Mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam and method of making same

Abstract

The present application relates to the technical field of sound insulation and noise reduction foams, and particularly relates to a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material and a preparation method thereof, wherein the foam material is prepared from the following raw materials in parts by mass: mesoporous ceramic 2-20 parts, chlorinated polypropylene carbonate 80-98 parts. The mesoporous ceramic / chlorinated polypropylene carbonate foam material has the advantages of high strength, low density, excellent sound insulation performance, environmental protection, etc., and the average transmission loss in the medium and high frequency range of 1000-6300 Hz can reach 46-51 dB, the compression modulus can reach 38-48 MPa, and the compression strength can reach 2.6-3.7 MPa, so that the material is an excellent new type of lightweight sound insulation foam material and can be applied to the fields of rail transit, recording studios, building walls, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sound insulation and noise reduction foam, and particularly relates to a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material and a preparation method thereof. BACKGROUND

[0002] With the acceleration of urbanization, noise pollution has become a prominent problem threatening public health and quality of life. The noise energy released in scenes such as traffic engines, mechanical processing and air conditioner outdoor units is mostly concentrated in the 1000-6300Hz mid-high frequency band. Such sound waves are not only easy to spread through building gaps, but also can form reverberation due to reflection and superposition, leading to deterioration of indoor sound environment. Traditional sound insulation materials such as glass fiber board or rock wool can absorb part of the high-frequency sound energy, but the fiber structure is easy to age and powder, and the transmission loss (TL) of the 1000-2000Hz key frequency band is insufficient (generally less than 25dB), which is difficult to meet the strict requirements of scenes such as precision laboratories and high-end office spaces. The sound insulation microporous foam realizes the "thin layer high efficiency" noise reduction breakthrough through the precise regulation of micrometer-sized pores: the microporous network forces the sound wave to occur viscous friction and heat conduction dissipation in the tortuous pore, and has good noise reduction performance in the mid-high frequency band (1000-6300Hz).

[0003] The current development of sound insulation microcellular foam still faces two major challenges: one is the insufficient uniform sound insulation performance in the wide frequency range (such as 1000-4000 Hz), and the existing materials often have a sharp drop in transmission loss in specific frequency bands due to single pore distribution; the second is the structural stability defect in complex environments, such as polymer matrix softening and pore collapse caused by high temperature, or sound impedance mismatch caused by oil pollution invading the microcell. In view of these problems, in 2023, the academic and industrial circles put forward multi-dimensional solutions: the Fraunhofer Institute in Germany developed a biomimetic "multi-layer heterogeneous pore size" foam, which arranged the 200 μm, 500 μm and 800 μm three-level pores vertically to improve the average transmission loss of 2000-5000 Hz frequency band to 42 dB, but the thickness reached 2.5 cm; In the ceramic composite sound insulation material actually developed by Toray Industries, Inc. (patent JP2021182234A published in 2021), the thickness of the silicon carbide modified polyimide microcellular foam is 3-5 mm, and the transmission loss of 2000-4000 Hz noise is stable at 28-32 dB (about equivalent to 90%-95% of incident sound energy barrier) in 100-120℃ environment, but there is still room for improvement in sound insulation performance. In addition, the team of Tsinghua University proposed the concept of "active regulation of microcell" (patent CN202410123456.7), which coupled piezoelectric materials with microcell structures to adjust the opening and closing state of the pores in real time to match the noise spectrum. Laboratory data shows that its instantaneous transmission loss to 3000 Hz burst noise can reach 50 dB, but it is only for specific frequencies. The present invention proposes a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microcellular foam material, which has excellent sound insulation performance in the medium and high frequency range (1000-6300 Hz), with a transmission loss of 46-51 dB, a density of 0.51-0.65 g / cm 3 , a porosity of 48-63%, a compression modulus of 38-48 MPa, and a compression strength of 2.6-3.6 MPa. It is an excellent new type of lightweight sound insulation foam material, which can be applied in rail transit, recording studio, building wall, etc. SUMMARY

[0004] One of the purposes of the present invention is to provide a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microcellular foam material with low density, excellent sound insulation performance, environmental protection and other advantages.

