiency in their interaction with hydrophilic biopolymers.
  • a first aspect of the present invention is the rigid composite foam, hereinafter composite foam of the invention, which comprises a biopolymeric matrix and silicate particles belonging to the family of fibrous clays.
  • This type of composite foam is obtained from the components (clay and biopolymer) that are combined in aqueous medium, preferably as gels or stable colloids, the water being subsequently removed from the dispersion by lyophilization or drying treatments under supercritical conditions.
  • a preferred aspect of the present invention is the composite foam of the invention in which the fibrous clay is sepiolite.
  • the use of sepiolite is considered advantageous over other clays because there are commercial sepiolite products called rheological grade that form gels that are very stable in water or polar liquids and this facilitates the preparation of the materials object of the present invention.
  • Another preferred aspect of the present invention is the composite foam of the invention in which the clay is palygorskite.
  • Another preferred aspect of the present invention is the composite foam of the invention in which the biopolymeric matrix is of the type of structural proteins.
  • a more preferred aspect of the present invention is the composite foam of the invention in which the structural protein of the polymeric matrix is gelatin.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the structural protein of the polymer matrix is collagen.
  • Another preferred aspect of the present invention is the composite foam of the invention in which the biopolymeric matrix is of the type of neutral polysaccharides.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymeric matrix is starch.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymer matrix is agar.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymer matrix is garrof ⁇ n rubber.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymer matrix is guar gum.
  • Another preferred aspect of the present invention is the composite foam of the invention comprising a biopolymer matrix of positively charged polysaccharides.
  • a more preferred aspect of the present invention is the composite foam of the invention in which the positively charged polysaccharide of the biopolymeric matrix is chitosan.
  • Another preferred aspect of the present invention is the composite foam of the invention comprising a biopolymer matrix of negatively charged polysaccharides.
  • a more preferred aspect of the present invention is the composite foam of the invention in which the negatively charged polysaccharide of the biopolymeric matrix is alginate.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the negatively charged polysaccharide of the biopolymeric matrix is xanthan.
  • Another more preferred aspect of the present invention is the composite foam of the invention in which the negatively charged polysaccharide of the biopolymeric matrix is some carrageenan.
  • the advantages of all the biopolymers considered here are their biodegradability and their high biocompatibility.
  • a second aspect of the present invention is the process of preparing the composite foam of the invention, hereinafter the method of the invention, which comprises the following steps: a) Mixing a colloidal dispersion of a biopolymer with a colloidal dispersion of a clay fibrous b) Homogenization of the mixture obtained in a) until a gel is obtained c) Water removal process from the gel prepared in stage b)
  • stage c) It is performed by freezing the gel obtained in b) subsequently applying a lyophilization process consisting of the sublimation of the ice generated.
  • Another preferred aspect of the present invention is the process of the invention in which the freezing stage prior to the lyophilization process takes place at a temperature between 77 K and 273 K.
  • This freezing stage prior to the lyophilization process can be carried out in different media such as atmospheric cold air, by immersion in liquid nitrogen or produced by cooling by the action of a cooling liquid, such as low temperature thermostated polyethylene glycol temperature and for different periods of time, which are related to the medium in which the composite to be frozen is located.
  • a cooling liquid such as low temperature thermostated polyethylene glycol temperature and for different periods of time, which are related to the medium in which the composite to be frozen is located.
  • stage c is performed by supercritical drying processes.
  • Another preferred aspect of the present invention is the process of the invention in which in step a) the colloidal solutions or dispersions of the biopolymer and of the clay are mixed so as to produce a single homogeneous and stable colloidal dispersion.
  • Another preferred aspect of the present invention is that in which the relative proportions by weight of the biopolymer versus that of the clay in the process of the invention relative to step a) are between 1: 10 and 10: 1
  • Another more preferred aspect of The present invention is that in which the relative proportions by weight of biopolymer versus that of clay in the process of the invention relative to step a) are around 1: 1.
  • Another more preferred aspect of the present invention is the process of the invention in which in step a) a relative biopolymer ratio lower than that of clay is used.
  • a crosslinking agent is defined as species such as dialdehydes, diacrylates, diepoxides, diamines and diisocyanates, among others.
  • cross-linking species are formaldehyde, glutaraldehyde, diethylene glycol diacrylate, diethylene glycol methacrylate, ethylene glycol diacrylate, N, N-methylene bisacrylamide, diglycidyl ester of bisphenol A, among others.
  • Another preferred aspect of the present invention is the process of the invention in which the composite foam obtained in c) is stabilized by crosslinking reaction of the polymer chains through the amino, amide, hydroxyl and carboxyl functions by treatment with different agents. monomeric crosslinkers.
  • Another preferred aspect of the present invention is the process of the invention in which a concentration or dilution procedure is applied to the gel generated in step b), such as centrifugation, drying or solvent addition respectively, depending on of the intended density.
  • Another preferred aspect of the present invention is the process of the invention in which steps b) and c) are carried out in a mold that imparts the final shape of the composite.
  • Another more preferred aspect of the present invention is the process of the invention in which steps b) and c) is carried out in a mold of polymeric or metallic nature, which has low roughness, absence of textural irregularities and low coefficient of thermal expansion.
  • the composite foam prepared by the process of the invention can be subjected to chemical modifications to achieve altering its structural or functional properties.
  • Another preferred aspect of the present invention is the process of the invention in which the composite foam obtained in c) is subsequently modified by the silanization of the hydroxyl functions of the material, to increase the hydrophobic character of the composite foam.
  • a third aspect of the present invention is the use of the composite foam of the invention in thermal and acoustic insulation of buildings and other civil works, as well as in means of transport such as airplanes, trains and automobiles.
  • another aspect of the present invention is the use of the composite foam of the invention for its application as a packaging material and as a support for solids with specific properties such as electrical, magnetic and optical, species or fragments of species of biological origin as per example algae and viruses, as well as medications and other bioactive species such as pesticides.
  • the advantages of being environmentally friendly and even in certain biocompatible cases, together with the property of being flame retardant, are also in front of other rigid foams of polymeric type.
  • the resulting composite has a variation of the relative amount of biopolymer against clay from 1: 1 to 1: 3, according to data obtained by chemical analysis.
  • the resulting composite has an elastic compression module of 41.8 MPa obtained in compression tests at a constant speed of 5 mm / min in triplicate measurement experiments.
  • This value represents an improvement over 300% compared to a composite material prepared with a lamellar clay (Cloisite, Southern Clay Sciences) following the same procedure.
  • the material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
  • the material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
  • Example 3 Preparation of the composite foam comprising xanthan and sepiolite 0.5 g of xanthan are added to 50 ml_ of ultrapure or distilled water, keeping the preparation under magnetic stirring for 2 h. 1 g of sepiolite is dispersed Pangel® S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, keeping under magnetic stirring for 2 h the preparation. Next, the xanthan solution is mixed with the sepiolite suspension, stirring the mixture in a magnetic stirrer at 400 rpm for 2 h at room temperature.
  • the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24h at a temperature of -80 0 C and a pressure of 0.030 mbar.
  • the resulting foams have macroporos of approximately 250 ⁇ m in diameter according to observation under an optical microscope and a density of 0.02 g / cm 3 .
  • Example 4 Preparation of the composite foam comprising garrofin and sepiolite rubber
  • the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24h at a temperature of -80 0 C and a pressure of 0.030 mbar.
  • the material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
  • the material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
  • Example 7 Preparation of the foam composite comprising starch and palygorskite 50 ml_ distilled water or ultrapure are heated to 80 0 C and 5 g of potato starch is added, maintaining the preparation under magnetic stirring and a constant temperature of 8O 0 C for 2h, until homogenization. 5 g of palygorskite (previously dried at 100 ° C, 24h) are dispersed in 50 ml_ of ultrapure or distilled water, keeping the preparation under magnetic stirring for 2h. Then, the starch solution is mixed with The suspension of sepiolite, stirring the mixture with an overhead stirrer at 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.
  • the resulting composite has an elastic compression module of 16.8 MPa obtained in compression tests at a constant speed of 5 mm / min performed in triplicate.
  • the resulting composite has an elastic compression module of 21.5 MPa obtained in compression tests at a constant speed of 5mm / min performed in triplicate.
  • Example 10 Preparation of the composite foam comprising iotacarbonate and sepiolite 50 ml_ of ultrapure or distilled water are heated to 80 0 C and 5 g of iota-carrageenan are added, keeping the preparation at a constant temperature of 8O 0 C and stirrer of rods for 2h, until homogenization. 5 g of sepiolite Pangel® disperse S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, maintaining the preparation under magnetic stirring for 2h.
