Intrinsic heat-conducting epoxy resin cured product and preparation method thereof
阅读说明：本技术 一种本征导热环氧树脂固化物及其制备方法 (Intrinsic heat-conducting epoxy resin cured product and preparation method thereof ) 是由 袁彦超 刘诗博 吴叔青 张正国 袁文辉 凌子夜 于 2021-07-28 设计创作，主要内容包括：本发明属于热固性高分子材料领域,公开了一种本征导热环氧树脂固化物及其制备方法,该环氧树脂固化物由环氧预聚物、固化剂和催化剂固化而成,其中至少一种环氧预聚物和至少一种固化剂中均含有芳香酰胺结构；所述具有芳香酰胺结构的环氧预聚物为如结构式(1)或(2)或其混合结构；本发明同时通过环氧预聚物和固化剂向固化物中引入芳香酰胺结构,利用分子链间酰胺键产生的氢键强相互作用向环氧树脂固化网络中引入局域微观有序结构增大声子传播自由程,提高树脂本征导热性能。本发明环氧树脂固化物同时具有优良的机械、耐热性能,且制备工艺简单、结构可调,具有广阔的应用前景。(The invention belongs to the field of thermosetting high polymer materials, and discloses an intrinsic heat-conducting epoxy resin cured product and a preparation method thereof, wherein the epoxy resin cured product is formed by curing an epoxy prepolymer, a curing agent and a catalyst, wherein at least one epoxy prepolymer and at least one curing agent both contain aromatic amide structures; the epoxy prepolymer having an aromatic amide structureIs structural formula (1) or (2) or a mixed structure thereof; according to the invention, an aromatic amide structure is introduced into a cured product through an epoxy prepolymer and a curing agent, and a local microscopic ordered structure is introduced into an epoxy resin curing network by utilizing the strong interaction of hydrogen bonds generated by amide bonds between molecular chains, so that the phonon propagation free path is increased, and the intrinsic heat conductivity of the resin is improved. The epoxy resin condensate has excellent mechanical and heat-resistant properties, and the preparation process is simple, the structure is adjustable, and the epoxy resin condensate has wide application prospect.)
1. The intrinsic heat-conducting epoxy resin condensate is characterized by being formed by solidifying an epoxy prepolymer, a curing agent and a catalyst, wherein at least one epoxy prepolymer and at least one curing agent both contain aromatic amide structures;
the epoxy prepolymer with the aromatic amide structure is represented by the following structural formula (1) or (2) or a mixed structure thereof:
the R is1、R2Can be any one of the following structures:
2. the cured epoxy resin according to claim 1, wherein the curing agent having an aromatic amide structure is one or more of the following structures:
3. the cured epoxy resin according to claim 2, wherein the catalyst is 2,4, 6-tris (dimethylaminomethyl) phenol, 2,4, 6-tris (dimethylaminomethyl) phenol tris (2-ethylhexanoate), 2,4, 6-tris (dimethylaminomethyl) phenol trioleate, triethylamine, triethanolamine, benzyldimethylamine, o-hydroxybenzyldimethylamine, acetylacetonate, triphenylphosphine and its phosphonium salts, N- (2-hydroxyphenyl) -N ', N ' -dimethylurea, N- (2-hydroxy-4-nitrophenyl) -N ', N ' -dimethylurea, N- (2-hydroxy-5-nitrophenyl) -N ', N ' -dimethylurea, N- (4-chloro-2-hydroxyphenyl) -N ', one or more of N ' -dimethylurea, N- (5-chloro-2-hydroxyphenyl) -N ', N ' -dimethylurea, N- (3, 5-dimethyl-2-hydroxyphenyl) -N ', N ' -dimethylurea, N- (4-chloro) -N ', N ' -dimethylurea, imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-ethylimidazole, 1-aminoethyl-2-methylimidazole, imidazoline, and benzoyl peroxide.
4. The cured epoxy resin according to claim 1,2 or 3, wherein the ratio of the epoxy prepolymer to the curing agent is a stoichiometric ratio of the reactive groups, and the amount of the catalyst is 0.1 to 5 wt% based on the total mass.
5. The method for producing a cured epoxy resin according to claim 1,2, 3 or 4, comprising the steps of:
(1) heating, melting and mixing the components uniformly, pouring the mixture into a mold for degassing, or dissolving all or part of the components in a solvent for uniformly mixing, pouring the mixture into the mold for degassing, drying the solvent, or grinding the components into powder and spraying the powder by a spray gun;
(2) precuring for 5 min-12 h at 60-150 ℃, and further post-curing for 10 min-6 h at 150-250 ℃ to obtain the cured epoxy resin.
