METHOD FOR SYNTHESIZING DIHYDROXYL-TERMINATED POLYPHENYLENE OXIDE OLIGOMER

Abstract

Disclosed is a method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer, comprising oxidatively copolymerizing monohydric phenol and dihydric phenol in the presence of a metal-polyethyleneimine complex as a catalyst, to obtain the dihydroxyl-terminated polyphenylene oxide oligomer. The synthesizing method of the present disclosure uses a metal-polyethyleneimine complex as a catalyst, which has a milder catalytic activity, can effectively promote the reaction between the dihydric phenol and the monohydric phenol, increases the hydroxyl content of the product, meanwhile reduces the amount of the residual dihydric phenol monomer in the product, so that the quality of the product can be improved. The dihydroxyl-terminated polyphenylene oxide oligomer prepared can be used as additive and copolymerization block in other thermoplastic plastics, thermoplastic elastomers and thermosetting materials, thereby improving the performances of the material, such as thermal performance, adhesion, mechanical property, chemical resistance, and electrical property.

Claims

1. A method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer, comprising oxidatively copolymerizing monohydric phenol and dihydric phenol in the presence of metal-polyethyleneimine complex as a catalyst, to obtain the dihydroxyl-terminated polyphenylene oxide oligomer; and the structure of the dihydroxyl-terminated polyphenylene oxide oligomer is as shown in formula (I): ##STR00007## wherein, in formula (I), m and n are respectively an integer greater than or equal to 0, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11, or R.sub.12 independently represents a hydrogen atom, an alkyl group, a phenyl group, an alkoxy group, an aminoalkyl group, halogen or a halogenated alkyl group, Y has a structure selected from the following: ##STR00008## or Y is not present, wherein Q.sub.1, Q.sub.2, or Q.sub.3 respectively independently represents a hydrogen atom, an alkyl group or a halogenated alkyl group; the number average molecular weight of the dihydroxyl-terminated polyphenylene oxide oligomer is 800˜8000.

2. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 1, wherein the metal-polyethyleneimine complex is a complex formed from a metal salt and a polyethyleneimine ligand; the metal salt is at least one selected from the group consisting of copper salt, manganese salt, cobalt salt, and iron salt; the polyethyleneimine ligand is at least one selected from the group consisting of linear polyethyleneimine, branched polyethyleneimine, and alkylated polyethyleneimine.

3. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 2, wherein in the metal-polyethyleneimine complex, the number average molecular weight of the polyethyleneimine ligand is 500˜10000.

4. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 2, wherein in the metal-polyethyleneimine complex, the molar ratio of polyethyleneimine ligand to metal is (0.3˜15):1.

5. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 1, wherein the structure of the monohydric phenol is as shown in formula (II): ##STR00009## in the formula (II), R.sub.1, R.sub.2, R.sub.3, or R.sub.4 respectively independently represents a hydrogen atom, an alkyl group, a phenyl group, an alkoxy group, an aminoalkyl group, halogen or a halogenated alkyl group; the structure of the dihydric phenol is as shown in formula (III): ##STR00010## in the formula (III), R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11, or R.sub.12 respectively independently represents a hydrogen atom, an alkyl group, a phenyl group, an alkoxy group, an aminoalkyl group, halogen or a halogenated alkyl group; Y has a structure selected from the following: ##STR00011## or Y is not present, wherein Q.sub.1, Q.sub.2, or Q.sub.3 respectively independently represents a hydrogen atom, an alkyl group or a halogenated alkyl group.

6. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 1, specifically comprising the following steps: 1) in a reaction kettle, dissolving the monohydric phenol and the dihydric phenol in a solvent, adding a solution of the polyethyleneimine ligand and the metal salt, and performing an oxidative copolymerization reaction under the action of an oxidant, to obtain a polymer solution; 2) mixing and reacting the polymer solution obtained in step 1) with a chelating agent solution, then separating and extracting an oil phase product; 3) concentrating and purifying the oil phase product obtained in step 2), to obtain the dihydroxyl-terminated polyphenylene oxide oligomer having the structure of formula (I).

7. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 6, wherein in step 1), the molar ratio of the monohydric phenol to the dihydric phenol is (2˜20):1; the molar ratio of the polyethyleneimine ligand to the monohydric phenol is (0.001˜0.05):1.

8. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 6, wherein in step 1), the solvent is C.sub.6˜C.sub.18 aromatic hydrocarbon, or a mixed solvent of C.sub.6˜C.sub.18 aromatic hydrocarbon and C.sub.1˜C.sub.10 alkyl alcohol; the oxidant is oxygen, air, or a mixed gas composed of oxygen and inert gas.

9. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 7, wherein in step 1), the temperature of the oxidative copolymerization reaction is 20° C.˜60° C.; the time of the oxidative copolymerization reaction is 1 hour˜3 hours.