  • the dissolution iota carrageenan is mixed with the suspension of sepiolite, stirring the mixture with an overhead stirrer at 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.

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Abstract

The present invention relates to rigid foams of composite type comprising a biopolymer matrix and particles of silicates belonging to the fibrous clays family (sepiolite and palygorskite). The invention furthermore relates to the procedure for preparation of these materials wherein the phase of drying through lyophilisation or supercritical drying is fundamental for the obtainment of materials having high porosity, together with the use thereof in diverse applications such as acoustic and thermal insulation, packing material, support for solids having electrical, magnetic and optical properties and for drugs and biological species.

Description

ESPUMAS RÍGIDAS DE TIPO COMPOSITE BASADAS EN BIOPOLIMEROS COMBINADOS CON ARCILLAS FIBROSAS Y SU MÉTODO DE RIGID FOAMS OF COMPOSITE TYPE BASED ON BIOPOLYMERS COMBINED WITH FIBROSIVE CLAYS AND THEIR METHOD OF
PREPARACIÓNPREPARATION
SECTOR DE LA TÉCNICASECTOR OF THE TECHNIQUE
La presente invención se refiere a materiales compuestos, también conocidos como composites, de alta porosidad que se presentan como espumas rígidas y que comprenden arcillas fibrosas (sepiolita y palygorskita) y biopolímeros que pueden funcionar como aislantes acústicos y térmicos, protectores en envasado o empaquetado de mercancías, soporte de fármacos y especies biológicas, implantes para regeneración de tejidos. Por tanto, Ia invención se encuentra dentro del sector de los nuevos materiales, mientras que su aplicación se ubica principalmente en el sector de Ia construcción, transporte, envasado y biomedicina.The present invention relates to composite materials, also known as composites, of high porosity that are presented as rigid foams and comprising fibrous clays (sepiolite and palygorskite) and biopolymers that can function as acoustic and thermal insulators, protective packaging or packaging. merchandise, support of drugs and biological species, implants for tissue regeneration. Therefore, the invention is within the sector of new materials, while its application is mainly located in the construction, transport, packaging and biomedicine sector.
ESTADO DE LA TÉCNICASTATE OF THE TECHNIQUE
Las espumas rígidas o materiales celulares ampliamente aplicados para aislamiento y embalaje, están generalmente asociados a polímeros como el poliuretano o el poliestireno preparados de forma que el material polimérico se conforma embebiendo burbujas de tamaño variable (nanómetros a milímetros) de un gas como el aire. En Ia presente patente, las espumas rígidas objeto de Ia invención están basadas en materiales composites en lugar de polímeros. Se denominan materiales composites, aquellos constituidos por dos o más fases sólidas, siendo los más comunes aquellos constituidos por un polímero orgánico que constituye Ia fase continua (matriz) y un sólido inorgánico como fase dispersa que actúa como agente o carga reforzante del polímero. Típicamente, dichos materiales composites presentan mejoras sustanciales de sus propiedades con respecto a los componentes de partida debido a un efecto sinérgico de los mismos. En el caso particular en que el componente de refuerzo, comúnmente denominado "carga" o "filie?, presenta dimensiones nanométricas, los materiales composites resultantes se denominan "nanocomposites", y presentan mejoras aún más notables en muchas de sus propiedades en comparación con los composites convencionales. Dichas mejoras son originadas por un contacto más eficiente entre las partículas de refuerzo y el polímero, que se produce debido a un relativamente elevado valor de Ia razón entre el área superficial de las partículas y su masa. Un ejemplo de materiales nanocomposites, así como su método de preparación (US2008039570, 2008-02-14, N. Bhiwankar Nikhil, A. Weiss Robert, "Polymer- clay nanocomposites and methods for making the same", University of Connecticut) utiliza una arcilla laminar y poliestireno modificado para favorecer Ia intercalación en fase fundida del polímero en el espacio interlaminar de Ia arcilla, generando láminas de espesor nanométrico que pueden dispersarse aisladamente en el material composite. El nanocomposite generado presenta mejoras significativas en sus propiedades térmicas. Aunque las matrices poliméricas más ampliamente aplicadas en el desarrollo de nanocomposites sean poliolefinas, como el polipropileno y el polietileno, otros polímeros vinílicos como el poliestireno y el policloruro de vinilo, así como otro tipo de polímeros, como las resinas epoxi, las resinas fenólicas, los polilactatos o los poliuretanos han sido de gran interés para producir nanocomposites.Rigid foams or cellular materials widely applied for insulation and packaging are generally associated with polymers such as polyurethane or polystyrene prepared so that the polymeric material is formed by embedding bubbles of varying size (nanometers to millimeters) of a gas such as air. In the present patent, the rigid foams object of the invention are based on composite materials instead of polymers. Composite materials are called, those constituted by two or more solid phases, the most common being those constituted by an organic polymer that constitutes the continuous phase (matrix) and an inorganic solid as a dispersed phase that acts as a polymer reinforcing agent or filler. Typically, said composite materials have substantial improvements in their properties with respect to the starting components due to their synergistic effect. In the particular case where the reinforcement component, commonly called "load" or "filie ?, has nanometric dimensions, the resulting composite materials are called "nanocomposites", and present even more notable improvements in many of their properties compared to conventional composites. Said improvements are caused by a more efficient contact between the reinforcing particles and the polymer, which is produced due to a relatively high value of the ratio between the surface area of the particles and their mass. An example of nanocomposites materials, as well as their method of preparation (US2008039570, 2008-02-14, N. Bhiwankar Nikhil, A. Weiss Robert, "Polymer clay nanocomposites and methods for making the same", University of Connecticut) uses a laminated clay and modified polystyrene to favor the interleaving in the molten phase of the polymer in the interlaminar space of the clay, generating sheets of nanometric thickness that can be dispersed in isolation in the composite material. The generated nanocomposite shows significant improvements in its thermal properties. Although the most widely applied polymer matrices in the development of nanocomposites are polyolefins, such as polypropylene and polyethylene, other vinyl polymers such as polystyrene and polyvinylchloride, as well as other types of polymers, such as epoxy resins, phenolic resins, Polylactates or polyurethanes have been of great interest to produce nanocomposites.
Se está verificando recientemente un auge en Ia utilización de matrices de origen biológico como son los polipéptidos, los lípidos y los polisacáridos, es decir polímeros de origen natural (biopolímeros) para preparar materiales nanocomposites. Dichos materiales están constituidos por una matriz de origen biológico o bien por un polímero sintético biocompatible, así como de un sólido particulado de dimensiones nanométricas, se denominan bionanocomposites (M. Darder, P. Aranda, E. Ruiz-Hitzky, "Bio-nanocomposites: a new concept of ecological, bioinspired and functional hybrid materials" Adv. Mater. 2007, 19, 1309-1319). Estos materiales tienen particular interés para aplicación en el envasado de alimentos y aplicaciones biomédicas.A boom in the use of matrices of biological origin such as polypeptides, lipids and polysaccharides, that is to say naturally occurring polymers (biopolymers) to prepare nanocomposites materials is being recently verified. These materials are constituted by a matrix of biological origin or a biocompatible synthetic polymer, as well as a particulate solid of nanometric dimensions, they are called bionanocomposites (M. Darder, P. Aranda, E. Ruiz-Hitzky, "Bio-nanocomposites : a new concept of ecological, bioinspired and functional hybrid materials "Adv. Mater. 2007, 19, 1309-1319). These materials have particular interest for application in food packaging and biomedical applications.
