Carbon nanotube reinforced epoxy resin high-strength sound insulation cotton and preparation method thereof

Abstract

The invention relates to the technical field of sound insulation materials, in particular to carbon nanotube reinforced epoxy resin high-strength sound insulation cotton which is prepared from the following raw materials: epoxy resin, acidification modified carbon nanotubes, an anhydride curing agent, an imidazole accelerant and a silane coupling agent. The silane coupling agent is combined with the acidified modified carbon nanotube, and the diameter of the acidified modified carbon nanotube is 5-30 nm and the length of the acidified modified carbon nanotube is 3-15 [mu] m. By adopting the technical scheme of coordination of acidification modification of the carbon nanotubes and the coupling agent, the problem of dispersion caused by surface inertia of the carbon nanotubes is fundamentally solved, the interface bonding force between the reinforcing agent and a resin matrix is remarkably improved, the mechanical strength of the material is qualitatively improved, meanwhile, the sound insulation performance is optimized, and the service life of the material is prolonged. The problem that strength and sound insulation are difficult to consider in a traditional reinforcing scheme is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sound insulation materials, and particularly relates to a carbon nanotube reinforced epoxy resin high-strength sound insulation cotton and a preparation method thereof. BACKGROUND

[0002] In the fields of building, transportation, electronic equipment and the like, both the mechanical strength and the sound insulation performance of sound insulation materials are required to be strict, and epoxy resin becomes a commonly used matrix material for sound insulation cotton due to excellent formability and stability. However, the existing epoxy resin sound insulation cotton has many technical bottlenecks, which limits its application range.

[0003] In the traditional scheme, some products do not add reinforcing agents and only rely on the compactness of the resin itself to achieve sound insulation, which leads to insufficient mechanical strength and easy cracking in the vibration or stress scene. In another scheme, traditional reinforcing agents such as glass fibers are used, which can improve the strength to a certain extent, but the density is large, the interface bonding with the resin is poor, and the sound insulation performance is limited. As a high-performance reinforcing material, carbon nanotubes should have high specific surface area and high strength characteristics, but the existing technology mostly uses unmodified carbon nanotubes, which have strong surface inertness, poor compatibility with epoxy resin, and are prone to agglomeration. Not only can it not play a reinforcing role, but it also affects the uniformity of the material. At the same time, the existing technology lacks a synergistic design of toughness and strength, and after adding a toughening agent, the antagonistic problem of strength decline often occurs, and the process parameters are rigid, and the ultrasonic and molding steps are not dynamically adjusted for different raw material combinations, which is difficult to adapt to diversified scene requirements. In addition, the raw material selection of the existing scheme is limited to specific types of epoxy resin and a single type of reinforcing agent, and the combination advantages of different performance raw materials have not been explored, resulting in poor performance adjustability of the product, which cannot meet the multi-scene adaptation requirements from flexibility to high strength, and there is an urgent need for a solution to solve the core problems of dispersion, toughening and process adaptation. SUMMARY

[0004] The primary object of the present application is to provide a carbon nanotube reinforced epoxy resin high-strength sound insulation cotton and a preparation method thereof.

[0005] A further object of the present application is to provide a carbon nanotube reinforced epoxy resin high-strength sound insulation cotton, which is prepared from the following raw materials: epoxy resin, acid-modified carbon nanotubes, acid anhydride curing agent, imidazole accelerator and silane coupling agent. The silane coupling agent is combined with the acid-modified carbon nanotubes, and the diameter of the acid-modified carbon nanotubes is 5-30 nm and the length is 3-15 μm.

[0006] A preparation method of a carbon nanotube reinforced epoxy resin high-strength sound insulation cotton, comprising the following steps: (1) Pretreatment: adding acid-modified carbon nanotubes and silane coupling agent into anhydrous ethanol and ultrasonic dispersion, and then removing ethanol; (2) Mixing: after the epoxy resin is warmed, the acid-modified carbon nanotube treated by step (1) is added, stirring and ultrasonic treatment under heat preservation; (3) Curing system addition: an acid anhydride curing agent and an imidazole accelerator are added to the mixture obtained in step (2), and stirring is performed to obtain a uniform slurry; (4) Molding: the slurry obtained in step (3) is poured into a mold, and after pressure warming and curing, the mold is cooled and demolded.