6. The method according to claim 5, wherein the pre-curing conditions are as follows: precuring for 0.5-2 h at 100-150 ℃; the post-curing conditions were: curing at 160-210 ℃ for 0.5-2 h.
7. The method according to claim 6, wherein the pre-curing conditions are as follows: precuring for 1-2 h at 120-130 ℃; the post-curing conditions were: curing for 1-2 h at 180-200 ℃.
8. The production method according to claim 5, 6 or 7, wherein the solvent is N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, tetrahydrofuran, benzene, toluene, xylene, ethanol, butanol, isobutanol, cyclohexanone, methylcyclohexanone, acetone, butanone, ethyl acetate, butyl acetate, cellosolve.
Technical Field
The invention relates to the field of thermosetting high polymer materials, in particular to an intrinsic heat-conducting epoxy resin cured material and a preparation method thereof.
Background
Thermosetting resins and composite materials thereof have been widely used in high-tech fields such as aerospace, transportation, electronic packaging and the like. With the continuous development of the technology, the requirements of light weight and miniaturization of scientific and technical products are increasing day by day, and the trend that a high polymer original piece replaces a metal element is developed, so that the problems of heat dissipation, flammability, thermal stability and the like need to be solved more effectively, particularly, the thermal conductivity of common thermosetting resin is generally low, and the development of the thermosetting resin in various fields is severely restricted. The heat-conducting polymer prepared by filling high-heat-conductivity particles has been industrially applied, and has the advantages of low cost, simple and convenient processing, suitability for industrial production and the like, but the mechanical property of the heat-conducting polymer is seriously deteriorated due to higher filling amount of the particles, and the improvement of the heat conductivity is limited. Research and theoretical calculation show that improving the thermal conductivity of the composite material by improving the matrix resin is far more effective than improving the thermal conductivity of the heat conducting particles. The existing thermosetting resin is difficult to meet the requirements of high heat conductivity, high heat-resistant temperature, easy processing and the like.
Disclosure of Invention
The invention aims to provide a thermosetting high polymer material with high thermal conductivity, and simultaneously an aromatic amide structure is introduced into a cured product through an epoxy prepolymer and a curing agent, a local microcosmic ordered structure is introduced into an epoxy resin curing network by utilizing the strong interaction of hydrogen bonds generated by amide bonds between molecular chains to increase the phonon propagation free path, and the prepared resin has higher thermal conductivity, and simultaneously keeps the performances of high heat-resistant temperature, good mechanical strength and the like.
The invention also aims to provide a preparation method of the intrinsic heat-conducting epoxy resin containing the aromatic amide structure.
The purpose of the invention is realized by the following technical scheme:
an intrinsic heat-conducting epoxy resin cured product is formed by curing an epoxy prepolymer, a curing agent and a catalyst, wherein at least one epoxy prepolymer and at least one curing agent both contain aromatic amide structures;
the structure of the other epoxy prepolymer used in combination with the epoxy prepolymer containing aromatic amide structure is not limited, and the following can be exemplified: diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl 1, 2-epoxycyclohexane-4, 5-dicarboxylate, diglycidyl endomethyltetrahydrophthalate, triglycidyl trimesate, 4' -diaminodiphenylmethane glycidyl ether, dimethylhydantoin glycidyl ether, bisphenol a glycidyl ether, polyphenol type glycidyl ether, and the like.
The epoxy prepolymer with the aromatic amide structure is represented by the following structural formula (1) or (2) or a mixed structure thereof:
the R is1、R2Can be any one of the following structures:
preferably, the curing agent having an aromatic amide structure is any one or more of the following structures:
the structure of other types of curing agents used in combination with the curing agent containing an aromatic amide structure is not limited, and the following can be exemplified: p-aminobenzoate, di-p-aminophenyl terephthalate, bis (p-aminobenzoic acid) -1, 5-naphthalenediester, bis (4-aminophenyl) -5- (4-aminobenzoyl) isophthalate, p-phenylenediamine, m-phenylenediamine, 4' -diaminodiphenyl ether, 3,4' -diaminodiphenyl ether, 4' -diaminobenzophenone, 4' -diaminodiphenyl sulfone, 3,4' -diaminodiphenyl sulfone, 4' -diaminodiphenylmethane, 4' - (9-fluorenylidene) diphenylamine, benzidine, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis [4- (4-aminophenoxy) benzene) ] hexafluoropropane, and mixtures thereof, Bis [4- (4-aminophenoxy) phenyl ] sulfone, 4' -bis (4-aminophenoxy) bis, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, dicyandiamide, aliphatic amine, alicyclic amine, boron trifluoride-amine complex, and the like.