[0005] The second purpose of the present invention is to provide a preparation method of mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microcellular foam material, which precisely controls the cell size and sample size of mesoporous ceramic / chlorinated polypropylene carbonate microcellular foam through physical binding supercritical CO2 foaming technology, thereby having good full-band noise reduction performance.

[0006] The scheme adopted by one of the purposes of the present application is: a mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material is made of the following mass fraction of raw materials: mesoporous ceramic 2-20 parts, chlorinated polypropylene carbonate (CPPC) 80-98 parts.

[0007] Preferably, the mesoporous ceramic is prepared by mixing basic sodium bentonite, pitch and water-soluble starch, silver citrate, ferrous citrate aqueous solution, drying under air isolation conditions, and then calcining at 800-1200℃ for 7-8h and cooling and grinding. The prepared mesoporous ceramic has a particle size of 100-1000nm and a pore size of 20-30nm.

[0008] The present application effectively increases the contact area of the mesoporous ceramic with the CPPC matrix by constructing a composite structure of hook-shaped iron nanoparticles and silver nanoparticles on the surface of the mesoporous ceramic. The mesoporous ceramic plays a dual role in the composite material: on the one hand, as a heterogeneous nucleating agent, it effectively refines the cell structure by promoting cell nucleation during material foaming, prolongs the sound wave propagation path to enhance the acoustic performance; on the other hand, as a reinforcing phase, it significantly improves the mechanical properties of the foam material. This dual optimization design of structure and function enables the material to simultaneously have excellent sound insulation performance and mechanical strength.

[0009] Preferably, the chlorinated polypropylene carbonate is prepared by modifying polypropylene carbonate through water phase suspension chlorination reaction.

[0010] The scheme adopted by the second purpose of the present application is: a preparation method of the mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material, wherein the mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material is prepared by using physical binding supercritical fluid foaming technology.

[0011] Preferably, the method comprises the following steps:

[0012] (1) uniformly mixing the raw materials according to the required mass fraction to obtain a mixed raw material;

[0013] (2) melt blending the mixed raw material in step (1) to obtain a chlorinated polypropylene carbonate-based composite material;

[0014] (3) hot pressing the melt blended chlorinated polypropylene carbonate-based composite material in step (2) to prepare a chlorinated polypropylene carbonate-based composite material sheet;

[0015] (4) supercritical CO2 foaming the composite material sheet by controlling the foaming temperature, foaming pressure and physical binding size to obtain a mesoporous ceramic / chlorinated polypropylene carbonate microporous foam material.

[0016] Preferably, in step (1), the rotation speed during mixing is 1500-2500r / min.

[0017] Preferably, in step (2), the rotating speed is 50-70 r / min and the temperature is 120-140 DEG C during the melt blending.

[0018] Preferably, in step (3), the hot-pressing conditions are that the hot-pressing temperature is 120-140 DEG C, the pressure is 12-16 MPa, the pressure-keeping time is 5-15 min, and the thickness of the chlorinated polypropylene carbonate-based composite sheet is 2-5 mm.

[0019] Preferably, in step (4), the foaming conditions are that the foaming temperature is 32-60 DEG C, the foaming pressure is 12-16 MPa, the saturation time is 18-24 h, and the foaming time is 10-20 s.

[0020] Preferably, in step (4), the physical restraint makes the thickness of the material after the foaming of the composite sheet be 1.5-2 times, and the average pore size of the cells be 5-7 mu m.

[0021] The present application has the following advantages and beneficial effects:

[0022] The sound insulation composite material of the present application realizes efficient noise reduction through the synergistic effect of the multi-scale pore structure. The core structure is composed of three elements: (1) a composite cell system composed of micrometer-sized closed pores of CPPC matrix and nanometer-sized open pores of mesoporous ceramic; (2) mesoporous ceramic with nanoscale pore characteristics; (3) CPPC (chlorinated polypropylene carbonate) matrix as the continuous phase. The structure realizes noise reduction through a double sound energy dissipation mechanism: first, the synergistic effect of micrometer-sized closed pores and nanometer-sized open pores in the composite cell system promotes multiple reflection, refraction and turbulent effects of incident sound waves at the pore interface, realizing primary energy attenuation; second, the mesoporous ceramic combined with the CPPC matrix interface utilizes its nanoscale porous structure to absorb the residual sound waves penetrating the matrix, further weakening the sound energy through sound wave interference and viscous dissipation effects in the nanopore channel. The spatial coupling of this micro-nano multi-scale pore structure enables the material to exhibit excellent sound insulation performance in a wide frequency range.

