A heat storage and temperature regulation multifunctional composite material and its preparation method and application

Abstract

The present invention discloses a heat storage and temperature regulation multifunctional composite material and its preparation method and application, relating to the technical field of heat storage and temperature regulation materials. The present invention selects naturally occurring porous materials such as attapulgite, diatomaceous earth, and montmorillonite as carriers of phase change materials. Not only are the raw materials easily available and low in cost, but the flame retardant elements contained in these porous materials can also give the material good thermal stability. The present invention also enhances the heat storage and temperature regulation performance of the phase change material by introducing metal particles, and can give the polylactic acid material multifunctional properties such as flame retardancy, smoke suppression, or antibacterial properties by selecting the type of metal particles.

Description

Technical field:

[0001] The present invention relates to the technical field of heat storage and temperature regulation materials, and in particular to a heat storage and temperature regulation multifunctional composite material and a preparation method and application thereof. Background technology:

[0002] Phase change materials (PCMs) are a type of latent heat energy storage material that absorbs or releases high amounts of latent heat during their phase change process. When the temperature rises above the phase transition point, PCMs absorb heat, undergoing a phase change and transferring thermal energy. During this process, the temperature of the PCM remains nearly constant, while heat flowing through the PCM is "trapped" within the material, absorbing a significant amount of latent heat and controlling temperature. Therefore, PCMs are widely used in thermal storage and temperature regulation.

[0003] Polylactic acid (PLA), with its renewable, biodegradable, biocompatible, and skin-friendly properties, holds great promise for application in the clothing industry. Developing PLA materials with phase-change thermoregulatory properties and expanding their applications in cold protection and warmth protection are key areas for the development of functional PLA. Furthermore, developing PLA thermal storage materials for diverse applications is a crucial research priority.

[0004] The organic phase-change material polyethylene glycol (PEG) offers advantages such as an adjustable phase transition temperature, high latent heat of phase change, good chemical and thermal stability, and biodegradability, making it an excellent thermal energy storage and temperature-regulating material. However, leakage in the molten state is a challenge that hinders the practical application of phase-change materials. Using porous framework materials to load and encapsulate the phase-change material, achieving fixed shape while improving material performance, is an effective means to address the leakage problem of phase-change materials. However, the preparation process of most porous framework materials is complex, time-consuming, and expensive, which also affects the biodegradability of PEG. Furthermore, PEG's low thermal conductivity limits its heat storage and release rates, thus reducing its application in thermal energy storage. Improving the thermal conductivity of phase-change materials can improve their energy conservation and release properties during thermal cycling, thereby enabling more effective practical applications. Some studies have embedded metal and metal oxide particles as fillers into phase-change materials, leveraging the thermal conductivity of the metal particles to improve the low thermal conductivity of phase-change materials. Existing reports on introducing metal particles into phase change materials usually require additional packaging operations for the metal particles or separate processing steps, and the preparation method is complicated. Summary of the invention:

[0005] The technical problem to be solved by the present invention is to provide a porous skeleton fixed phase change material and a preparation method thereof, wherein the phase change material is adsorbed on the porous skeleton, and metal particles are introduced into the porous skeleton fixed phase change material through an in-situ reaction, and the obtained heat storage and temperature regulation multifunctional composite material is then applied to polylactic acid material, thereby optimizing the application performance of polylactic acid material and expanding the application field of polylactic acid material.

[0006] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0007] One of the purposes of the present invention is to provide a method for preparing a porous skeleton fixed phase change material, which comprises adding a phase change material to a solvent, heating to melt the phase change material, and then adding a porous skeleton for impregnation treatment to obtain a porous skeleton fixed phase change material.

[0008] Preferably, the phase change material is polyethylene glycol (PEG) with a degree of polymerization of 500-2000.

[0009] Preferably, the solvent is water. Using water as a solvent can dissolve PEG while improving environmental friendliness.

[0010] Preferably, the mass fraction of the phase change material in the solvent is 1 to 5%.

[0011] Preferably, the heating temperature is 80-100°C.

