Preparation method of polysiloxane modified polyurethane material

Abstract

The invention relates to a preparation method of a polysiloxane modified polyurethane material, which comprises the following steps: activating the surface of a polyurethane film material, and reacting with micromolecular diisocyanate in anhydrous toluene under the action of a catalyst to obtain a film with-NCO groups grafted on the surface; and placing the surface-activated thin film in anhydrous toluene containing polysiloxane, reacting, removing unreacted diisocyanate and polysiloxane, cleaning and drying to obtain the polyurethane film material with the surface grafted with polysiloxane. Compared with an unmodified polyurethane film material, the modified film material has better chemical stability, the reaction condition is mild, and the whole preparation process is simple and pollution-free.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a method for preparing a polysiloxane-modified polyurethane material. Background Art

[0002] Polyurethane (PU) is a type of high molecular polymer that has developed rapidly in recent years. Its molecular chain is composed of soft segments and hard segments in the form of blocks, grafts or inter-transfer networks, and the basic structural unit is urethane. Polyurethane has excellent physical properties such as elasticity, toughness, wear resistance, and oil resistance. It is widely used in various industrial fields. At the same time, its good body compliance and biocompatibility make it widely used in the biomedical field.

[0003] However, a single polyurethane material also has disadvantages in terms of heat resistance, weather resistance, and biological stability. Specifically, polyurethane has experienced varying degrees of failure when used in the human body as a long-term implant material or blood-contact material. The reason is that it catalyzes polymer degradation mechanisms under physiological conditions, including hydrolysis, environmental stress cracking (ESC), and metal ion oxidation (MIO). The degradation of polyurethane inevitably causes collective damage to implanted devices, which limits its application in the biomedical field.

[0004] Silicone is chemically stable, thermally stable, and oxidatively stable. The Si-O bond energy of polysiloxane is large (452 ​​kJ / mol), the bond length is relatively long, the polarity of the Si-O-Si bond is large, and it has an ionization tendency of 51%. It has a dipole induction effect on the hydrocarbon group connected to the Si atom, making its structure have excellent stability. However, the mechanical properties of polysiloxane are poor.

[0005] Chinese patent CN 109337077 A discloses a method for preparing a comb-structured silicone-polyurethane copolymer. The method first pre-prepare single-end polyhydroxy-terminated phenyl-modified polysiloxane and amino-terminated polysiloxane, then use polyisocyanate to react with polyol and the above two modified polysiloxanes in sequence, and then obtain a comb-structured silicone-polyurethane copolymer having the advantages of both polyurethane and polysiloxane through chain extension. However, the comb-structured copolymer has poor compatibility and poor thermal stability.

[0006] Chinese patent CN 107903369 A discloses a method for preparing a silicone-polyurethane thermoplastic elastomer. A solubilizer with a special structure is selected to change the characteristics of the hard segment, and the compatibility between the polyorganosiloxane and the hard segment is improved by optimizing the preparation process. The obtained silicone-polyurethane thermoplastic elastomer product has good mechanical properties, but the addition of the solubilizer may cause side reactions and thus reduce the physical and chemical properties of the product.

[0007] Chinese patent CN 115124659 A discloses an organosilicon polyurethane material with high blood compatibility and a preparation method thereof. The organosilicon polyurethane material prepared by the method based on polyaddition and functionalization reaction of unsaturated double bonds has durable and stable mechanical properties and blood compatibility, but the preparation process is relatively complicated and has high requirements on the process, which is not easy to promote. Summary of the invention

[0008] The purpose of the present invention is to provide a method for preparing a polysiloxane-modified polyurethane material, which utilizes the structural and performance characteristics of the two components of polysiloxane and polyurethane to prepare polysiloxane-modified polyurethane to achieve complementary advantages and have the excellent properties of both components, thereby solving the problems of easy degradation, insufficient heat resistance, weather resistance, stability and complicated procedures of existing polyurethane materials.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The preparation method of polysiloxane modified polyurethane material comprises the following steps:

[0011] Step 1: After washing the polyurethane particles with anhydrous ethanol and deionized water respectively, the polyurethane particles are placed in a 40-55° C. oven and dried thoroughly, and then the dried polyurethane particles are dissolved in tetrahydrofuran to form an 8%-15% (w / v) solution; a polyurethane film A with a thickness of 150-300 μm is obtained from the solution by dip coating, and the polyurethane film A is washed with anhydrous ethanol and deionized water and dried at 40-50° C.;

[0012] Step 2: Disperse diisocyanate in anhydrous toluene, add a catalyst, immerse the polyurethane film A in the diisocyanate-toluene solution, heat to 45-55° C. and react for 2.0-3.5 hours to obtain a polyurethane film B with -NCO groups grafted on the surface;

[0013] Step 3: Disperse polysiloxane in anhydrous toluene, then place the activated polyurethane film B in the polysiloxane-toluene solution, and react at 40-50° C. for 20-24 hours to obtain a polyurethane film C with surface grafted polysiloxane;

[0014] Step 4: Rinse the polyurethane film C with anhydrous toluene to remove unreacted diisocyanate and polysiloxane; vacuum dry the polyurethane film C at 40-60° C. for 6.0-8.0 h to obtain a polysiloxane-modified polyurethane film material.

