Sustainable composite material and method for making a sustainable composite material

Abstract

A composite material (1), comprising a geopolymeric matrix (2) and carbon material inclusions (3) included and stabilized within the geopolymeric matrix (2).

Description

"Sustainable composite material and method for making a sustainable composite material"

[0001] Field of the invention

[0002] The present invention relates to a sustainable composite material, in particular a geopolymeric matrix composite material with carbon material inclusions, and to a method for making a sustainable geopolymeric matrix composite material with carbon material inclusions.

[0003] Background art

[0004] Geopolymers are a class of inorganic materials which have received considerable attention in recent decades by virtue of the excellent physical and mechanical properties thereof, such as high heat resistance, durability, low cost, and resistance to acid and alkaline environment.

[0005] These materials, sometimes referred to as “green” cements, have shown great potential for replacing traditional clinker-based cements due to the lower environmental impact and better strength thereof.

[0006] In the prior art, geopolymeric matrix composites are used in various fields, including construction, aerospace, automotive, and chemical industries, by virtue of the versatility thereof.

[0007] The inventors are aware of developments of composite materials with different geopolymeric matrices and reinforcements of different nature (ceramic, metal, fibreglass, carbon fibre, etc.), aiming at obtaining a material with customizable properties according to the specific application needs.

[0008] Despite the multiple advantages and applications of geopolymers, there are still challenges limiting the application thereof on a large scale.

[0009] For example, in the prior art the production of geopolymers requires high temperatures, the choice of precursors is limited, and the understanding of the polymerization reactions is still partial.

[0010] As for the material inclusions, in particular plastic materials, especially if waste material, the prior art is highly limited. Most plastic waste is not biodegradable and the management thereof is a big environmental problem.

[0011] Inventors know the attempts to use recycled plastic as an aggregate in composite materials, but these often exhibit compatibility, adhesion, and degradation issues. Thermosetting resins, in particular, are known to be difficult to recycle due to the cross-linked nature thereof.

[0012] Therefore, the need is felt to have a sustainable and improved composite material as compared to the prior art.

[0013] Solution

[0014] It is the object of the present invention to provide a composite material with a geopolymeric matrix which includes and stabilizes different types of carbon materials, i.e., including carbon, therein.

[0015] It is a particular object of the present invention to provide a geopolymeric matrix composite material which includes and stabilizes various types of plastic materials therein, including thermosetting resins and waste materials.

[0016] These and other objects are achieved by a geopolymeric matrix composite material, and a method for making a composite material, according to the independent claims.

[0017] The dependent claims relate to preferred and advantageous embodiments of the present invention.

[0018] The geopolymeric matrix composite material of the invention differs from the geopolymeric composite materials known to the inventors for the ability thereof to incorporate and stabilize carbon materials and in particular waste plastics.

[0019] Moreover, the materials to be incorporated by the present geopolymeric matrix composite material include the so-called phase-change materials ("PCMs"), i.e., plastic materials (e.g., paraffins and / or derivatives of complex alcohols) capable of switching from the solid state to the liquid state at or near ambient temperature, thus offering a sustainable and resistant option for various construction applications.

[0020] Figures

[0021] In order to better understand the invention and appreciate the advantages thereof, some non-limiting exemplary embodiments thereof will be described below with reference to the accompanying drawings, in which:

[0022] - figure 1 is a depiction of a composite material according to an embodiment of the invention;

[0023] - figure 2 is a depiction of a mixing device in operating configuration during a mixing and blending step of a method for marking a composite material, according to an embodiment of the invention;

[0024] - figure 3 is a diagrammatic depiction of a method for making a composite material, according to an embodiment of the invention.

[0025] Description of some preferred embodiments

[0026] With reference to the figures, a composite material is generally indicated by reference numeral 1.

[0027] The composite material 1 comprises a geopolymeric matrix 2.

[0028] According to an aspect of the invention, the composite material 1 comprises carbon material inclusions 3. The carbon material inclusions 3 are included and stabilized within the geopolymeric matrix 2.