[0012] Preferably, the porous skeleton is at least one of attapulgite, diatomaceous earth, and montmorillonite. Other types of natural porous materials known in the art may also be used.

[0013] Preferably, the mass ratio of the porous skeleton to the phase change material is (1-3):1.

[0014] Preferably, the immersion treatment lasts for 15 to 60 minutes. The immersion time depends on the adsorption properties of the porous skeleton used, and the immersion can be performed at room temperature or under heating conditions.

[0015] A second object of the present invention is to provide a porous skeleton fixed phase change material obtained according to the above-mentioned preparation method.

[0016] A third objective of the present invention is to provide the use of the porous skeleton-fixed phase-change material in a multifunctional composite material for heat storage and temperature regulation. By introducing metal particles into the porous skeleton-fixed phase-change material, the resulting composite material not only has heat storage and temperature regulation functions, but also has flame retardancy, smoke suppression, and antibacterial properties.

[0017] The fourth object of the present invention is to provide a method for preparing a heat storage, temperature regulation, flame retardant and smoke suppression composite material, adding alkali to the porous skeleton fixed phase change material, stirring evenly, then adding a metal compound, heating to react, washing with water, and drying to obtain a heat storage, temperature regulation, flame retardant and smoke suppression composite material.

[0018] Preferably, the base is a NaOH or KOH solution with a concentration of 5-15%.

[0019] Preferably, the metal compound is a magnesium or aluminum compound, more preferably at least one of magnesium sulfate, magnesium chloride, aluminum sulfate, and aluminum chloride. Other soluble magnesium salts or aluminum salts known in the art may also be used.

[0020] Preferably, the molar ratio of the metal compound to the base is 1:(1-3). The magnesium or aluminum compound reacts with the base to generate Al(OH)3 or Mg(OH)2 which has flame retardant and smoke suppression effects.

[0021] Preferably, the heating reaction temperature is 80-100° C. and the time is 0.5-2 h.

[0022] A fifth object of the present invention is to provide a heat-storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material obtained according to the aforementioned preparation method.

[0023] The sixth object of the present invention is to provide a method for preparing a heat storage, temperature regulation and antibacterial composite material, which comprises adding ammonia water and silver nitrate to the porous skeleton fixed phase change material, stirring evenly, then adding a reducing agent, heating for reaction, washing with water, and drying to obtain a heat storage, temperature regulation and antibacterial composite material.

[0024] Preferably, the ammonia water is an ammonia water solution with a concentration of 5 to 10%.

[0025] Preferably, the molar ratio of silver nitrate to ammonia water is 1:(1-2).

[0026] Preferably, the reducing agent is at least one of glucose, dopamine, and sodium borohydride. Ammonia and silver nitrate react to form a complex, which is then reduced by the reducing agent to form silver with antibacterial effect.

[0027] Preferably, the mass ratio of the reducing agent to silver nitrate is 1:(1-2).

[0028] Preferably, the heating reaction temperature is 80-100° C. and the time is 0.5-2 h.

[0029] A seventh object of the present invention is to provide a heat-storage temperature-regulating antibacterial composite material obtained according to the aforementioned preparation method.

[0030] The eighth object of the present invention is to provide the application of the heat storage temperature regulating flame retardant smoke suppression composite material or the heat storage temperature regulating antibacterial composite material in polylactic acid material.

[0031] The ninth object of the present invention is to provide a heat storage and temperature regulation multifunctional polylactic acid material, which is prepared by melt blending and extrusion granulation of polylactic acid resin, the heat storage and temperature regulation flame retardant and smoke suppression composite material or the heat storage and temperature regulation antibacterial composite material.

[0032] Preferably, the mass percentage of the heat-storage temperature-regulating flame-retardant and smoke-suppressing composite material or the heat-storage temperature-regulating antibacterial composite material to the heat-storage temperature-regulating multifunctional polylactic acid material is 10-15%.

[0033] Preferably, the melt blending temperature is 170-190°C.

[0034] The beneficial effects of the present invention are:

[0035] (1) The present invention uses naturally occurring porous materials such as attapulgite, diatomaceous earth, and montmorillonite as carriers of phase change materials. Not only are the raw materials easily available and low in cost, but the flame retardant elements contained in these porous materials can also give the materials good thermal stability.