[0015] In the preparation method of the polysiloxane-modified polyurethane material, the diisocyanate in step 2 includes any one of 1,6-hexamethylene diisocyanate (HDI), 4,4'-diphenylmethane diisocyanate (MDI), and L-lysine diisocyanate (LDI).

[0016] In the above method for preparing the polysiloxane-modified polyurethane material, the polyurethane A in step 1 is a material containing a carbamate group; or the polyurethane A is a polyurethane material that is insoluble in anhydrous toluene or water.

[0017] In the above method for preparing the polysiloxane-modified polyurethane material, the catalyst in step 2 includes triethylamine or dibutylene dilaurate.

[0018] In the above method for preparing the polysiloxane-modified polyurethane material, the polysiloxane in step three is hydroxyl-terminated polysiloxane or amino-terminated polysiloxane.

[0019] The beneficial effects of the present invention are:

[0020] (1) The modified polyurethane material prepared by the present invention grafts polysiloxane into the main chain of polyurethane. The introduced polysiloxane part gives the main chain of polyurethane good heat resistance, weather resistance and hydrophobicity, effectively making up for the performance defects of single polyurethane material. Compared with the unmodified polyurethane material, the mechanical properties have no obvious change, the tensile strength is 42.50-44.87MPa, and the elongation at break is 1138.10%-1154.15%; the chemical properties are stable, and the in vitro degradation test results show that the unmodified polyurethane material ages and turns yellow, while the modified polyurethane material has no obvious change.

[0021] (2) The modification method provided by the present invention has mild reaction conditions. Compared with the methods in the prior art, the method does not damage the mechanical properties of the polyurethane material, and the overall preparation process is simple and pollution-free. The method is applicable to most polyurethane materials, not limited to film materials, but also to other profile polyurethanes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the chemical reaction equation of the present invention.

[0023] Figure 2 This is the infrared absorption spectrum of the polyurethane film A-1 in Example 1 of the present invention;

[0024] Figure 3 This is the infrared absorption spectrum of the polysiloxane-modified polyurethane film C-1 in Example 1 of the present invention;

[0025] Figure 4 This is an EDS image of silicon (Si) element on the surface of the polysiloxane-modified polyurethane film C-1 in Example 1 of the present invention;

[0026] Figure 5 Appearance images of the polyurethane film A-1 (left) and the polysiloxane-modified polyurethane film C-1 (right) in Example 1 of the present invention;

[0027] Figure 6Appearance images of the polyurethane film A-1 (left) and the polysiloxane-modified polyurethane film C-1 (right) in Example 1 of the present invention after 60 days of in vitro degradation test. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Embodiment 1:

[0030] refer to Figures 1 to 6 The present invention relates to a polyurethane modified material, Figure 1 The present invention relates to a method for preparing a polysiloxane-modified polyurethane material, comprising the following steps:

[0031] Step 1: After washing the polyurethane particles containing carbamate groups with anhydrous ethanol and deionized water respectively, the polyurethane particles are placed in a 40°C oven to be thoroughly dried, and then the dried polyurethane particles are dissolved in tetrahydrofuran to form an 8% (w / v) solution; a 10 mm×10 mm polyurethane film A-1 with a thickness of 150 μm is obtained from the solution by dip coating, and the polyurethane film A-1 is washed with anhydrous ethanol and deionized water and then dried at 50°C.

[0032] Step 2: Place the dried 10mm×10mm polyurethane film A-1 (thickness 150μm) in a blue-mouth bottle containing 100mL of anhydrous toluene containing 7.2mL of 1,6-hexamethylene diisocyanate and 3.4mL of triethylamine. After sealing, heat it in a water bath to 45°C. After reacting for 2.5h, take out the film and wash it with anhydrous toluene to obtain a film B-1 with -NCO groups grafted on the surface.

