WO2024085756A1 - Matériaux à changement de phase dans des réseaux polymères - Google Patents

Matériaux à changement de phase dans des réseaux polymères Download PDF

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WO2024085756A1
WO2024085756A1 PCT/NL2023/050547 NL2023050547W WO2024085756A1 WO 2024085756 A1 WO2024085756 A1 WO 2024085756A1 NL 2023050547 W NL2023050547 W NL 2023050547W WO 2024085756 A1 WO2024085756 A1 WO 2024085756A1
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gelsat
phase
composition
formula
solution
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PCT/NL2023/050547
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Shuaiqiao PENG
Mohammad MEHRALI
Johan Evert Ten Elshof
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Universiteit Twente
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/02—Materials undergoing a change of physical state when used
    • C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
    • C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials

Definitions

  • compositions comprising a phase-change material and a polymer network, and methods of making or using same.
  • phase change materials have drawn huge attention because of their ability to fulfil the inconsistency of traditional heat harvesting and to achieve heat management in a green, non-toxic and purely physical way.
  • organic PCMs inorganic PCMs are more advantageous, since the latter are non-flammable, have a higher energy density, typically only demonstrate a slight volume change during phase transition, etc.
  • Inorganic PCMs typically comprise salt hydrates.
  • PCMs may phase-separate, severely limiting its long-term use.
  • this problem is often observed when salt hydrates are used as PCMs.
  • the liquid-solid phase separation can cause an inconsistent distribution of energy density inside the material, and as the cycling time increases, the phenomenon will only become worse.
  • thickening agents Even when thickening agents are added, phase separation is only postponed to an unsatisfactory extent. Thus, the addition of thickening agents does not provide a long-term solution to phase-separation. Moreover, some thickening agents such as xanthan gum can also affect the heat transfer and lower the thermal conductivity of the PCM.
  • PCMs polystyrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene, polystyrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-styrene-sty
  • the present invention pertains to a composition
  • the invention in another aspect, relates to a method for preparing a composition as defined in any one of the preceding claims, wherein said method comprises the steps of: a) contacting the phase-change material as defined herein with a polymer network as defined herein; or b) contacting the phase-change material as defined herein, with a solvent, a polymerization initiator, and the at least three monomers as defined herein; so as to obtain a second solution; and c) copolymerizing the at least three monomers in the second solution.
  • the invention also relates to a composition obtainable by a method according to the invention.
  • the invention also pertains to a composition according to the invention for use as a medicament.
  • the invention also relates to a composition according to the invention for use in thermotherapy.
  • the invention also pertains to a non-therapeutic use of a composition according to the invention as a heat supply; and/or for the thermal management of an electronic device; preferably the heat supply is a household heat supply; and preferably the electronic device is a flexible electronic device.
  • Figure 1 depicts the synthesis of GELSAT-# (with # being 2, 4, 6, or 8), which is a composition according to the invention.
  • Figure 2 depicts in panel (a) the DSC curves and heat of fusion of GELSAT-2, GELSAT-4, GELSAT-6, GELSAT-8, and SAT; in panels (b)-(d) GELSAT-4 in different rotation angles; and in panel (e) the flexibility of GELSAT-4.
  • Figure 3 depicts in panel (a) supercooled SAT; in panel (b) supercooled GELSAT-4F (comparative example) before cycling; in panel (c) supercooled GELSAT-4F after 1 cycle; in panel (d) XRD results of GELSAT-4; and in panel (e) XRD results of GELSAT-4F.
  • Figure 4 depicts in panel (a) FTIR of polyacrylic acid (PAA), polyacrylamide (PAM), and a copolymer of acrylic acid and acrylamide (PAA-co-PAM), SAT and GELSAT-4; in panel (b) the schematic structure of a comparative example, viz. GELSAT-4F with leakage; in panel (c) the schematic structure of GELSAT according to the invention; and in panel (d) a schematic representation of the molecular interactions of which the inventors believe are present within GELSAT according to the invention.
  • Figure 5 depicts in panel (a) the melting process of GELSAT-4; and in panel (b) the UV-vis results of pure water and GELSAT-4.
  • Figure 6 depicts in panel (a) the elastic deformation of supercooled GELSAT-6 while being squeezed and while lifting a metal cylinder of 50 g; in panel (b) the stretch of supercooled GELSAT-6; and in panel (c) a 50 g metal cylinder standing on the solidified GELSAT-6.
  • Figure 8 depicts in panel (a) the crystallization process of GELSAT-4; and in panel (b) the crystallization process of GELSAT-6.
  • Figure 9 depicts in panel (a) the DSC results of GELSAT-4 before and after cycles; and in panel (b) TGA analysis of pure SAT and GELSAT-4.
  • Figure 10 depicts in panel (a) the heating-cooling curve of the samples at the 1 st cycle; and in panel (b) the heating-cooling curve of the samples at the 7 th cycle.
  • Figure 11 depicts in panel (a) the crystallization curve of GELSAT-4 at the 1 st and 7 nd cycle, and in panel (b) the crystallization curve of GELSAT-6 at the 1 st and 7 th cycle.
  • Figure 12 depicts the thermal conductivity results of pure SAT, GELSAT-4 and GELSAT-6.
  • Figure 13 depicts the results from Example 7, wherein GELSAT-4 is made using varying wt/wt ratios of acrylamide (AAM) and acrylic acid (AA), from 10:90 to 80:20. The different compositions were subjected to one heating-cooling cycle.
  • AAM acrylamide
  • AA acrylic acid
  • Figure 14 depicts the results from Example 7, viz. the triggering of crystallization in GELSAT-4 using electrodes.
  • Panel (a) shows GELSAT-4 with electrodes inserted therein before applying a voltage
  • panel (b) shows the setup directly after applying a voltage
  • panel (c) shows that crystallization proceeds through the entire composition of GELSAT-4.
  • compositions according to the invention are flexible, provide improved latent heat, demonstrate excellent cycling stability (e.g. reduced phase separation, stable heat generation, and/or reduced shrinkage upon cycling), can be transparent, and/or can be produced using green methods.
  • cycling stability e.g. reduced phase separation, stable heat generation, and/or reduced shrinkage upon cycling
  • the compositions of the invention can be prepared at low cost, and can be finetuned if necessary to meet specific requirements.
  • the inventors believe that the advantageous properties of the composition arise from the combination of monomer residues in the polymer network, in particular the combination of monomer residues P and Q as described herein, which are the polymerized forms of monomers of Formula (1) and Formula (2), respectively. Still without wishing to be bound by theory, the inventors believe that the combination of amide groups in P and the carboxylic acid groups (and their conjugated bases) or esters in Q do not only improve the mechanical properties of the composition of the invention, but also the crystallization of the phase-change material.
  • indefinite article “a” or “an” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there is one and only one of the elements.
  • the indefinite article “a” or “an” thus usually means “at least one”.
  • the compounds may occur in different tautomeric forms.
  • the compounds according to the invention are meant to include all tautomeric forms, unless stated otherwise.
  • the structure of a compound is depicted as a specific tautomer, it is to be understood that the invention of the present application is not limited to that specific tautomer, unless stated otherwise.
  • the compounds of the invention and/or groups thereof may be protonated or deprotonated. It will be understood that it is possible that a compound may bear multiple charges which may be of opposite sign. For example, in a compound containing an amine and a carboxylic acid, the amine may be protonated while simultaneously the carboxylic acid is deprotonated.
  • Phase-change material refers to a substance which releases/absorbs sufficient energy at phase transition to provide useful heat or cooling.
  • phase-change material can refer to the substance itself, or the entire material containing said substance.
  • phase-change material refers to the substance itself, preferably to a salt hydrate, and not the material containing said substance. Typically, herein said material is referred to as “the composition”.
  • a “cycle” refers to a phase-change material transitioning from one phase to another and back to the original phase.
  • salts in particular salt hydrates, mentioned herein, insofar as appropriate also their ionic forms are intended to be covered. It will be understood that if a salt is dissolved, the ions making up the salt generally dissociate. Thus, in embodiments wherein the salts as described herein are dissolved, “salt” should be interpreted as referring to the ions originally making up said salt.
  • alkyl In several chemical formulae and texts below reference is made to “alkyl”, “heteroalkyl”, “aryl”, “heteroaryl”, “alkylene”, “arylene”, “arenetriyl”, and the like.