[0029] Advantageously, the composite material 1 thus configured, in addition to high physical and mechanical properties, has a significantly reduced environmental impact by virtue of the stabilized carbon material inclusions, in particular plastic waste materials, incorporated and stabilized within the geopolymeric matrix 2.

[0030] Geopolymeric matrix means a matrix made of geopolymers, i.e., synthetic materials based on aluminosilicates.

[0031] Carbon materials mean organic materials or in any case materials comprising carbon.

[0032] According to an embodiment, the geopolymeric matrix 2 is formed by aluminosilicates.

[0033] In particular, the geopolymeric matrix 2 can be formed by iron aluminosilicates or calcium aluminosilicates or sodium aluminosilicates or by a combination thereof.

[0034] According to an embodiment, the geopolymeric matrix 2 is formed by a combination of different aluminosilicates.

[0035] According to an embodiment, the geopolymeric matrix 2 is at least 50% of the weight of the composite material 1.

[0036] According to an embodiment, the geopolymeric matrix 2 is at most 99% of the weight of the composite material 1.

[0037] According to an embodiment, the geopolymeric matrix 2 is from 50% to 99% by weight of the composite material 1.

[0038] According to an embodiment, the geopolymeric matrix 2 is from 50% to 90% by weight of the composite material 1.

[0039] According to an embodiment, the geopolymeric matrix 2 is from 63% to 90% by weight of the composite material 1.

[0040] According to an embodiment, the geopolymeric matrix 2 is from 65% to 90% by weight of the composite material 1.

[0041] According to an embodiment, the geopolymeric matrix 2 is from 70% to 90% by weight of the composite material 1.

[0042] According to an embodiment, the geopolymeric matrix 2 is from 50% to 70% by weight of the composite material 1.

[0043] According to an embodiment, the geopolymeric matrix 2 is from 50% to 65% by weight of the composite material 1.

[0044] According to an embodiment, the geopolymeric matrix 2 is from 50% to 63% by weight of the composite material 1.

[0045] According to an embodiment, the geopolymeric matrix 2 consists of blast furnace slag, or rice husk, or rice husk ash, or eggshell sand, or amorphous silica, or any combination of the above.

[0046] According to an embodiment, the carbon material inclusions 3 are at least 1% of the weight of the composite material 1.

[0047] According to an embodiment, the carbon material inclusions 3 are at most 50% of the weight of the composite material 1.

[0048] According to an embodiment, the carbon material inclusions 3 are from 1% to 50% by weight of the composite material 1.

[0049] According to an embodiment, the carbon material inclusions 3 are from 1% to 40% by weight of the composite material 1.

[0050] According to an embodiment, the carbon material inclusions 3 are from 1% to 30% by weight of the composite material 1.

[0051] According to an embodiment, the carbon material inclusions 3 are from 1% to 25% by weight of the composite material 1.

[0052] According to an embodiment, the carbon material inclusions 3 are from 1% to 20% by weight of the composite material 1.

[0053] According to an embodiment, the carbon material inclusions 3 are from 1% to 3% by weight of the composite material 1.

[0054] According to an embodiment, the carbon material inclusions 3 are from 3% to 50% by weight of the composite material 1.

[0055] According to an embodiment, the carbon material inclusions 3 are from 20% to 50% by weight of the composite material 1.

[0056] According to an embodiment, the carbon material inclusions 3 are from 25% to 50% by weight of the composite material 1.

[0057] According to an embodiment, the carbon material inclusions 3 are from 30% to 50% by weight of the composite material 1.

[0058] According to an embodiment, the carbon material inclusions 3 are from 40%to 50% by weight of the composite material 1.

[0059] According to an embodiment, the carbon material inclusions 3 comprise plastic materials, or thermoset resins, or paraffins, or alcohols, or thermoplastic resins, or carbon fibres, or graphene, or any combination of the above.