Preferably, the catalyst is 2,4, 6-tris (dimethylaminomethyl) phenol, 2,4, 6-tris (dimethylaminomethyl) phenol tris (2-ethylhexanoate) salt, 2,4, 6-tris (dimethylaminomethyl) phenol trioleate, triethylamine, triethanolamine, benzyldimethylamine, o-hydroxybenzyldimethylamine, acetylacetonate, triphenylphosphine and its phosphonium salt, N- (2-hydroxyphenyl) -N ', N ' -dimethylurea, N- (2-hydroxy-4-nitrophenyl) -N ', N ' -dimethylurea, N- (2-hydroxy-5-nitrophenyl) -N ', N ' -dimethylurea, N- (4-chloro-2-hydroxyphenyl) -N ', one or more of N ' -dimethylurea, N- (5-chloro-2-hydroxyphenyl) -N ', N ' -dimethylurea, N- (3, 5-dimethyl-2-hydroxyphenyl) -N ', N ' -dimethylurea, N- (4-chloro) -N ', N ' -dimethylurea, imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-ethylimidazole, 1-aminoethyl-2-methylimidazole, imidazoline, and benzoyl peroxide.
Preferably, the proportion of the epoxy prepolymer to the curing agent is the stoichiometric ratio of the reactive groups, and the amount of the catalyst is 0.1-5 wt% of the total mass.
The preparation method of the cured epoxy resin comprises the following steps:
(1) heating, melting and mixing the components uniformly, pouring the mixture into a mold for degassing, or dissolving all or part of the components in a solvent for uniformly mixing, pouring the mixture into the mold for degassing, drying the solvent, or grinding the components into powder and spraying the powder by a spray gun;
(2) precuring for 5 min-12 h at 60-150 ℃, and further post-curing for 10 min-6 h at 150-250 ℃ to obtain the cured epoxy resin.
Preferably, the conditions of the pre-curing are: precuring for 0.5-2 h at 100-150 ℃; the post-curing conditions were: curing at 160-210 ℃ for 0.5-2 h.
Preferably, the conditions of the pre-curing are: precuring for 1-2 h at 120-130 ℃; the post-curing conditions were: curing for 1-2 h at 180-200 ℃.
Preferably, the solvent is N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, tetrahydrofuran, benzene, toluene, xylene, ethanol, butanol, isobutanol, cyclohexanone, methylcyclohexanone, acetone, butanone, ethyl acetate, butyl acetate, cellosolve.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the intrinsic heat-conducting epoxy resin condensate prepared by introducing the aromatic amide structure into the condensate through the epoxy prepolymer and the curing agent has excellent heat-conducting, mechanical and heat-resisting properties: the thermal conductivity of the cured epoxy resin can reach 0.36-0.51W/(m.K); the tensile strength, the modulus and the elongation at break can respectively reach 86.5-97.8 MPa, 3.6-4.5 GPa and 4.3-6.7 percent; the bending strength can reach 147.5-163.7 MPa; the glass transition temperature is 205-226 ℃, and the 5% decomposition temperature is 325-359 ℃. Can be used as an advanced composite material thermosetting resin matrix.
(2) The intrinsic heat-conducting epoxy resin condensate prepared by the invention has an arbitrarily adjustable structure, and the preparation method is simple and is easy for large-scale production.
Drawings
FIG. 1 is an infrared spectrum of an intrinsically thermal conductive epoxy resin prepared in example 1 of the present invention.
Detailed Description
The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.
Example 1
45.1g of 4, 4-diaminobenzanilide glycidyl ether22.7g of 4, 4-diaminobenzanilideAnd 0.2g of 2-ethyl-4-methylimidazole in 100mL of N, N-dimethylformamide, pouring into a mold, degassing, and drying the solvent. Precuring for 1h at 120 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. FIG. 1 is an infrared spectrum of an intrinsically thermally conductive epoxy. The thermal conductivity was measured according to ISO 22007 standard to be 0.43W/(m.K). The tensile properties were measured according to ASTM D638-14, tensile strength, modulus and elongation at break were 95.3MPa, 4.1GPa and 5.1%, respectively; flexural properties were measured according to ASTM D790-10 with a flexural strength of 151.6 MPa; the glass transition temperature of the resin was 205 ℃ and the initial decomposition temperature was 325 ℃.