[0036] (2) The present invention uses metal particles generated by an in-situ reaction as fillers. The preparation method is simple and does not require additional packaging operations for the metal particles or separate processing steps, effectively shortening the preparation time and steps.

[0037] (3) The present invention not only enhances the heat storage and temperature regulation performance of the phase change material by introducing metal particles, but also can give the polylactic acid material multifunctional properties such as flame retardancy, smoke suppression or antibacterial properties by selecting the type of metal particles. Specific implementation method:

[0038] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments.

[0039] The thermoregulation properties of polylactic acid (PLA) were tested using DSC. The test procedure was as follows: the temperature was rapidly increased from room temperature to 100°C at a rate of 30°C / min, held constant for 5 minutes; then cooled to -10°C at a rate of 10°C / min, held constant for 2 minutes, and then increased by 50°C at a rate of 10°C / min. N2 was used as the protective gas throughout the entire process.

[0040] The thermal conductivity of polylactic acid material is tested according to the standard GB / T 32064-2015.

[0041] The limiting oxygen index of polylactic acid material was tested according to the standard GB / T 5454-1997.

[0042] The vertical burning performance of polylactic acid materials was tested according to the ASTM D3801-2010 standard.

[0043] The smoke suppression performance of the polylactic acid material was tested according to the standard GB / T 16172-2007, and the smoke density (SEA) of the control sample 2 was recorded as 100%.

[0044] The antibacterial properties of polylactic acid materials were tested according to the third part of the oscillation method of standard GB / T 20944-2008.

[0045] Example 1

[0046] 10g of PEG-2000 was added to 1000mL of water and heated to 100°C to melt the PEG-2000. Next, 10g of attapulgite was added and allowed to soak for 30 minutes to allow the molten PEG to adsorb into the attapulgite, resulting in a porous framework-immobilized phase-change material. 200mL of a 5% KOH solution was added to the porous framework-immobilized phase-change material, stirred evenly, and then 8g of AlCl₃ was added. The material was heated to 100°C and reacted for 1 hour to generate Al(OH)₃ particle filler in situ. The material was then cooled to room temperature, washed with water, and dried to obtain a thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material.

[0047] The thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 20g of the thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material was mixed evenly with 180g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0048] Example 2

[0049] Add 20g of PEG-1000 to 1000mL of water and heat to 100°C to melt the PEG-1000. Then, add 60g of diatomaceous earth and soak for 60 minutes to allow the molten PEG to adsorb into the diatomaceous earth, thereby obtaining a porous framework-fixed phase-change material. Add 200mL of a 10% NaOH solution to the porous framework-fixed phase-change material, stir evenly, then add 22.2g of AlCl3. Heat to 100°C and react for 1 hour to generate Al(OH)3 particle filler in situ. Cool to room temperature, rinse with water, and dry to obtain a heat-storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material.

[0050] The thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 30g of the thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material was mixed evenly with 170g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0051] Example 3

[0052] Add 50g of PEG-600 to 1000mL of water and heat to 80°C to melt the PEG-600. Then, add 50g of montmorillonite and soak for 60 minutes to allow the molten PEG to adsorb into the montmorillonite, resulting in a porous framework-fixed phase-change material. Add 100mL of a 15% NaOH solution to the porous framework-fixed phase-change material, stir evenly, then add 21.4g of Al2(SO4)3. Heat to 80°C and react for 1 hour to generate Al(OH)3 particle filler in situ. Cool to room temperature, rinse with water, and dry to obtain a thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material.

[0053] The thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 30g of the thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material was mixed evenly with 170g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0054] Example 4

[0055] Add 10g of PEG-2000 to 1000mL of water and heat to 100°C to melt the PEG-2000. Next, add 20g of montmorillonite and soak for 30 minutes to allow the molten PEG to adsorb into the montmorillonite, resulting in a porous framework-fixed phase-change material. Add 200mL of a 10% KOH solution to the porous framework-fixed phase-change material, stir evenly, then add 17g of MgCl2. Heat to 100°C and react for 1 hour to generate Mg(OH)2 particle filler in situ. Cool to room temperature, rinse with water, and dry to obtain a thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material.

