Hyperbranched polyamide, composite membrane and preparation method

Abstract

The invention discloses hyperbranched polyamide, a composite membrane and a preparation method. Polymerized monomers of the hyperbranched polyamide include: a first monomer selected from alkyl compounds with a carbon atom number not less than 10, one of terminal groups and non-terminal groups each containing at least one functional group, the functional groups including but not limited to amido, hydroxyl and / or carboxyl; and the second monomer is selected from adipic acid or hexamethylenediamine. The hyperbranched polyamide has relatively high glass transition temperature and good cohesiveness; no organic solvent is used in preparation of the polymer and the composite membrane, so that pollution and process procedures are reduced, and the mechanical property is excellent.

Description

Technical Field

[0001] The invention belongs to the field of new polymer materials, and specifically relates to a hyperbranched polyamide, a composite film and a preparation method. Background Art

[0002] As one of the engineering plastics in my country, polyamide has the advantages of light weight, oil resistance, good dimensional stability, etc., and its application field has been continuously expanded in recent years. However, in the fields of anti-corrosion coatings, adhesives, membrane materials, composite materials, etc., polyamide is required to be more resistant to organic solvents and have excellent mechanical properties. Polyamide cross-linking is a commonly used method. At present, CN1293214A uses a diisocyanate with high toxicity as a chain extender, which will seriously limit its application. In US10384172B2, a cross-linked polyamide composite film is formed by an infiltration method, which will also cause certain pollution to the environment.

[0003] The following problems exist in the prior art:

[0004] (1) Monomers that produce cross-linking reactions in polyamides can cause pollution;

[0005] (2) The method of cross-linking reaction of polyamide is complicated. Summary of the invention

[0006] In order to improve the above technical problems, the present invention provides a hyperbranched polyamide, wherein the polymerization monomers include:

[0007] The first monomer is selected from an alkyl compound having not less than 10 carbon atoms and having at least one functional group in one of the terminal groups and the non-terminal groups;

[0008] The functional groups include, but are not limited to, amine, hydroxyl and / or carboxyl groups;

[0009] The second monomer is selected from adipic acid or hexamethylenediamine.

[0010] According to an embodiment of the present invention, the number of carbon atoms of the alkyl compound may be 10 to 30, for example 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29.

[0011] According to an embodiment of the present invention, the sum of the masses of the first monomer and the second monomer is calculated as 100 parts, and the mass ratio of the first monomer to the second monomer is (30-99):(1-70), preferably (30-90):(10-70), for example 30:70, 50:50, 70:30, 90:10.

[0012] According to an embodiment of the present invention, both terminal groups may contain at least one functional group; when the two terminal groups are amine groups, the alkyl compound is an alkyl diamine; when the two terminal groups are carboxyl groups, the alkyl compound is an alkyl diacid.

[0013] According to an embodiment of the present invention, the non-terminal group may contain one, two, three or more functional groups, and preferably the non-terminal functional groups are distributed in the middle section of the alkyl chain, ie, the 1 / 3 to 2 / 3 segment of carbon atoms.

[0014] According to an embodiment of the present invention, the functional groups on the terminal groups are the same as or different from the functional groups on the non-terminal groups.

[0015] According to an embodiment of the present invention, when the non-terminal group contains two or more functional groups, each functional group may be the same or different.

[0016] According to an embodiment of the present invention, when the terminal group contains two or more functional groups, each functional group may be the same or different.

[0017] According to an embodiment of the present invention, the two terminal groups each contain a functional group a, and the non-terminal group contains two functional groups b; the functional groups a and b are the same or different;

[0018] In one embodiment, the functional group a is an amine group, and the functional group b is an amine group, a hydroxyl group, or a carboxyl group;

[0019] In one embodiment, the functional group a is a carboxyl group, and the functional group b is an amine group, a hydroxyl group or a carboxyl group.

