Thermoplastic polyurethane-based microporous membranes and methods of making the same

Abstract

The application discloses a thermoplastic polyurethane-based microporous membrane and a preparation method thereof. The thermoplastic polyurethane-based microporous membrane comprises the following components in mass fractions: 79.5-94.9 parts of MQ silicon resin grafted high-strength TPU resin, 5-20 parts of porous carbon and 0.1-0.5 parts of hyperbranched dispersant. After the TPU is grafted on the MQ silicon resin, the tensile strength of the TPU is improved, and the filtering efficiency and the thermal stability of the thermoplastic polyurethane microporous membrane are also significantly improved.

Description

Technical fields:

[0001] This invention relates to the field of microporous membrane technology, specifically to a thermoplastic polyurethane-based microporous membrane and its preparation method. Background technology:

[0002] While petroleum coke has applications in various industries, such as as fuel, as a raw material in aluminum and steel plants or carbon plants, as a raw material for carbide production, or as a raw material for electrode manufacturing, its effective utilization rate remains insufficient. To increase the added value of petroleum coke, one emerging utilization method in recent years is to use it as a raw material to prepare ultra-high specific surface area activated carbon with a well-developed pore structure, which can be applied in the field of adsorption separation. Thermoplastic polyurethane resin (TPU) is a thermoplastic processable material that combines high elasticity and plastic properties. It has excellent radiation resistance, impact resistance, insulation, wear resistance, and heat insulation advantages, and is now gaining increasing attention in various fields of separation technology, with applications in microfiltration, ultrafiltration, reverse osmosis, perevaporation, membrane bioreactors, and membrane sensors. Therefore, combining porous carbon prepared from petroleum coke with TPU to prepare high-performance microporous membranes has broad application prospects. Summary of the Invention:

[0003] This invention solves the problems existing in the prior art and provides a thermoplastic polyurethane-based microporous membrane and its preparation method. The preparation method can realize the high-value utilization of petroleum coke and significantly improve the filtration efficiency and thermal stability of the thermoplastic polyurethane microporous membrane.

[0004] The purpose of this invention is to provide a thermoplastic polyurethane-based microporous membrane, comprising the following components by weight: 79.5-94.9 parts of high-strength TPU resin grafted with MQ silicone resin, 5-20 parts of porous carbon, and 0.1-0.5 parts of hyperbranched dispersant.

[0005] Preferably, the porous carbon is prepared by the following method:

[0006] (1) Mix potassium hydroxide and dry petroleum coke in a mass ratio of 3:1 until homogeneous;

[0007] (2) A uniformly mixed mixture of potassium hydroxide and petroleum coke is loaded into a reaction vessel for carbonization reaction. After the reaction is completed, the mixture is naturally cooled, the product is washed, and dried to obtain the porous carbon.

[0008] The drying conditions for the petroleum coke in step (1) are: drying in an oven at 110℃ for 6 hours.

[0009] After the reaction in step (2) is completed, the product is naturally cooled, washed, and dried. The specific steps are as follows: Natural cooling, when the temperature is below 80℃, stop the nitrogen gas flow; take out the product after the reaction, wash the product thoroughly with hydrochloric acid, wash it repeatedly with distilled water and filter until the washing liquid is neutral, place it in an oven and dry for 24 hours to obtain dry porous carbon.

[0010] Further preferred, the specific steps of the carbonization reaction in step (2) are as follows: after sealing the reaction container, open the gas passage, introduce inert gas for protection, the heating rate is 5-10℃ / min, and when the reaction temperature reaches 700℃-850℃, keep the temperature constant for 30-60min.

[0011] Further preferred, the inert gas in step (2) is nitrogen, and the flow rate of nitrogen is 60-300 mL / min.

[0012] Preferably, the hyperbranching dispersant is C100 and / or C181.