En el área de los materiales nanocomposites Ia porosidad es una característica textural de elevada importancia en innumerables aplicaciones. La generación de macroporosidad (definida según las normas IUPAC como existencia de poros de dimensiones superiores a 50 nm) en estos materiales imparte características relevantes en distintos campos de aplicación. Un ejemplo paradigmático de Ia utilidad de los poros en materiales composites se refiere a Ia generación de implantes óseos que compaginen excelentes propiedades mecánicas con una arquitectura de poros estructurada de forma que se pueda promover Ia funcionalidad del órgano a sustituir (osteogénesis, osteoinducción, etc.) (V. Thomas, D. R. Dean, Y.K. Vohra, "Nanostructured Biomaterials for regenerative medicine", Current Nanoscience, 2006, 2, 155-177). Otros ejemplos de Ia importancia de Ia generación de estructuras con alta macroporosidad consiste en el desarrollo de materiales macroporosos, también conocidos como espumas rígidas o materiales celulares, que presentan baja densidad y buenas propiedades como aislantes térmicos (WO2005082993, 2005-09-09, K. Woo-Nyon, S. Won-Jin, H. Jae-Sung, "Clay-polyurethane nanocomposite and method for preparing the same", Korea University Industry, K. Woo-Nyon, S. Won-Jin, H. Jae-Sung), y aislantes acústicos (JP3247546, 1991-11-05, U. Kazuaki, O. Yuzo, O. Masayuki, K. Yoshitaka, N. Takashi, Y. Wakio, "Sound insulation panel", Matsushita Electric Works Ltd.), así como sustratos que favorecen el crecimiento celular de utilidad en ingeniería de tejidos (scaffolds) (J. P. Zheng, C. Z. Wang, X. X. Wang, H. Y. Wang, H. Zhuang, K. D. Yao, "Preparation of biomimetic three-dimensional gelatin/montmorillonite-chitosan scaffold for tissue engineering", React. Funct. Polym. 67 (2007) 780-788).In the area of nanocomposites materials, porosity is a textural characteristic of high importance in innumerable applications. The generation of macroporosity (defined according to IUPAC standards as the existence of pores with dimensions greater than 50 nm) in these materials imparts relevant features in different fields of application. A paradigmatic example of the utility of pores in composite materials refers to the generation of bone implants that combine excellent mechanical properties with a structured pore architecture so that the functionality of the organ to be replaced can be promoted (osteogenesis, osteoinduction, etc.). ) (V. Thomas, DR Dean, YK Vohra, "Nanostructured Biomaterials for regenerative medicine", Current Nanoscience, 2006, 2, 155-177). Other examples of the importance of the generation of structures with high macroporosity consist in the development of macroporous materials, also known as rigid foams or cellular materials, which have low density and good properties as thermal insulators (WO2005082993, 2005-09-09, K Woo-Nyon, S. Won-Jin, H. Jae-Sung, "Clay-polyurethane nanocomposite and method for preparing the same", Korea University Industry, K. Woo-Nyon, S. Won-Jin, H. Jae- Sung), and acoustic insulators (JP3247546, 1991-11-05, U. Kazuaki, O. Yuzo, O. Masayuki, K. Yoshitaka, N. Takashi, Y. Wakio, "Sound insulation panel", Matsushita Electric Works Ltd. ), as well as substrates that favor cell growth useful in tissue engineering (scaffolds) (JP Zheng, CZ Wang, XX Wang, HY Wang, H. Zhuang, KD Yao, "Preparation of biomimetic three-dimensional gelatin / montmorillonite- chitosan scaffold for tissue engineering ", React. Funct. Polym. 67 (2007) 780-788).
Dada Ia importancia de Ia macroporosidad en los materiales, se han desarrollado distintas técnicas de generación de poro. Entre las técnicas más relevantes se destaca Ia liofilización, que consiste en Ia generación de poros por sublimación del hielo y el secado supercrítico, técnica que induce el secado de Ia muestra por inyección de CO2 o de otros disolventes en las denominadas "condiciones supercríticas".Given the importance of macroporosity in materials, different pore generation techniques have been developed. Among the most relevant techniques, lyophilization stands out, which consists of the generation of pores by sublimation of ice and supercritical drying, a technique that induces drying of the sample by injection of CO2 or other solvents in the so-called "supercritical conditions".
Recientemente se han preparado bionanocomposites procesados como espumas rígidas que comprenden un biopolímero y una arcilla en los que Ia arcilla es de tipo laminar (montmorillonita) y el polisacárido es agar, gelatina, almidón, alginato sódico o carboximetil celulosa (S. Ohta, H. Nakazawa, "Porous clay-organic composites: potencial substitutes for polystyrene foam", Appl. Clay Sci. 9 (1995) 425-431 ). Algunos de estos materiales han sido objeto de una patente, concretamente aquellos que incorporan almidón, alginato sódico o carboximetil celulosa (US 6,228,501 B1 , 2001-05-08, "Porous body of polysaccharide or polysaccharide-clay composite, and process for its production" H. Nakazawa, S. Ohta, National Institute for Research in Inorganic Materials).Recently, processed bionanocomposites have been prepared as rigid foams comprising a biopolymer and a clay in which the clay is of the laminar type (montmorillonite) and the polysaccharide is agar, gelatin, starch, sodium alginate or carboxymethyl cellulose (S. Ohta, H. Nakazawa, "Porous clay-organic composites: potential substitutes for polystyrene foam", Appl. Clay Sci. 9 (1995) 425-431). Some of these materials have been the subject of a patent, specifically those that incorporate starch, sodium alginate or carboxymethyl cellulose (US 6,228,501 B1, 2001-05-08, "Porous body of polysaccharide or polysaccharide-clay composite, and process for its production" H. Nakazawa, S. Ohta, National Institute for Research in Inorganic Materials).
También se ha descrito Ia preparación de materiales macroporosos de tipo ternario por combinación de montmorillonita con gelatina y quitosano y su aplicación como soporte para el crecimiento de células en ingeniería de tejidos (J. P. Zheng, C. Z. Wang, X. X. Wang, H. Y. Wang, H. Zhuang, K. D. Yao, "Preparation of biomimetic three-dimensional gelatin/montmorillonite-chitosan scaffold for tissue engineering", React. Funct. Polym. 67 (2007) 780-788).The preparation of macroporous ternary-type materials has also been described by combining montmorillonite with gelatin and chitosan and its application as a support for the growth of cells in tissue engineering (JP Zheng, CZ Wang, XX Wang, HY Wang, H. Zhuang , KD Yao, "Preparation of biomimetic three-dimensional gelatin / montmorillonite-chitosan scaffold for tissue engineering", React. Funct. Polym. 67 (2007) 780-788).
El empleo de arcillas de tipo fibroso en Ia preparación de bionanocomposites ha sido descrito para el desarrollo de materiales que implican biopolímeros como el colágeno (N. Olmo, M. A. Lizarbe, J. G. Gavilanes, "Biocompatibility and degradability of sepiolite collagen complex" Biomaterials 1987, 8, 67-69.), el quitosano (M. Darder, M. López-Blanco, P. Aranda, A. J. Aznar, J. Bravo, E. Ruiz-Hitzky, "Microfibrous chitosan-sepiolite nanocomposites" Chem. Mater. 2006, 18, 1602-1610) o Ia gelatina (F. M. Fernandes, A. I. Ruiz, M. Darder, P. Aranda, E. Ruiz-Hitzky, "Gelatin-Clay Bio-Nanocomposites: Structural and Functional Properties as Advanced Materials" J. Nanosci. Nanotechnol. 2009, 9, 221-229), pero en ninguno de estos casos se han empleado técnicas de secado que originen espumas rígidas de elevada porosidad. No se tiene constancia de materiales composites altamente porosos del tipo de las espumas rígidas objeto de Ia presente invención que comprenden biopolímeros y arcillas fibrosas. De hecho, el uso de arcillas fibrosas en este tipo de materiales es totalmente novedoso. DESCRIPCIÓN BREVEThe use of fibrous clays in the preparation of bionanocomposites has been described for the development of materials that involve biopolymers such as collagen (N. Olmo, MA Lizarbe, JG Gavilanes, "Biocompatibility and degradability of sepiolite collagen complex" Biomaterials 1987, 8 , 67-69.), Chitosan (M. Darder, M. López-Blanco, P. Aranda, AJ Aznar, J. Bravo, E. Ruiz-Hitzky, "Microfibrous chitosan-sepiolite nanocomposites" Chem. Mater. 2006, 18, 1602-1610) or the jelly (FM Fernandes, AI Ruiz, M. Darder, P. Aranda, E. Ruiz-Hitzky, "Gelatin-Clay Bio-Nanocomposites: Structural and Functional Properties as Advanced Materials" J. Nanosci. Nanotechnol. 2009, 9, 221-229), but in none of these cases have drying techniques that cause rigid foams of high porosity been used. There is no evidence of highly porous composite materials of the type of rigid foams object of the present invention comprising biopolymers and fibrous clays. In fact, the use of fibrous clays in this type of materials is completely new. BRIEF DESCRIPTION
La presente invención se basa en tres aspectos fundamentales:The present invention is based on three fundamental aspects:
Un primer aspecto de Ia invención es Ia espuma rígida de tipo composite que comprende una matriz biopolímérica y partículas de silicatos pertenecientes a Ia familia de las arcillas fibrosas.A first aspect of the invention is the rigid composite foam comprising a biopolymeric matrix and silicate particles belonging to the family of fibrous clays.