Comparative example 1
50g of bisphenol A glycidyl ether NPEL-128After preheating at 80 ℃ 12.5g of 4,4' -diaminodiphenylmethane are addedAnd 0.1g of 2-ethyl-4-methylimidazole, stirred for about 15min to form a homogeneous solution, degassed, and then cast in a mold preheated at 100 ℃. CuringThe procedure is as follows: 100 ℃, 1h, 150 ℃ and 2h, and naturally cooling to room temperature after solidification. The thermal conductivity is 0.19W/(m.K), the tensile strength, the modulus and the elongation at break are 85.7MPa, 2.9GPa and 6.5 percent respectively, the bending strength is 114.2MPa, the glass transition temperature of the resin is 211 ℃, and the initial decomposition temperature is 374 ℃.
Example 2
22.6g of 3, 3-diaminobenzanilide glycidyl ether22.6g of 3, 4-diaminobenzanilide glycidyl ether11.4g of 4, 4-diaminobenzanilide17.3g N, N' -bis (4-aminophenyl) terephthalamideAnd 0.3g of 2,4, 6-tris (dimethylaminomethyl) phenol in 150mL of N-methylpyrrolidone, poured into a mold, degassed and the solvent dried. Precuring for 1h at 120 ℃, post-curing for 1h at 200 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.51W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 90.5MPa, 4.5GPa and 4.3 percent, the bending strength is 163.7MPa, the glass transition temperature of the resin is 223 ℃, and the initial decomposition temperature is 356 ℃.
Comparative example 2
22.6g of 3, 3-diaminobenzanilide glycidyl ether22.6g of 3, 4-diaminobenzanilide glycidyl ether19.8g of 4,4' -diaminodiphenylmethaneAnd 0.3g of 2,4, 6-tris (dimethylaminomethyl) phenol in 150mL of N-methylpyrrolidone, poured into a mold, degassed and the solvent dried. Precuring for 1h at 120 ℃, post-curing for 1h at 200 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.22W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 84.7MPa, 4.3GPa and 4.6 percent, the bending strength is 160.3MPa, the glass transition temperature of the resin is 207 ℃, and the initial decomposition temperature is 364 ℃.
Example 3
17.1g of 4-hydroxy-N- (4-hydroxyphenyl) benzamide glycidyl etherAnd 16.3g of diglycidyl 1, 2-epoxycyclohexane-4, 5-dicarboxylateHeating to 80 deg.C, adding 11.4g of 4, 4-diaminobenzanilide4.2g dicyandiamideAnd 0.2g N- (2-hydroxyphenyl) -N ', N' -dimethylurea, pouring into a mold, and degassing. Precuring for 1h at 130 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.40W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 97.8MPa, 3.8GPa and 6.7 percent, the bending strength is 153.4MPa, the glass transition temperature of the resin is 214 ℃, and the initial decomposition temperature is 344 ℃.
Comparative example 3
32.6g of 1, 2-epoxycyclohexane-4, 5-dicarboxylic acid diglycidyl esterHeating to 80 deg.C, adding 11.4g of 4, 4-diaminobenzanilide4.2g dicyandiamideAnd 0.2g N- (2-hydroxyphenyl) -N ', N' -dimethylurea, pouring into a mold, and degassing. Precuring for 1h at 130 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.20W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 98.6MPa, 4.1GPa and 6.2 percent, the bending strength is 158.9MPa, the glass transition temperature of the resin is 223 ℃, and the initial decomposition temperature is 351 ℃.
Example 4
57.0g N, N' -bis (4-aminophenyl) terephthalamide glycidyl ether17.3g N, N' -bis (4-aminophenyl) terephthalamide2.7g of p-phenylenediamine5.7g of p-aminobenzoic acid p-aminophenyl esterAnd 0.1g of benzyldimethylamine in 150mL of N, N-dimethylformamide, poured into a mold, degassed and then the solvent was dried. Precuring for 1h at 120 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.39W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 86.5MPa, 4.3GPa and 4.9 percent, the bending strength is 161.3MPa, the glass transition temperature of the resin is 207 ℃, and the initial decomposition temperature is 355 ℃.