[0023] The mesoporous ceramic / chlorinated polypropylene carbonate foam material described in the present application has the advantages of high strength, low density, excellent sound insulation performance, environmental protection, etc. The average transmission loss in the medium-high frequency range of 1000-6300 Hz can reach 46-51 dB, the compression modulus can reach 38-48 MPa, and the compression strength can reach 2.6-3.7 MPa. It is an excellent new type of lightweight sound insulation foam material and can be applied in the fields of rail transportation, recording studios, building walls, etc.

[0024] The preparation method of the present application precisely controls the pore size and sample size of the mesoporous ceramic / chlorinated polypropylene carbonate microporous foam through the physical restraint supercritical CO2 foaming technology, thereby having good full-band noise reduction performance. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 This is a microscopic morphology diagram of the mesoporous ceramic of the present invention;

[0026] Figure 2 This is a microscopic morphology diagram of the mesoporous ceramic / chlorinated polypropylene carbonate sound insulation foam of the present invention. Detailed Implementation

[0027] To better understand the present invention, the following embodiments are further illustrations of the present invention, but the content of the present invention is not limited to the following embodiments.

[0028] In this invention, chlorinated polypropylene carbonate was provided by the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (Chinese Patent ZL201410155108.8), and mesoporous ceramics were provided by Wuhan Maifeite Technology Co., Ltd.

[0029] The mesoporous ceramic is prepared by mixing alkaline sodium bentonite (1000 mesh), pitch (1000 mesh), water-soluble starch (1000 mesh), silver citrate, and ferrous citrate aqueous solution, drying under air-isolated conditions, calcining at 800-1200℃ for 7-8 hours, and then cooling and grinding.

[0030] like Figure 1 The microstructure characterization results of the mesoporous ceramics show that the material has mesopores of approximately 25 nm. Notably, a large number of 5-10 nm hook-like anchoring structures exist on its surface and within the pore channels. This unique morphology is composed of a composite of zero-valent iron nanoparticles and silver nanoparticles. By increasing the interfacial area between the material and the matrix, enlarging the sound wave propagation path, and improving the pore structure, the introduction of this composite structure significantly enhances the acoustic noise reduction performance of the mesoporous ceramic / CPPC foam.

[0031] Example 1

[0032] (1) After drying the chlorinated polypropylene ester in an oven at 40°C for 5 hours, take out 5 parts of mesoporous ceramic and 96 parts of chlorinated polypropylene ester, mix them evenly in a mixer at a speed of 1500 r / min for 30 seconds.

[0033] (2) Pour the mixture into a torque rheometer and melt-blend at 120°C and 50 r / min for 12 min to obtain CPPC-based composite material.

[0034] (3) The CPPC-based composite material is hot-pressed to a thickness of 2 mm at a temperature of 120℃, a pressure of 16MPa, and a holding time of 15min.

[0035] (4) Put the CPPC-based composite material sheet into the high-pressure reactor, the physical restraint thickness is 4mm, and then 12MPa of CO2 gas is introduced, and then saturated at 60℃ for 20h.

[0036] (5) Remove the oil bath heating device, quickly depressurize, and a large amount of gas is overflowed in the mesoporous ceramic / CPPC composite material and forms uniform cells, and the foaming time is 15s. Then, the high-temperature reactor is placed in an ice-water mixture to cool to room temperature, and a mesoporous ceramic / CPPC microporous foam material is obtained. The mesoporous ceramic / CPPC microporous foam material prepared in this example is tested for performance.

[0037] The density of the prepared mesoporous ceramic / CPPC microporous foam material is 0.54g / cm 3 , the porosity is 55%, the average cell diameter is 6.5μm, the compressive modulus is 40MPa, the compressive strength is 2.9MPa, and the average transmission loss of 1000-6300Hz is 46dB, and the micro-morphology diagram is shown in Figure 2 (d), the pore structure is elliptical closed cell, the shape is regular, the pore size is reduced, the pore wall is reduced, and the sound insulation performance and mechanical properties are improved.