  • a butyl group substituted with a -OCH3 group is designated as a C4 alkyl, because the carbon atom in the substituent is not included in the carbon count.
  • Unsubstituted alkyl groups have the general formula C n H2n+i and may be linear or branched.
  • the alkyl groups are substituted by one or more substituents further specified in this document.
  • the alkyl groups are not substituted. Examples of alkyl groups include methyl, ethyl, propyl, 2-propyl, t-butyl, 1 -hexyl, 1 -dodecyl, etc.
  • An aryl group refers to an aromatic hydrocarbon ring system, and may include monocyclic and polycyclic structures. When the aryl group is a polycyclic structure, it is preferably a bicyclic structure. Optionally, the aryl group may be substituted by one or more substituents further specified in this document. Examples of aryl groups are phenyl and naphthyl.
  • Heteroaryl groups comprise at least two carbon atoms (i.e. at least C2) and one or more heteroatoms N, O, P or S.
  • heteroaryl groups comprise at least two carbon atoms (i.e. at least C2) and one or more oxygen atoms.
  • a heteroaryl group may have a monocyclic or a bicyclic structure.
  • the heteroaryl group may be substituted by one or more substituents further specified in this document.
  • heteroaryl groups examples include pyridinyl, quinolinyl, pyrimidinyl, pyrazinyl, pyrazolyl, imidazolyl, thiazolyl, pyrrolyl, furanyl, triazolyl, benzofuranyl, indolyl, purinyl, benzoxazolyl, thienyl, phospholyl and oxazolyl.
  • the prefix hetero- denotes that the group contains one or more heteroatoms selected from the group consisting of O, N, S, P, and Si.
  • the groups with the prefix hetero- contain one or more oxygen atoms.
  • the suffix -ene denotes divalent groups, i.e. that the group is linked to at least two other moieties.
  • An example of an alkylene is propylene (-CH2-CH2-CH2-), which is linked to another moiety at both termini.
  • the suffix -triyl denotes trivalent groups, i.e. that the group is linked to at least three other moieties.
  • An example of an arenetriyl is depicted below: wherein the wiggly lines denote bonds to different groups of the main compound.
  • any group disclosed herein is understood to be linear or branched.
  • alkyl groups, alkenyl groups, alkanetriyl groups, heteroalkanetriyl groups, and the like are linear or branched, unless stated otherwise.
  • Dalton The unified atomic mass unit or Dalton is herein abbreviated to Da.
  • Dalton is a regular unit for molecular weight and that 1 Da is equivalent to 1 g/mol (grams per mole).
  • the composition of the invention comprises a phase-change material and a polymer network.
  • the phase-change material is dispersed within the polymer network, as shown in Figures 4(c)-(d).
  • the phase-change material is a salt hydrate
  • the salt hydrate may dissociate into a cation, an anion, and water molecules, after which one or more of these components may move through the polymer network, and/or interact with said polymer network either physically, chemically, or both.
  • the composition of the invention comprises the phase-change material in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 89 wt% to 95 wt%, as compared to the total weight of the composition.
  • phase-change material is present in said composition in an amount of from 92 wt% to 96 wt%, more preferably of from 93 wt% to 95 wt%, and most preferably of from 93.5 wt% to 94.5 wt%, as compared to the total weight of the composition.
  • the composition of the invention comprises the polymer network in an amount of from 1.0 wt% to 19.0 wt%, more preferably of from 1.5 wt% to 15.0 wt%, even more preferably of from 2.0 wt% to 10.0 wt%, yet more preferably of from 2.5 wt% to 9.0 wt%, more preferably still of from 3.0 wt% to 8.0 wt%, and most preferably of from 3.5 wt% to 7.5 wt%, as compared to the total weight of the composition.
  • composition of the invention comprises the polymer network in an amount of from 3.4 wt% to 4.2 wt%, more preferably of from 3.5 wt% to 4.0 wt%, most preferably of from 3.6 wt% to 3.9 wt%, as compared to the total weight of the composition.
  • the composition of the invention comprises the phase-change material in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 88 wt% to 95 wt%, as compared to the dry weight of the composition.
  • dry weight refers to the weight of the dry matter of the composition, viz. without the weight of any liquid, and that for the calculation of the amount of phase-change material as compared to the dry weight, the anhydrous form of said phase-change material is chosen if said phase-change material is a salt hydrate.
  • the composition of the invention comprises the polymer network in an amount of from 2.0 wt% to 25.0 wt%, more preferably of from 2.5 wt% to 20.0 wt%, even more preferably of from 3.0 wt% to 17.5 wt%, yet more preferably of from 3.5 wt% to 15.0 wt%, more preferably still of from 4.0 wt% to 13.0 wt%, and most preferably of from 5 wt% to 12.0 wt%, as compared to the dry weight of the composition.
  • composition of the invention may comprise a liquid, preferably water. It will be understood that in case the phase-change material is a salt hydrate, said water is additional to the water originating from the salt hydrate. As such, the composition of the invention is preferably a hydrogel.
  • the liquid preferably water
  • the liquid is present in the composition in an amount of from 0.5 wt% to 9.5 wt%, more preferably of from 0.8 wt% to 7.5 wt%, even more preferably of from 1.0 wt% to 5.0 wt%, yet more preferably of from 1.3 wt% to 4.5 wt%, more preferably still of from 1.5 wt% to 4.0 wt%, and most preferably of from 1.75 wt% to 3.75 wt%, as compared to the total weight of the composition.
  • the composition of the invention consists essentially of the polymer network and the phase-change material, and optionally the liquid, all as defined herein.
  • the total water content in the composition of the invention is at most 60 wt%, more preferably at most 55 wt%, even more preferably at most 50 wt%, yet more preferably at most 47 wt%, more preferably still at most 45 wt%, and most preferably at most 40 wt%, as compared to the total weight of the composition.
  • the total water content includes any optionally added water, and the water contained in the phase-change material if the phase-change material is a salt hydrate.
  • the total water content in the composition of the invention is in an amount of from 0.5 wt% to 60 wt%, more preferably of from 5 wt% to 55 wt%, even more preferably of from 10 wt% to 50 wt%, yet more preferably of from 20 wt% to 47 wt%, more preferably still of from 25 wt% to 45 wt%, and most preferably of from 35 wt% to 40 wt%, as compared to the total weight of the composition.
  • composition of the invention does not require the presence of components other than the polymer network and phase-change material as described herein, said composition may contain one or more additives if desired.
  • additives include colorants, fillers, thickening agents, and photon capturers (such as CuS). Nevertheless, to reduce the number of resources required and hence costs, it is preferred that the composition of the invention does not include such additives.
  • the polymer network as used in the invention is a copolymer, preferably a random copolymer, comprising a structure according to Formula (A):
  • CL indicates a crosslinker residue
  • the wiggly lines indicate bonds to the rest of the copolymer.
  • Suitable crosslinker residues for use in a copolymer of Formula (A) are known to the skilled person.
  • Each Xi is independently selected from the group consisting of hydrogen and C1.3 alkyl.
  • Xi is hydrogen or methyl, and most preferably Xi is hydrogen.
  • Each X2 is independently selected from the group consisting of hydrogen and C1.3 alkyl.
  • X2 is hydrogen or methyl, and most preferably X2 is hydrogen.
  • Each X3 is independently selected from the group consisting of hydrogen and C1.3 alkyl.
  • X3 is hydrogen or methyl, and most preferably X3 is hydrogen.
  • the variables p, q, and r indicate the mole fractions of their respective monomer residues, viz. monomer residues P (i.e. the monomer residue comprising Xi), Q (i.e. the monomer residue comprising X2), and A (i.e. the monomer residue containing CL).
  • additional monomer residues other than P, Q, and R may be present in the polymer network of the invention.
  • the sum of the mole fractions p, q, and r is at least 0.7, more preferably at least 0.8, even more preferably at least 0.9, more preferably still at least 0.95, yet more preferably at least 0.97, and most preferably at least 0.99.
  • 1 refers to the sum of all mole fractions of all monomer residues making up the polymer network.
  • /? is larger than zero.
  • q is larger than zero.
  • r is larger than zero.
  • the polymer network as used in the invention consists essentially of a structure according to Formula (A).
  • the weight ratio of the monomer residues P and Q (i.e. the weight of P compared to the weight of Q) is at most 1 : 1, more preferably at most 1 : 1.5, more preferably at most 1 :2, more preferably still at most 1 :3, and most preferably at most 1 :4; with the proviso that both monomer residues P and Q are present in the polymer network.