[0020] According to one embodiment of the present invention, the first monomer is selected from an alkyl compound having 10 to 30 carbon atoms, two terminal groups each containing one functional group a and non-terminal groups containing two functional groups b;

[0021] Illustratively, the first monomer is selected from at least one of 9,10-diaminooctadecanediamine, 9,10-dihydroxyoctadecanedioic acid, and 9,10-dicarboxyoctadecanedioic acid.

[0022] According to an exemplary embodiment of the present invention, the polymerization monomer of the hyperbranched polyamide is selected from any one of the following combinations:

[0023] 9,10-Diaminooctadecanediamine and adipic acid;

[0024] 9,10-Dihydroxyoctadecane dioic acid and hexamethylenediamine;

[0025] Alternatively, 9,10-dicarboxyoctadecanediolic acid and hexamethylenediamine.

[0026] According to an embodiment of the present invention, based on the hyperbranched polyamide, the end group content thereof is higher than 0.5 mmol / g.

[0027] The present invention also provides a method for preparing the hyperbranched polyamide, comprising: a first monomer and a second monomer are polymerized to obtain the hyperbranched polyamide;

[0028] The first monomer and the second monomer have the definitions shown above.

[0029] According to an embodiment of the present invention, the polymerization reaction is carried out under an inert atmosphere.

[0030] According to an embodiment of the present invention, the polymerization reaction is carried out under negative pressure conditions.

[0031] According to an embodiment of the present invention, the preparation method comprises:

[0032] (1) adding a first monomer and a second monomer into a reaction kettle, wherein the reaction kettle is filled with an inert atmosphere;

[0033] (2) heating the reaction vessel so that the temperature reaches 210 to 250° C. (e.g., 220 to 240° C.) and the pressure reaches 2.2 to 2.7 MPa (e.g., 2.4 to 2.6 MPa);

[0034] (3) After 30 to 60 minutes (e.g., 40 to 50 minutes), the pressure is reduced to atmospheric pressure, and at the same time, the temperature in the reactor is raised to 270 to 290° C. (e.g., 275 to 285° C.);

[0035] (4) evacuating the reactor, maintaining the temperature of the reactor at 270-280° C., and evacuating the reactor until the pressure is less than 0 (for example, the pressure is −0.06 MPa), thereby obtaining the hyperbranched polyamide.

[0036] According to an embodiment of the present invention, no auxiliary agent is required in the preparation method of the hyperbranched polyamide, for example, no chain extender such as diisocyanate is required.

[0037] The present invention also provides application of the hyperbranched polyamide in preparing a polyamide composite membrane.

[0038] According to an embodiment of the present invention, the glass transition temperature of the polyamide composite film is not lower than 24°C, preferably not lower than 26°C, for example, 26-60°C.

[0039] According to an embodiment of the present invention, the tensile strength of the polyamide composite film is not less than 55 MPa, preferably not less than 60 MPa, for example, 60 to 120 MPa.

[0040] The present invention also provides a polyamide composite membrane, which is obtained by placing the above-mentioned hyperbranched polyamide between two layers of polyamide 66 (ie, a polymer of hexamethylenediamine and adipic acid) membranes and performing hot pressing molding.

[0041] According to an embodiment of the present invention, the glass transition temperature of the polyamide composite film is not lower than 24°C, preferably not lower than 26°C, for example, 26-60°C.

[0042] According to an embodiment of the present invention, the tensile strength of the polyamide composite film is not less than 55 MPa, preferably not less than 60 MPa, for example, 60 to 120 MPa.

[0043] The present invention also provides a method for preparing the polyamide composite membrane, comprising: placing the hyperbranched polyamide between two layers of polyamide 66 membranes, and performing hot pressing to obtain the polyamide composite membrane.

[0044] According to an embodiment of the present invention, the temperature of the hot pressing molding is 260-300°C, such as 270-290°C.

[0045] In the present application, the hyperbranched polyamide may also be referred to as a (highly) cross-linked polymer, and the composite membrane may also be referred to as a (highly) cross-linked composite membrane.