[0033] Step 3: Place the activated membrane B-1 in a blue-mouth bottle containing 12 mL of hydroxy-terminated polydimethylsiloxane and 100 mL of anhydrous toluene, seal it, heat it in a water bath to 40°C, and react for 20 hours to obtain a polyurethane membrane C-1 with surface grafted polysiloxane;

[0034] Step 4: The polyurethane film C-1 was washed with anhydrous toluene and purified water three times in sequence, and vacuum dried at 40° C. for 6.0 h to obtain a dry polyurethane film C-1 material with surface grafted polydimethylsiloxane.

[0035] Embodiment 2:

[0036] Step 1: After washing the water-insoluble polyurethane particles with anhydrous ethanol and deionized water respectively, the polyurethane particles are placed in a 55°C oven to be thoroughly dried, and then the dried polyurethane particles are dissolved in tetrahydrofuran to form a 15% (w / v) solution; a polyurethane film A-2 with a thickness of 10 mm×10 mm and a thickness of 250 μm is obtained from the solution by dip coating, and the polyurethane film A-2 is washed with anhydrous ethanol and deionized water and then dried at 40°C.

[0037] Step 2: Place the dried 10mm×10mm polyurethane film A-2 (thickness 250μm) in a blue-mouth bottle containing 100mL of anhydrous toluene containing 8.0mL of 4,4'-diphenylmethane diisocyanate (MDI) and 3.7mL of triethylamine. After sealing, heat it in a water bath to 50°C. After reacting for 2.0h, take out the film and wash it with anhydrous toluene to obtain a film B-2 with -NCO groups grafted on the surface.

[0038] Step 3: Place the activated membrane B-2 in a blue-mouth bottle containing 15 mL of hydroxy-terminated polydimethylsiloxane and 100 mL of anhydrous toluene, seal it, heat it in a water bath to 45°C, and react for 24 hours to obtain a polyurethane membrane C-2 with surface grafted polysiloxane;

[0039] Step 4: The polyurethane film C-2 was washed with anhydrous toluene and purified water three times in sequence, and vacuum dried at 50° C. for 7.0 h to obtain a dry polyurethane film C-2 material with surface grafted polydimethylsiloxane.

[0040] Embodiment 3:

[0041] Step 1: After washing the polyurethane particles insoluble in anhydrous toluene with anhydrous ethanol and deionized water respectively, the polyurethane particles are placed in a 50°C oven and thoroughly dried, and then the dried polyurethane particles are dissolved in tetrahydrofuran to form a 10% (w / v) solution; a polyurethane film A-3 with a size of 10 mm×10 mm and a thickness of 300 μm is obtained from the solution by dip coating, and the polyurethane film A-3 is washed with anhydrous ethanol and deionized water and then dried at 45°C.

[0042] Step 2: Place the dried 10mm×10mm polyurethane film A-3 (thickness 300μm) in a blue-mouth bottle containing 100mL of anhydrous toluene containing 7.5mL L-lysine diisocyanate (LDI) and 3.5mL of dibutyl dilaurate. After sealing, heat it in a water bath to 55°C. After reacting for 3.5h, take out the film and wash it with anhydrous toluene to obtain a film B-3 with -NCO groups grafted on the surface.

[0043] Step 3: Place the activated membrane B-3 in a blue-mouth bottle containing 20 mL of amino-terminated polydimethylsiloxane and 100 mL of anhydrous toluene, seal it, and heat it in a water bath to 50°C. After reacting for 22 hours, a polyurethane membrane C-3 with surface grafted polysiloxane is obtained;

[0044] Step 4: The polyurethane film C-3 was washed with anhydrous toluene and purified water three times in sequence, and vacuum dried at 60° C. for 8.0 h to obtain a dry polyurethane film C-3 material with surface grafted polydimethylsiloxane.

[0045] Performance Testing

[0046] The following analytical methods were used in all examples unless otherwise stated.

[0047] Infrared spectroscopy: Fourier transform infrared spectroscopy (FT-IR) was performed on the Great20 spectrometer of Zhongke Ruijie (Tianjin) Technology Co., Ltd. Take an appropriate amount of sample and spread it evenly on the transmission panel glass, and use the rotating upper arm to press the sample for scanning. Set the scanning range to 4000~400cm -1 , resolution 4cm -1 .

[0048] Mechanical properties: The mechanical properties tests of polyurethane membrane materials were all conducted on the WDW-5 microcomputer-controlled electronic universal testing machine of Shanghai Hualong Testing Instrument Co., Ltd. Before the test, the samples were dried in a 40℃ oven for 6.0h to eliminate the influence of moisture on the mechanical properties of the samples. The test was carried out at room temperature, with a chuck spacing of 20mm and a tensile rate of 100mm / min. The samples were tested in parallel 3 times and the results were averaged.