[0007] Preferably, the epoxy resin is a bisphenol A type epoxy resin, and the bisphenol A type epoxy resin includes at least one of E-20 type, E-44 type, E-51 type, E-54 type, and E-56 type.

[0008] Preferably, the acid-modified carbon nanotube includes at least one of acid-modified single-walled carbon nanotubes, acid-modified multi-walled carbon nanotubes, and acid-modified few-walled carbon nanotubes.

[0009] Preferably, the acid anhydride curing agent includes at least one of methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and methyltetrahydrophthalic anhydride; the imidazole accelerator includes at least one of 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenylimidazole, and 2-methylimidazole; and the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-glycidyl ether propyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0010] Preferably, in step (2), the end-functionalized butyl nitrile rubber is first added and stirred to dissolve, and then the acid-modified carbon nanotube treated by step (1) is added; and the end-functionalized butyl nitrile rubber includes at least one of carboxyl-terminated butyl nitrile rubber, hydroxyl-terminated butyl nitrile rubber, and epoxy-terminated butyl nitrile rubber.

[0011] Preferably, in step (2), after ultrasonic treatment under heat preservation, a vacuum degassing step is further included, and the time for vacuum degassing is 15 minutes.

[0012] Preferably, in step (2), ultrasonic treatment is performed in an ultrasonic-stirring alternating manner, and the specific operation of the ultrasonic-stirring alternating manner is that 500W ultrasonic treatment is performed for 20 minutes, followed by 600rpm stirring for 10 minutes, and the operation is repeated at least 2 times.

[0013] Preferably, in step (4), cooling is performed in a segmented cooling manner, and the rate of the segmented cooling is 50℃ per hour.

[0014] Preferably, the bisphenol A type epoxy resin is a mixture of E-20 type, E-51 type, and E-56 type in a ratio of 1:1:1.

[0015] Compared with the prior art, the present application has the following advantages: 1、The present application adopts the technical scheme of carbon nanotube acidification modification and coupling agent cooperation, which fundamentally solves the dispersion problem caused by the inert surface of carbon nanotubes, significantly improves the interfacial bonding force of the reinforcing agent and the resin matrix, and makes the material mechanics strength leap forward in quality, while optimizing the sound insulation performance and avoiding the problem that strength and sound insulation are difficult to be considered in traditional reinforcing scheme.

[0016] 2、The present application successfully realizes the technical breakthrough of toughening without reducing strength through the cooperative design of end-functionalized butyl nitrile rubber and carbon nanotubes, effectively alleviates the brittleness defect of epoxy resin, and makes the material have good impact resistance and flexibility while maintaining high strength, which is suitable for complex use scenarios such as vibration and bending.

[0017] 3、The present application realizes precise control of product performance through the combination of different types of epoxy resins, combined with ultrasonic-stirring alternating dispersion, vacuum degassing, and segmented cooling optimization process, and can flexibly adjust core indicators such as mechanical strength and flexibility according to different scene requirements, covering a wide range of application requirements from low-strength flexible scenarios to high-strength harsh scenarios.

[0018] 4、The technical scheme of the present application has strong industrialization adaptability, the selected raw materials are easy to obtain, the process steps do not require special special equipment, and the scale production can be realized through existing equipment modification, which not only reduces the industrialization threshold, but also stably produces high-performance products, and has significant technical value and market application prospect. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described below. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] Embodiment 1: (1) Raw material ratio (mass fraction) E-20 type epoxy resin (epoxy value 0.20 eq / 100g) 100 parts, unmodified multi-walled CNT 0.8 parts, THPA 60 parts (corresponding to 0.9 times the epoxy value of E-20 type epoxy resin), 2-PZ 0.3 parts, KH-570 0.024 parts (3% of the mass of CNT), CTBN 0 parts.