  • the weight ratio of the monomer residues P and Q (i.e. the weight of P compared to the weight of Q) is in a range of from 1 :25 to 2: 1, preferably from 1 : 10 to 1 : 1, more preferably of from 1 :9 to 1 :2, more preferably of from 1 :8 to 1 :2.5, more preferably of from 1 :6 to 1 :3, more preferably still of from 1 :4.5 to 1 :3.5, most preferably about 1 :4.
  • the weight ratio of the monomer residue R as compared to the combined weight of all monomer residues is in a range of from 1 :80 to 1 : 10, preferably from 1 :60 to 1 : 15, more preferably of from 1 : 50 to 1 :20, more preferably still of from 1 : 40 to 1 :30, most preferably about 1 :33.
  • copolymer of Formula (A) is a copolymer according to Formula (Al): Formula (Al)
  • each X4 is independently selected from the group consisting of hydrogen and C1.3 alkyl.
  • X4 is hydrogen or methyl, and most preferably X4 is hydrogen.
  • each X5 indicates the remainder of the crosslinker residue.
  • each X5 is independently selected from moi eties according to Formula (A2):
  • n is 0 or 1, preferably each n is 1.
  • S p is a spacer.
  • the spacer can be of any length.
  • spacers such as -NH-CH2-NH- in the commonly used N,RT - methylenebisacrylamide, or very long spacers (e.g. in crosslink 1 as disclosed in Postma et al., Angewandte Chemie International Edition 2017, volume 56, pages 1794-1798).
  • spacer S p has a molecular weight of at most 2000 Da, more preferably at most 1500 Da, even more preferably at most 1000 Da, and most preferably at most 500 Da.
  • the spacer S p is -NXs-Ci-ioalkyl-NXs-, wherein each X5 independently is hydrogen or C1.3 alkyl, preferably hydrogen. Most preferably, the spacer S p is -NH-CH2-NH-.
  • the polymer network is obtainable by copolymerizing at least three monomers in a solution.
  • the total concentration of said at least three monomers in said solution is of from 1 wt% to 19 wt% as compared to the total weight of the solution. It will be understood that this concentration refers to all monomers present in said solution taken together, and it is not intended that said solution comprises e.g. 19 wt% of a first monomer, 19 wt% of a second monomer, and 14 wt% of a third monomer.
  • said total concentration of said at least three monomers in said solution is of from 1.5 wt% to 15.0 wt%, more preferably of from 2.0 wt% to 10.0 wt%, yet more preferably of from 2.5 wt% to 9.0 wt%, more preferably still of from 3.0 wt% to 8.0 wt%, and most preferably of from 3.5 wt% to 7.5 wt%, as compared to the total weight of the solution.
  • said total concentration of said at least three monomers in said solution is of from 3.4 wt% to 4.2 wt%, more preferably of from 3.5 wt% to 4.0 wt%, most preferably of from 3.6 wt% to 3.9 wt%, as compared to the total weight of the solution.
  • said at least three monomers comprise a monomer according to Formula (1), a monomer according to Formula (2), and a crosslinker. While other monomers may be present in said solution, it is preferred that at least 70 mol%, more preferably at least 80 mol%, even more preferably at least 90 mol%, more preferably still at least 95 mol%, yet more preferably at least 97 mol%, and most preferably at least 99 mol% of all monomers in said solution are the sum of the mole percentages of the monomer according to Formula (1), the monomer according to Formula (2), and the crosslinker. In preferred embodiments, said at least three monomers consist essentially of a monomer according to Formula (1), a monomer according to Formula (2), and a crosslinker.
  • the weight ratio of the monomer of Formula (1), preferably acrylamide, over the monomer of Formula (2), preferably acrylic acid is at most 1 : 1, more preferably at most 1 : 1.5, more preferably at most 1 :2, more preferably still at most 1 :3, and most preferably at most 1 :4, with the proviso that said solution comprises both acrylamide and acrylic acid.
  • the weight ratio of the monomer of Formula (1), preferably acrylamide, over the monomer of Formula (2), preferably acrylic acid is in a range of from 1 :25 to 2: 1, preferably from 1 : 10 to 1 : 1, more preferably of from 1 :9 to 1 :2, more preferably of from 1 :8 to 1 :2.5, more preferably of from 1 :6 to 1 :3, and most preferably of from 1 :5 to 1 :3.5.
  • the weight ratio of the crosslinker, preferably N, N"- methylenebisacrylamide, as compared to the combined weight of all monomers in said solution is in a range of from 1 :80 to 1 : 10, preferably from 1 :60 to 1 : 15, more preferably of from 1 :50 to 1 :20, more preferably still of from 1 :40 to 1 :30, and most preferably about 1 :33.
  • said solution further comprises a solvent.
  • the solvent is selected from the group consisting of water, acetic acid, acetonitrile, dimethylformamide, dimethyl sulfoxide, methanol, benzene, butanol, n-butyl acetate, carbon tetrachloride, chloroform, cyclohexane, 1,2-di chloroethane, di chloromethane, diethyl ether, diisopropyl ether, ethyl acetate, heptane, hexane, isooctane, methyl ethyl ketone, methyl tert-butyl ether, pentane, toluene, trichloroethylene, and xylene.
  • the solvent is selected from the group consisting of water, acetic acid, acetonitrile, dimethylformamide, dimethyl sulfoxide, and methanol. More preferably still, the solvent comprises water, and yet more preferably consists essentially of water. Most preferably, the solvent is water.
  • the polymerization initiator is selected from the group consisting of persulfates, riboflavin, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, camphorquinon, curcumin, eosin Y, Ru(bpy)3C12, a-ketoglutaric acid, and cerium(IV)- nitrilotriacetic acid. More preferably, the polymerization initiator is potassium persulfate or ammonium persulfate, and most preferably the polymerization initiator is potassium persulfate.
  • the skilled person is aware of suitable temperatures at which the copolymerization can be conducted. Typically, ambient temperatures (e.g. of from 15°C to 30°C) are employed, but much higher temperatures can be used as well. Thus, preferably the temperature of the copolymerization is in a range of from 10°C to 90°C, and more preferably in a range of from 15°C to 85°C.
  • Ri is selected from the group consisting of hydrogen and C1.3 alkyl. Preferably, Ri is hydrogen or methyl, and most preferably Ri is hydrogen.
  • the monomer of Formula (1) is acrylamide or methacrylamide, most preferably acrylamide.
  • R2 is selected from the group consisting of hydrogen and C1.3 alkyl.
  • R2 is hydrogen or methyl, and most preferably R2 is hydrogen.
  • R4 is selected from the group consisting of hydrogen and C1.3 alkyl.
  • R4 is hydrogen or methyl, and most preferably R4 is hydrogen.
  • the monomer of Formula (2) is acrylic acid or methacrylic acid, most preferably acrylic acid.
  • the crosslinker monomer can be readily selected by the skilled person, and is generally suitable for copolymerization with a monomer of Formula (1) and a monomer of Formula (2).
  • the crosslinker has a structure according to Formula (3):
  • Each R3 independently is hydrogen or C1.3 alkyl, preferably each R3 is hydrogen or methyl, most preferably each R3 is hydrogen.
  • the variable n and S p are as defined for Formula (A2).
  • crosslinker according to Formula (3) is N,N"- m ethylenebisacrylamide.
  • the composition of the invention comprises a phase-change material.
  • the phase-change material is a salt.
  • the phase-change material comprises a cation and an anion, and optionally water. More preferably, the phase-change material consists essentially of a cation and an anion, and optionally water.
  • Preferred cations are sodium, potassium, lithium, calcium, magnesium, iron(III), and iron(II), more preferably sodium and potassium, and most preferably sodium.
  • Preferred anions are acetate, chloride, nitrate, sulfate, thiosulfate, phosphate, hydrogen phosphate, and dihydrogen phosphate, most preferably acetate.
  • the phase-change material is selected from the group consisting of sodium acetate trihydrate, calcium chloride hexahydrate, lithium nitrate trihydrate, sodium sulfate decahydrate, sodium hydrogen phosphate dodecahydrate, ferric chloride hexahydrate, sodium thiosulfate pentahydrate, magnesium sulfate heptahydrate, ferric sulfate heptahydrate, the anhydrous forms thereof, and combinations thereof.
