Polyimide modified by polyethyleneimine and preparation process thereof

Abstract

The invention discloses polyethyleneimine modified polyimide and a preparation process thereof, and belongs to the technical field of polyimide modified.The preparation process comprises the steps that polyimide is subjected to strong base roughening treatment, polyethyleneimine is modified through glutaraldehyde, phenyltrimethylsilane and diisopropylcarbodiimide, and then polyethyleneimine modified polyimide is obtained; and after the polyimide generates a COO-group, the polyimide and the modified polyethyleneimine are subjected to a cross-linking reaction. The preparation method comprises the following specific steps: 1, performing strong alkali roughening treatment on polyimide to generate a COO-group; 2, carrying out a cross-linking modification reaction on polyethyleneimine and glutaraldehyde to obtain modified polyethyleneimine; and 3, carrying out graft modification on the polyimide subjected to strong base roughening treatment by using modified polyethyleneimine. The modified polyimide material prepared by the invention has relatively high mechanical properties, the tensile strength can reach 138.15 Mpa, and the impact strength is 201.18 KJ / m < 2 >.

Description

Technical Field

[0001] The present invention relates to the technical field of polyimide modification, and particularly relates to a polyimide modified by polyethyleneimine and a preparation process thereof. Background Art

[0002] The polyimide film is a kind of film insulation material, which is widely used in various fields such as aerospace, microelectronics, atomic energy, electrical insulation, liquid crystal display, and membrane separation technology. It is called the "golden film" because of its high price, high technical barriers, and excellent performance. The surface of the polyimide material is smooth and dense, with high chemical inertness and poor hydrophilicity. When metallizing the surface of a polyimide workpiece, active particles cannot be effectively adsorbed, and problems such as poor bonding strength between the metal coating and the polyimide workpiece, such as coating blistering, are likely to occur.

[0003] Polyethyleneimine (PEI), as a water-soluble cationic organic polymer, contains a large number of highly active primary amine groups, and at the same time has high cationicity, good adsorption of metal ions, and outstanding reactivity. It can efficiently chelate specific metal ions, such as Ag + , Cu 2+ , Pb 2+ , etc. in a neutral or alkaline environment.

[0004] Therefore, polyethyleneimine can be used as a graft modifier to modify polyimide (PI) substrates, thereby providing a cationic selective adsorption layer with excellent performance on the surface of the PI substrates.

[0005] However, there is a problem in directly using polyethyleneimine to modify polyimide: the multi-chain structure of polyethyleneimine makes the mechanical properties of the modified layer poor, resulting in the mechanical properties of the polyimide after modification needing to be improved.

[0006] Based on this, the present invention designs a polyimide modified by polyethyleneimine and a preparation process thereof to solve the above problems. Summary of the Invention

[0007] In view of the above-mentioned drawbacks of the prior art, the present invention provides a polyimide modified by polyethyleneimine and a preparation process thereof.

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0009] A preparation process of a polyimide modified by polyethyleneimine. First, the polyimide is subjected to strong alkali roughening treatment, and polyethyleneimine is modified by glutaraldehyde, phenyltrimethylsilane, and diisopropylcarbodiimide. After the polyimide generates COO- groups, a cross-linking reaction is carried out with the modified polyethyleneimine.

[0010] Furthermore, the specific steps include:

[0011] 1. Coarsely treat the polyimide with strong base to generate COO- groups;

[0012] The process of the strong base coarsening treatment: Place the polyimide in the coarsening treatment solution for coarsening treatment. The coarsening treatment solution is an aqueous solution containing NaOH, potassium permanganate, and lauramidopropyl hydroxysulfobetaine;

[0013] 2. Polyethyleneimine and glutaraldehyde undergo a cross-linking modification reaction to obtain modified polyethyleneimine; the specific steps are as follows:

[0014] (1) Take polyethyleneimine, glutaraldehyde, phenyltrimethylsilane, and diisopropylcarbodiimide for standby;