[0038] Example 2

[0039] (1) After drying the chlorinated polypropylene carbonate in a 40℃ oven for 5h, take it out, take 2 parts of mesoporous ceramic, 98 parts of chlorinated polypropylene carbonate, and mix them evenly in a mixer at a speed of 2000r / min for 40s.

[0040] (2) Pour the mixture into a torque rheometer, melt blend at a temperature of 130℃ and a speed of 60r / min for 12min to obtain a CPPC-based composite material.

[0041] (3) Heat the CPPC-based composite material at a temperature of 130℃, a pressure of 16MPa, and a pressure holding time of 15min, and hot-press the CPPC-based composite material sheet to a thickness of 5mm.

[0042] (4) Put the CPPC-based composite material sheet into the high-pressure reactor, the physical restraint thickness is 8mm, and then 14MPa of CO2 gas is introduced, and then saturated at 50℃ for 22h.

[0043] (5) Remove the oil bath heating device, quickly depressurize, and a large amount of gas is overflowed in the mesoporous ceramic / CPPC composite material and forms uniform cells, and the foaming time is 20s. Then, the high-temperature reactor is placed in an ice-water mixture to cool to room temperature, and a mesoporous ceramic / CPPC microporous foam material is obtained. The mesoporous ceramic / CPPC microporous foam material prepared in this example is tested for performance.

[0044] The mesoporous ceramic / CPPC microporous foam material prepared in this example was tested for performance.

[0045] The mesoporous ceramic / CPPC microporous foam material prepared has a density of 0.51 g / cm 3 , a porosity of 48%, an average pore size of 5.6 μm, a compression modulus of 38 MPa, a compression strength of 2.6 MPa, and an average transmission loss of 46 dB at 1000-6300 Hz, and a micro-morphology as shown in Fig. (e), wherein the pore structure is round closed pores, the shape is regular, the pore size is reduced, and the sound insulation performance and mechanical properties are improved. Figure 2

[0046] Example 3

[0047] (1) The chlorinated polypropylene carbonate was dried in an oven at 40°C for 5 h, then taken out, and 16 parts of mesoporous ceramic, 84 parts of chlorinated polypropylene carbonate were weighed and mixed uniformly in a mixer at a speed of 2000 r / min for 40 s.

[0048] (2) The mixture was poured into a torque rheometer and melt blended at a temperature of 130°C and a speed of 60 r / min for 12 min to obtain a CPPC-based composite material.

[0049] (3) The CPPC-based composite material was hot-pressed into a CPPC-based composite material sheet at a temperature of 130°C, a pressure of 14 MPa, and a pressure holding time of 10 min, and a hot-pressing thickness of 4 mm.

[0050] (4) The CPPC-based composite material sheet was placed in a high-pressure reaction kettle, the physical binding thickness was 7 mm, 14 MPa of CO2 gas was introduced, and then saturated at 50°C for 24 h.

[0051] (5) The oil bath heating device was removed, the pressure was quickly released, a large amount of gas overflowed from the mesoporous ceramic / CPPC composite material and uniform pores were formed, and the foaming time was 12 s. The high-temperature reaction kettle was then placed in an ice-water mixture and cooled to room temperature to obtain a mesoporous ceramic / CPPC microporous foam material. The mesoporous ceramic / CPPC microporous foam material prepared in this example was tested for performance.

[0052] The mesoporous ceramic / CPPC microporous foam material prepared has a density of 0.57 g / cm 3 , a porosity of 63%, an average pore size of 5.9 μm, a compression modulus of 43 MPa, a compression strength of 3.3 MPa, and an average transmission loss of 51 dB at 1000-6300 Hz, and a micro-morphology as shown in Fig. (f), wherein the pore structure is elliptical and round, the pore size is reduced, the pore wall is thinned, and the sound insulation performance and mechanical properties are greatly improved. Figure 2

[0053] ​​Example 4

[0054] (1) The chlorinated polypropylene carbonate was dried in a 40℃ oven for 5h, then removed, 20 parts of mesoporous ceramic, 80 parts of chlorinated polypropylene carbonate were weighed and mixed uniformly in a mixer at a speed of 2500r / min for 60s.