  • the anhydrous forms of said salts are sodium acetate, calcium chloride, lithium nitrate, sodium sulfate, sodium hydrogen phosphate, ferric chloride, sodium thiosulfate, magnesium sulfate, and ferric sulfate, respectively.
  • anhydrous forms thereof refers to all salts preceding said phrase in the list presented in this paragraph, and that “combinations thereof’ refers to any combination of the anhydrous and/or hydrated forms of the salts listed in this paragraph.
  • the phase-change material is a salt hydrate.
  • Table 1 lists the preferred salt hydrates of the present invention and their respective phase-change temperatures (i.e. melting temperatures).
  • Table 1 shows that the compositions of the invention can maintain a wide range of temperatures.
  • these temperatures can be finetuned by combining two or more salt hydrates, and/or by tuning the properties of the polymer network.
  • phase-change material is sodium acetate trihydrate (SAT).
  • SAT is preferred because of its high latent heat (300 J/g), low cost, and phase change temperature of 58°C which renders it ideal for various applications.
  • the invention also pertains to methods for preparing the composition according to the invention. These methods are economical and sustainable, since typically the materials used therein are used at an efficiency of 100% or close to 100% with no substantial waste or any substantial side product.
  • the invention relates to a method for preparing a composition according to the invention, wherein said method comprises the steps of: a. contacting the phase-change material as defined herein with a polymer network as defined herein; or b. contacting the phase-change material as defined herein, with a solvent, a polymerization initiator, and the at least three monomers as defined herein; so as to obtain a second solution; and c. copolymerizing the at least three monomers in the second solution.
  • said method comprises steps b and c rather than step a. While it is in principle possible to first prepare the polymer network and then contact said polymer network with a phase-change material as described herein, due to the typically high amounts of phasechange materials used in the compositions of the invention this procedure may not yield the best results. Instead, it is preferred to synthesize the polymer network as described herein in the presence of the phase-change material as defined herein, as done in steps b and c of the method of the invention.
  • the solvent, polymerization initiator, the at least three monomers, and/or amounts thereof are as defined for the “polymer network obtainable by copolymerizing at least three monomers in a solution”.
  • the solvent, polymerization initiator, the at least three monomers, and amounts thereof, in relation to said solution can also be applied to the second solution as mentioned in said steps b and c.
  • step b preferably the phase-change material is present in said second solution in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 89 wt% to 95 wt%, as compared to the total weight of the second solution.
  • the phase-change material of the invention is preferably a salt hydrate.
  • the method as described above comprises the steps of: i. melting the salt hydrate so as to obtain a melted salt hydrate; ii.
  • the salt hydrate needs to be brought to a temperature above its melting temperature.
  • the melting temperature is the same as the phase-change temperature, which are all known for known salt hydrates.
  • the phase-change temperatures of the preferred salt hydrates of the invention are listed in Table 1. If the salt hydrate is the preferred sodium acetate trihydrate, it is preferred that in step i the salt hydrate is brought to a temperature of at least 58°C, preferably in a range of from 58°C to 100°C, more preferably 65°C to 95°C, more preferably still of from 70°C to 90°C, most preferably of from 75°C to 85°C, and typically of about 80°C.
  • step ii preferably in said second solution the phase-change material is present in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 89 wt% to 95 wt%, as compared to the total weight of the second solution.
  • phase-change material is present in said second solution in an amount of from 92 wt% to 96 wt%, more preferably of from 93 wt% to 95 wt%, and most preferably of from 93.5 wt% to 94.5 wt%, as compared to the total weight of the second solution.
  • the melted salt hydrate, solvent, polymerization initiator, and the at least three monomers can be contacted in any order. However, it is preferred to first contact the at least three monomers, the solvent, and the polymerization initiator, which can then be contacted with the melted salt hydrate. More preferably, the at least three monomers and the polymerization initiator are first dissolved in said solvent prior to contacting the resulting solution with the melted salt hydrate. This dissolving step can be performed at ambient temperatures, e.g. from 15°C to 30°C. By first dissolving the at least three monomers and the polymerization initiator prior to contacting them with the melted salt hydrate, a more well- controlled and evenly distributed polymerization process is typically observed.
  • the polymerization initiator and at least three monomers are powders at room temperature, and if the polymerization initiator and the at least three monomers are still (partially) in solid form upon contact with the melted salt hydrate, the rates of polymerization may be different at different locations within the reaction mixture. While this may not necessarily present a major problem when preparing the composition of the invention, the best results are obtained when the polymerization initiator and the at least three monomers are dissolved in said solvent prior to contact the resulting solution with the melted salt hydrate.
  • the second solution obtained in step ii is maintained at a temperature above the melting temperature of the salt hydrate. It will be understood that typically step iii of the invention is then initiated immediately after step ii is completed. Preferably, the second solution obtained in step ii is briefly mixed for at most 1 minute, preferably for at most 30 seconds, most preferably for at most 20 seconds. Mixing can be performed by any standard method known in the art, but stirring is preferred.
  • the temperature in step iii of the method of the invention is at most 100°C, more preferably at most 90°C, and most preferably at most 85°C.
  • a temperature in a range of from 60°C to 100°C, more preferably of from 70°C to 90°C, most preferably of from 75°C to 85°C is used, and typically of about 80°C.
  • lower temperatures for copolymerization can be used, it is preferred to use a temperature of at least the melting temperature of the salt hydrate in step iii of the method of the invention. In that way, the salt hydrate maintains in its melted form during the copolymerization of the at least three monomers, which results in the best possible dispersion of the phase-change material in the resulting polymer network.
  • the temperature in step iii is at least 58°C, more preferably in a range of from 58°C to 95°C, most preferably in a range of from 75°C to 85°C.
  • the copolymerization in step iii is typically quite fast, and the polymer network is generally formed within minutes. It is preferred that the copolymerization is conducted for at least 5 minutes, more preferably at least 10 minutes, even more preferably at least 15 minutes, more preferably still at least 20 minutes, and most preferably at least 25 minutes. There is not necessarily an upper limit for the duration of the copolymerization step, since the reaction is typically complete or sufficiently complete within the time periods mentioned in the preceding sentence. For practical reasons, the copolymerization is preferably conducted for at most 1 day, more preferably at most 12 hours, at most 6 hours, at most 3 hours, at most 1.5 hours, and most preferably at most 45 minutes.
  • the solvent, polymerization initiator, the at least three monomers, and/or amounts thereof are as defined for the “polymer network obtainable by copolymerizing at least three monomers in a solution”.
  • the solvent, polymerization initiator, the at least three monomers, and amounts thereof, in relation to said solution can also be applied to the second solution as mentioned in said steps ii and iii.
  • the invention also pertains to a composition obtainable by a method according to the invention, which is preferably characterized as disclosed herein in relation to compositions of the invention, in particular regarding the polymer network and phase-change material, and concentrations thereof.
  • thermotherapy heat is applied to a subject in order to prevent or treat one or more symptoms of a disease.
  • thermotherapy is typically used for pain relief, for the treatment of rheumatoid arthritis, increasing the extensibility of collagen tissues; decreasing joint stiffness; relieving muscle spasms; reducing inflammation, edema, and aids in the post-acute phase of healing; and increasing blood flow.
  • the increased blood flow to the affected area provides proteins, nutrients, and oxygen for better healing.
  • heat therapy can also aid in the treatment of neurodegenerative diseases like Alzheimer's; as well as for cardiovascular benefits.
  • the compositions of the invention can also be used in therapeutic applications addressing one or more of these diseases and conditions, and/or achieve one or more of these therapeutic effects.
  • the invention covers a composition according to the invention for use as a medicament. More particularly, the composition of the invention is for use in thermotherapy.
  • the invention covers a phase-change material as defined herein dispersed in a polymer network as disclosed herein for use as a medicament, more preferably for use in thermotherapy.
  • the therapeutic applications of the phasechange material are as defined herein for the composition of the invention.
  • composition of the invention, or the phase-change material as defined herein dispersed in a polymer network as disclosed herein are also for use in treating or preventing pain, rheumatoid arthritisjoint stiffness, muscle spasms, inflammation, edema, cancer, neurodegenerative diseases, and cardiovascular diseases.
  • a preferred neurodegenerative disease that can be treated with the invention is Alzheimer’s disease.
  • the composition of the invention can be applied to the exterior or interior of a subject.
  • the composition of the invention is applied to or close to the exterior of a subject.
  • said composition is applied in such a way that sufficient heat can reach the body (e.g. skin, hair, nails, and the like) of the subject.