[0013] Preferably, the MQ silicone resin grafted high-strength TPU resin is prepared by the following steps: 16-19 parts by weight of thermoplastic polyurethane, 0.5-2 parts by weight of vinyl MQ silicone resin and 0.1 parts by weight of initiator are mixed evenly, and reactively melt-extruded in a twin-screw extruder at a speed of 150-250 r / min, with an extrusion temperature of 140℃-160℃, to obtain the MQ silicone resin grafted high-strength TPU resin.

[0014] Further preferably, the initiator is dicumyl peroxide.

[0015] This invention also protects a method for preparing the thermoplastic polyurethane-based microporous membrane, comprising the following steps:

[0016] (1) Add the high-strength TPU resin grafted with MQ silicone resin to N,N-dimethylformamide (DMF) and stir thoroughly until it is completely dissolved to form a transparent solution;

[0017] (2) Add the hyperbranched dispersant and porous carbon to the above transparent solution and stir thoroughly until a uniformly dispersed slurry is formed;

[0018] (3) The slurry is coated on a glass plate, solidified for 15-25 minutes, washed with water, and dried to obtain the thermoplastic polyurethane-based microporous membrane.

[0019] Step (3) is as follows: the slurry is scraped onto a glass plate and slowly placed into a coagulation tank to coagulate for 15-25 minutes. After taking it out, it is washed with 50°C water 8-10 times and dried at 110°C for 5-10 minutes to obtain a high-strength thermoplastic polyurethane-based microporous membrane.

[0020] Preferably, the mass ratio of N,N-dimethylformamide to MQ silicone resin grafted high-strength TPU resin is 0.9-1.1:1. More preferably, the mass ratio of N,N-dimethylformamide to MQ silicone resin grafted high-strength TPU resin is 1:1.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) This invention realizes the high-value utilization of petroleum coke. The prepared porous carbon has high porosity and small pore size down to the nanometer level. When added to thermoplastic polyurethane, it can significantly improve the filtration efficiency of TPU microporous membrane and make the filtration size accurate to the nanometer level, thus solving the problem that TPU microporous membrane has a large pore size and poor filtration effect on nano-sized particles.

[0023] (2) The porous carbon proposed in this invention has excellent thermal stability, and its addition to TPU also improves the thermal stability of TPU microporous membrane.

[0024] (3) After grafting TPU with MQ silicone resin, the present invention not only significantly improves the tensile strength of TPU, but also the MQ silicone resin with core-shell microsphere structure can further increase the compatibility between TPU resin matrix and porous carbon. At the same time, the introduction of super dispersant can improve the dispersion uniformity of porous carbon in TPU matrix, thereby further improving the compatibility between TPU resin matrix and porous carbon. Detailed implementation method:

[0025] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments and implementation schemes of this invention will be described in further detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. The following description of at least one example is merely illustrative and is in no way intended to limit the invention or its application or use. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0027] Example 1

[0028] A thermoplastic polyurethane-based microporous membrane comprises, by weight, the following components: 79.5-94.9 parts of high-strength TPU resin grafted with MQ silicone resin, 5-20 parts of porous carbon, and 0.5 parts of hyperbranched dispersant C100.

[0029] High-strength TPU resin grafted with high-strength MQ silicone resin is prepared by the following steps: thermoplastic polyurethane, vinyl MQ silicone resin and dicumyl peroxide are mixed evenly in a mass ratio of 160:5:1 and then reactively melt-extruded in a micro twin-screw extruder at a speed of 200 r / min. The extrusion temperature is set to 150℃ to obtain the high-strength TPU resin grafted with MQ silicone resin.