[0015] (2) Drop glutaraldehyde into polyethyleneimine at a dropping rate of 30 - 50 drops / min. After the dropping is completed, continue to stir and react for 5 - 10 min;

[0016] (3) Then cool down to -18 - 0 °C, and drop diisopropylcarbodiimide at a dropping rate of 3 - 5 drops / min. After the dropping is completed, continue to stir and react for 1 - 3 h;

[0017] (4) After heating to 5 - 8 °C, add phenyltrimethylsilane, and oscillate and react at 60 - 200 rpm for 0.5 - 1 h; continue to heat to 40 - 50 °C, and then oscillate and react at 250 - 300 rpm for 1 - 2 h to obtain the modified polyethyleneimine;

[0018] 3. Use the modified polyethyleneimine to graft-modify the polyimide after the strong base coarsening treatment.

[0019] Furthermore, in step 1, the content of NaOH is 480 - 530 g / L.

[0020] Furthermore, in step 1, the content of potassium permanganate is 10 - 17 g / L.

[0021] Furthermore, in step 1, the content of lauramidopropyl hydroxysulfobetaine is 8 - 11 g / L.

[0022] Furthermore, in step 1, the coarsening treatment temperature is 40 - 45 °C, and the treatment time is 5 - 10 min.

[0023] Furthermore, in step 2, the molar ratio of polyethyleneimine: glutaraldehyde: phenyltrimethylsilane: diisopropylcarbodiimide is (11 - 13):(9 - 11):(2.5 - 4):0.2.

[0024] Furthermore, the specific steps of step 3 are as follows:

[0025] (1) Preheat the modified polyethyleneimine to 60 - 100 °C;

[0026] (2) Slowly add the modified polyethyleneimine to the polyimide while stirring.

[0027] Furthermore, in step 3.2, the stirring temperature is 100 - 120 °C, the stirring speed is 200 - 300 rpm, and the stirring time is 1 - 3 h.

[0028] To better achieve the object of the present invention, the present invention also provides a polyimide prepared according to the above - mentioned preparation process.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] In the present invention, polyethyleneimine is used as a graft modifier to modify polyimide, which can provide a cation - selective adsorption layer with excellent performance on the surface of polyimide. When metallizing the surface of polyimide workpieces, it can improve the adsorption efficiency of active particles, ensure the bonding strength between the metal coating and the polyimide workpiece, and can be preferably applied in scenarios such as electroplating / electroless plating.

[0031] In the present invention, polyimide is first subjected to strong - base roughening treatment, and polyethyleneimine is modified with glutaraldehyde, phenyltrimethylsilane, and diisopropylcarbodiimide. After the polyimide generates COO - groups, it undergoes a cross - linking reaction with the modified polyethyleneimine. The prepared modified polyimide material has high mechanical properties, with a tensile strength of up to 138.15 Mpa and an impact strength of 201.18 KJ / m 2 . Description of the Drawings

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is a schematic diagram of the synthesis principle of polyimide. Detailed Embodiments

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0035] Example 1

[0036] Put the polyimide into a roughening treatment solution at 40 °C (480 g / L NaOH, 10 g / L potassium permanganate, 8 g / L lauramidopropyl hydroxysulfobetaine, the rest is water) for roughening treatment for 5 min, and COO- groups are generated on the polyimide; Take 11 mol of polyethyleneimine, 9 mol of glutaraldehyde, 2.5 mol of phenyltrimethylsilane and 0.2 mol of diisopropylcarbodiimide. Drop glutaraldehyde into polyethyleneimine at a dropping rate of 30 drops / min. After dropping, continue stirring and reacting for 5 min; Then cool down to -18 °C, and dropwise add diisopropylcarbodiimide at a dropping rate of 3 drops / min. After dropping, continue stirring and reacting for 1 h; After heating to 5 °C, add phenyltrimethylsilane and shake and react at 60 rpm for 0.5 h; Continue heating to 40 °C and shake and react at 250 rpm for 1 h to obtain modified polyethyleneimine; Preheat the modified polyethyleneimine to 60 °C; Slowly add the modified polyethyleneimine to the polyimide while stirring. The stirring temperature is 100 °C, the stirring speed is 200 rpm, and the stirring time is 1 h.