Un segundo aspecto de Ia invención es el procedimiento de preparación este tipo de material que comprende las etapas de mezcla de una dispersión coloidal de biopolímero con una dispersión coloidal de arcilla, homogenización de Ia mezcla obtenida hasta obtener un gel y eliminación del agua del gel preparado mediante técnicas de liofilización o de secado supercrítico.A second aspect of the invention is the process of preparing this type of material comprising the steps of mixing a colloidal dispersion of biopolymer with a colloidal dispersion of clay, homogenization of the mixture obtained until obtaining a gel and elimination of water from the prepared gel by lyophilization or supercritical drying techniques.
Un tercer aspecto de Ia presente invención es el uso de este tipo este tipo de espumas como aislantes acústicos y térmicos, material de embalaje, soporte de sólidos con propiedades específicas, así como de fármacos y especies biológicas. Estos materiales presentan Ia ventaja, frente a otras espumas rígidas de tipo polimérico, de ser respetuosas con el medioambiente e incluso en ciertos casos biocompatibles, junto con Ia propiedad de ser ignífuga.A third aspect of the present invention is the use of this type of foam such as acoustic and thermal insulators, packaging material, solids support with specific properties, as well as drugs and biological species. These materials have the advantage, compared to other rigid foams of polymeric type, of being respectful of the environment and even in certain biocompatible cases, together with the property of being flame retardant.
DESCRIPCIÓN DETALLADA DE LA INVENCIÓN La presente invención se basa en Ia preparación mediante aplicación de técnicas de liofilización o de secado supercrítico de nuevos materiales nanocomposites que comprenden biopolímeros hidrofílicos (proteínas estructurales y polisacáridos), como matriz de base biológica, y micro- o nano- partículas de uno o varios silicatos del tipo de las arcillas de morfología fibrosa, es decir sepiolita y palygorskita (esta última también conocida como atapulgita). El uso de arcillas fibrosas objeto de Ia presente invención supone una ventaja frente al uso ya descrito de arcillas de morfología laminar como Ia montmorillonita y otras esmectitas, ya que las arcillas fibrosas aquí consideradas contienen grupos silanoles superficiales, que junto a su morfología proporcionan una mayor eficiencia en su interacción con biopolímeros hidrofílicos.DETAILED DESCRIPTION OF THE INVENTION The present invention is based on the preparation by applying lyophilization or supercritical drying techniques of new nanocomposites materials comprising hydrophilic biopolymers (structural proteins and polysaccharides), as a biological base matrix, and micro- or nano- particles of one or more silicates of the type of clays of fibrous morphology, ie sepiolite and palygorskite (the latter also known as attapulgite). The use of fibrous clays object of the present invention supposes an advantage over the already described use of laminar morphology clays such as montmorillonite and other smectites, since the fibrous clays considered herein contain superficial silanoles groups, which together with their Morphology provide greater efficiency in their interaction with hydrophilic biopolymers.
Por tanto, un primer aspecto de Ia presente invención es Ia espuma rígida de tipo composite, en adelante espuma composite de Ia invención, que comprende una matriz biopolímérica y partículas de silicatos pertenecientes a Ia familia de las arcillas fibrosas. Este tipo de espumas composites se obtienen a partir de los componentes (arcilla y biopolímero) que se combinan en medio acuoso, preferentemente como geles o coloides estables, eliminándose ulteriormente el agua de Ia dispersión mediante tratamientos de liofilización o de secado en condiciones supercríticas.Therefore, a first aspect of the present invention is the rigid composite foam, hereinafter composite foam of the invention, which comprises a biopolymeric matrix and silicate particles belonging to the family of fibrous clays. This type of composite foam is obtained from the components (clay and biopolymer) that are combined in aqueous medium, preferably as gels or stable colloids, the water being subsequently removed from the dispersion by lyophilization or drying treatments under supercritical conditions.
Un aspecto preferente de Ia presente invención es Ia espuma composite de Ia invención en el que Ia arcilla fibrosa es sepiolita. El uso de sepiolita se considera ventajoso frente a otras arcillas porque existen productos comerciales de sepiolita denominados de grado reológico que forman geles muy estables en agua o en líquidos polares y esto facilita Ia preparación de los materiales objeto de Ia presente invención.A preferred aspect of the present invention is the composite foam of the invention in which the fibrous clay is sepiolite. The use of sepiolite is considered advantageous over other clays because there are commercial sepiolite products called rheological grade that form gels that are very stable in water or polar liquids and this facilitates the preparation of the materials object of the present invention.
Otro aspecto preferente de Ia presente invención es Ia espuma composite de Ia invención en el que Ia arcilla es palygorskita.Another preferred aspect of the present invention is the composite foam of the invention in which the clay is palygorskite.
Otro aspecto preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que Ia matriz biopolimérica es del tipo de las proteínas estructurales.Another preferred aspect of the present invention is the composite foam of the invention in which the biopolymeric matrix is of the type of structural proteins.
Un aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que Ia proteína estructural de Ia matriz polimérica es gelatina. Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que Ia proteína estructural de Ia matriz polimérica es colágeno.A more preferred aspect of the present invention is the composite foam of the invention in which the structural protein of the polymeric matrix is gelatin. Another more preferred aspect of the present invention is the composite foam of the invention in which the structural protein of the polymer matrix is collagen.
Otro aspecto preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que Ia matriz biopolimérica es del tipo de los polisacáridos neutros. Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido neutro de Ia matriz polimérica es almidón.Another preferred aspect of the present invention is the composite foam of the invention in which the biopolymeric matrix is of the type of neutral polysaccharides. Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymeric matrix is starch.
Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido neutro de Ia matriz polimérica es agar.Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymer matrix is agar.
Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido neutro de Ia matriz polimérica es goma garrofín.Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymer matrix is garrofín rubber.
Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido neutro de Ia matriz polimérica es goma guar.Another more preferred aspect of the present invention is the composite foam of the invention in which the neutral polysaccharide of the polymer matrix is guar gum.
Otro aspecto preferente de Ia presente invención es Ia espuma composite de Ia invención que comprende una matriz biopolimérica de polisacáridos cargados positivamente. Un aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido cargado positivamente de Ia matriz biopolimérica es quitosano.Another preferred aspect of the present invention is the composite foam of the invention comprising a biopolymer matrix of positively charged polysaccharides. A more preferred aspect of the present invention is the composite foam of the invention in which the positively charged polysaccharide of the biopolymeric matrix is chitosan.
Otro aspecto preferente de Ia presente invención es Ia espuma composite de Ia invención que comprende una matriz biopolimérica de polisacáridos cargados negativamente.Another preferred aspect of the present invention is the composite foam of the invention comprising a biopolymer matrix of negatively charged polysaccharides.
Un aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido cargado negativamente de Ia matriz biopolimérica es alginato.A more preferred aspect of the present invention is the composite foam of the invention in which the negatively charged polysaccharide of the biopolymeric matrix is alginate.
Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido cargado negativamente de Ia matriz biopolimérica es xantano.Another more preferred aspect of the present invention is the composite foam of the invention in which the negatively charged polysaccharide of the biopolymeric matrix is xanthan.
Otro aspecto más preferente de Ia presente invención es Ia espuma composite de Ia invención en Ia que el polisacárido cargado negativamente de Ia matriz biopolimérica es algún carragenato. Las ventajas que presentan todos los biopolímeros aquí considerados son su biodegradabilidad y su alta biocompatibilidad.Another more preferred aspect of the present invention is the composite foam of the invention in which the negatively charged polysaccharide of the biopolymeric matrix is some carrageenan. The advantages of all the biopolymers considered here are their biodegradability and their high biocompatibility.
Un segundo aspecto de Ia presente invención es el procedimiento de preparación de Ia espuma composite de Ia invención, en adelante procedimiento de Ia invención, que comprende las siguientes etapas: a) Mezcla de una dispersión coloidal de un biopolímero con una dispersión coloidal de una arcilla fibrosa b) Homogenización de Ia mezcla obtenida en a) hasta obtener un gel c) Proceso de eliminación del agua del gel preparado en Ia etapa b) Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que Ia etapa c) se realiza mediante congelación del gel obtenido en b) aplicando posteriormente un proceso de liofilización consistente en Ia sublimación del hielo generado.A second aspect of the present invention is the process of preparing the composite foam of the invention, hereinafter the method of the invention, which comprises the following steps: a) Mixing a colloidal dispersion of a biopolymer with a colloidal dispersion of a clay fibrous b) Homogenization of the mixture obtained in a) until a gel is obtained c) Water removal process from the gel prepared in stage b) Another preferred aspect of the present invention is the process of the invention in which stage c) It is performed by freezing the gel obtained in b) subsequently applying a lyophilization process consisting of the sublimation of the ice generated.
Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que Ia etapa de congelación previa al proceso de liofilización tiene lugar a una temperatura comprendida entre 77 K y 273 K.Another preferred aspect of the present invention is the process of the invention in which the freezing stage prior to the lyophilization process takes place at a temperature between 77 K and 273 K.
Esta etapa de congelación previa al proceso de liofilización puede llevarse a cabo en distintos medios como por ejemplo al aire frío atmosférico, por inmersión en nitrógeno líquido o producida mediante enfriamiento por Ia acción de un líquido de refrigeración, como por ejemplo el polietilenglicol termostatizado a baja temperatura y durante distintos periodos de tiempo, que se relacionan con el medio en el que se encuentra el composite a congelar.This freezing stage prior to the lyophilization process can be carried out in different media such as atmospheric cold air, by immersion in liquid nitrogen or produced by cooling by the action of a cooling liquid, such as low temperature thermostated polyethylene glycol temperature and for different periods of time, which are related to the medium in which the composite to be frozen is located.
Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que Ia etapa c) se realiza mediante procesos de secado supercrítico.Another preferred aspect of the present invention is the process of the invention in which stage c) is performed by supercritical drying processes.
Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que en Ia etapa a) las disoluciones o dispersiones coloidales del biopolímero y de Ia arcilla, son mezcladas de forma que produzcan una única dispersión coloidal, homogénea y estable. Otro aspecto preferente de Ia presente invención es aquel en que las proporciones relativas en peso del biopolímero frente al de Ia arcilla en el procedimiento de Ia invención relativo a Ia etapa a) están comprendidas entre 1 :10 y 10:1 Otro aspecto más preferente de Ia presente invención es aquel en que las proporciones relativas en peso de biopolímero frente al de Ia arcilla en el procedimiento de Ia invención relativo a Ia etapa a) están en torno a 1 :1.Another preferred aspect of the present invention is the process of the invention in which in step a) the colloidal solutions or dispersions of the biopolymer and of the clay are mixed so as to produce a single homogeneous and stable colloidal dispersion. Another preferred aspect of the present invention is that in which the relative proportions by weight of the biopolymer versus that of the clay in the process of the invention relative to step a) are between 1: 10 and 10: 1 Another more preferred aspect of The present invention is that in which the relative proportions by weight of biopolymer versus that of clay in the process of the invention relative to step a) are around 1: 1.
Otro aspecto más preferente de Ia presente invención es el procedimiento de Ia invención en el que en Ia etapa a) se utiliza una proporción relativa biopolímero inferior a Ia de arcilla.Another more preferred aspect of the present invention is the process of the invention in which in step a) a relative biopolymer ratio lower than that of clay is used.
La espuma composite obtenida a partir del procedimiento de Ia invención puede ser estabilizada mediante reacción de entrecruzamiento de las cadenas poliméricas por tratamiento con distintos agentes entrecruzantes monoméricos. En Ia presente invención se define como agente entrecruzante a especies como los dialdehídos, diacrilatos, diepóxidos, diaminas y diisocianatos, entre otros. Ejemplos de especies entrecruzantes son el formaldehído, el glutaraldehído, el dietilenglicoldiacrilato, el dietilenglicolmetacrilato, el etileneglicoldiacrilato, Ia N,N-metilenbisacrilamida, el diglicidilester del bisfenol A, entre otros. Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que Ia espuma composite obtenida en c) es estabilizada mediante reacción de entrecruzamiento de las cadenas poliméricas a través de las funciones amino, amida, hidroxilo y carboxilo por tratamiento con distintos agentes entrecruzantes monoméricos. Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que al gel generado en Ia etapa b) se Ie aplica un procedimiento de concentración o dilución, como son Ia centrifugación, el secado o Ia adición de disolvente respectivamente, en función de Ia densidad pretendida.The composite foam obtained from the process of the invention can be stabilized by crosslinking reaction of the polymer chains by treatment with different monomeric crosslinking agents. In the present invention, a crosslinking agent is defined as species such as dialdehydes, diacrylates, diepoxides, diamines and diisocyanates, among others. Examples of cross-linking species are formaldehyde, glutaraldehyde, diethylene glycol diacrylate, diethylene glycol methacrylate, ethylene glycol diacrylate, N, N-methylene bisacrylamide, diglycidyl ester of bisphenol A, among others. Another preferred aspect of the present invention is the process of the invention in which the composite foam obtained in c) is stabilized by crosslinking reaction of the polymer chains through the amino, amide, hydroxyl and carboxyl functions by treatment with different agents. monomeric crosslinkers. Another preferred aspect of the present invention is the process of the invention in which a concentration or dilution procedure is applied to the gel generated in step b), such as centrifugation, drying or solvent addition respectively, depending on of the intended density.
Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que las etapas b) y c) se realizan en un molde que imparta Ia forma final del composite. Otro aspecto más preferente de Ia presente invención es el procedimiento de Ia invención en el que las etapas b) y c) se realiza en un molde de naturaleza polimérica o metálica, que presenta baja rugosidad, ausencia de irregularidades texturales y bajo coeficiente de expansión térmica. La espuma composite preparada mediante el procedimiento de Ia invención puede ser sometida a modificaciones químicas para lograr alterar sus propiedades estructurales o funcionales.Another preferred aspect of the present invention is the process of the invention in which steps b) and c) are carried out in a mold that imparts the final shape of the composite. Another more preferred aspect of the present invention is the process of the invention in which steps b) and c) is carried out in a mold of polymeric or metallic nature, which has low roughness, absence of textural irregularities and low coefficient of thermal expansion. The composite foam prepared by the process of the invention can be subjected to chemical modifications to achieve altering its structural or functional properties.
Otro aspecto preferente de Ia presente invención es el procedimiento de Ia invención en el que Ia espuma composite obtenida en c) es posteriormente modificada mediante Ia silanización de las funciones hidroxilo del material, para aumentar el carácter hidrofóbico de Ia espuma composite.Another preferred aspect of the present invention is the process of the invention in which the composite foam obtained in c) is subsequently modified by the silanization of the hydroxyl functions of the material, to increase the hydrophobic character of the composite foam.
Un tercer aspecto de Ia presente invención es el uso de Ia espuma composite de Ia invención en aislamiento térmico y acústico de edificios y otras obras civiles, así como en medios de transporte como aviones, trenes y automóviles. Asimismo, otro aspecto de Ia presente invención es el uso de Ia espuma composite de Ia invención para su aplicación como material de embalaje y como soporte de sólidos con propiedades específicas como eléctricas, magnéticas y ópticas, especies o fragmentos de especies de origen biológico como por ejemplo algas y virus, así como de medicamentos y otras especies bioactivas como pesticidas. Presentan además frente a otras espumas rígidas de tipo polimérico las ventajas de ser respetuosas con el medioambiente e incluso en ciertos casos biocompatibles, junto con Ia propiedad de ser ignífugas.A third aspect of the present invention is the use of the composite foam of the invention in thermal and acoustic insulation of buildings and other civil works, as well as in means of transport such as airplanes, trains and automobiles. Likewise, another aspect of the present invention is the use of the composite foam of the invention for its application as a packaging material and as a support for solids with specific properties such as electrical, magnetic and optical, species or fragments of species of biological origin as per example algae and viruses, as well as medications and other bioactive species such as pesticides. The advantages of being environmentally friendly and even in certain biocompatible cases, together with the property of being flame retardant, are also in front of other rigid foams of polymeric type.
EJEMPLOS DEMOSTRATIVOS DE LA INVENCIÓNDEMOSTRATIVE EXAMPLES OF THE INVENTION
Ejemplo 1. Preparación de Ia espuma composite que comprende gelatina y sepiolita concentrada por centrifugaciónExample 1. Preparation of the composite foam comprising gelatin and sepiolite concentrated by centrifugation
Se calientan 50 ml_ de agua ultrapura o destilada a 600C. Paralelamente se mezclan 2,5 gramos de sepiolita Pangel® S9 suministrada por Ia empresa TOLSA S.A. (secada a 1200C, 12h) con 2,5 gramos de gelatina tipo A de origen porcino hasta obtener una mezcla de sólidos homogénea. Se añade a dicha mezcla Ia cantidad de agua previamente referida manteniendo Ia temperatura de 600C durante 12h sin agitar hasta que se homogenice. Se efectúa enseguida un paso de centrifugación del gel obtenido a 5000 rpm durante 20 minutos, se descarta Ia fase sobrenadante. Se distribuye Ia fase resultante de Ia centrifugación en moldes de polimetilmetacrilato a 6O0C y se enfría a 40C durante 12 h. Se somete en seguida el conjunto a enfriamiento en un congelador con atmosfera de aire a -2O0C durante 12h y se elimina el disolvente mediante liofilización durante 24h a una temperatura de -80 0C y presión de 0,030 mbar.50 ml_ of ultrapure or distilled water are heated to 60 0 C. In parallel, 2.5 grams of Pangel ® S9 sepiolite mixed by the company TOLSA SA (dried at 120 0 C, 12h) are mixed with 2.5 grams of type A gelatin originally pig until a homogeneous solid mixture is obtained. To said mixture the amount of water previously referred maintaining the temperature of 60 0 C for 12 h without stirring until homogenize is added. A centrifugation step of the gel obtained at 5000 rpm for 20 minutes is carried out immediately, the supernatant phase is discarded. The resulting phase of the centrifugation is distributed in polymethylmethacrylate molds at 6O 0 C and cooled at 4 0 C for 12 h. It then undergoes a cooling assembly in a freezer with air at -2O 0 C for 12h and the solvent is removed by lyophilization for 24 h at -80 0 C and pressure of 0.030 mbar.