[0030] Porous carbon is prepared according to the following steps:

[0031] (1) Dry the petroleum coke in an oven at 110°C for 6 hours to obtain dried petroleum coke;

[0032] (2) Take potassium hydroxide and dry petroleum coke in a mass ratio of 3:1, put them in a pulverizer to grind and mix them thoroughly;

[0033] (3) After the petroleum coke and potassium hydroxide are mixed evenly, they are loaded into a reaction ceramic boat and placed in a horizontal tubular carbonization furnace. After sealing, the gas passage is opened and N2 (flow rate of 60 mL / min) is introduced for protection. The heating rate is 5℃ / min. When the temperature reaches the set temperature of 700℃, the reaction is carried out at a constant temperature for 60 min. After the reaction is completed, the mixture is cooled naturally. When the temperature is below 80℃, the nitrogen gas is stopped. The ceramic boat is taken out, and the product is thoroughly acid-washed with hydrochloric acid. Then, it is repeatedly washed and filtered with distilled water until the washing liquid is neutral. The product is placed in an oven to dry for 24 h to obtain dry porous carbon. The carbon is taken out, collected, weighed, and placed in a desiccator.

[0034] High-strength thermoplastic polyurethane microporous membranes are prepared according to the following steps:

[0035] (1) Add the high-strength TPU resin grafted with MQ silicone resin to DMF and stir thoroughly for 6 hours until it is completely dissolved to form a transparent solution. The mass ratio of the high-strength TPU resin grafted with MQ silicone resin to DMF is 1:1.

[0036] (2) Add the hyperbranched dispersant C100 and porous carbon to the above transparent solution and stir thoroughly for 30 minutes until a uniformly dispersed slurry is formed.

[0037] (3) The slurry is scraped onto a glass plate and slowly placed into a coagulation tank to solidify for 20 minutes. After being taken out, it is washed 8 times with water at 50°C and dried at 110°C for 5 minutes to obtain a thermoplastic polyurethane-based microporous membrane.

[0038] Example 2

[0039] A thermoplastic polyurethane-based microporous membrane comprises, by weight, the following components: 94.9 parts of high-strength TPU resin grafted with MQ silicone resin, 5 parts of porous carbon, and 0.1 parts of hyperbranched dispersant C100.

[0040] The high-strength TPU resin grafted with MQ silicone resin is prepared by the following steps: thermoplastic polyurethane, vinyl MQ silicone resin and dicumyl peroxide are mixed evenly in a mass ratio of 190:20:1, and reactively melt-extruded in a micro twin-screw extruder at a speed of 200 r / min. The extrusion temperature is set to 150℃ to obtain the high-strength TPU resin grafted with MQ silicone resin.

[0041] Porous carbon is prepared according to the following steps:

[0042] (1) Dry the petroleum coke in an oven at 110°C for 6 hours to obtain dried petroleum coke;

[0043] (2) Take potassium hydroxide and dry petroleum coke in a mass ratio of 3:1, put them in a pulverizer to grind and mix them thoroughly;

[0044] (3) After the petroleum coke and potassium hydroxide are mixed evenly, they are placed in a reaction ceramic boat and placed in a horizontal tubular carbonization furnace. After sealing, the gas passage is opened and N2 (flow rate of 300 mL / min) is introduced for protection. The heating rate is 10℃ / min. When the temperature reaches the set temperature of 850℃, the reaction is carried out at a constant temperature for 30 min. After the reaction is completed, the mixture is cooled naturally. When the temperature is lower than 80℃, the nitrogen gas is stopped. The ceramic boat is taken out, and the product is thoroughly acid-washed with hydrochloric acid. Then, it is repeatedly washed and filtered with distilled water until the washing liquid is neutral. The product is placed in an oven to dry for 24 h to obtain dry porous carbon. The carbon is taken out, collected, weighed, and placed in a desiccator.

[0045] High-strength thermoplastic polyurethane micropores are prepared according to the following steps:

[0046] (1) Add the high-strength TPU resin grafted with MQ silicone resin to DMF and stir thoroughly for 6 hours until it is completely dissolved to form a transparent solution. The mass ratio of the high-strength TPU resin grafted with MQ silicone resin to DMF is 1:1.

[0047] (2) Add hyperbranched dispersant C100 and porous carbon to the above solution and stir thoroughly for 30 minutes until a uniformly dispersed slurry is formed;

[0048] (3) The slurry is scraped onto a glass plate and slowly placed into a coagulation tank to solidify for 20 minutes. After being taken out, it is washed 10 times with water at 50°C and dried at 110°C for 10 minutes to obtain a thermoplastic polyurethane-based microporous membrane.