[0046] Beneficial Effects

[0047] The hyperbranched (highly cross-linked) polyamide provided by the present invention has many branching points, the molecular chains are not easily entangled, and have abundant terminal functional groups, which are easy to be modified. Moreover, as an intermediate layer, it is easy to combine with the polyamide of the outer layer to form a close composite layer structure.

[0048] Specifically, the highly cross-linked polymer generated by the polymerization reaction has a high glass transition temperature and good adhesion; and the preparation of the polymer and the composite film does not use organic solvents, which reduces pollution and process procedures, and has excellent mechanical properties. DETAILED DESCRIPTION

[0049] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0050] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. The first monomers A, B and C can be prepared according to the method disclosed in the document Zhao, Kang, et al. "A biphosphine copolymer encapsulated single-site Rh catalyst for heterogeneous regioselective hydroaminomethylation of alkenes." Chemical Communications, 58 (2022): 8093-8096. For example, the first monomer A is catalytically aminized by octadecane diamine, the first monomer B is catalytically oxidized by octadecane dicarboxylic acid or further oxidized by the first monomer A, and the first monomer C is catalytically oxidized by octadecane dicarboxylic acid.

[0051]

[0052] First monomer A (9,10-diaminooctadecanediamine)

[0053]

[0054] First monomer B (9,10-dihydroxyoctadecane dioic acid)

[0055]

[0056] First monomer C (9,10-dicarboxy octadecane dioic acid)

[0057] When preparing the composite membranes in the various embodiments and comparative examples, the polyamide 66 membranes used were the same.

[0058] Example 1

[0059] 1. Polymerization: The first monomer A and the second monomer adipic acid are added into a high-temperature and high-pressure reactor in a mass ratio of 70:30. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GA with an end group content higher than 0.5 mmol / 1g.

[0060] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GA between two layers of polyamide 66 film, and hot press mold it.

[0061] Example 2

[0062] 1. Polymerization: The first monomer A and the second monomer adipic acid are added into a high-temperature and high-pressure reactor in a mass ratio of 50:50. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GA with an end group content higher than 0.5 mmol / 1g.

[0063] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GA between two layers of polyamide 66 film, and hot press mold it.

[0064] Example 3

[0065] 1. Polymerization: The first monomer A and the second monomer adipic acid are added into a high-temperature and high-pressure reactor in a mass ratio of 30:70. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GA with an end group content higher than 0.5 mmol / 1g.

[0066] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GA between two layers of polyamide 66 film, and hot press mold it.

[0067] Example 4

[0068] 1. Polymerization: The first monomer B and the second monomer hexamethylenediamine are added into a high-temperature and high-pressure reactor in a mass ratio of 70:30. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GB with an end group content higher than 0.5 mmol / 1g.

[0069] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GB between two layers of polyamide 66 film, and hot press mold it.

[0070] Example 5

[0071] 1. Polymerization: The first monomer B and the second monomer hexamethylenediamine are added into a high-temperature and high-pressure reactor in a mass ratio of 50:50. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GB with an end group content higher than 0.5 mmol / 1g.

[0072] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GB between two layers of polyamide 66 film, and hot press mold it.

[0073] Example 6

[0074] 1. Polymerization: The first monomer B and the second monomer hexamethylenediamine are added into a high-temperature and high-pressure reactor in a mass ratio of 30:70. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GB with an end group content higher than 0.5 mmol / 1g.

[0075] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GB between two layers of polyamide 66 film, and hot press mold it.

[0076] Example 7

[0077] 1. Polymerization: The first monomer C and the second monomer hexamethylenediamine are added into a high-temperature and high-pressure reactor in a mass ratio of 70:30. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GC with an end group content higher than 0.5 mmol / 1g.

[0078] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GC between two layers of polyamide 66 film, and hot press mold it.