  • the composition is preferably applied directly onto the body of the subject, it is also possible to leave some material such as clothes, plastic, towels, and the like between the subject’s body and the composition of the invention.
  • the composition of the invention is applied to the interior of a subject, it is preferably applied directly or close to the part of the body that is to be treated, e.g. the brain, heart, tumour, liver, kidney, pancreas, lung, stomach, intestine, bladder, and the like.
  • the subject is a mammal, more preferably a primate, and most preferably a human being.
  • the disclosure also pertains to a method of treating or preventing a disease or condition in a subject, wherein said method comprises the step of applying the composition of the invention to a subject.
  • the method of treatment pertains to thermotherapy.
  • the disclosure also pertains to the use of a composition of the invention for the manufacture of a medicament.
  • the medicament is for thermotherapy.
  • the disclosure also pertains to the use of a composition of the invention for the manufacture of a medicament for the treatment or prevention of pain, rheumatoid arthritis oint stiffness, muscle spasms, inflammation, edema, cancer, neurodegenerative diseases, and cardiovascular diseases.
  • compositions of the invention can also be advantageously applied in non- therapeutic applications.
  • the invention also covers the use of a composition according to the invention as a heat supply.
  • the composition according to the invention is used a household heat supply.
  • the invention covers the use of a composition of the invention for the thermal management of an electronic device.
  • the electronic devices are flexible.
  • This use of the composition of the invention is particularly advantageous as compared to other materials, since the composition of the invention is typically flexible itself as well while it manages the temperature of the electronic device.
  • long-term typically refers to at least one day, more preferably at least three days, more preferably at least a week, even more preferably at least two weeks, more preferably still at least three weeks, more preferably at least a month, more preferably at least six months, and most preferably at least a year.
  • Embodiment 1 A composition comprising a phase-change material and a polymer network
  • Embodiment 2 The composition according to Embodiment 1, wherein the phase-change material is dispersed within the polymer network.
  • Embodiment 3 The composition according to any one of the preceding Embodiments, wherein the composition is a hydrogel.
  • Embodiment 4 The composition according to any one of the preceding Embodiments, wherein the phase-change material is a salt.
  • Embodiment 5 The composition according to any one of the preceding Embodiments, wherein the phase-change material is a salt hydrate.
  • Embodiment 6 The composition according to any one of the preceding Embodiments, wherein the phase-change material is selected from the group consisting of sodium acetate trihydrate, calcium chloride hexahydrate, lithium nitrate trihydrate, sodium sulfate decahydrate, sodium hydrogen phosphate dodecahydrate, ferric chloride hexahydrate, sodium thiosulfate pentahydrate, magnesium sulfate heptahydrate, ferric sulfate heptahydrate, the anhydrous forms thereof, and combinations thereof.
  • the phase-change material is selected from the group consisting of sodium acetate trihydrate, calcium chloride hexahydrate, lithium nitrate trihydrate, sodium sulfate decahydrate, sodium hydrogen phosphate dodecahydrate, ferric chloride hexahydrate, sodium thiosulfate pentahydrate, magnesium sulfate heptahydrate, ferric sulfate heptahydrate, the anhydrous forms thereof, and combinations
  • Embodiment 7 The composition according to any one of the preceding Embodiments, wherein the phase-change material is selected from the group consisting of sodium acetate trihydrate, calcium chloride hexahydrate, lithium nitrate trihydrate, sodium sulfate decahydrate, sodium hydrogen phosphate dodecahydrate, ferric chloride hexahydrate, sodium thiosulfate pentahydrate, magnesium sulfate heptahydrate, ferric sulfate heptahydrate, and combinations thereof.
  • the phase-change material is selected from the group consisting of sodium acetate trihydrate, calcium chloride hexahydrate, lithium nitrate trihydrate, sodium sulfate decahydrate, sodium hydrogen phosphate dodecahydrate, ferric chloride hexahydrate, sodium thiosulfate pentahydrate, magnesium sulfate heptahydrate, ferric sulfate heptahydrate, and combinations thereof.
  • Embodiment 8 The composition according to any one of the preceding Embodiments, wherein the phase-change material is sodium acetate trihydrate.
  • Embodiment 9 The composition according to any one of Embodiments 4-8, wherein the salt is in dissociated form, viz. dissociated into ions.
  • Embodiment 10 The composition according to any one of the preceding Embodiments, wherein the phase change material comprises sodium ions and acetate ions.
  • Embodiment 11 The composition according to any one of the preceding Embodiments, wherein said composition comprises the phase-change material in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 89 wt% to 95 wt%, as compared to the total weight of the composition.
  • Embodiment 12 The composition according to any one of the preceding Embodiments, wherein said composition comprises the phase-change material in an amount of from 92 wt% to 96 wt%, more preferably of from 93 wt% to 95 wt%, and most preferably of from 93.5 wt% to 94.5 wt%, as compared to the total weight of the composition.
  • Embodiment 13 The composition according to any one of the preceding Embodiments, wherein said composition comprises the phase-change material in an amount of the phasechange material in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 88 wt% to 95 wt%, as compared to the dry weight of the composition.
  • Embodiment 14 The composition according to any one of the preceding Embodiments, wherein said composition comprises the phase-change material in an amount of the phasechange material in an amount of from 94.0 wt% to 98.0 wt%; more preferably of from 94.5 wt% to 97.5 wt%, more preferably of from 95.0 wt% to 97.0 wt%, and most preferably of from 95.5 wt% to 96.5 wt%, as compared to the dry weight of the composition.
  • Embodiment 15 The composition according to any one of the preceding Embodiments, wherein said composition comprises the polymer network in an amount of from 1.0 wt% to 19.0 wt%, more preferably of from 1.5 wt% to 15.0 wt%, even more preferably of from 2.0 wt% to 10.0 wt%, yet more preferably of from 2.5 wt% to 9.0 wt%, more preferably still of from 3.0 wt% to 8.0 wt%, and most preferably of from 3.5 wt% to 7.5 wt%, as compared to the total weight of the composition.
  • Embodiment 16 The composition according to any one of the preceding Embodiments, wherein said composition comprises the polymer network in an amount of from 3.4 wt% to 4.2 wt%, more preferably of from 3.5 wt% to 4.0 wt%, most preferably of from 3.6 wt% to 3.9 wt%, as compared to the total weight of the composition.
  • Embodiment 17 The composition according to any one of the preceding Embodiments, wherein said composition comprises the polymer network in an amount of from 2.0 wt% to 25.0 wt%, more preferably of from 2.5 wt% to 20.0 wt%, even more preferably of from 3.0 wt% to 17.5 wt%, yet more preferably of from 3.5 wt% to 15.0 wt%, more preferably still of from 4.0 wt% to 13.0 wt%, and most preferably of from 5 wt% to 12.0 wt%, as compared to the dry weight of the composition.
  • Embodiment 18 The composition according to any one of the preceding Embodiments, wherein the polymer network is a copolymer, preferably a random copolymer, comprising a structure according to Formula (A) as defined herein, preferably a structure according to Formula (Al) as defined herein.
  • Embodiment 19 The composition according to any one of the preceding Embodiments, wherein the polymer network is a copolymer of acrylamide, acrylic acid, and TV, TV 7 - methylenebisacrylamide.
  • Embodiment 20 The composition according to any one of the preceding Embodiments, wherein said composition further comprises a liquid, preferably water.
  • Embodiment 21 The composition according to Embodiment 20, wherein said composition comprises the liquid, preferably water, in an amount of from 0.5 wt% to 9.5 wt%, more preferably of from 0.8 wt% to 7.5 wt%, even more preferably of from 1.0 wt% to 5.0 wt%, yet more preferably of from 1.3 wt% to 4.5 wt%, more preferably still of from 1.5 wt% to 4.0 wt%, and most preferably of from 1.75 wt% to 3.75 wt%, as compared to the total weight of the composition.
  • Embodiment 22 Embodiment 22.
  • composition according to Embodiment 20 wherein said composition comprises the liquid, preferably water, in an amount of from 1.5 wt% to 2.3 wt%, more preferably of from 1.6 wt% to 2.2 wt%, more preferably of from 1.7 wt% to 2.1 wt%, and most preferably of from 1.8 wt% to 2.0 wt%, as compared to the total weight of the composition.