[0049] Example 3

[0050] A thermoplastic polyurethane-based microporous membrane comprises, by weight, the following components: 90 parts of high-strength TPU resin grafted with MQ silicone resin, 9.7 parts of porous carbon, and 0.3 parts of hyperbranched dispersant C100.

[0051] The high-strength TPU resin grafted with MQ silicone resin is prepared by the following steps: thermoplastic polyurethane, vinyl MQ silicone resin and dicumyl peroxide are mixed evenly in a mass ratio of 180:10:1, and reactively melt-extruded in a micro twin-screw extruder at a speed of 200 r / min. The extrusion temperature is set to 150℃ to obtain the high-strength TPU resin grafted with MQ silicone resin.

[0052] Porous carbon is prepared according to the following steps:

[0053] (1) Dry the petroleum coke in an oven at 110°C for 6 hours to obtain dried petroleum coke.

[0054] (2) Weigh potassium hydroxide and dry petroleum coke in a mass ratio of 3:1, place them in a pulverizer and pulverize and mix them thoroughly.

[0055] (3) After the petroleum coke and potassium hydroxide are mixed evenly, they are loaded into a reaction ceramic boat and placed in a horizontal tubular carbonization furnace. After sealing, the gas passage is opened and N2 (flow rate of 200 mL / min) is introduced for protection. The heating rate is 8℃ / min. When the temperature reaches the set temperature of 800℃, the reaction is carried out at a constant temperature for 45 min. After the reaction is completed, the mixture is cooled naturally. When the temperature is lower than 80℃, the nitrogen gas is stopped. The ceramic boat is taken out, and the product is thoroughly acid-washed with hydrochloric acid. Then, it is repeatedly washed and filtered with distilled water until the washing liquid is neutral. The product is placed in an oven to dry for 24 h to obtain dry porous carbon. The carbon is taken out, collected, weighed, and placed in a desiccator.

[0056] High-strength thermoplastic polyurethane microporous membranes were prepared according to the following steps:

[0057] (1) Add the high-strength TPU resin grafted with MQ silicone resin to DMF and stir thoroughly for 6 hours until it is completely dissolved to form a transparent solution. The mass ratio of the high-strength TPU resin grafted with MQ silicone resin to DMF is 1:1.

[0058] (2) Add hyperbranched dispersant C100 and porous carbon to the above solution and stir thoroughly for 30 minutes until a uniformly dispersed slurry is formed.

[0059] (3) The slurry is scraped onto a glass plate and slowly placed into a coagulation tank to solidify for 20 minutes. After being taken out, it is washed 9 times with water at 50°C and dried at 110°C for 8 minutes to obtain a thermoplastic polyurethane-based microporous membrane.

[0060] Comparative Example 1

[0061] A thermoplastic polyurethane-based microporous membrane comprises, by weight, the following components: 90 parts thermoplastic polyurethane, 9.7 parts porous carbon, and 0.3 parts hyperbranched dispersant C100. The thermoplastic polyurethane has not been grafted with MQ silicone resin.

[0062] Porous carbon is prepared according to the following steps:

[0063] (1) Dry the petroleum coke in an oven at 110°C for 6 hours to obtain dried petroleum coke.

[0064] (2) Weigh potassium hydroxide and dry petroleum coke in a mass ratio of 3:1, place them in a pulverizer and pulverize and mix them thoroughly.

[0065] (3) After the petroleum coke and potassium hydroxide are mixed evenly, they are loaded into a reaction ceramic boat and placed in a horizontal tubular carbonization furnace. After sealing, the gas passage is opened and N2 (flow rate of 200 mL / min) is introduced for protection. The heating rate is 8℃ / min. When the temperature reaches the set temperature of 800℃, the reaction is carried out at a constant temperature for 45 min. After the reaction is completed, the mixture is cooled naturally. When the temperature is lower than 80℃, the nitrogen gas is stopped. The ceramic boat is taken out, and the product is thoroughly acid-washed with hydrochloric acid. Then, it is repeatedly washed and filtered with distilled water until the washing liquid is neutral. The product is placed in an oven to dry for 24 h to obtain dry porous carbon. The carbon is taken out, collected, weighed, and placed in a desiccator.