[0021] (2) Preparation steps Pretreatment: add unmodified CNT and KH-570 to anhydrous ethanol (40 times the mass of CNT), ultrasonically disperse for 20 minutes at 200W, and remove ethanol by rotary evaporation at 70℃; Mixing: the epoxy resin was warmed to 50℃, CNT was added, 400 rpm stirring for 25 minutes, 70℃ preservation condition 300W ultrasonic for 30 minutes; Curing system addition: THPA and 2-PZ were added, 500 rpm stirring for 15 minutes to obtain a uniform slurry; Mold forming: the slurry was poured into a 200mmx200mmx10mm mold, warmed to 100℃ under 1MPa pressure for 1.5 hours, then warmed to 130℃ for 3 hours, and cooled to 40℃ in the furnace to demold.

[0022] Example 2: (1) Raw material ratio (mass fraction) E-56 type epoxy resin (epoxy value 0.60 eq / 100g) 100 parts, acid-modified single-walled CNT 3 parts, MTHPA 110 parts (1.3 times the epoxy value of E-56 type epoxy resin), 2-MI 2.5 parts, KH-792 0.6 parts (20% of the mass of CNT), CTBN 0 parts.

[0023] (2) Preparation steps Pretreatment: acid-modified single-walled CNT and KH-792 were added to anhydrous ethanol (60 times the mass of CNT), 600W ultrasonic dispersion for 90 minutes, 90℃ rotary evaporation to remove ethanol; Mixing: the epoxy resin was warmed to 70℃, CNT was added, 700 rpm stirring for 40 minutes, 90℃ preservation condition 500W ultrasonic for 60 minutes; Curing system addition: MTHPA and 2-MI were added, 800 rpm stirring for 25 minutes to obtain a uniform slurry; Mold forming: the slurry was poured into a 200mmx200mmx10mm mold, warmed to 160℃ under 5MPa pressure for 1 hour, then warmed to 180℃ for 2 hours, and cooled to demold.

[0024] Example 3: (1) Raw material ratio (mass fraction) E-44 and E-56 type epoxy resin (mixed ratio 2:1) 100 parts, acid-modified few-walled CNT 1.5 parts, HHPA 85 parts, BMI 1.2 parts, KH-560 0.225 parts (15% of the mass of CNT), HTBN 8 parts (hydroxyl content 2.5%).

[0025] (2) Preparation steps Pretreatment: refer to the acid-modified few-walled CNT and KH-560 treatment method of Example 2 to complete the pretreatment; Mixing: the epoxy resin was warmed to 65℃, HTBN was first added, stirred at 600 rpm for 50 minutes until completely dissolved, then CNT was added, stirred at 550 rpm for 35 minutes, 85℃ under the condition of 450W ultrasonic for 45 minutes, then vacuum degassing for 15 minutes; Curing system addition: add HHPA and BMI, stir at 700 rpm for 20 minutes to get a uniform slurry; Molding: pour the slurry into a 200mm x 200mm x 10mm mold, warm up to 140℃ under 3MPa pressure for 1.2 hours, then warm up to 160℃ for 2.5 hours, and then demold by furnace cooling.

[0026] Example 4: (1) Raw material ratio (mass fraction) E-20 type, E-51 type, E-56 type epoxy resin (mixed ratio 1:1:1) 100 parts, acid modified multi-walled CNT 2.2 parts, MHHPA 90 parts (corresponding to 1.1 times the epoxy value of mixed epoxy resin), EMI-2,4 41.8 parts, KH-550 0.33 parts (15% of the mass of CNT), ETBN 5 parts (epoxy group content 1.8%).

[0027] (2) Preparation steps Pretreatment: add acid modified multi-walled CNT and KH-550 to anhydrous ethanol, 500W ultrasonic for 30 minutes, then pause the ultrasonic, stir for 15 minutes, repeat the ultrasonic-stir operation 2 times, and vacuum dry at 85℃; Mixing: warm the mixed epoxy resin to 62℃, add ETBN and stir for 45 minutes, then add CNT, use 500W ultrasonic for 20 minutes + 600 rpm stirring for 10 minutes in an alternating manner for 3 times, and then cool to 48℃; Curing system addition: add MHHPA and EMI-2,4, stir at 650 rpm for 22 minutes to get a uniform slurry; Molding: pour the slurry into a 200mm x 200mm x 10mm mold, warm up to 135℃ under 3.5MPa pressure for 1.4 hours, then warm up to 155℃ for 2.2 hours, and then demold by subcooling to room temperature at a rate of 50℃ / hour.