  • Embodiment 23 The composition according to any one of the preceding Embodiments, wherein the total water content in said composition is at most 60 wt%, more preferably at most 55 wt%, even more preferably at most 50 wt%, yet more preferably at most 47 wt%, more preferably still at most 45 wt%, and most preferably at most 40 wt%, as compared to the total weight of the composition; wherein the total water content includes any optionally added water, and the water contained in the phase-change material if the phase-change material is a salt hydrate.
  • Embodiment 24 The composition according to any one of the preceding Embodiments, wherein the total water content in said composition is in an amount of from 0.5 wt% to 60 wt%, more preferably of from 5 wt% to 55 wt%, even more preferably of from 10 wt% to 50 wt%, yet more preferably of from 20 wt% to 47 wt%, more preferably still of from 25 wt% to 45 wt%, and most preferably of from 35 wt% to 40 wt%, as compared to the total weight of the composition; wherein the total water content includes any optionally added water, and the water contained in the phase-change material if the phase-change material is a salt hydrate.
  • Formula (2) is H2C
  • Embodiment 27 A method for preparing a composition as defined in any one of the preceding Embodiments, wherein said method comprises the steps of: a. contacting a phase-change material with a polymer network; or b. contacting a phase-change material, with a solvent, a polymerization initiator, and the at least three monomers as defined in Embodiment 21; so as to obtain a second solution; and c. copolymerizing the at least three monomers in the second solution.
  • Embodiment 28 A method according to Embodiment 27, wherein said method comprises step a, wherein preferably step a comprises contacting a phase-change material with a polymer network and a solvent.
  • Embodiment 29 A method according to any one of Embodiments 27-28, wherein said polymer network is as defined in any one of Embodiments 19, 20, and 26.
  • Embodiment 30 A method according to Embodiment 27, wherein said method comprises steps b and c.
  • Embodiment 31 A method according to any one of Embodiments 27-30, wherein said phasechange material is as defined in any one of Embodiments 4-10.
  • Embodiment 32 A method according to any one of Embodiments 27, 28, and 31, wherein the phase-change material is a salt hydrate, preferably as defined in any one of Embodiment 6-10, and wherein the method comprises the steps of: i. melting the salt hydrate so as to obtain a melted salt hydrate; ii. contacting the melted salt hydrate with a solvent, a polymerization initiator, and the at least three monomers as defined in Embodiment 26, so as to obtain a second solution; and iii. copolymerizing the at least three monomers in the second solution at a temperature of at least the melting temperature of said salt hydrate.
  • Embodiment 33 The method according to Embodiment 32, wherein the salt hydrate is sodium acetate trihydrate, and wherein the temperature in step iii is at least 58°C; wherein preferably the temperature in step iii is in a range of from 58°C to 95°C; and most preferably the temperature in step iii in a range of from 75°C to 85°C.
  • Embodiment 34 The method according to any one of Embodiments 27 to 33, wherein the solvent comprises water; and preferably consists essentially of water.
  • Embodiment 35 The composition according to Embodiment 26, or the method according to any one of Embodiments 27, and 30 to 34, wherein the polymerization initiator is selected from the group consisting of persulfates, riboflavin, 2,2 '-azobi s(2-methylpropionami dine) dihydrochloride, camphorquinon, curcumin, eosin Y, Ru(bpy)3Ch, a-ketoglutaric acid, and cerium(IV)-nitrilotriacetic acid; wherein preferably the polymerization initiator is potassium persulfate or ammonium persulfate; more preferably the polymerization initiator is potassium persulfate.
  • the polymerization initiator is selected from the group consisting of persulfates, riboflavin, 2,2 '-azobi s(2-methylpropionami dine) dihydrochloride, camphorquinon, curcumin, eosin Y, Ru(
  • Embodiment 36 The composition or method according to any one of Embodiments 26, 27, and 30-35, wherein the concentration of the at least three monomers in said solution or in said second solution is of from 1.5 wt% to 15.0 wt%; more preferably of from 2.0 wt% to 10.0 wt%, yet more preferably of from 2.5 wt% to 9.0 wt%; more preferably still of from 3.0 wt% to 8.0 wt%; and most preferably of from 3.5 wt% to 7.5 wt%, as compared to the total weight of said solution.
  • Embodiment 37 The composition or method according to any one of Embodiments 26, 27, and 30-35, wherein the concentration of the at least three monomers in said solution or in said second solution is of from 3.4 wt% to 4.2 wt%, more preferably of from 3.5 wt% to 4.0 wt%, most preferably of from 3.6 wt% to 3.9 wt%, as compared to the total weight of the solution.
  • Embodiment 38 The composition or method according to any one of Embodiments 26, 27, and 30-37, wherein in said solution or said second solution the weight ratio of the monomer 1 of Formula (1), preferably acrylamide, over the monomer of Formula (2), preferably acrylic acid, is at most 1 : 1, more preferably at most 1 : 1.5, more preferably at most 1 :2, more preferably still at most 1 :3, and most preferably at most 1 :4, with the proviso that said solution comprises both a monomer of Formula (1) and a monomer of Formula (2).
  • the weight ratio of the monomer 1 of Formula (1), preferably acrylamide, over the monomer of Formula (2), preferably acrylic acid is at most 1 : 1, more preferably at most 1 : 1.5, more preferably at most 1 :2, more preferably still at most 1 :3, and most preferably at most 1 :4, with the proviso that said solution comprises both a monomer of Formula (1) and a monomer of Formula (2).
  • Embodiment 39 The composition or method according to any one of Embodiments 26, 27, and 30-37, wherein in said solution or said second solution the weight ratio of the monomer of Formula (1) over the monomer of Formula (2) is in a range of from 1 :25 to 2: 1; preferably from 1 : 10 to 1 : 1; more preferably of from 1 :9 to 1 :2; more preferably of from 1 :8 to 1 :2.5; more preferably of from 1 :6 to 1 :3; and most preferably of from 1 :5 to 1 :3.5.
  • Embodiment 40 The composition or method according to any one of Embodiments 26, 27, and 30-37, wherein the crosslinker has a structure according to Formula (3): (Formula (3)) wherein each R 3 independently is hydrogen or Ci- 3 alkyl; n is 0 or 1; and S p is a spacer; preferably each R 3 is hydrogen; preferably each n is 1; preferably S p is -NH-CFF-NH-; and preferably the crosslinker according to Formula (3) is A,7V’-methylenebisacrylamide.
  • Formula (3) Formula (3) wherein each R 3 independently is hydrogen or Ci- 3 alkyl; n is 0 or 1; and S p is a spacer; preferably each R 3 is hydrogen; preferably each n is 1; preferably S p is -NH-CFF-NH-; and preferably the crosslinker according to Formula (3) is A,7V’-methylenebisacrylamide.
  • Embodiment 41 The method according to any one of Embodiments 27, and 30-40, wherein in said second solution the phase-change material is present in an amount of from 81 wt% to 99 wt%, more preferably of from 83 wt% to 98 wt%, even more preferably of from 85 wt% to 97 wt%, more preferably still of from 87 wt% to 96 wt%, and most preferably of from 89 wt% to 95 wt%, as compared to the total weight of the second solution.
  • Embodiment 42 The method according to any one of Embodiments 27, and 30-41, wherein in said second solution the phase-change material is present in an amount of from 92 wt% to 96 wt%, more preferably of from 93 wt% to 95 wt%, and most preferably of from 93.5 wt% to 94.5 wt%, as compared to the total weight of the second solution.
  • Embodiment 43 A composition obtainable by a method according to any one of Embodiments 27 to 42.
  • Embodiment 44 The composition according to Embodiment 43, wherein said composition is as defined in any one of Embodiments 1 to 26.
  • Embodiment 45 The composition according to any one of Embodiments 1-26, 35-40, 43 and 44 for use as a medicament.
  • Embodiment 46 The composition according to any one of 1-26, 35-40, 43 and 44 for use in thermotherapy.
  • Embodiment 47 The composition according to any one of 1-26, 35-40, 43 and 44 for use in the treatment or prevention of pain, rheumatoid arthritis, joint stiffness, muscle spasms, inflammation, edema, cancer, neurodegenerative diseases, and cardiovascular diseases.
  • Embodiment 48 A method of treating or preventing a disease or condition in a subject, wherein said method comprises the step of applying the composition according to any one of 1-26, 35-40, 43 and 44 to a subject.
  • Embodiment 49 The method according to Embodiment 48, wherein the method of treatment pertains to thermotherapy.
  • Embodiment 50 Use of a composition of any one of 1-26, 35-40, 43 and 44 for the manufacture of a medicament.