[0066] High-strength thermoplastic polyurethane microporous membranes were prepared according to the following steps:

[0067] (1) Add thermoplastic polyurethane to DMF and stir thoroughly for 6 hours until it is completely dissolved to form a transparent solution. The mass ratio of thermoplastic polyurethane to DMF is 1:1.

[0068] (2) Add hyperbranched dispersant C100 and porous carbon to the above solution and stir thoroughly for 30 minutes until a uniformly dispersed slurry is formed.

[0069] (3) The slurry is scraped onto a glass plate and slowly placed into a coagulation tank to solidify for 20 minutes. After being taken out, it is washed 9 times with water at 50°C and dried at 110°C for 8 minutes to obtain a thermoplastic polyurethane-based microporous membrane.

[0070] Comparative Example 2

[0071] A thermoplastic polyurethane-based microporous membrane comprises, by weight, the following components: 90 parts of high-strength TPU resin grafted with MQ silicone resin, 9.7 parts of porous carbon, and 0.3 parts of hyperbranched dispersant C100.

[0072] The high-strength TPU resin grafted with MQ silicone resin is prepared by the following steps: thermoplastic polyurethane, vinyl MQ silicone resin and dicumyl peroxide are mixed evenly in a mass ratio of 180:10:1, and reactively melt-extruded in a micro twin-screw extruder at a speed of 200 r / min. The extrusion temperature is set to 150℃ to obtain the high-strength TPU resin grafted with MQ silicone resin.

[0073] Porous carbon is prepared according to the following steps:

[0074] (1) Dry rice straw in an oven at 110℃ for 6 hours to obtain dried rice straw.

[0075] (2) Weigh potassium hydroxide and dry rice straw in a mass ratio of 3:1, place them in a pulverizer to crush and mix them thoroughly.

[0076] (3) After mixing rice straw and potassium hydroxide evenly, put them into a reaction ceramic boat and place it in a horizontal tubular carbonization furnace. After sealing, open the gas passage and introduce N2 (flow rate of 200 mL / min) for protection. The heating rate is 8℃ / min. When the temperature reaches the set temperature of 800℃, keep the temperature constant for 45 min for the reaction. After the reaction is completed, let it cool naturally. When the temperature is below 80℃, stop the nitrogen gas supply. Take out the ceramic boat, wash the product thoroughly with hydrochloric acid, and then wash and filter it repeatedly with distilled water until the washing liquid is neutral. Place it in an oven to dry for 24 h to obtain dry porous carbon. Take it out, collect it, weigh it, and put it into a desiccator.

[0077] High-strength thermoplastic polyurethane microporous membranes were prepared according to the following steps:

[0078] (1) Add the high-strength TPU resin grafted with MQ silicone resin to DMF and stir thoroughly for 6 hours until it is completely dissolved to form a transparent solution. The mass ratio of the high-strength TPU resin grafted with MQ silicone resin to DMF is 1:1.

[0079] (2) Add hyperbranched dispersant C100 and porous carbon to the above solution and stir thoroughly for 30 minutes until a uniformly dispersed slurry is formed.

[0080] (3) The slurry is scraped onto a glass plate and slowly placed into a coagulation tank to solidify for 20 minutes. After being taken out, it is washed 9 times with water at 50°C and dried at 110°C for 8 minutes to obtain a thermoplastic polyurethane-based microporous membrane.