[0060] According to an embodiment, the thermoset resins are pulverized.

[0061] According to an embodiment, the paraffins can be microencapsulated or nonmicroencapsulated.

[0062] According to an embodiment, the alcohols can be complex alcohols, including solid dodecanol.

[0063] According to an embodiment, the thermoplastic resins are pulverized.

[0064] According to an embodiment, the composite material 1 further comprises additional inclusions. The additional inclusions are additional inclusions with respect to the carbon material inclusions 3 previously described.

[0065] According to an embodiment, the additional inclusions comprise glass fibres, or aluminum oxides, or iron oxides, or aluminosilicate wastes, or any combination of the above.

[0066] According to an embodiment, the aluminosilicate wastes can be of various nature, including for example quarry waste, or by-products of quartz sand separation processes, or by-products of marble processing.

[0067] According to an embodiment, the composite material 1 comprises an alkaline aqueous solution 4.

[0068] The alkaline aqueous solution 4 has a pH > 10.

[0069] Advantageously, the alkaline aqueous solution 4 promotes the inclusion and stabilization of carbon material inclusions 3 within the geopolymeric matrix 2.

[0070] According to an embodiment, the alkaline aqueous solution 4 is a solution based on silicic acid, or sodium hydroxide, or sodium salts, or any combination of the above.

[0071] According to an embodiment, the alkaline aqueous solution 4 is at least 5% of the weight of the composite material 1.

[0072] According to an embodiment, the alkaline aqueous solution 4 is at most 50% of the weight of the composite material 1.

[0073] According to an embodiment, the alkaline aqueous solution 4 is from 5% to 50% by weight of the composite material 1.

[0074] According to an embodiment, the alkaline aqueous solution 4 is from 5% to10% by weight of the composite material 1.

[0075] According to an embodiment, the alkaline aqueous solution 4 is from 7% to 50% by weight of the composite material 1.

[0076] According to an embodiment, the alkaline aqueous solution 4 is from 7% to 10% by weight of the composite material 1.

[0077] According to an embodiment, the composite material 1 comprises the geopolymeric matrix 2, the carbon material inclusions 3 and the alkaline aqueous solution 4.

[0078] According to an embodiment, the geopolymeric matrix 2, the carbon material inclusions 3 and the alkaline aqueous solution 4 are the following percentages of the weight of the composite material 1 :

[0079] 10% of alkaline aqueous solution, 20% of carbon material inclusions, 70% of geopolymeric matrix; or

[0080] 10% of alkaline aqueous solution, 25% of carbon material inclusions, 65% of geopolymeric matrix; or

[0081] 10% of alkaline aqueous solution, 40% of carbon material inclusions, 50% of geopolymeric matrix; or

[0082] 7% of alkaline aqueous solution, 30% of carbon material inclusions, 63% of geopolymeric matrix; or

[0083] 7% of alkaline aqueous solution, 3% of carbon material inclusions, 90% of geopolymeric matrix.

[0084] Advantageously, the by-weight compositions and in particular the selection of the materials discussed above allows making a composite material 1 with high physical and mechanical properties and in particular with a significantly reduced environmental impact, and allows reusing and recovering waste carbon materials which are otherwise unusable and polluting.

[0085] According to a further aspect of the invention, a method 100 for the making a composite material 1 comprising a geopolymeric matrix 2 and carbon material inclusions 3 included and stabilized within the geopolymeric matrix 2, is described below.

[0086] The method 100 comprises the following manufacturing steps:

[0087] - selection and mixing 200 of materials intended to form a geopolymeric matrix2 and carbon material inclusions 3, so as to produce a solid mixture 5;

[0088] - addition and mixing 300 of an alkaline aqueous solution 4 having pH > 10 to the solid mixture 5, so as to produce a mixed suspension 6;

[0089] - curing 400 of the mixed suspension 6, so as to produce the composite material 1.