[0028] Comparative Example 1: (1) Raw materials: remove the unmodified multi-walled CNT and KH-570 in Example 1, the rest of the raw materials and the ratio are the same as Example 1; (2) Preparation steps: consistent with Example 1 (no CNT pretreatment step); Comparative Example 2: (1) Raw materials: replace the acid-modified single-walled CNTs in Example 2 with unmodified single-walled CNTs, and the rest of the raw materials and the ratio are consistent with Example 2; (2) Preparation steps: consistent with Example 2; Comparative Example 3: (1) Raw materials: consistent with Example 3; (2) Preparation steps: remove the vacuum degassing step in Example 3, and the rest of the steps are consistent with Example 3; Comparative Example 4: (1) Raw materials: consistent with Example 4; (2) Preparation steps: replace the ultrasonic-stirring alternation operation in Example 4 with continuous 500W ultrasonic for 45 minutes, and the rest of the steps are consistent with Example 4; Performance test and result analysis: Performance test method: (1) Mechanical properties: tensile strength according to GB / T1040.1-2006, Type I sample, tensile speed 5mm / min; (2) Bending strength according to GB / T9341-2008, 80mmx10mmx4mm sample, span 40mm, bending speed 2mm / min; (3) Compression strength according to GB / T1041-2008, 10mmx10mmx10mm sample, compression speed 1mm / min; (4) Sound insulation performance: air sound average sound insulation according to GB / T19889.3-2005, standing wave tube method, test frequency 100 to 4000Hz; (5) CNT dispersibility: transmission electron microscopy (TEM) observation of CNT agglomeration size; (6) Thermal stability: thermogravimetric analysis (TGA) according to N2 atmosphere, 10℃ / min heating rate, test 5% weight loss temperature (T5%) and 800℃ carbon residue rate; (7) Density and porosity: density according to GB / T1463-2005 drainage method; porosity calculated according to Archimedes principle.

[0029] Test results are as follows in Table 1:

[0030] From the above Table 1, the result analysis is as follows: (1) Example 1 uses unmodified multi-walled CNTs, although the interface is preliminarily improved by coupling agent, but TEM shows that the agglomeration size is still 900 to 1100 nm, and the tensile strength is only 58 MPa; while Example 2 is replaced by acid-modified single-walled CNTs, the agglomeration size is reduced to 250 to 350 nm, the tensile strength is increased by 64% to 95 MPa, and the average sound insulation is increased by 38% to 36 dB. As can be seen from Comparative Example 2, the high specific surface area of single-walled CNTs cannot play a reinforcing role, and it is necessary to introduce hydroxyl groups by acidification and bridge the resin with coupling agent. This synergistic modification mechanism effectively solves the problem of CNT dispersion difficulty in the prior art.

[0031] (2) Example 3 adds 8 parts of HTBN based on acidified few-walled CNTs, and adds a vacuum degassing step, the bending strength reaches 112 MPa, which is 14% higher than that of Example 2, and the tensile strength of 88 MPa is only 7% lower than that of Example 2, which is much better than the level of more than 10% decrease in strength when the amount of toughening agent in the prior art is more than 5%; as can be seen from Comparative Example 3, vacuum degassing can effectively eliminate the bubble defects caused by high amount of toughening agent, so that the hydroxyl groups of HTBN and the epoxy groups of the resin can fully react to form an elastic network, and the interface reinforcing effect of CNTs is complementary, realizing the synergistic effect of toughening without reducing strength.

[0032] (3) Example 4 uses a ternary mixed resin of E-20, E-51 and E-56, combined with 2.2 parts of acid-modified multi-walled CNTs and 5 parts of ETBN, as well as ultrasonic-stirring alternating dispersion and staged cooling process, finally realizes the overall excellent performance of tensile strength 93 MPa, bending strength 120 MPa, average sound insulation 35 dB, T5% 352℃; as can be seen from Comparative Example 4, the alternating dispersion process can avoid the degradation of resin caused by long-time ultrasonic, while ensuring the uniform dispersion of CNTs, and the combination of ternary resin balances the flexibility of low epoxy value resin and the strength of high epoxy value resin, so that the product can adapt to vibration scene and meet the demand for high strength.