[0079] Example 8

[0080] 1. Polymerization: The first monomer C and the second monomer hexamethylenediamine are added into a high-temperature and high-pressure reactor in a mass ratio of 50:50. After three positive and negative pressure replacements, the reactor contains 0.04 MPa of nitrogen. The temperature is heated to 230°C and the pressure is 2.5 MPa. After 40 minutes, the pressure is reduced to atmospheric pressure, and the temperature is raised to 280°C, and vacuumed. The temperature is maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GC with an end group content higher than 0.5 mmol / 1g.

[0081] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GC between two layers of polyamide 66 film, and hot press mold it.

[0082] Example 9

[0083] 1. Polymerization: The modified monomer C and the second monomer hexamethylenediamine were added into a high-temperature and high-pressure reactor in a mass ratio of 30:70. After three positive and negative pressure replacements, the reactor contained 0.04 MPa of nitrogen. The temperature was heated to 230°C and the pressure reached 2.5 MPa. After 40 minutes, the pressure was reduced to atmospheric pressure, and the temperature was raised to 280°C, and vacuumed. The temperature was maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GC with an end group content higher than 0.5 mmol / 1g.

[0084] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GC between two layers of polyamide 66 film, and hot press mold it.

[0085] Comparative Example 1

[0086] Preparation of polyamide 66 membrane:

[0087] Preparation of single-layer film: Heat the molding machine to 280°C, place polyamide 66 in a double-layer iron plate mold, isolate it with a polyimide film, maintain the pressure at 2MPa and the temperature at 280°C for 20 minutes, then lower the temperature to room temperature and take out the polyamide 66 single-layer film.

[0088] Preparation of composite film: Place a single layer of polyamide 66 film between two layers of polyamide 66 film and heat press them into shape.

[0089] Comparative Example 2

[0090] Preparation of polyamide 612 composite membrane:

[0091] Preparation of single-layer film: Heat the molding machine to 280°C, place polyamide 612 in a double-layer iron plate mold, separate it with a polyimide film, maintain the pressure at 2MPa and the temperature at 280°C for 20 minutes, then cool the temperature to room temperature and take out the polyamide 612 film.

[0092] Preparation of composite film: Heat the molding machine to 280°C, place the polyamide 612 film between two layers of polyamide 66 film, and heat press to form.

[0093] Comparative Example 3

[0094] Preparation of polyamide 18 composite membrane:

[0095] Preparation of single-layer film: Heat the molding machine to 280°C, place polyamide 18 in a double-layer iron plate mold, separate it with a polyimide film, maintain the pressure at 2MPa and the temperature at 280°C for 20 minutes, then cool the temperature to room temperature and take out the polyamide 18 film.

[0096] Preparation of composite film: Heat the molding machine to 280°C, place the polyamide 18 film between two layers of polyamide 66 film, and perform hot pressing molding.

[0097] Comparative Example 4

[0098] 1. Polymerization: The first monomer C and hexamethylenediamine were added into a high-temperature and high-pressure reactor in a mass ratio of 1:99. After three positive and negative pressure replacements, 0.04 MPa of nitrogen was contained in the reactor. The temperature was heated to 230°C and the pressure was 2.5 MPa. After 40 minutes, the pressure was reduced to atmospheric pressure, and the temperature was raised to 280°C, and vacuumed. The temperature was maintained at 275°C and vacuumed to -0.06 MPa to form a cross-linked polymer GC with an end group content of less than 0.5 mmol / 1g.

[0099] 2. Preparation of high cross-linked composite film: Heat the molding machine to 280°C, place the cross-linked polymer GC between two layers of polyamide 66 film, and hot press mold it.

[0100] The glass transition temperature and tensile strength of the polyamide films prepared in the examples and comparative examples were tested in accordance with ISO 528. The test results are shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] As can be seen from the above table, the present invention prepares a cross-linked polyester amide composite film through three first monomers, wherein the first monomer B exhibits a higher glass transition temperature and excellent active performance due to its relatively active reaction functional group. With the increase of the content of the modified functional group, such as Example 4 to Example 6, the hydrogen bonds between molecules increase, and the glass transition temperature increases accordingly. The better the tensile strength of the prepared polyamide, the better the mechanical properties. This result also appears in Examples 1 to 3 and Examples 7 to 9. In Example 8, it is known that in the case of containing the same length segment content, by comparing the comparative example, it is known that the glass transition temperature and mechanical properties of the comparative example are not improved.