  • Embodiment 51 The use of Embodiment 50, wherein the medicament is for thermotherapy.
  • Embodiment 52 The use of Embodiment 50, wherein the medicament is for the manufacture of a medicament for the treatment or prevention of pain, rheumatoid arthritis joint stiffness, muscle spasms, inflammation, edema, cancer, neurodegenerative diseases, and cardiovascular diseases.
  • Embodiment 53 Non-therapeutic use of a composition according to any one of 1-26, 35-40, 43 and 44 as a heat supply; and/or for the thermal management of an electronic device; preferably the heat supply is a household heat supply; and preferably the electronic device is a flexible electronic device.
  • Embodiment 54 Non-therapeutic use of a composition according to any one of 1-26, 35-40, 43 and 44 for long-term storage of thermal energy, wherein preferably “long-term” refers to at least one day, more preferably at least three days, more preferably at least a week, even more preferably at least two weeks, more preferably still at least three weeks, more preferably at least a month, more preferably at least six months, and most preferably at least a year.
  • long-term refers to at least one day, more preferably at least three days, more preferably at least a week, even more preferably at least two weeks, more preferably still at least three weeks, more preferably at least a month, more preferably at least six months, and most preferably at least a year.
  • the one-pot synthesis of the composition of the invention consists of 4 steps. Firstly, pure sodium acetate trihydrate (SAT) was melted in an 80°C oil bath for 1 hour. Secondly, the desired monomers (typically acrylic acid and acrylamide and a crosslinker, preferably N,N'- methylenebisacrylamide (MBA)) were contacted with a polymerization initiator, preferably potassium persulfate (KPS), and a solvent, preferably water, to obtain a mixture.
  • SAT sodium acetate trihydrate
  • MSA N,N'- methylenebisacrylamide
  • the mixture is stirred until the liquid is homogenous and clear.
  • the SAT was totally melted, it was taken out of the oil bath, and contacted with said mixture from the last step to obtain a sample.
  • the sample was stirred for 20 seconds at room temperature at 400 rpm to obtain a second mixture.
  • the second mixture was poured into a sample bottle and put in an oven for 30 minutes at 80°C.
  • phase-change materials in particular salt hydrates, can be employed instead of or in addition to SAT.
  • GELSAT-# wherein # is a value (2, 4, 6, or 8) that represents the weight percentage of the polymer network relative to sodium acetate trihydrate (SAT).
  • # is a value (2, 4, 6, or 8) that represents the weight percentage of the polymer network relative to sodium acetate trihydrate (SAT).
  • the monomers were acrylic acid and acrylamide, wherein the amount of acrylamide used was 25 wt% as compared to the amount of acrylic acid used;
  • the crosslinker was N,N'-methylenebisacrylamide, used in an amount of 3 wt% compared to the sum of the weight of the monomers (viz. the combined weight of acrylamide, acrylic acid and N,N' -methylenebisacrylamide); and (c) the weight percentage of added water used in the preparation of the mixture is half as much as the sum of the weight of the monomers (viz. the combined weight of acrylamide, acrylic acid and N,N' -methylenebisacrylamide).
  • about 3 wt% thereof are residues of the crosslinker
  • about 77.6 wt% are residues of acrylic acid
  • about 19.4 wt% are residues of acrylamide.
  • the water content of the GELSATs described herein can be kept constant, but it may also be lowered by e.g. evaporation during storage. Unless stated otherwise, the water content of the GELSATs described herein is kept constant.
  • GELSAT-4F was prepared using the protocol of Example 1.
  • GELSAT-4F is like GELSAT-4 in terms of SAT content, polymer content, crosslinker content, and the choice of crosslinker.
  • acrylic acid is the only monomer used.
  • GELSAT-4F does not contain residues of acrylamide, and thus the polymer network of GELSAT-4F consists of about 3 wt% of residues of the crosslinker, and about 97 wt% of residues of acrylic acid.
  • Differential scanning calorimeter was used to characterize the phase change properties of the composition of the invention from 20°C to 80°C at a rate of 5°C min' 1 under a nitrogen atmosphere.
  • a thermogravimetric analyzer was applied to test the thermal stability from room temperature up to 110°C at a rate of 10°C min' 1 under a nitrogen atmosphere.
  • the thermal distribution during the phase change of composition of the invention was observed by an Infrared camera (HIKMICRO M10). Scanning electron microscope (SEM) images were taken to observe the morphology.
  • the composition of the invention was examined by Fourier transform infrared spectroscopy (FTIR) with attenuated total reflectance (ATR).
  • FTIR Fourier transform infrared spectroscopy
  • ATR attenuated total reflectance
  • the crystal structure was observed and analyzed by a polarizing microscope (POM) and the X-ray diffraction (XRD) method.
  • Ultraviolet-visible (UV-vis) spectra was applied to show the transparency of the composition of the invention.
  • the sample was put into a cuvette (12.5*12.5*45 mm) and triggered from the top under its supercooled state. The time and distance of a crystal growth from one point to another were recorded and the speed was calculated by dividing the distance by time. Three sets of data were recorded to ensure the accuracy.
  • a Thermal Analyzer KD2-Pro, Decagon was used to measure the thermal conductivity of the composition of the invention.
  • Figure 2(a) shows the DSC results of the GELSAT-2, GELSAT-4, GELSAT-6, GELSAT-8, and SAT.
  • the exothermic peak is not included since all samples showed no exothermal behavior during cooling, indicating a large supercooling degree of at least over 30°C.
  • the heat of fusion decreases as the weight percentage of polymers increases, while the onset temperature of phase change could vary from 50.4°C to 54°C.
  • GELSAT-2 is still in a liquid state which has phase separation, so it is not an ideal sample for further studying even though it has a high latent heat of 271.4 J/g. The rest of the samples with higher portions of polymers all showed no phase separation.
  • GELSAT-4 is a perfect representative which achieved no phase separation with the lowest ratio of polymers and high heat of fusion (264 J/g), which can be seen in Figure 2(a)-(d). Being a polymer-modified material, GELSAT-4 showed both good form stability and flexibility (Figure 2 (e)).
  • FIG 3(b) shows the results for control product GELSAT-4F, of which the properties are evidently worse as compared to those of GELSAT-4.
  • the phase separation of GELSAT-4F not only comes from the salt and the liquid, but also from the shrinkage of the polymer itself (see Figure 3(c)).
  • transparency is the most evident difference that can be noticed when comparing GELSAT-4 to GELSAT-4F, with GELSAT-4 being transparent and GELSAT-4F being entirely opaque.
  • SA anhydrous sodium acetate
  • the PAM is not pH sensitive as it does not contain an ionizable group, it has a consistent structure and will not be affected by ion-shielding. This makes PAM a perfect binder for the copolymer chain to become more stretched, resulting in a better crosslinked network ( Figure 4 (c)). This improved crosslinking network not only eliminated phase separation completely, but also achieved a flexible structure. Other than this, both XRD results and the transparent appearance showed that there is no anhydrous SA appearing in the GELSAT-4, which further supported the inventor’s belief that the interaction between the polymers and the SAT is not only physical, but also chemical.
  • GELSAT -4 was displayed in a sample bottle of 30 mm in diameter and the depth of the sample is 5 mm.
  • a paper with the logo of the University of Twente was put beneath the sample bottle and the photos were taken from the top.
  • FIG 5(a) The switch of two different states of GELSAT-4 when being heated up could be observed as the transparency changes (from solid to soft gel).
  • GELSAT-4 has excellent transparency as the logo beneath it can be seen clearly.
  • a UV-vis test was performed to verify the transparency of the supercooled GELSAT - 4, as shown in Figure 5(b).
  • the transmittance range of GELSAT-4 is from 77.6% to 81.1%.
  • the energy state of the material can be easily recognized from its appearance. This is surprising, since this was not achieved by previous SAT -based materials, because the modifications applied to eliminate the phase separation always made the whole material opaque. This unique property brings the GELSAT lots of possibilities in real applications since the energy status of the material can be easily recognized at the first sight.
  • GELSAT-6 was polymerized in a cylinder mold (30 mm in diameter, 70 mm in height) as a sample.
  • the reason to choose GELSAT-6 is that, GELSAT-6 contains more polymers which help to form a stronger network, resulting in better shape stability compared to GELSAT-4.