[0033] (4) The performance data of Comparative Example 1 further proves the indispensability of CNT in reinforcement and sound insulation, and highlights the technical solution formed by CNT modification, toughening synergy and process optimization in the present application. Compared with the existing non-reinforcing agent, traditional reinforcing agent or single CNT improvement scheme, the present application realizes the qualitative improvement in mechanical properties, sound insulation performance, thermal stability and scene adaptability, and all the performance improvements have clear raw material selection logic and process design support.

[0034] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details and do not limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to provide the best illustration of the application principles and their practical application, so that those skilled in the art can well understand and utilize the application.

Claims

1. A carbon nanotube reinforced epoxy resin high-strength soundproof cotton, characterized in that, It is prepared from the following raw materials: epoxy resin, acid-modified carbon nanotubes, acid anhydride curing agent, imidazole accelerator, and silane coupling agent; wherein the silane coupling agent is combined with the acid-modified carbon nanotubes, wherein the acid-modified carbon nanotubes have a diameter of 5 to 30 nm and a length of 3 to 15 μm.

2. A method for preparing carbon nanotube reinforced epoxy resin high-strength soundproof cotton, characterized in that, Includes the following steps: (1) Pretreatment: Acidified modified carbon nanotubes and silane coupling agent were added to anhydrous ethanol and ultrasonically dispersed, and then the ethanol was removed; (2) Mixing: After heating the epoxy resin, add the acidified modified carbon nanotubes treated in step (1), stir and keep warm with ultrasound; (3) Addition of curing system: Add anhydride curing agent and imidazole accelerator to the mixture obtained in step (2) and stir to obtain a uniform slurry; (4) Molding: Pour the slurry obtained in step (3) into the mold, pressurize and heat to solidify, and then cool down to demold.

3. The carbon nanotube reinforced epoxy resin high-strength acoustic insulation cotton according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin, and the bisphenol A type epoxy resin includes at least one of E-20, E-44, E-51, E-54 and E-56 types.

4. The carbon nanotube reinforced epoxy resin high strength acoustic insulation wool according to claim 1, characterized in that, The acid-modified carbon nanotubes include at least one of acid-modified single-walled carbon nanotubes, acid-modified multi-walled carbon nanotubes, and acid-modified few-walled carbon nanotubes.

5. The carbon nanotube reinforced epoxy resin high strength acoustic insulation wool according to claim 1, characterized in that, The anhydride curing agent includes at least one of methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and methyltetrahydrophthalic anhydride; the imidazole accelerator includes at least one of 2-ethyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 2-phenylimidazolium, and 2-methylimidazolium; the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

6. The production method according to claim 2, characterized by, In step (2), when mixing, first add the end-functionalized nitrile rubber and stir until dissolved, then add the acid-modified carbon nanotubes treated in step (1); The terminal functional group nitrile rubber includes at least one of terminal carboxyl nitrile rubber, terminal hydroxyl nitrile rubber, and terminal epoxy nitrile rubber.

7. The preparation method according to claim 2, characterized in that, In step (2), after heat preservation and ultrasound, there is also a vacuum degassing step, and the vacuum degassing time is 15 minutes.

8. The preparation method according to claim 2, characterized in that, In step (2), the ultrasound is performed by alternating ultrasound and stirring. The specific operation of alternating ultrasound and stirring is to use 500W ultrasound for 20 minutes and then stir at 600rpm for 10 minutes. This operation is repeated at least twice.

9. The preparation method according to claim 2, characterized in that, In step (4), the cooling is carried out in a segmented cooling manner, and the segmented cooling rate is 50°C per hour.

10. The carbon nanotube-reinforced epoxy resin high-strength sound insulation cotton according to claim 3, characterized in that, The bisphenol A type epoxy resin is a mixture of E-20, E-51 and E-56 types in a 1:1:1 ratio.

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