10. The method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer according to claim 6, wherein in step 2), the chelating agent is at least one selected from the group consisting of nitrilotriacetate and ethylenediaminetetraacetate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 is the infrared spectrum of Example 1.

DETAILED DESCRIPTION

[0047] The content of the present disclosure will be further described in detail below via specific examples. The raw materials used in the examples can be obtained from a conventional commercial way, unless otherwise indicated.

Example 1

[0048] A method for synthesizing dihydroxyl-terminated polyphenylene oxide oligomer, comprised the following steps:

[0049] 1) adding 335.50 g of 2,6-dimethylphenol, 57.00 g of bisphenol A, 779.13 g of toluene and 114.00 g of methanol into a reactor equipped with a reflux condensation unit, stirring until all the monomers were dissolved, then adding 16.50 g of dodecyl polyethyleneimine ligand (M.sub.n=2000) and 6.17 g of the hydrobromic acid solution of cuprous bromide (prepared freshly by using 0.45 g of cuprous oxide and 5.72 g of 48% hydrobromic acid), mixing well, then passing oxygen (flow rate was 200 sccm), and reacting at 40° C. for 150 minutes;

[0050] 2) adding the polymer solution after completion of the reaction into 50.81 mL of 10% nitrilotriacetic acid trisodium salt solution, reacting at 70° C. for 60 minutes, and then subjecting to liquid-liquid centrifugation to remove the water phase;

[0051] 3) concentrating the oil phase obtained by centrifugation in step 2) to about 900 mL, adding 9000 mL of methanol, precipitating out, filtering, washing 3 times with methanol, and drying under vacuum at 80° C. overnight, to obtain the dihydroxyl-terminated polyphenylene oxide oligomer of Example 1.

Example 2

[0052] A method for synthesizing the dihydroxyl-terminated polyphenylene oxide oligomer, comprised the following steps:

[0053] 1) adding 305.00 g of 2,6-dimethylphenol, 47.33 g of tetramethylbisphenol A, 942.62 g of toluene and 94.00 g of methanol into a reaction kettle equipped with a reflux condensation unit, stirring until all the monomers were dissolved, then adding 12.53 g of branched polyethyleneimine ligand (M.sub.n=600) and 4.11 g of the hydrobromic acid solution of cuprous bromide (prepared freshly by using 0.30 g of cuprous oxide and 3.81 g of 48% hydrobromic acid), mixing well, then passing oxygen (the flow rate was 200 sccm), and reacting at 40° C. for 150 minutes;

[0054] 2) adding the polymer solution after completion of the reaction into 33.87 mL of 10% nitrilotriacetic acid trisodium salt solution, reacting at 70° C. for 60 minutes, and then subjecting to liquid-liquid centrifugation to remove the water phase;

[0055] 3) concentrating the oil phase obtained by centrifugation in step 2) to about 900 mL, adding 9000 mL of methanol, precipitating out, filtering, washing 3 times with methanol, and drying under vacuum at 80° C. overnight, to obtain the dihydroxyl-terminated polyphenylene oxide oligomer of Example 2.

Example 3

[0056] A method for synthesizing the dihydroxyl-terminated polyphenylene oxide oligomer, comprised the following steps:

[0057] 1) adding 341.60 g of 2,6-dimethylphenol, 80.00 g of bisphenol F, 801.26 g of toluene and 160.00 g of methanol into a reaction kettle equipped with a reflux condensation unit, stirring until all the monomers were dissolved, then adding 16.85 g of linear polyethyleneimine ligand (M.sub.n=1200) and 5.22 g of the hydrochloric acid solution of cuprous chloride (prepared freshly by using 0.60 g cuprous oxide and 4.62 g 37% hydrochloric acid), mixing well, then passing oxygen (the flow rate was 200 sccm), and reacting at 45° C. for 150 minutes;

[0058] 2) adding the polymer solution after completion of the reaction into 33.87 mL of 20% nitrilotriacetic acid trisodium salt solution, reacting at 70° C. for 60 minutes, and then subjecting to liquid-liquid centrifugation to remove the water phase;

[0059] 3) concentrating the oil phase obtained by centrifugation in step 2) to about 900 mL, adding 9000 mL of methanol, precipitating out, filtering, washing 3 times with methanol, and drying under vacuum at 80° C. overnight, to obtain the dihydroxyl-terminated polyphenylene oxide oligomer of Example 3.