  • Figure 6(a) shows the elastic deformation of supercooled GELSAT-6 when attaching to a metal cylinder of 50 g at its bottom. GELSAT-6 could not only be squeezed but also be stretched by the weight of the metal. Additionally, GELSAT-6 could be easily stretched to 2 times its original length ( Figure 6(b)).
  • the stiffness of the GELSAT could enable it to stand the weight of the same metal cylinder on top of it, as shown in Fig. 6 (c).
  • the phase change of GELSAT also brings interesting reversible switches between two different mechanical states, from flexible to formstable.
  • the presence of polymers inside the GELSAT-4 also resulted in a smaller crystal size and slower growth rate (as was observed in a video) because the polymers also provide resistance by blocking the growing path of SAT. Since the GELSAT-4 is reversible between two states without any leakage, it is suggested that the polymer network inside it is strong enough to survive during crystallization, while the smooth growing edge is also helpful in preventing the network from being corrupted.
  • the highest temperature that can be reached after solidification is 49.5 °C for pure SAT, while the GELSAT-4 can still achieve 46.2 °C even with a decrease in the weight ratio of crystals. With a higher weight ratio of polymers, the heat-releasing rate will become even slower.
  • the GELSAT can advantageously be customized to meet different requirements of various discharge rates.
  • IR images were also taken after the sample was triggered from the center in the sample bottle ( Figure 7(e)).
  • GELSAT-4 showed an excellent distribution of heat during the crystallization as the expanding heated area is always in a regular round shape, indicating that the radius of heat spreading is equal in each direction.
  • the GELSAT-4 is well synthesized with a homogenous structure, which makes it a reliable heat battery material.
  • the curve of H d shows slight fluctuation as the cycle time increases, while the highest value was either at the top or the bottom part alternatively. This further strengthened the fact from the results of IR images that the GELSAT-4 was homogenously synthesized. In general, the DSC tests confirmed the longterm thermal stability of GELSAT through cycles.
  • an inflection point can be observed on the curve of only pure SAT but not the GELSAT, which is considered the phase separation point. This is due to the precipitation of anhydrous SA under a certain temperature from the supersaturated SAT solution, which usually comes with a small amount of heat released. Interestingly, the phase separation point was actually shifting to a lower temperature each time as the cycle time increased. The inventors believe that, after each phase separation, a new liquid phase will form at the top of anhydrous SA, which is less saturated at the current temperature. This will result in a lower and lower precipitation temperature at each cycle. During all cycles, GELSAT-4 showed excellent stability with almost no variation on the heating-cooling curves, while GELSAT-6 was experiencing slower heating and cooling after each cycle. Nevertheless, no sign of phase separation could be observed from both curves of GELSAT.
  • Figure 11 shows the heat-releasing curve of GELSAT-4 and GELSAT-6 at the 1 st and 7 th cycles.
  • GELSAT-4 there is only a slight difference observed on its crystallization behavior before and after 6 cycles.
  • the highest temperature that GELSAT-4 could reach under 10°C was 53.41°C, which dropped by only 1% (0.55°C).
  • a large difference could be noticed on the shape of the GELSAT-6 solidification curve. Instead of staying tall and sharp, the peak has become wider and lower over cycles.
  • the mean thermal conductivity of pure SAT, GELSAT-4 and GELSAT-6 was obtained by testing each sample for 5 times with KD2-Pro Thermal Analyzer. For all samples, the standard deviation was calculated as only 0.001 W/(m*K). As shown in Figure 12, after being modified with 2 wt% of water and 4 wt% of polymers, the thermal conductivity actually dropped from 0.631 W/(m*K) to 614 W/(m*K), while the value increased to 674 W/(m*K) and is even higher than SAT when 3 wt% of water and 6 wt% of polymers were added.
  • Stable supercooling is an original property of SAT, enabling it to preserve energy at a large supercooling degree of over 30°C.
  • stable supercooling is crucial as well since it aims for long-term thermal energy storage, mostly at room temperature. If the supercooling is not stable enough and the PCM is triggered spontaneously during storage, a heat waste will occur.
  • GELSAT-4 and GELSAT-6 were put into 4 sample bottles separately, 2 for each. They were stored at room temperature and in the fridge (5°C) separately for 3 months. Surprisingly, both 4 samples stayed supercooled stably after 3 months of storage, while they can also be discharged.
  • Example 7 varying ratio of acrylamide vs. acrylic acid
  • the monomers were acrylic acid and acrylamide, wherein the amount of acrylamide used was varied as compared to the amount of acrylic acid used; the wt/wt ratios of acrylamide versus acrylic acid were 80:20; 60:40; 40:60; 20:80; and 10:90;
  • the crosslinker was N,N'-methylenebisacrylamide, used in an amount of 3 wt% compared to the sum of the weight of the monomers (viz. the combined weight of acrylamide, acrylic acid and N,N' -methylenebisacrylamide); and
  • the weight percentage of added water used in the preparation of the mixture is half as much as the sum of the weight of the monomers (viz. the combined weight of acrylamide, acrylic acid and N,N' -methylenebisacrylamide).
  • GELSAT-4 was prepared according to Example 2. As both anode and cathode, pure silver electrodes (99.9% pure; 2 mm diameter) were used. The cathode was pre-treated by polishing the cathode together with sodium acetate trihydrate (SAT) solid particles with sand paper from lower number to higher number (for example, P800-P1500-P3000), and then immersing the cathode in hot water of about 70 °C to remove extra crystals for 30 minutes. Then, the electrodes were placed into the supercooled GELSAT-4 at a distance of 5-10 mm between the cathode and the anode.
  • SAT sodium acetate trihydrate
  • a polymer-based flexible material GELSAT was developed using an one-pot green synthesis method. Compared with pure SAT, the GELSAT completely eliminated the phase separation, resulting in a transparent gel with no anhydrous SA observed during the melting state, while the interaction mechanism inside the material was analyzed and revealed. The modified material showed high enthalpy and good thermal stability. With GELSAT-4, an average energy density of over 262.2 J/g could be achieved, which still preserved 260.2 J/g after 20 cycles. The heat releasing rate was decreased by one-third with the addition of polymers for GELSAT-4, which could be also adjusted by controlling the ratio of polymers to suit different application backgrounds. TGA tests showed that under 105°C, the GELSAT-4 still preserved 68.14% of weight, 5.03% higher than the value of pure SAT which is 63.11%.
  • the mechanical properties of the GELSAT are also unique. Different from traditional materials, the GELSAT is not in a liquid state, but a gel state that prevents leakage. The polymer-modified materials could easily switch from an elastic form to a solid form by charging and discharging, while the stiffness of the gel could be manipulated by changing the ratio of polymers inside it. With its superb energy storage property and flexibility, GELSAT can be utilized in various backgrounds of research or industry, as a highly efficient and sustainable energy solution.

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Abstract

La présente invention concerne des compositions comprenant un matériau à changement de phase et un réseau polymère, ainsi que des procédés de fabrication ou d'utilisation de celles-ci. Le réseau polymère est un copolymère contenant des résidus monomères avec un groupe amide et des résidus monomères avec un groupe acide carboxylique. Les compositions de l'invention présentent des propriétés avantageuses, y compris mécaniques ( par exemple . Flexibilité, retrait réduit) et thermique (chaleur latente améliorée, excellente stabilité de cycle).
PCT/NL2023/050547 2022-10-19 2023-10-19 Matériaux à changement de phase dans des réseaux polymères WO2024085756A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0133803A2 (fr) * 1983-08-12 1985-03-06 Ciba Specialty Chemicals Water Treatments Limited Compositions pour le stockage de l'énergie thermique
US4537695A (en) * 1982-02-23 1985-08-27 Malcolm Hawe Thermal energy storage compositions
EP0273779A1 (fr) * 1987-01-02 1988-07-06 Sumitomo Chemical Company, Limited Procédé pour produire des matériaux de stockage de la chaleur

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4537695A (en) * 1982-02-23 1985-08-27 Malcolm Hawe Thermal energy storage compositions
EP0133803A2 (fr) * 1983-08-12 1985-03-06 Ciba Specialty Chemicals Water Treatments Limited Compositions pour le stockage de l'énergie thermique
EP0273779A1 (fr) * 1987-01-02 1988-07-06 Sumitomo Chemical Company, Limited Procédé pour produire des matériaux de stockage de la chaleur

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
POSTMA ET AL., ANGEWANDTE CHEMIE INTERNATIONAL EDITION, vol. 56, 2017, pages 1794 - 1798

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