[0055] (2) The mixture was poured into a torque rheometer and melt blended at a temperature of 140℃ and a speed of 70r / min for 12min to obtain a CPPC-based composite material.

[0056] (3) The CPPC-based composite material was hot-pressed into a 3mm CPPC-based composite material sheet at a temperature of 140℃, a pressure of 14MPa, and a holding time of 10min.

[0057] (4) The CPPC-based composite material sheet was placed in a high-pressure reaction kettle with a physical restraint thickness of 5mm, and 16MPa of CO2 gas was introduced, then saturated at 40℃ for 18h.

[0058] (5) The oil bath heating device was removed, and the pressure was quickly released. A large amount of gas overflowed from the mesoporous ceramic / CPPC composite material and formed uniform cells, and the foaming time was 17s. The high-temperature reaction kettle was then placed in an ice-water mixture and cooled to room temperature to obtain a mesoporous ceramic / CPPC microcellular foam material. The mesoporous ceramic / CPPC microcellular foam material prepared in this example was tested for performance.

[0059] The density of the prepared mesoporous ceramic / CPPC microcellular foam material was 0.65g / cm 3 , the porosity was 51%, the average cell diameter was 6.0μm, the compression modulus was 48MPa, the compression strength was 3.7MPa, and the average transmission loss at 1000-6300Hz was 48dB. The micro-morphology of the mesoporous ceramic / CPPC microcellular foam material is shown in Figure 2 (g), the pore structure is circular, the shape is regular, the pore size is reduced, the pore wall is thinned, and the sound insulation performance and mechanical properties are greatly improved.

[0060] Example 5

[0061] (1) The chlorinated polypropylene carbonate was dried in a 40℃ oven for 5h, then removed, 20 parts of mesoporous ceramic, 80 parts of chlorinated polypropylene carbonate were weighed and mixed uniformly in a mixer at a speed of 2500r / min for 60s.

[0062] (2) The mixture was poured into a torque rheometer and melt blended at a temperature of 140℃ and a speed of 70r / min for 12min to obtain a CPPC-based composite material.

[0063] (3) The CPPC-based composite material is hot-pressed to a thickness of 5 mm at a temperature of 140℃, a pressure of 12MPa, and a holding time of 5 min.

[0064] (4) Place the CPPC-based composite material sheet in a high-pressure reactor with a physical binding thickness of 8 mm, introduce CO2 gas at 16 MPa, and then saturate it at 32°C for 20 h.

[0065] (5) Remove the oil bath heating device and quickly depressurize. A large amount of gas overflows from the mesoporous ceramic / CPPC composite material, forming uniform bubbles. The foaming time is 13 seconds. Then, place the high-temperature reactor in an ice-water mixture to cool to room temperature, thus obtaining the mesoporous ceramic / CPPC microporous foam material. The performance of the mesoporous ceramic / CPPC microporous foam material prepared in this embodiment is tested.

[0066] The density of the prepared mesoporous ceramic / CPPC microporous foam material is 0.61 g / cm³. 3 It has a porosity of 59%, an average pore size of 5.8 μm, a compressive modulus of 44 MPa, a compressive strength of 3.4 MPa, and an average transmission loss of 49 dB in the 1000-6300 Hz range. Its microstructure is shown in the figure below. Figure 2 As shown in (h), the pore structure is circular, regular in shape, with reduced pore size and uniform distribution, resulting in significant improvements in sound insulation and mechanical properties.

[0067] Comparative Example 1

[0068] (1) After drying the chlorinated polypropylene ester in an oven at 40°C for 5 hours, take out 100 parts of the chlorinated polypropylene ester and mix them evenly in a mixer at a speed of 1500 r / min for 30 seconds.

[0069] (2) Pour the mixture into a torque rheometer and melt-blend at 120°C and 50 r / min for 12 min to obtain CPPC-based composite material.

[0070] (3) The CPPC-based composite material is hot-pressed to a thickness of 5 mm at a temperature of 120℃, a pressure of 12MPa, and a holding time of 5 min.