El composite resultante presenta una variación de Ia cantidad relativa de biopolímero frente a arcilla del 1 :1 al 1 :3, según datos obtenidos por análisis químico.The resulting composite has a variation of the relative amount of biopolymer against clay from 1: 1 to 1: 3, according to data obtained by chemical analysis.
El composite resultante presenta un módulo elástico de compresión de 41 ,8 MPa obtenido en ensayos de compresión a una velocidad constante de 5 mm/min en experimentos de medida realizados por triplicado. Dicho valor representa una mejora superior al 300% respecto a un material composite preparado con una arcilla laminar (Cloisite, Southern Clay Sciences) siguiendo el mismo procedimiento. El material presenta, bajo observación al microscopio electrónico de barrido, una textura porosa formada por zonas compactas donde las fibras se integran en Ia matriz de Ia gelatina y zonas sin material, denominadas poros. Dichos poros, que se originan por sublimación del hielo en el proceso de liofilización, son de tamaño micrométrico y están interconectados.The resulting composite has an elastic compression module of 41.8 MPa obtained in compression tests at a constant speed of 5 mm / min in triplicate measurement experiments. This value represents an improvement over 300% compared to a composite material prepared with a lamellar clay (Cloisite, Southern Clay Sciences) following the same procedure. The material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
Ejemplo 2. Preparación de Ia espuma composite que comprende gelatina y sepiolitaExample 2. Preparation of the composite foam comprising gelatin and sepiolite
Se calientan 50 ml_ de agua ultrapura o destilada a 600C. Paralelamente se mezclan 2,5 gramos de sepiolita Pangel® S9 (secada a 1200C, 12h) con 2,5 gramos de gelatina tipo A de origen porcino hasta obtener una mezcla de sólidos homogénea. Se añade a dicha mezcla Ia cantidad de agua previamente referida manteniendo Ia temperatura de 600C durante 12h sin agitar hasta que se homogenice Ia mezcla. Posteriormente se distribuye el gel formado en moldes de polimetilmetacrilato a 6O0C y se enfría a 40C durante 12 h. Se somete enseguida el conjunto a enfriamiento en congelador en una atmosfera de aire a -2O0C durante 12h y se elimina el disolvente mediante liofilización durante 24h a una temperatura de -80 0C y una presión de 0,030 mbar.50 ml_ of ultrapure or distilled water are heated to 60 0 C. In parallel, 2.5 grams of Pangel ® S9 sepiolite (dried at 120 0 C, 12h) are mixed with 2.5 grams of porcine origin A type gelatin until a homogeneous solid mixture. The amount of water is previously added to said mixture referred maintaining the temperature of 60 0 C for 12h without stirring until the mixture is homogenized. Subsequently, the gel formed in polymethylmethacrylate molds is distributed at 6O 0 C and cooled to 4 0 C for 12 h. The whole was immediately subjected to cooling in freezer in an air atmosphere at -2O 0 C for 12h and the solvent is removed by lyophilization for 24 h at -80 0 C and a pressure of 0.030 mbar.
El material presenta, bajo observación al microscopio electrónico de barrido, una textura porosa formada por zonas compactas donde las fibras se integran en Ia matriz de Ia gelatina y zonas sin material, denominadas poros. Dichos poros, que se originan por sublimación del hielo en el proceso de liofilización, son de tamaño micrométrico y están interconectados.The material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
Ejemplo 3. Preparación de Ia espuma composite que comprende xantano y sepiolita Se añaden 0,5 g de xantano a 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2 h. Se dispersa 1 g de sepiolita Pangel® S9 (previamente secada a 1000C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2 h. A continuación, se mezcla Ia disolución de xantano con Ia suspensión de sepiolita, agitando Ia mezcla en un agitador magnético a 400 rpm durante 2 h a temperatura ambiente. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h a una temperatura de -80 0C y una presión de 0,030 mbar. Las espumas resultantes presentan macroporos de aproximadamente 250 μm de diámetro según observación bajo microscopio óptico y una densidad de 0,02 g/cm3. Ejemplo 4. Preparación de Ia espuma composite que comprende goma garrofín y sepiolitaExample 3. Preparation of the composite foam comprising xanthan and sepiolite 0.5 g of xanthan are added to 50 ml_ of ultrapure or distilled water, keeping the preparation under magnetic stirring for 2 h. 1 g of sepiolite is dispersed Pangel® S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, keeping under magnetic stirring for 2 h the preparation. Next, the xanthan solution is mixed with the sepiolite suspension, stirring the mixture in a magnetic stirrer at 400 rpm for 2 h at room temperature. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24h at a temperature of -80 0 C and a pressure of 0.030 mbar. The resulting foams have macroporos of approximately 250 μm in diameter according to observation under an optical microscope and a density of 0.02 g / cm 3 . Example 4. Preparation of the composite foam comprising garrofin and sepiolite rubber
Se calientan 50 ml_ de agua ultrapura o destilada a 75°C y se añaden 0,5 g de goma garrofín, manteniendo Ia preparación bajo agitación magnética y temperatura constante de 750C durante 16 h. Se dispersa 1 g de sepiolita Pangel® S9 (previamente secada a 1000C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de goma garrofín con Ia suspensión de sepiolita, agitando Ia mezcla en un agitador magnético a 400 rpm y 80 0C durante 2 h. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h a una temperatura de -80 0C y una presión de 0,030 mbar.50 ml_ of ultrapure distilled water or heated to 75 ° C and 0.5 g of locust bean gum were added, maintaining the preparation under magnetic stirring and a constant temperature of 75 0 C for 16 h. 1 g of sepiolite is dispersed Pangel® S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, keeping under magnetic stirring the preparation for 2h. Then the dissolution carob gum is mixed with the suspension of sepiolite, shaking the mixture on a magnetic stirrer at 400 rpm and 80 0 C for 2 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24h at a temperature of -80 0 C and a pressure of 0.030 mbar.
El material presenta, bajo observación al microscopio electrónico de barrido, una textura porosa formada por zonas compactas donde las fibras se integran en Ia matriz de Ia gelatina y zonas sin material, denominadas poros. Dichos poros, que se originan por sublimación del hielo en el proceso de liofilización, son de tamaño micrométrico y están interconectados.The material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
Ejemplo 5. Preparación de Ia espuma composite que comprende goma garrofín y sepiolita concentrada por centrifugaciónExample 5. Preparation of the composite foam comprising garrofín gum and sepiolite concentrated by centrifugation
Se calientan 50 ml_ de agua ultrapura o destilada a 75°C y se añaden 0,5 g de goma garrofín, manteniendo Ia preparación bajo agitación magnética y temperatura constante de 750C durante 16 h. Se dispersa 1 g de sepiolita Pangel® S9 (previamente secada a 1000C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de goma garrofín con Ia suspensión de sepiolita, agitando Ia mezcla en un agitador magnético a 400 rpm y 80 0C durante 2 h. Posteriormente se centrifuga Ia preparación a 10000 rpm durante 15 min y se desecha el líquido sobrenadante. De esta forma se obtiene una mezcla de goma garrofín y sepiolita con una concentración próxima a 10% (peso/volumen). Finalmente, se congela el gel resultante de Ia centrifugación a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h a una temperatura de -80 0C y una presión de 0,030 mbar.50 ml_ of ultrapure distilled water or heated to 75 ° C and 0.5 g of locust bean gum were added, maintaining the preparation under magnetic stirring and a constant temperature of 75 0 C for 16 h. 1 g of sepiolite is dispersed Pangel® S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, keeping under magnetic stirring the preparation for 2h. Then the dissolution carob gum is mixed with the suspension of sepiolite, shaking the mixture on a magnetic stirrer at 400 rpm and 80 0 C for 2 h. Subsequently, the preparation is centrifuged at 10,000 rpm for 15 min and the supernatant liquid is discarded. In this way a mixture of garrofín and sepiolite gum is obtained with a concentration close to 10% (weight / volume). Finally, the gel resulting from the centrifugation is frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h at a temperature of -80 0 C and a pressure of 0.030 mbar.