[0090] Advantageously, a method 100 thus configured allows making a composite material 1 with high physical and mechanical properties and in particular with a significantly reduced environmental impact, and allows reusing and recovering waste carbon materials which are otherwise unusable and polluting.

[0091] In particular, the method 100 described above allows effectively incorporating and stabilizing carbon material inclusions 3 within the composite material 1 , and in particular within the geopolymeric matrix 2.

[0092] According to an embodiment, the selection and mixing step 200 comprises the following manufacturing steps:

[0093] - selection and mixing 210 of solid materials intended to form the geopolymeric matrix 2, so as to produce a geopolymeric solid mixture 7;

[0094] - then, selection of solid materials intended to form carbon material inclusions3, and mixing 220 the solid materials intended to form carbon material inclusions 3 in the geopolymeric solid mixture 7, so as to produce the solid mixture 5.

[0095] According to an embodiment, following the addition and mixing step 300, a mixed suspension 6 is obtained, consisting of the solid mixture 5 dispersed and suspended in the alkaline aqueous solution 4.

[0096] According to an embodiment, the addition and mixing step 300 comprises a step of:

[0097] - mixing 310, via a mixing device 8, the alkaline aqueous solution 4 and the solid mixture 5,

[0098] - at the same time blending 320, through the movement of the mixing device8 in a substantially circular or concentric or helical manner, the aqueous solution 4 and the solid mixture 5.

[0099] The mixing device 8 is an electromechanical device comprising at least one propeller, preferably a plurality of rotating propellers, e.g., a whisk.

[0100] Advantageously, this allows imparting, by means of the mixing device 8, a double movement, i.e., two synergistic movements, to the set of alkaline aqueous solution 4 and solid mixture 5.

[0101] In fact, a first movement is given by the mixing device 8 itself, which is configured to mix the set of alkaline aqueous solution 4 and solid mixture 5. Moreover, during the mixing step 310, the mixing device 8 is moved along a substantially circularor concentric or spiral path, in order to impart a further movement to the set of alkaline aqueous solution 4 and solid mixture 5 (fig. 2).

[0102] In essence, the mixing device 8 acts both as a whisk (step 310) and as a stand mixer (step 320).

[0103] With further advantage, by simultaneously carrying out the steps of mixing 310 and blending 320, a better distribution of the alkaline aqueous solution 4 on the solid mixture 5 is obtained. Blending 320 allows blending larger amounts of components forming the solid mixture 5, while mixing 310 allows "wetting" smaller amounts of the solid mixture 5 within the overall mixture, i.e. , the set of alkaline aqueous solution 4 and solid mixture 5. This combination of mixing 310 and blending 320 ensures a more homogeneous mixing 300 at the microscopic level, avoiding the formation of lumps or areas of irregular concentration of the materials.

[0104] Moreover, this combination provides a benefit in terms of reducing the amounts of alkaline aqueous solution 4 needed to make the activation of the geopolymeric matrix 2 occur, as a poor mixing would lead to an addition of liquid to compensate for the lower wettability of the solid.

[0105] Finally, this combination reduces the risk of segregation of the different solid materials during the process, helping to prevent the separation of heavier components from lighter ones or the formation of unwanted stratifications. This ensures a uniform and cohesive mixed solution 6 which maintains the desired properties over time.

[0106] According to an embodiment, following the addition and mixing step 300 and prior to the curing step 400, the method 100 comprises a step of:

[0107] - pouring 500 the mixed suspension 6 inside one or more moulds. The moulds can be of any shape, size, and material.

[0108] Advantageously, this allows obtaining a composite material 1 of the desired shape and size.

[0109] According to an embodiment, following the pouring step 500 and prior to the curing step 400, the method 100 comprises a step of:

[0110] - pressing and / or vibrocompacting 600 the mixed suspension 6 contained within the moulds.

[0111] According to an embodiment, following the curing step 400, the method 100 comprises a step of:

[0112] - demoulding 700 the composite materials 1 from the respective moulds.

[0113] According to an embodiment, following the deforming step 700, the method100 comprises a step of:

[0114] - ageing 800 the composite material 1 .