[0056] The thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 24g of the thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material were mixed evenly with 176g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0057] Example 5

[0058] 30g of PEG-600 was added to 1000mL of water and heated to 80°C to melt the PEG-600. Then, 60g of attapulgite was added and soaked for 60 minutes to allow the molten PEG to adsorb into the attapulgite, resulting in a porous framework-fixed phase-change material. 200mL of a 15% NaOH solution was added to the porous framework-fixed phase-change material, stirred evenly, and then 45g of MgSO4 was added. The material was heated to 60°C and reacted for 1 hour to generate Mg(OH)2 particle filler in situ. The material was then cooled to room temperature, washed with water, and dried to obtain a thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material.

[0059] The thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 30g of the thermal storage, temperature-regulating, flame-retardant, and smoke-suppressing composite material was mixed evenly with 170g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0060] Example 6

[0061] 20g of PEG-2000 was added to 1000mL of water and heated to 100°C to melt the PEG-2000. Next, 60g of attapulgite was added and soaked for 60 minutes to allow the molten PEG to adsorb into the attapulgite, resulting in a porous framework-immobilized phase-change material solution. To this porous framework-immobilized phase-change material solution, 10mL of 10% ammonia water was added, followed by 5g of AgNO₃. After stirring, 2.7g of glucose was added. The solution was heated to 100°C for 1 hour to generate Ag particle filler in situ. The solution was then cooled to room temperature, washed with water, and dried to obtain a thermal storage and temperature-regulating antibacterial composite material.

[0062] The thermal storage, temperature-regulating, and antimicrobial composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 30g of the thermal storage, temperature-regulating, and antimicrobial composite material was mixed with 170g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200 rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0063] Example 7

[0064] 20g of PEG-1000 was added to 1000mL of water and heated to 100°C to melt the PEG-1000. Next, 40g of diatomaceous earth was added and allowed to soak for 60 minutes to allow the molten PEG to adsorb into the diatomaceous earth, resulting in a porous framework-immobilized phase-change material. 20mL of 10% ammonia water was added to the porous framework-immobilized phase-change material solution, followed by 10g of AgNO₃. After stirring, 5.5g of glucose was added. The solution was heated to 100°C for 1 hour to generate Ag particle filler in situ. The solution was then cooled to room temperature, washed with water, and dried to obtain a thermal storage, temperature-regulating, and antibacterial composite material.

[0065] The thermal storage and temperature-regulating antimicrobial composite material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 20g of the thermal storage and temperature-regulating antimicrobial composite material was mixed with 180g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200 rpm, extruded into pellets, and then hot-pressed at 180°C to form 2mm thick strips.

[0066] Comparative Example 1

[0067] The preparation method of the porous skeleton material loaded with phase change material is the same as that of Example 2, but without introducing metal particles.

[0068] Add 20g of PEG-1000 to 1000mL of water and heat to 100°C to melt the PEG-1000. Next, add 60g of diatomaceous earth and soak for 60 minutes to allow the melted PEG to adsorb into the diatomaceous earth, thereby obtaining a porous framework-immobilized phase-change material. Cool to room temperature, rinse with water, and dry to obtain a porous framework-immobilized phase-change material.

[0069] The porous framework-immobilized phase-change material and polylactic acid resin were dried at 60°C for 24 hours to remove moisture. After drying, 30g of the porous framework-immobilized phase-change material was mixed with 170g of polylactic acid resin. The mixture was then melt-blended in a twin-screw extruder at 180°C and 200 rpm. The mixture was extruded into pellets and then hot-pressed at 180°C to form 2mm thick strips.

[0070] Comparative Example 2

[0071] The polylactic acid resin without any component added was dried at 60°C for 24 hours to remove moisture, then added to a twin-screw extruder for melt blending at 180°C at a speed of 200 rpm, extruded into granules, and then hot-pressed at 180°C into strip materials with a thickness of 2 mm.