[0105] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hyperbranched polyamide, characterized in that The polymerization monomers of the hyperbranched polyamide include: The first monomer is selected from an alkyl compound having not less than 10 carbon atoms and having at least one functional group in one of the terminal groups and in the non-terminal groups; The functional groups include, but are not limited to, amine, hydroxyl and / or carboxyl groups; The second monomer is selected from adipic acid or hexamethylenediamine.

2. The hyperbranched polyamide according to claim 1, characterized in that The alkyl compound has 10 to 30 carbon atoms.

3. The hyperbranched polyamide according to claim 1, characterized in that The sum of the masses of the first monomer and the second monomer is based on 100 parts, and the mass ratio of the first monomer to the second monomer is (30-99):(1-70), preferably (30-90):(10-70).

4. The hyperbranched polyamide according to claim 1, characterized in that Both end groups contain at least one functional group; And / or, the non-terminal group contains one, two, three or more functional groups, preferably the non-terminal functional groups are distributed in the middle section of the alkyl chain, ie, the section with 1 / 3 to 2 / 3 carbon atoms.

5. The hyperbranched polyamide according to claim 1, characterized in that The functional group on the terminal group is the same as or different from the functional group on the non-terminal group; and / or, when the non-terminal group contains two or more functional groups, the functional groups are the same or different; And / or, when the terminal group contains two or more functional groups, the functional groups are the same or different.

6. The hyperbranched polyamide according to claim 1, characterized in that The first monomer is selected from an alkyl compound having 10 to 30 carbon atoms, two terminal groups each containing one functional group a and a non-terminal group containing two functional groups b; For example, functional group a is an amine group, and functional group b is an amine group, a hydroxyl group, or a carboxyl group; or, functional group a is a carboxyl group, and functional group b is an amine group, a hydroxyl group, or a carboxyl group; Preferably, the first monomer is selected from at least one of 9,10-diaminooctadecanediamine, 9,10-dihydroxyoctadecanedioic acid and 9,10-dicarboxyoctadecanedioic acid.

7. The hyperbranched polyamide according to claim 1, characterized in that Calculated on the basis of the hyperbranched polyamide, the end group content is higher than 0.5 mmol / g.

8. The method for preparing a hyperbranched polyamide according to any one of claims 1 to 7, characterized in that: The preparation method comprises: a first monomer and a second monomer are polymerized to obtain the hyperbranched polyamide; Preferably, the preparation method comprises: (1) adding a first monomer and a second monomer into a reaction kettle, wherein the reaction kettle is filled with an inert atmosphere; (2) heating the reactor so that the temperature reaches 210-250° C. and the pressure reaches 2.2-2.7 MPa; (3) After 30 to 60 minutes, the pressure is reduced to atmospheric pressure, and at the same time, the temperature in the reactor is raised to 270 to 290° C.; (4) evacuating the reactor, maintaining the temperature of the reactor at 270-280° C., and evacuating the reactor until the pressure is less than 0 to obtain the hyperbranched polyamide.

9. A polyamide composite membrane, characterized in that: The polyamide composite membrane is obtained by placing the hyperbranched polyamide according to any one of claims 1 to 7 between two layers of polyamide 66 membranes and hot pressing; Preferably, the glass transition temperature of the polyamide composite film is not less than 24° C., and / or the tensile strength of the polyamide composite film is not less than 55 MPa.

10. The method for preparing the polyamide composite membrane according to claim 9, characterized in that: The preparation method comprises: placing the hyperbranched polyamide between two layers of polyamide 66 films, and performing hot pressing to obtain the polyamide composite film.

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