[0115] Preferably, ageing 800 is carried out in atmospheric conditions, i.e., a natural ageing of the composite material 1 is carried out.

[0116] According to an embodiment, the curing step 400 is carried out at a substantially constant temperature or at a variable temperature between 25°C and 99°C, or between 30°C and 80°C, or between 40°C and 80°C, or between 35°C and 70°C.

[0117] According to an embodiment, the curing step 400 is carried out for a time between 1 hour and 36 hours, or 2 hours and 30 hours, or 3 hours and 20 hours, or 5 hours and 10 hours.

[0118] According to an embodiment, the curing step 400 is carried out inside a stove or an oven.

[0119] Following the curing 400, the composite material 1 has a solid consistency.

[0120] Obviously, those skilled in the art will be able to make changes or adaptations to the present invention, without however departing from the scope of the following claims.LIST OF REFERENCE NUMERALS1. Composite material2. Geopolymeric matrix3. Carbon material inclusions4. Alkaline aqueous solution5. Solid mixture6. Mixed suspension7. Solid geopolymeric mixture8. Mixing device100. Method for making a composite material200. Selection and mixing210. Selection and mixing of solid geopolymeric materials220. Selection and mixing of carbon materials300. Addition and mixing310. Mixing320. Blending400. Curing500. Pouring600. Pressing and / or vibrocompacting700. Demoulding800. Ageing

Claims

Claims1. A composite material (1), comprising a geopolymeric matrix (2) and carbon material inclusions (3) included and stabilized within the geopolymeric matrix (2).

2. Composite material (1) according to claim 1 , wherein the geopolymeric matrix is formed by aluminosilicates, and / or iron aluminosilicates, and / or calcium aluminosilicates, and / or a combination of different aluminosilicates, and / or wherein the geopolymeric matrix (2) constitutes at least 50% of the weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes at most 99% of the weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 50% to 99% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 50% to 90% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 63% to 90% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 65% to 90% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 70% to 90% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 50% to 70% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 50% to 65% in weight of the composite material (1), or wherein the geopolymeric matrix (2) constitutes from 50% to 63% in weight of the composite material (1).

3. Composite material (1) according to claim 1 or 2, wherein the geopolymeric matrix (2) is formed from blast furnace slag, or rice husk, or rice husk ash, or eggshell sand, or amorphous silica, or any combination of the above.

4. Composite material (1) according to any one of the preceding claims, wherein carbon material inclusions (3) constitute at least 1% of the weight of the composite material (1), orwherein carbon material inclusions (3) constitute at most 50% of the weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 1% to 50% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 1% to 40% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 1% to 30% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 1% to 25% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 1% to 20% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 1% to 3% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 3% to 50% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 20% to 50% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 25% to 50% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 30% to 50% in weight of the composite material (1), or wherein carbon material inclusions (3) constitute from 40% to 50% in weight of the composite material (1).

5. Composite material (1) according to any one of the preceding claims, wherein carbon material inclusions (3) comprise plastic materials, or thermoset resins, or paraffins, or alcohols, or thermoplastic resins, or carbon fibres, or graphene, or any combination of the above.

6. Composite material (1) according to claim 5, further comprising additional inclusions, additional to the carbon material inclusions (3), wherein the additional inclusions comprise glass fibres, or aluminium oxides, or iron oxides, or aluminosilicate wastes, or any combination of the above.

7. Composite material (1) according to any one of the preceding claims, comprising an alkaline aqueous solution having pH > 10, wherein the alkaline aqueous solution is based on silicic acid, or sodium hydroxide, or sodium salts, or any combination of the above, and / or wherein the alkaline aqueous solution constitutes at least 5% of the weight of the composite material (1), or wherein the alkaline aqueous solution (4) constitutes at most 50% of the weight of the composite material (1), or wherein the alkaline aqueous solution (4) constitutes from 5% to 50% in weight of the composite material (1), or wherein the alkaline aqueous solution (4) constitutes from 5% to 10% in weight of the composite material (1), or wherein the alkaline aqueous solution (4) constitutes from 7% to 50% in weight of the composite material (1), or wherein the alkaline aqueous solution (4) constitutes from 7% to 10% in weight of the composite material (1).