[0072] The above Examples 1-5 prepare heat-storage temperature-regulating flame-retardant and smoke-suppressing polylactic acid materials, and Examples 6-7 prepare heat-storage temperature-regulating and antibacterial polylactic acid materials.

[0073] Table 1 shows the heat storage and temperature regulation, flame retardancy, smoke suppression and antibacterial properties of the polylactic acid materials obtained in Examples 1-7 and Comparative Examples 1 and 2.

[0074] Table 1

[0075]

[0076] The polylactic acid materials prepared in Examples 1-7 all exhibited obvious phase change behavior during the heating and cooling process, with the highest phase change enthalpy being 10.3 J / g, demonstrating good heat storage and temperature regulation performance. Compared with Control Example 1, after the introduction of metal particles, the thermal conductivity of Examples 1-7 increased, indicating that the thermal conductivity of the polylactic acid material was improved, thereby improving the heat storage and heat release performance of the polylactic acid material in the thermal cycle. Among them, in Examples 1-5 where Mg(OH)2 or Al(OH)3 particles were introduced, the flame retardant and smoke suppression properties of the polylactic acid material were improved; in Examples 6-7 where Ag particles were introduced, the polylactic acid material obtained excellent antibacterial properties, indicating that the polylactic acid material can be endowed with multifunctional properties such as flame retardancy, smoke suppression or antibacterial properties by selecting the type of metal particles.

[0077] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A multifunctional polylactic acid material for heat storage and temperature regulation, characterized by: The heat storage and temperature regulation multifunctional polylactic acid material is prepared by melt blending and extrusion granulation of polylactic acid resin, heat storage and temperature regulation flame retardant and smoke suppression composite material or heat storage and temperature regulation antibacterial composite material; The mass percentage of the heat storage and temperature regulation flame retardant smoke suppression composite material or the heat storage and temperature regulation antibacterial composite material to the heat storage and temperature regulation multifunctional polylactic acid material is 10-15%; The temperature of the melt blending is 170-190°C; The preparation method of the heat-storage temperature-regulating flame-retardant and smoke-suppressing composite material comprises: adding an alkali to a porous skeleton fixed phase change material, stirring uniformly, then adding a metal compound, heating for reaction, washing with water, and drying to obtain the heat-storage temperature-regulating flame-retardant and smoke-suppressing composite material; wherein the alkali is a NaOH or KOH solution with a concentration of 5-15%; the metal compound is a magnesium or aluminum compound; the molar ratio of the metal compound to the alkali is 1:(1-3); the heating reaction temperature is 80-100°C, and the time is 0.5-2 hours; The preparation method of the heat-storage temperature-regulating antibacterial composite material comprises: adding ammonia water and silver nitrate to a porous skeleton fixed phase change material, stirring evenly, then adding a reducing agent, heating for reaction, washing with water, and drying to obtain the heat-storage temperature-regulating antibacterial composite material; wherein the ammonia water is an ammonia solution with a concentration of 5-10%; the molar ratio of the silver nitrate to the ammonia water is 1:(1-2); the reducing agent is at least one of glucose, dopamine, and sodium borohydride; the mass ratio of the reducing agent to the silver nitrate is 1:(1-2); the heating reaction temperature is 80-100°C, and the time is 0.5-2 hours; The preparation method of the porous skeleton fixed phase change material includes: adding a phase change material to a solvent, heating to melt the phase change material, and then adding a porous skeleton for impregnation treatment to obtain the porous skeleton fixed phase change material; wherein the phase change material is polyethylene glycol with a degree of polymerization of 500-2000; the solvent is water; the mass fraction of the phase change material in the solvent is 1-5%; the heating temperature is 80-100°C; the porous skeleton is at least one of attapulgite, diatomaceous earth, and montmorillonite; the mass ratio of the porous skeleton to the phase change material is (1-3):1; and the impregnation treatment time is 15-60 min.

2. The heat storage and temperature regulating multifunctional polylactic acid material according to claim 1, characterized in that: The metal compound is at least one of magnesium sulfate, magnesium chloride, aluminum sulfate and aluminum chloride.

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