[0071] (4) Place the CPPC-based composite sheet in a high-pressure reactor with a physical binding thickness of 7 mm, introduce CO2 gas at 12 MPa, and then saturate it at 60 °C for 18 h.

[0072] (5) remove the oil bath heating device, quickly depressurize, and a large amount of gas is overflowed in the CPPC and forms uniform cells, the foaming time is 10 s. Then, the high-temperature reaction kettle is placed in an ice-water mixture to cool to room temperature, and the CPPC microcellular foam material is obtained. The density of the CPPC microcellular foam material prepared in the comparative example is 0.49 g / cm 3 , the porosity is 45%, the average cell diameter is 7.2 μm, the compression modulus is 32 MPa, the compression strength is 2.1 MPa, the transmission loss at 1000-6300 Hz is 31 dB, and the micro-morphology diagram is shown in (a) of FIG. 6. Figure 2

[0073] Comparative Example 2

[0074] (6) The chlorinated polypropylene carbonate is dried in a 40°C oven for 5 h, then taken out, 10 parts of the mesoporous ceramic and 90 parts of the chlorinated polypropylene carbonate are weighed, and mixed uniformly in a mixer at a speed of 1800 r / min for 40 s.

[0075] (7) The mixture is poured into a torque rheometer, and melt-blended at a temperature of 130°C and a speed of 50 r / min for 12 min to obtain the CPPC-based composite material.

[0076] (8) The CPPC-based composite material is hot-pressed at a temperature of 130°C, a pressure of 13 MPa, and a pressure holding time of 10 min to obtain a CPPC-based composite material sheet with a thickness of 2 mm.

[0077] (9) The CPPC-based composite material sheet is placed in a high-pressure reaction kettle, the physical bound thickness is 5 mm, 12 MPa of CO2 gas is introduced, and then saturated at 50°C for 20 h.

[0078] (10) The oil bath heating device is removed, and quickly depressurized, a large amount of gas is overflowed in the mesoporous ceramic / CPPC composite material and forms uniform cells, and the foaming time is 18 s. Then, the high-temperature reaction kettle is placed in an ice-water mixture to cool to room temperature, and the mesoporous ceramic / CPPC microcellular foam material is obtained. The mesoporous ceramic / CPPC microcellular foam material prepared in the example is tested for performance.

[0079] The density of the mesoporous ceramic / CPPC microcellular foam material prepared in the example is 0.42 g / cm 3 , the porosity is 46%, the average cell diameter is 7.5 μm, the compression modulus is 23 MPa, the compression strength is 1.5 MPa, and the average transmission loss at 1000-6300 Hz is 32 dB, and the micro-morphology diagram is shown in (b) of FIG. 6. Figure 2 ​​

[0080] Comparative Example 3

[0081] (11) The chlorinated polypropylene carbonate was dried in an oven at 40°C for 5h, then removed, and 13 parts of mesoporous ceramic and 87 parts of chlorinated polypropylene carbonate were weighed and mixed uniformly in a mixer at a speed of 2500r / min for 60s.

[0082] (12) The mixture was poured into a torque rheometer and melt blended at a temperature of 120°C and a speed of 60r / min for 12min to obtain a CPPC-based composite material.

[0083] (13) The CPPC-based composite material was hot-pressed into a CPPC-based composite material sheet at a temperature of 120°C, a pressure of 15MPa, and a pressure holding time of 8min.

[0084] (14) The CPPC-based composite material sheet was placed in a high-pressure reaction kettle, the physical restraint thickness was 6mm, and 12MPa of CO2 gas was introduced, and then saturated at 40°C for 22h.

[0085] (15) The oil bath heating device was removed, and the mesoporous ceramic / CPPC composite material overflowed with a large amount of gas and formed uniform cells in 10s. Then the high-temperature reaction kettle was placed in an ice-water mixture for cooling to room temperature to obtain a mesoporous ceramic / CPPC microcellular foam material. The mesoporous ceramic / CPPC microcellular foam material prepared in this example was tested for performance.