[0037] Example 2

[0038] Put the polyimide into a roughening treatment solution at 45 °C (530 g / L NaOH, 17 g / L potassium permanganate, 11 g / L lauramidopropyl hydroxysulfobetaine, the rest is water) for roughening treatment for 10 min, and COO- groups are generated on the polyimide; Take 13 mol of polyethyleneimine, 11 mol of glutaraldehyde, 4 mol of phenyltrimethylsilane and 0.2 mol of diisopropylcarbodiimide. Drop glutaraldehyde into polyethyleneimine at a dropping rate of 50 drops / min. After dropping, continue stirring and reacting for 10 min; Then cool down to 0 °C, and dropwise add diisopropylcarbodiimide at a dropping rate of 5 drops / min. After dropping, continue stirring and reacting for 3 h; After heating to 8 °C, add phenyltrimethylsilane and shake and react at 200 rpm for 1 h; Continue heating to 50 °C and shake and react at 300 rpm for 2 h to obtain modified polyethyleneimine; Preheat the modified polyethyleneimine to 100 °C; Slowly add the modified polyethyleneimine to the polyimide while stirring. The stirring temperature is 120 °C, the stirring speed is 300 rpm, and the stirring time is 3 h.

[0039] Example 3

[0040] The polyimide was put into a roughening treatment solution at 42 °C (500 g / L NaOH, 15 g / L potassium permanganate, 9 g / L lauramidopropyl hydroxysulfobetaine, and the rest was water) for roughening treatment for 8 min, and COO- groups were generated on the polyimide. 12 mol of polyethyleneimine, 10 mol of glutaraldehyde, 3 mol of phenyltrimethylsilane, and 0.2 mol of diisopropylcarbodiimide were taken. Glutaraldehyde was added dropwise to polyethyleneimine at a dropping rate of 35 drops / min. After the addition was completed, stirring reaction was continued for 8 min. Then the temperature was lowered to -5 °C, and diisopropylcarbodiimide was added dropwise at a dropping rate of 4 drops / min. After the addition was completed, stirring reaction was continued for 2 h. After the temperature was raised to 7 °C, phenyltrimethylsilane was added, and the reaction was shaken at 100 rpm for 0.7 h. The temperature was further raised to 45 °C, and the reaction was shaken at 280 rpm for 1.6 h to obtain modified polyethyleneimine. The modified polyethyleneimine was preheated to 80 °C. The modified polyethyleneimine was slowly added to the polyimide while stirring. The stirring temperature was 110 °C, the stirring speed was 240 rpm, and the stirring time was 1.6 h.

[0041] Comparative Example 1

[0042] Different from Example 1, 11 mol of polyethyleneimine, 9 mol of glutaraldehyde, 2.5 mol of phenyltrimethylsilane, and 0.4 mol of diisopropylcarbodiimide were taken, and diisopropylcarbodiimide was added dropwise at a dropping rate of 15 drops / min.

[0043] Comparative Example 2

[0044] Different from Example 1, phenyltrimethylsilane was not added.

[0045] Comparative Example 3

[0046] Different from Example 1, after the temperature was raised to 15 °C, phenyltrimethylsilane was added, and the reaction was shaken at 60 rpm for 0.5 h. Then the temperature was further raised to 30 °C, and the reaction was shaken at 250 rpm for 1 h to obtain modified polyethyleneimine.

[0047] Experimental Example

[0048] The modified polyimide materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were put into a flat fluidized bed die to form plates with a size of 4 mm × 150 mm × 108 mm. And the performance was tested (tensile strength GB / T 1040.3 - 2006, impact strength GB / T 1843 - 2008). The results are shown in Table 1.