8. Composite material (1) according to any one of the preceding claims, comprising a geopolymeric matrix (2), carbon material inclusions (3) and an alkaline aqueous solution (4), wherein the weight of the composite material (1) consists of:- 10% of alkaline aqueous solution, 20% of carbon material inclusions, 70% of geopolymeric matrix; or- 10% of alkaline aqueous solution, 25% of carbon material inclusions, 65% of geopolymeric matrix; or- 10% of alkaline aqueous solution, 40% of carbon material inclusions, 50% of geopolymeric matrix; or- 7% of alkaline aqueous solution, 30% of carbon material inclusions, 63% of geopolymeric matrix; or- 7% of alkaline aqueous solution, 3% of carbon material inclusions, 90% of geopolymeric matrix.

9. A method (100) for the production of a composite material (1), comprising a geopolymeric matrix (2) and carbon material inclusions (3) included and stabilized within the geopolymeric matrix (2), comprising the following manufacturing steps:- selection and mixing (200) of materials destined to compose a geopolymeric matrix (2) and carbon material inclusions (3), so as to produce a solid mixture (5);- addition and mixing (300) of an alkaline aqueous solution (4) having pH > 10 to the solid mixture (5), so as to produce a mixed suspension (6);- curing (400) of the mixed suspension (6), so as to produce the composite material (1).

10. Method (100) according to claim 9, wherein the step of selection and mixing (200) comprises the following manufacturing steps:- selection and mixing (210) of solid materials destined to compose the geopolymeric matrix (2), so as to produce a geopolymeric solid mixture (7);- subsequently, selection of solid materials destined to compose carbon material inclusions (3), and mixing (220) of the solid materials destined to compose carbon material inclusions (3) in the geopolymeric solid mixture (7), so as to produce the solid mixture (5).

11. Method (100) according to claim 9 or 10, wherein after the step of addition and mixing (300) a mixed suspension is obtained (6) consisting of the solid mixture (5) dispersed and suspended in the alkaline aqueous solution (4), or wherein the step of addition and mixing (300) comprises a step of:- mixing (310), via a mixing device (8), the alkaline aqueous solution (4) and the solid mixture (5),- at the same time, blending (320), via motion of the mixing device (8) in a substantially circular or concentric or spiralling way, the aqueous solution (4) and the solid mixture (5).

12. Method (100) according to one of the claims from 9 to 11 , wherein, subsequent to the step of addition and mixing (300) and prior to the curing step (400), the method (100) comprises a step of:- pouring (500) the mixed suspension (6) inside one or more molds. The molds can be of any form, dimension and material, and, optionally, wherein subsequent to the pouring step (500) and prior to the curing step (400), the method (100) comprises a step of:- pressing and / or vibrocompacting (600) the mixed suspension (6) contained within the molds.

13. Method (100) according to one of the claims from 9 to 12, wherein subsequent to thecuring step (400), the method (100) comprises a step of:- demolding (700) the composite materials (1) from their respective molds, subsequent to the demolding step (700), the method (100) comprises a step of:- ageing (800) of the composite material (1), subsequent to the demolding step (700), wherein, preferably, ageing (800) is carried out in atmospheric conditions.

14. Method (100) according to one of the claims from 9 to 13, wherein the curing step (400) is carried out at a substantially constant temperature or at a variable temperature ranging between 25°C and 99°C, or between 30°C and 80°C, or between 40°C and 80°C, or between 35°C and 70°C, or wherein the curing step (400) is carried out for a time duration ranging between 1 hour and 36 hours, or 2 hours and 30 hours, or 3 hours and 20 hours, or 5 hours and 10 hours.

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