[0049] In vitro degradation test: Place a 10mm×10mm polyurethane film material in a brown bottle, take 10mL of aging solution and pour it into the bottle to completely cover the film, evaluate the stability of the sample at 37°C, and change the solution every 3 to 4 days. Compared with in vivo oxidative degradation, in vitro degradation test can accelerate the degradation rate by 15 times.

[0050] The mechanical properties of the polyurethane films and polysiloxane-modified polyurethane films in Examples 1-3 are shown in Table 1.

[0051] Table 1 Mechanical properties parameters of polyurethane membrane materials

[0052]

[0053] Figure 2 The infrared absorption spectrum of the polyurethane film A-1 in Example 1 is at 2932 cm -1 The absorption peak at 1740cm is the stretching vibration peak of CH2; -1The absorption peak at 1245cm is the stretching vibration peak of C=O; -1 The absorption peak at is the stretching vibration peak of CO.

[0054] Figure 3 The infrared absorption spectrum of the polyurethane film C-1 in Example 1 is located at 1000-1100 cm -1 The absorption peak at is the stretching vibration peak of Si-O, which proves that polysiloxane is successfully grafted onto the polyurethane chain segment.

[0055] Figure 4 This is an EDS image of silicon (Si) element on the surface of the polysiloxane-modified polyurethane film C-1 in Example 1. The silicon element is aggregated and evenly distributed on the surface of the modified polyurethane film.

[0056] Figure 5 The images are the appearance of the polyurethane film A-1 (left) and the polysiloxane-modified polyurethane film C-1 (right) in Example 1. The polyurethane film A-1 appears as a colorless and transparent film, and the polysiloxane-modified polyurethane film C-1 appears as a milky white film with low transparency.

[0057] Figure 6 The following are the appearance images of the polyurethane film A-1 (left) and the polysiloxane-modified polyurethane film C-1 (right) in Example 1 after 60 days of in vitro degradation test. As can be seen from the figure, after 60 days of degradation test, the appearance of the polyurethane film A-1 turned yellow, indicating that it had undergone oxidative degradation reaction, thus causing the film to turn yellow; the appearance of the polysiloxane-modified polyurethane film C-1 did not change significantly, and its surface was relatively smooth, proving that the modified polyurethane film became stronger and less prone to degradation due to grafting polysiloxane, and its chemical stability was significantly improved.

[0058] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a polysiloxane-modified polyurethane material, characterized in that: The steps include: Step 1: After washing the polyurethane particles with anhydrous ethanol and deionized water respectively, the polyurethane particles are placed in a 40-55° C. oven and dried thoroughly, and then the dried polyurethane particles are dissolved in tetrahydrofuran to form an 8%-15% (w / v) solution; a polyurethane film A with a thickness of 150-300 μm is obtained from the solution by dip coating, and the polyurethane film A is washed with anhydrous ethanol and deionized water and dried at 40-50° C.; Step 2: Disperse diisocyanate in anhydrous toluene, add a catalyst, immerse the polyurethane film A in the diisocyanate-toluene solution, heat to 45-55° C. and react for 2.0-3.5 hours to obtain a polyurethane film B with -NCO groups grafted on the surface; Step 3: Disperse polysiloxane in anhydrous toluene, then place the activated polyurethane film B in the polysiloxane-toluene solution, and react at 40-50° C. for 20-24 hours to obtain a polyurethane film C with surface grafted polysiloxane; Step 4: Rinse the polyurethane film C with anhydrous toluene to remove unreacted diisocyanate and polysiloxane; vacuum dry the polyurethane film C at 40-60° C. for 6.0-8.0 h to obtain a polysiloxane-modified polyurethane film material.

2. The method for preparing the polysiloxane-modified polyurethane material according to claim 1, characterized in that: The diisocyanate in step 2 includes any one of 1,6-hexamethylene diisocyanate (HDI), 4,4'-diphenylmethane diisocyanate (MDI), and L-lysine diisocyanate (LDI).

3. The method for preparing the polysiloxane-modified polyurethane material according to claim 1, characterized in that: In step 1, the polyurethane A is a material containing a carbamate group; or the polyurethane A is a polyurethane material insoluble in anhydrous toluene or water.

4. The method for preparing the polysiloxane-modified polyurethane material according to claim 1, characterized in that: In step 2, the catalyst includes triethylamine or dibutylene dilaurate.

5. The method for preparing the polysiloxane-modified polyurethane material according to claim 1, characterized in that: In step 3, the polysiloxane is hydroxyl-terminated polysiloxane or amino-terminated polysiloxane.

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