[0086] The density of the prepared mesoporous ceramic / CPPC microcellular foam material was 0.57g / cm 3 , the porosity was 45%, the average cell diameter was 6.1μm, the compressive modulus was 36MPa, the compressive strength was 2.7MPa, and the average transmission loss in the range of 1000-6300Hz was 34dB. The micro-morphology of the prepared mesoporous ceramic / CPPC microcellular foam material is shown in (c) of Figure 2 , the pore structure is elliptical closed cells, the pore size distribution is wide, there are more large pores and small pores, and the sound insulation performance and mechanical properties are general.

[0087] Table 1 Performance parameters of sound insulation microcellular foams prepared in Comparative Examples 1-3 and Examples 1-5

[0088]

[0089]

[0090] Table 2 Transmission loss performance parameters of sound insulation microcellular foams prepared in Comparative Examples 1-3 and Examples 1-5

[0091]

[0092] According to the data analysis of Comparative Examples 1-3 and Example 1-5 in Table 1, the mesoporous ceramic / chlorinated polypropylene carbonate soundproof microporous foam material developed in the application exhibits significant comprehensive performance advantages. The density is 0.51-0.65 g / cm 3 ; in terms of acoustic performance in the medium-high frequency band (1000-6300 Hz), the average sound wave transmission loss value is increased to the interval of 46-51 dB, compared with CPPC foam, 48%-65% optimization of acoustic performance is achieved; in terms of mechanical performance, the compression modulus reaches 38-48 MPa, which is increased by 19%-50% compared with CPPC foam, and the compression strength index is increased to 2.6-3.7 MPa, which is increased by 24%-76%. This multi-scale structure design successfully realizes the synergistic improvement of acoustic protection performance and mechanical bearing capacity while maintaining the lightweight property of the material.

[0093] The above is only a preferred embodiment of the application, and of course cannot limit the scope of protection of the application. It should be pointed out that for ordinary skilled persons in the art, without departing from the principles of the application, a number of improvements and changes can be made, and these improvements and changes are also considered to be within the scope of protection of the application.

Claims

1. A mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam material characterized in that, The mesoporous ceramic is prepared by mixing alkaline sodium bentonite, pitch, water-soluble starch, silver citrate and ferrous citrate aqueous solution, drying under air isolation, calcining at 800-1200 o C for 7-8 h, cooling and grinding, wherein the particle size of the prepared mesoporous ceramic is 100-1000 nm and the pore size is 20-30 nm. The mesoporous ceramic / chlorinated polypropylene carbonate sound insulation microporous foam material is prepared by using the physical binding supercritical fluid foaming technology with mesoporous ceramic and chlorinated polypropylene carbonate; the foaming conditions are as follows: foaming temperature 32-60 ℃, foaming pressure 12-16 MPa, saturation time 18-24 h, and foaming time 10-20 s; the physical binding makes the material thickness of the foamed composite sheet material increased by 1.5-2 times.

2. The mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam of claim 1, wherein: The chlorinated polypropylene carbonate is prepared by modifying the polypropylene carbonate through the water phase suspension chlorination reaction.

3. A process for the preparation of a mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam according to claim 1 or 2, characterized in that, The method comprises the following steps: (1) uniformly mixing raw materials according to the required mass fraction to obtain mixed raw materials; (2) melt blending the mixed raw materials in step (1) to obtain chlorinated polypropylene carbonate-based composite material; (3) hot pressing the melt blended chlorinated polypropylene carbonate-based composite material in step (2) to prepare chlorinated polypropylene carbonate-based composite material sheet; (4) supercritical CO2 foaming the composite material sheet by controlling the foaming temperature, foaming pressure and physical binding size to obtain mesoporous ceramic / chlorinated polypropylene carbonate microporous foam material.

4. The method of making a mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam of claim 3, wherein: In step (1), the rotation speed during mixing is 1500-2500 r / min.

5. The method of making a mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam of claim 3, wherein: In step (2), the rotation speed during melt blending is 50-70 r / min, and the temperature is 120-140 ℃.

6. The method of making a mesoporous ceramic / chlorinated polypropylene carbonate acoustic microcellular foam of claim 3, wherein: In step (3), the hot pressing conditions are as follows: hot pressing temperature 120-140 ℃, pressure 12-16 MPa, pressure maintaining time 5-15 min, and the thickness of the chlorinated polypropylene carbonate-based composite material sheet is 2-5 mm.

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