El material presenta, bajo observación al microscopio electrónico de barrido, una textura porosa formada por zonas compactas donde las fibras se integran en Ia matriz de Ia gelatina y zonas sin material, denominadas poros. Dichos poros, que se originan por sublimación del hielo en el proceso de liofilización, son de tamaño micrométrico y están interconectados.The material presents, under observation by scanning electron microscope, a porous texture formed by compact areas where the fibers are integrated in the matrix of the jelly and areas without material, called pores. These pores, which are caused by sublimation of the ice in the lyophilization process, are micrometric in size and interconnected.
Ejemplo 6. Preparación de Ia espuma composite que comprende almidón y sepiolitaExample 6. Preparation of the composite foam comprising starch and sepiolite
Se calientan 50 ml_ de agua ultrapura o destilada a 800C y se añaden 5 g de almidón de patata, manteniendo Ia preparación bajo agitación magnética y temperatura constante de 8O0C durante 2h, hasta su homogenización. Se dispersan 5 g de sepiolita Pangel® S9 (previamente secada a 1000C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de almidón con Ia suspensión de sepiolita, agitando Ia mezcla con un agitador de varillas a 200 rpm y 80 0C durante 24 h. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h.50 ml_ of ultrapure or distilled water are heated to 80 0 C and 5 g of potato starch are added, keeping the preparation under magnetic stirring and constant temperature of 8O 0 C for 2h, until homogenization. 5 g of sepiolite Pangel® disperse S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, maintaining the preparation under magnetic stirring for 2h. Then the dissolution of starch is mixed with the suspension of sepiolite, stirring the mixture with an overhead stirrer at 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.
Ejemplo 7. Preparación de Ia espuma composite que comprende almidón y palygorskita Se calientan 50 ml_ de agua ultrapura o destilada a 800C y se añaden 5 g de almidón de patata, manteniendo Ia preparación bajo agitación magnética y temperatura constante de 8O0C durante 2h, hasta su homogenización. Se dispersan 5 g de palygorskita (previamente secada a 100°C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de almidón con Ia suspensión de sepiolita, agitando Ia mezcla con un agitador de varillas a 200 rpm y 80 0C durante 24 h. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h.Example 7. Preparation of the foam composite comprising starch and palygorskite 50 ml_ distilled water or ultrapure are heated to 80 0 C and 5 g of potato starch is added, maintaining the preparation under magnetic stirring and a constant temperature of 8O 0 C for 2h, until homogenization. 5 g of palygorskite (previously dried at 100 ° C, 24h) are dispersed in 50 ml_ of ultrapure or distilled water, keeping the preparation under magnetic stirring for 2h. Then, the starch solution is mixed with The suspension of sepiolite, stirring the mixture with an overhead stirrer at 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.
Ejemplo 8. Preparación de Ia espuma composite que comprende alginato y sepiolitaExample 8. Preparation of the composite foam comprising alginate and sepiolite
Se calientan 50 ml_ de agua ultrapura o destilada a 800C y se añaden 5 g de alginato de sodio, manteniendo Ia preparación bajo temperatura constante de 8O0C y agitador de varillas durante 2h, hasta su homogenización. Se dispersan 5 g de sepiolita Pangel® S9 (previamente secada a 1000C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de alginato con Ia suspensión de sepiolita, agitando Ia mezcla con un agitador de varillas a 200 rpm y 80 0C durante 24 h. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h.50 ml_ of ultrapure or distilled water are heated to 80 0 C and 5 g of sodium alginate are added, keeping the preparation under constant temperature of 8O 0 C and stirrer of rods for 2h, until homogenization. 5 g of sepiolite Pangel® disperse S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, maintaining the preparation under magnetic stirring for 2h. Then Ia alginate solution is mixed with the suspension of sepiolite, stirring the mixture with an overhead stirrer at 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.
El composite resultante presenta un módulo elástico de compresión de 16,8 MPa obtenido en ensayos de compresión a una velocidad constante de 5 mm/min realizados por triplicado.The resulting composite has an elastic compression module of 16.8 MPa obtained in compression tests at a constant speed of 5 mm / min performed in triplicate.
Ejemplo 9. Preparación de Ia espuma composite que comprende alginato y palygorskitaExample 9. Preparation of the composite foam comprising alginate and palygorskite
Se calientan 50 ml_ de agua ultrapura o destilada a 800C y se añaden 5 g de alginato de sodio, manteniendo Ia preparación bajo temperatura constante de50 ml_ of ultrapure or distilled water are heated to 80 0 C and 5 g of sodium alginate are added, keeping the preparation under constant temperature of
8O0C y agitador de varillas durante 2h, hasta su homogenización. Se dispersan8O 0 C and stirrer of rods for 2h, until homogenization. They disperse
5 g de palygorskita (previamente secada a 100°C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de alginato con Ia suspensión de palygorskita, agitando Ia mezcla con un agitador de varillas a 200 rpm y 80 0C durante 24 h. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h.5 g of palygorskite (previously dried at 100 ° C, 24h) in 50 ml_ of ultrapure or distilled water, keeping the preparation under magnetic stirring for 2h. Next, the alginate solution is mixed with the palygorskite suspension, stirring the mixture with a stirrer of rods to 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.
El composite resultante presenta un módulo elástico de compresión de 21 ,5 MPa obtenido en ensayos de compresión a una velocidad constante de 5mm/min realizados por triplicado.The resulting composite has an elastic compression module of 21.5 MPa obtained in compression tests at a constant speed of 5mm / min performed in triplicate.
Ejemplo 10. Preparación de Ia espuma composite que comprende iota- carragenato y sepiolita Se calientan 50 ml_ de agua ultrapura o destilada a 800C y se añaden 5 g de iota-carragenato, manteniendo Ia preparación bajo temperatura constante de 8O0C y agitador de varillas durante 2h, hasta su homogenización. Se dispersan 5 g de sepiolita Pangel® S9 (previamente secada a 1000C, 24h) en 50 ml_ de agua ultrapura o destilada, manteniendo Ia preparación bajo agitación magnética durante 2h. A continuación, se mezcla Ia disolución de iota- carragenato con Ia suspensión de sepiolita, agitando Ia mezcla con un agitador de varillas a 200 rpm y 80 0C durante 24 h. Finalmente, se distribuye Ia mezcla en moldes de polimetilmetacrilato, se congela a -2O0C durante 24 h y se elimina el disolvente mediante liofilización durante 24h. Example 10. Preparation of the composite foam comprising iotacarbonate and sepiolite 50 ml_ of ultrapure or distilled water are heated to 80 0 C and 5 g of iota-carrageenan are added, keeping the preparation at a constant temperature of 8O 0 C and stirrer of rods for 2h, until homogenization. 5 g of sepiolite Pangel® disperse S9 (previously dried at 100 0 C, 24h) in 50 ml_ of ultrapure water or distilled water, maintaining the preparation under magnetic stirring for 2h. Then the dissolution iota carrageenan is mixed with the suspension of sepiolite, stirring the mixture with an overhead stirrer at 200 rpm and 80 0 C for 24 h. Finally, the mixture is distributed in polymethylmethacrylate molds, frozen at -2O 0 C for 24 h and the solvent is removed by lyophilization for 24 h.

Claims

REIVINDICACIONES
1. Espuma rígida de tipo composite caracterizada porque comprende una matriz biopolimérica y partículas de silicatos pertenecientes a Ia familia de las arcillas fibrosas.1. Rigid composite foam characterized in that it comprises a biopolymeric matrix and silicate particles belonging to the family of fibrous clays.
2. Espuma composite según reivindicación 1 caracterizada porque Ia arcilla fibrosa es sepiolita.2. Composite foam according to claim 1 characterized in that the fibrous clay is sepiolite.
3. Espuma composite según reivindicación 2 caracterizada porque Ia arcilla fibrosa es palygorskita.3. Composite foam according to claim 2 characterized in that the fibrous clay is palygorskite.
4. Espuma composite según reivindicación 1 caracterizada porque Ia matriz biopolimérica es una proteína estructural.4. Composite foam according to claim 1 characterized in that the biopolymeric matrix is a structural protein.
5. Espuma composite según reivindicación 4 caracterizada porque Ia proteína estructural es gelatina.5. Composite foam according to claim 4 characterized in that the structural protein is gelatin.