[0081] Tensile tests and pore size distribution characterization were performed on the thermoplastic polyurethane microporous membranes prepared in Examples 1-3 and Comparative Examples 1-2. The results are shown in Table 1 below:

[0082] Table 1

[0083]

[0084]

[0085] As shown in Table 1, the tensile strength and elongation at break of Examples 1-3 are similar and significantly higher than those of Comparative Example 1, indicating that grafting MQ resin onto the TPU matrix can significantly improve the mechanical properties of the thermoplastic polyurethane microporous membrane. Compared with Comparative Example 2, the pore size distribution of Examples 1-3 shows a significantly higher proportion of pores below 10 nm and a significantly lower proportion of pores above 10 nm, especially above 100 nm. This indicates that the thermoplastic polyurethane microporous membrane prepared by the route of preparing porous carbon from petroleum coke has higher dimensional accuracy and can achieve a better nanoscale filtration effect. In this invention, while grafting MQ resin onto the TPU matrix, porous carbon is also prepared using petroleum coke, and the two have a synergistic effect. The mechanical properties of the thermoplastic polyurethane microporous membrane obtained in Example 3 are better than those of Comparative Examples 1 and 2, and the pore size distribution shows that the proportion of pores below 10 nm is higher than that of Comparative Examples 1 and 2, while the proportion of pores above 10 nm is significantly lower than that of Comparative Examples 1 and 2.

[0086] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A thermoplastic polyurethane-based microporous membrane, characterized in that, The product comprises, by weight parts, the following components: 79.5-94.9 parts of MQ silicone resin grafted high-strength TPU resin, 5-20 parts of porous carbon, and 0.1-0.5 parts of hyperbranched dispersant; the MQ silicone resin grafted high-strength TPU resin is prepared by the following steps: 16-19 parts by weight of thermoplastic polyurethane, 0.5-2 parts by weight of vinyl MQ silicone resin, and 0.1 parts by weight of initiator are mixed evenly, and reactively melt-extruded in a twin-screw extruder at a speed of 150-250 r / min, with an extrusion temperature of 140℃-160℃, to obtain the MQ silicone resin grafted high-strength TPU resin; The porous carbon is prepared by the following method: (1) Mix potassium hydroxide and dry petroleum coke in a mass ratio of 3:1 until homogeneous; (2) A uniformly mixed mixture of potassium hydroxide and petroleum coke is loaded into a reaction vessel for carbonization reaction. After the reaction is completed, the mixture is naturally cooled, the product is washed, and dried to obtain the porous carbon.

2. The thermoplastic polyurethane-based microporous membrane according to claim 1, characterized in that, The specific steps of the carbonization reaction described in step (2) are as follows: after sealing the reaction container, open the gas passage and introduce inert gas for protection. The heating rate is 5-10℃ / min. When the reaction temperature reaches 700℃-850℃, keep the temperature constant for 30-60min.

3. The thermoplastic polyurethane-based microporous membrane according to claim 2, characterized in that, The inert gas mentioned in step (2) is nitrogen, and the flow rate of nitrogen is 60-300 mL / min.

4. The thermoplastic polyurethane-based microporous membrane according to claim 1, characterized in that, The hyperbranched dispersant is C100 and / or C181.

5. The thermoplastic polyurethane-based microporous membrane according to claim 1, characterized in that, The initiator is dicumyl peroxide.

6. The method for preparing the thermoplastic polyurethane-based microporous membrane according to claim 1, characterized in that, Includes the following steps: (1) Add the high-strength TPU resin grafted with MQ silicone resin to N,N-dimethylformamide and stir thoroughly until it is completely dissolved to form a transparent solution; (2) Add the hyperbranched dispersant and porous carbon to the above transparent solution and stir thoroughly until a uniformly dispersed slurry is formed; (3) The slurry is coated on a glass plate, solidified for 15-25 minutes, washed with water, and dried to obtain the thermoplastic polyurethane-based microporous membrane.

7. The method for preparing the thermoplastic polyurethane-based microporous membrane according to claim 6, characterized in that, The mass ratio of N,N-dimethylformamide to MQ silicone grafted high-strength TPU resin is 0.9-1.1:1.

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