Comparative example 4
57.0g N, N' -bis (4-aminophenyl) terephthalamide glycidyl ether8.1g of p-phenylenediamine5.7g of p-aminobenzoic acid p-aminophenyl esterAnd 0.1g of benzyldimethylamine in 150mL of N, N-dimethylformamide, poured into a mold, degassed and then the solvent was dried. Precuring for 1h at 120 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.23W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 78.4MPa, 4.7GPa and 3.6 percent, the bending strength is 168.5MPa, the glass transition temperature of the resin is 224 ℃, and the initial decomposition temperature is 363 ℃.
Example 5
22.6g of 4, 4-diaminobenzanilide glycidyl etherAnd 34g of bisphenol A glycidyl ether NPEL-128Heating to 100 deg.C, adding 11.4g of 4, 4-diaminobenzanilide8.5g of 4,4' -diaminodiphenylmethaneAnd 0.1g of 2-ethyl-4-methylimidazole, pouring into a mold, and degassing. Precuring for 1h at 120 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.36W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 88.5MPa, 3.6GPa and 6.1 percent, the bending strength is 147.5MPa, the glass transition temperature of the resin is 226 ℃, and the initial decomposition temperature is 359 ℃.
Comparative example 5
73.5g of bisphenol A glycidyl ether NPEL-128Heating to 100 deg.C, adding 11.4g of 4, 4-diaminobenzanilide8.5g of 4,4' -diaminodiphenylmethaneAnd 0.1g of 2-ethyl-4-methylimidazole, pouring into a mold, and degassing. Precuring for 1h at 120 ℃, post-curing for 1h at 180 ℃, and naturally cooling to room temperature after curing to obtain the target product. The thermal conductivity is 0.20W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 86.2MPa, 3.0GPa and 6.3 percent, the bending strength is 125.3MPa, the glass transition temperature of the resin is 209 ℃, and the initial decomposition temperature is 366 ℃.
Comparative example 6
22.5g of 4, 4-diaminobenzanilide glycidyl etherAfter preheating at 100 ℃ 12.4g of 4,4' -diaminodiphenyl sulfone are addedAnd 0.1g of 2-ethyl-4-methylimidazole, stirred for about 10min to form a homogeneous solution, degassed, and then cast in a mold preheated at 100 ℃. The curing procedure was: 150 ℃, 1h, 200 ℃, 2h, and naturally cooling to room temperature after solidification. The thermal conductivity is 0.22W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 62.8MPa, 6.6GPa and 4.3 percent, the bending strength is 107.4MPa, the glass transition temperature of the resin is 245 ℃, and the initial decomposition temperature is 357 ℃.
Comparative example 7
50g of bisphenol A glycidyl ether NPEL-128After preheating at 150 ℃ 14.5g of 4, 4-diaminobenzanilide are addedAnd 0.1g of 2-ethyl-4-methylimidazole, stirred for about 20min to form a homogeneous solution, degassed, and then cast in a mold preheated at 100 ℃. The curing procedure was: 150 ℃, 1h, 200 ℃, 2h, and naturally cooling to room temperature after solidification. The thermal conductivity is 0.21W/(m.K), the tensile strength, the modulus and the elongation at break are respectively 78.7MPa, 3.4GPa and 5.1 percent, the bending strength is 126.7MPa, the glass transition temperature of the resin is 223 ℃, and the initial decomposition temperature is 366 ℃.
TABLE 1 thermal conductivity results for intrinsically thermally conductive epoxy resins containing aromatic amide structures
EXAMPLES/COMPARATIVE EXAMPLES
Thermal conductivity (W/(m.K))
Increased proportion (%)
Comparative example 1
0.19
-
Example 1
0.43
126
Comparative example 2
0.22
16
Example 2
0.51
168
Comparative example 3
0.20
5
Example 3
0.40
111
Comparative example 4
0.23
21
Example 4
0.39
105
Comparative example 5
0.20
5
Example 5
0.36
89
Comparative example 6
0.22
16
Comparative example 7
0.21
11
Remarking: the results of comparative example 1 were used as comparison targets.
The results in table 1 show that the thermal conductivity of the intrinsically heat-conductive epoxy resin can be significantly improved by introducing an aromatic amide structure into the cured product through the epoxy prepolymer and the curing agent.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.