6. Espuma composite según reivindicación 4 caracterizada porque Ia proteína estructural es colágeno.6. Composite foam according to claim 4 characterized in that the structural protein is collagen.
7. Espuma composite según reivindicación 1 caracterizada porque Ia matriz biopolimérica es un polisacárido neutro.7. Composite foam according to claim 1 characterized in that the biopolymeric matrix is a neutral polysaccharide.
8. Espuma composite según reivindicación 7 caracterizada porque el polisacárido neutro es almidón. 8. Composite foam according to claim 7 characterized in that the neutral polysaccharide is starch.
9. Espuma composite según reivindicación 7 caracterizada porque el polisacárido neutro es agar.9. Composite foam according to claim 7 characterized in that the neutral polysaccharide is agar.
10. Espuma composite según reivindicación 7 caracterizada porque el polisacárido neutro es goma garrotín .10. Composite foam according to claim 7 characterized in that the neutral polysaccharide is garrotine rubber.
11. Espuma composite según reivindicación 7 caracterizada porque el polisacárido neutro es goma guar.11. Composite foam according to claim 7 characterized in that the neutral polysaccharide is guar gum.
12. Espuma composite según reivindicación 1 caracterizada porque Ia matriz biopolimérica es un polisacárido cargado positivamente.12. Composite foam according to claim 1 characterized in that the biopolymeric matrix is a positively charged polysaccharide.
13. Espuma composite según reivindicación 12 caracterizada porque el polisacárido cargado positivamente es quitosano.13. Composite foam according to claim 12 characterized in that the positively charged polysaccharide is chitosan.
14. Espuma composite según reivindicación 1 caracterizada porque Ia matriz biopolimérica es un polisacárido cargado negativamente.14. Composite foam according to claim 1 characterized in that the biopolymeric matrix is a negatively charged polysaccharide.
15. Espuma composite según reivindicación 14 caracterizada porque el polisacárido cargado negativamente es alginato.15. Composite foam according to claim 14 characterized in that the negatively charged polysaccharide is alginate.
16. Espuma composite según reivindicación 14 caracterizada porque el polisacárido cargado negativamente es xantano.16. Composite foam according to claim 14 characterized in that the negatively charged polysaccharide is xanthan.
17. Espuma composite según reivindicación 14 caracterizada porque el polisacárido cargado negativamente es algún carragenato. 17. Composite foam according to claim 14 characterized in that the negatively charged polysaccharide is some carrageenan.
18. Procedimiento de preparación de Ia espuma composite descrita en las reivindicaciones anteriores caracterizado porque comprende las siguientes etapas: a. Mezcla de una dispersión coloidal de biopolímero con una dispersión coloidal de arcilla b. Homogenización de Ia mezcla obtenida en a) hasta obtener un gel c. Proceso de eliminación del agua del gel preparado en Ia etapa b).18. Method of preparing the composite foam described in the preceding claims characterized in that it comprises the following steps: a. Mixing a colloidal dispersion of biopolymer with a colloidal dispersion of clay b. Homogenization of the mixture obtained in a) until obtaining a gel c. Water removal process of the gel prepared in stage b).
19. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque Ia etapa c) se realiza mediante congelación del gel obtenido en b) aplicando posteriormente un proceso de liofilización consistente en Ia sublimación del hielo generado.19. Preparation process of the composite foam according to claim 18 characterized in that step c) is performed by freezing the gel obtained in b) subsequently applying a lyophilization process consisting of the sublimation of the ice generated.
20. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque Ia congelación tiene lugar a una temperatura comprendida entre 77 K y 273 K.20. Method of preparing the composite foam according to claim 18 characterized in that the freezing takes place at a temperature between 77 K and 273 K.
21. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque Ia etapa c) se realiza mediante procesos de secado supercrítico.21. Preparation process of the composite foam according to claim 18 characterized in that step c) is carried out by supercritical drying processes.
22. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque en Ia etapa a) las disoluciones o dispersiones coloidales del biopolímero y de Ia arcilla son mezcladas de forma que produzcan una única dispersión coloidal, homogénea y estable.22. Preparation process of the composite foam according to claim 18 characterized in that in step a) the colloidal solutions or dispersions of the biopolymer and the clay are mixed so as to produce a single colloidal, homogeneous and stable dispersion.
23. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque en Ia etapa a) las proporciones relativas en peso del biopolímero frente al de Ia arcilla están comprendidas entre 1 : 10 y 10: 1.23. Preparation process of the composite foam according to claim 18 characterized in that in stage a) the proportions relative in weight of the biopolymer versus that of the clay are between 1: 10 and 10: 1.
24. Procedimiento de preparación de Ia espuma composite según reivindicación 23 caracterizado porque Ia proporción relativa en peso del biopolímero frente al de Ia arcilla es 1 :1.24. Preparation process of the composite foam according to claim 23, characterized in that the relative weight ratio of the biopolymer to that of the clay is 1: 1.
25. Procedimiento de preparación de Ia espuma composite según reivindicación 23 caracterizado porque Ia proporción relativa de biopolímero es inferior a Ia de arcilla.25. Preparation process of the composite foam according to claim 23, characterized in that the relative proportion of biopolymer is lower than that of clay.
26. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque Ia espuma composite obtenida en c) es estabilizada mediante reacción de entrecruzamiento de las cadenas poliméricas a través de las funciones amino, amida, hidroxilo o carboxilo por tratamiento con distintos agentes entrecruzantes.26. Method of preparing the composite foam according to claim 18 characterized in that the composite foam obtained in c) is stabilized by cross-linking reaction of the polymer chains through the amino, amide, hydroxyl or carboxyl functions by treatment with different crosslinking agents.
27. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque al gel generado en Ia etapa b) se Ie aplica un procedimiento de concentración o dilución, como son Ia centrifugación, el secado o Ia adición de disolvente respectivamente, en función de Ia densidad pretendida.27. Preparation process of the composite foam according to claim 18 characterized in that a concentration or dilution procedure is applied to the gel generated in step b), such as centrifugation, drying or solvent addition respectively, depending on the intended density.
28. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque las etapas b) y c) se realizan en un molde que imparta Ia forma final del composite.28. Preparation process of the composite foam according to claim 18 characterized in that steps b) and c) are carried out in a mold that imparts the final shape of the composite.
29. Procedimiento de preparación de Ia espuma composite según reivindicación 28 caracterizado porque el molde es de naturaleza polimérica o metálica, que presenta baja rugosidad, ausencia de irregularidades texturales y bajo coeficiente de expansión térmica.29. Preparation process of the composite foam according to claim 28 characterized in that the mold is of a nature polymeric or metallic, which presents low roughness, absence of textural irregularities and low coefficient of thermal expansion.
30. Procedimiento de preparación de Ia espuma composite según reivindicación 18 caracterizado porque Ia espuma composite obtenida en c) es posteriormente modificada mediante Ia silanización de las funciones hidroxilo del material para aumentar el carácter hidrofóbico de30. Method of preparing the composite foam according to claim 18 characterized in that the composite foam obtained in c) is subsequently modified by means of silanization of the hydroxyl functions of the material to increase the hydrophobic character of
Ia espuma composite.The composite foam.
31. Uso de Ia espuma composite descrita en las reivindicaciones 1-17 como aislante térmico y acústico y retardante de paso de llama en edificios y otras obras civiles, así como en medios de transporte como aviones, trenes y automóviles.31. Use of the composite foam described in claims 1-17 as thermal and acoustic insulation and flame retardant in buildings and other civil works, as well as in means of transport such as airplanes, trains and automobiles.
32. Uso de Ia espuma composite descrita en las reivindicaciones 1-17 como material de embalaje.32. Use of the composite foam described in claims 1-17 as packaging material.
33. Uso de Ia espuma composite descrita en las reivindicaciones 1-17 como soporte de sólidos con propiedades eléctricas, magnéticas y ópticas.33. Use of the composite foam described in claims 1-17 as a solid support with electrical, magnetic and optical properties.
34. Uso de Ia espuma composite descrita en las reivindicaciones 1-17 como soporte de especies o fragmentos de origen biológico, por ejemplo algas y virus, así como de medicamentos y otras especies bioactivas como pesticidas. 34. Use of the composite foam described in claims 1-17 as a support for species or fragments of biological origin, for example algae and viruses, as well as medicines and other bioactive species such as pesticides.
PCT/ES2009/070542 2009-01-14 2009-12-01 Rigid foams of composite type based on biopolymers combined with fibrous clays and method for the preparation thereof WO2010081918A1 (en)

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