[0049] Table 1 Performance Test Results

[0050]

[0051] The present invention uses polyethyleneimine as a graft modifier to modify polyimide, which can provide a cation-selective adsorption layer with excellent performance on the surface of polyimide. When metallizing the surface of a polyimide workpiece, it can improve the adsorption efficiency of active particles, ensure the bonding strength between the metal coating and the polyimide workpiece, and can be preferably applied in scenarios such as electroplating / electroless plating.

[0052] Meanwhile, the modified polyimide material of the present invention has high mechanical properties, with a tensile strength of up to 138.15 Mpa and an impact strength of 201.18 KJ / m 2 .

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for preparing polyimide modified by polyethyleneimine, characterized in that: The polyimide is firstly subjected to a strong alkali roughening treatment, and then the polyethyleneimine is modified by using glutaraldehyde, phenyltrimethylsilane and diisopropylcarbodiimide. After the polyimide generates COO- groups, the polyimide undergoes a cross-linking reaction with the modified polyethyleneimine.

2. The process for preparing polyimide modified by polyethyleneimine according to claim 1, characterized in that: The specific steps include:

1. The polyimide is subjected to a strong base roughening treatment to generate COO- groups; Strong alkali roughening treatment process: put the polyimide into a roughening treatment solution for roughening treatment, and the roughening treatment solution is an aqueous solution containing NaOH, potassium permanganate, and lauramide propyl hydroxysulfobetaine; 2. Polyethyleneimine and glutaraldehyde undergo cross-linking modification reaction to obtain modified polyethyleneimine; the specific steps are as follows: (1) taking polyethyleneimine, glutaraldehyde, phenyltrimethylsilane, and diisopropylcarbodiimide and setting aside; (2) adding glutaraldehyde dropwise to polyethyleneimine at a rate of 30 to 50 drops / min, and continuing to stir the reaction for 5 to 10 minutes after the addition is complete; (3) Then, the temperature is lowered to -18 to 0°C, and diisopropylcarbodiimide is added dropwise at a rate of 3 to 5 drops / min. After the addition is completed, the reaction is continued by stirring for 1 to 3 hours; (4) After the temperature is raised to 5-8° C., phenyltrimethylsilane is added, and the mixture is shaken at 60-200 rpm for 0.5-1 h; after the temperature is further raised to 40-50° C., the mixture is shaken at 250-300 rpm for 1-2 h to obtain modified polyethyleneimine; 3. Use modified polyethyleneimine to graft modify the polyimide after strong alkali roughening treatment.

3. The process for preparing polyimide modified by polyethyleneimine according to claim 2, characterized in that: In step 1, the content of NaOH is 480-530 g / L.

4. The process for preparing polyimide modified by polyethyleneimine according to claim 3, characterized in that: In step 1, the content of potassium permanganate is 10-17 g / L.

5. The process for preparing polyimide modified by polyethyleneimine according to claim 4, characterized in that: In step 1, the content of lauramide propyl hydroxysulfobetaine is 8-11 g / L.

6. The process for preparing polyimide modified by polyethyleneimine according to claim 5, characterized in that: In step 1, the roughening treatment temperature is 40-45° C., and the treatment time is 5-10 min.

7. The process for preparing polyimide modified by polyethyleneimine according to claim 6, characterized in that: In step 2, the molar ratio of polyethyleneimine: glutaraldehyde: phenyltrimethylsilane: diisopropylcarbodiimide is (11-13): (9-11): (2.5-4): 0.

2.

8. The process for preparing polyimide modified by polyethyleneimine according to claim 7, characterized in that: Step 3 The specific steps are as follows: (1) preheating the modified polyethyleneimine to 60-100° C.; (2) Slowly add the modified polyethyleneimine into the polyimide while stirring.

9. The process for preparing polyimide modified by polyethyleneimine according to claim 8, characterized in that: In step 3.2, the stirring temperature is 100-120° C., the stirring speed is 200-300 rpm, and the stirring time is 1-3 h.

10. A polyimide prepared according to the preparation process according to claim 9.

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