Example 4

[0060] A method for synthesizing the dihydroxyl-terminated polyphenylene oxide oligomer, comprised the following steps:

[0061] 1) adding 325.00 g of 2,6-dimethylphenol, 76.00 g of bisphenol A, 767.02 g of toluene and 152.00 g of methanol into a reaction kettle equipped with a reflux condensation unit, stirring until all the monomers were dissolved, then adding 15.33 g of branched polyethyleneimine ligand (M.sub.n=800) and 6.17 g of the hydrobromic acid solution of cuprous bromide (prepared freshly by using 0.45 g of cuprous oxide and 5.72 g of 48% hydrobromic acid), mixing well, then passing oxygen (flow rate was 200 sccm), and reacting at 45° C. for 150 minutes;

[0062] 2) adding the polymer solution after completion of the reaction into 50.25 mL of 20% ethylenediaminetetraacetic acid tetrasodium salt solution, reacting at 70° C. for 60 minutes, and then subjecting to liquid-liquid centrifugation to remove the water phase;

[0063] 3) concentrating the oil phase obtained by centrifugation in step 2) to about 900 mL, adding 9000 mL of methanol, precipitating out, filtering, washing 3 times with methanol, and drying under vacuum at 80° C. overnight, to obtain the dihydroxyl-terminated polyphenylene oxide oligomer of Example 4.

Comparative Example 1

[0064] The dodecyl polyethyleneimine ligand of Example 1 was changed to N,N-dimethyl n-butylamine with an equimolar N content, and the other materials and reaction conditions remained unchanged.

Comparative Example 2

[0065] The branched polyethyleneimine ligand of Example 2 was changed to di-n-butylamine with an equimolar N content, and the other materials and reaction conditions remained unchanged.

[0066] FIG. 1 showed the infrared spectrum of the dihydroxyl-terminated polyphenylene oxide oligomer of Example 1. In FIG. 1, 1305 cm.sup.−1, 1188 cm.sup.−1, 1020 cm.sup.−1 were the characteristic absorption peaks of benzene ring C—O vibration; 1603 cm.sup.−1 and 1470 cm.sup.−1 were the characteristic absorption peaks of stretching vibration of benzene ring skeleton C═C; 2963 cm.sup.−1 and 2856 cm.sup.−1 were the characteristic absorption peak of stretching vibration of methyl C—H on the benzene ring; 1379 cm.sup.−1 was the characteristic absorption peak of flexural vibration of methyl C—H on the benzene ring, and 857 cm.sup.−1 was the characteristic absorption peak of flexural vibration of C—H on the benzene ring. The infrared spectrum was consistent with the standard infrared spectrum of polyphenylene oxide, indicating that the method of the present disclosure can be used to effectively prepare the polyphenylene oxide products.

[0067] Table 1 showed the performance testing results of the polyphenylene oxide products obtained in Examples 1˜4 and Comparative Examples 1˜2.

TABLE-US-00001 TABLE 1 The performance testing results of the polyphenylene oxide products obtained in Examples 1~4 and Comparative Examples 1~2 Number average Glass Residual monomer Intrinsic molecular transition Hydroxyl hydroxyl- (wt %) Example viscosity weight temperature equivalent terminated Dihydric Monohydric No. (dl/g) (g/mol) (° C.) (g/mol) functionality phenol phenol Example 1 0.09 1600 140 845 1.89 1.5 <0.05 Example 2 0.10 2100 145 1080 1.94 0.8 <0.05 Example 3 0.06 1050 115 580 1.81 1.9 <0.05 Example 4 0.07 1200 125 630 1.90 1.1 <0.05 Comparative 0.10 1950 150 1050 1.86 8.7 <0.05 Example 1 Comparative 0.11 2150 155 1130 1.90 2.5 <0.05 Example 2

[0068] It could be seen from the testing results, the polyphenylene oxide product prepared by the present disclosure had a low molecular weight, an intrinsic viscosity of less than 0.10 dl/g, and a hydroxyl-terminate functionality of greater than 1.8, indicating that the method of the present disclosure can be used to effectively prepare dihydroxyl-terminated polyphenylene oxide oligomer. Moreover, compared with the metal-small molecule ligand catalyst system, by using a metal-polyethyleneimine complex as a catalyst, the amount of the residual dihydric phenol monomer in the product was significantly reduced.

[0069] The polyphenylene oxide product prepared by the present disclosure had low number average molecular weight, high hydroxyl functionality, and less dihydric phenol monomer residue, and could be used as additives and copolymer blocks for various thermoplastics, thermoplastic elastomers and thermosetting materials, thereby improving the performances of materials, such as the thermal properties, adhesion, mechanical property, chemical resistance and electrical property. The polyphenylene oxide product prepared by the present disclosure can be widely used in the fields such as electronics and electrical, automobile industries, and machinery manufacturing.

[0070] The above-mentioned examples are only used to assist understanding the method and core idea of the present disclosure. The embodiments of the present disclosure are not limited to the above-mentioned examples, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present disclosure should all be equivalent replacements, and they are all included in the protection scope of the present disclosure.