Preparation method of high-toughness hydrophobic fiber membrane without electric field force

Abstract

The application belongs to the field of functional polymer materials, and particularly relates to a preparation method of a high-toughness hydrophobic fiber membrane without the action of an electric field force. An ultrahigh molecular weight polymer prepared by room temperature emulsion polymerization is fully dissolved in a high-boiling-point polar solvent, and a high-toughness polymer fiber membrane with good hydrophobicity is obtained by using a microfluidic nanogas jet spinning technology. The preparation method is simple to operate, does not need a static electric field, has strong controllability, good spinnability, can be tractionally stretched, can orderly form a film through a chemical reaction, has fast surface drying, and is low in energy consumption.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of functional polymer materials, and particularly relates to a preparation method of a high-toughness hydrophobic fiber membrane. BACKGROUND

[0002] General-purpose polystyrene is a thermoplastic resin, which is easy to process and has a wide range of applications. However, it is brittle and easy to crack, has low impact strength, and poor heat resistance, and can only be used at low temperatures and low loads. Ultra-high molecular weight polymers have unique strength and better mechanical properties than the same polymers with relatively low molecular weight. The high degree of chain entanglement greatly improves the mechanical properties, wear resistance, thermal stability, and chemical resistance of the polymer. Due to its excellent impact resistance, tensile strength, bending strength, elongation at break, and thermal decomposition temperature, ultra-high molecular weight polystyrene has a very wide range of applications in manufacturing, construction, packaging, and household appliances.

[0003] The main chain is a saturated carbon chain, and the side group is a benzene ring. The presence of the benzene ring increases the rigidity of the polymer chain, so polystyrene (PS) is a non-crystalline polymer. The polystyrene molecular structure does not contain polar groups and atoms, and can be used to prepare hydrophobic or superhydrophobic materials. Due to the unique surface properties of superhydrophobic materials, they can be widely used in waterproofing, antifouling, self-cleaning, fluid drag reduction, and antibacterial applications. They also have broad potential applications in biomedical engineering, metal rust prevention, fuel energy, and optical engineering. However, the ordinary film preparation method limits the application of polystyrene films in hydrophobic materials.

[0004] There are many methods for preparing superhydrophobic materials, but they are basically based on these two ideas: one is to modify the rough surface with low surface energy substances, and the other is to construct a rough structure on the material surface. Based on these two ideas, most of the superhydrophobic materials require the use of toxic fluorinated agents for treatment, which can cause environmental pollution, and the products have poor heat resistance and ultraviolet resistance, hindering the application of superhydrophobic materials. Therefore, it is urgent to develop green and non-toxic superhydrophobic films.

[0005] So far, most fiber membranes have been prepared by electrospinning technology, but the preparation process requires high voltage, which may pose a safety hazard. In addition, the electrospinning process for preparing nanofiber membranes also has the problem of low efficiency. In the prior art, only the effect of the solvent on the hydrophobicity of the general-purpose polystyrene fiber membrane prepared by electrospinning has been studied. The molecular weight of the polystyrene raw material in this case is generally less than 100,000. For ultra-high molecular weight polystyrene with a molecular weight greater than 1 million, the viscosity of the spinning solution is higher, and it is not clear how to prepare ultra-high molecular weight polystyrene fiber membranes by electrospinning. In addition, polystyrene is a rigid material, and it is difficult to obtain a high-toughness polystyrene fiber membrane. Moreover, the fiber membrane prepared by electrospinning is disordered and has poor mechanical properties.Figure 12 ), it is very difficult to prepare the tough polystyrene fiber film.

[0006] Compared with the electrospinning method, the solution gas jet spinning as a new technology is a new type of sub-micron / nanofiber preparation method based on the principle of high-speed airflow stretching, and is a fiber preparation technology without high-voltage current, energy saving, safety and simple operation. The technology does not need high-voltage collector and conductive collector, and has the advantages of convenient process, low energy consumption, scalability, high production efficiency and the like. Therefore, the microfluidic nanogas jet spinning technology has a broad application prospect for preparing the super high molecular weight polystyrene (molecular weight greater than 100 million) high toughness hydrophobic fiber film.

[0007] In view of the problem, the application provides a preparation method of the high toughness hydrophobic fiber film, the static water contact angle of the super high molecular weight polystyrene fiber film is adjusted by changing the type of the spinning solution solvent, so that the performance of the product is adjusted, and a new idea is provided for preparing the green and non-toxic high toughness hydrophobic fiber film. SUMMARY

[0008] The application aims to design and synthesize a super high molecular weight polystyrene by a green and environmentally friendly polymerization method, and the fiber film prepared by the microfluidic nanogas jet spinning technology has the potential of high toughness and super hydrophobic performance. The method is green, efficient and controllable, and the operation process is very simple.

[0009] The technical scheme adopted by the application is as follows:

[0010] (1) A certain amount of anionic emulsifier is weighed and dissolved in deionized water, then styrene monomer is added, and stirring is performed to make it into a uniform white emulsion. After the pre-emulsification is completed, oxygen is removed under the condition of stirring in an ice water bath-argon is passed, and an initiator is added under the condition of argon atmosphere. After being sealed, the emulsion polymerization reaction is carried out at room temperature. During the polymerization process, the emulsion is stable and blue light is generated. After 8 hours of reaction, the emulsion polymerization reaction is terminated, and the emulsion is broken to obtain a polystyrene polymer.

[0011] (2) A certain amount of polystyrene is weighed and dissolved in a polar solvent to prepare polystyrene spinning solution with different mass percentages. Solution gas jet spinning is carried out at room temperature. The spinning solution is placed in the push injection device of the microfluidic nanogas jet spinning machine, and the spinning process parameters are adjusted: the receiving distance is 10cm-30cm, and the pushing speed is 0.5cm / min-3cm / min. After the spinning is completed, the obtained fiber film is placed in a 30℃ vacuum drying box for drying to constant weight, and a polystyrene fiber film is obtained.

[0012] In the preferred technical scheme, the relative weight average molecular weight of the prepared super high molecular weight polystyrene is higher than 1000000g / mol.

[0013] In a preferred technical solution, the solvent in step (2) is N,N-dimethylformamide;

[0014] In a preferred technical solution, the mass percentage of the ultra-high molecular weight polystyrene spinning solution in step (2) is 1% to 5%;

[0015] In a preferred technical solution, the viscosity of the polystyrene spinning solution is 180-200 Pa·s.

[0016] In a preferred technical solution, if the polystyrene spinning solution in step (2) is a general-purpose polystyrene spinning solution, the mass percentage is 1% to 25%;

[0017] The ultra-high molecular weight polystyrene prepared by the above method has a simple polymerization reaction system, easy operation, room temperature reaction, energy saving and cost saving, environmental friendliness, and can be produced on a large scale. Through the microfluidic nanogas jet spinning technology, a high-toughness hydrophobic polystyrene fiber membrane is prepared.

[0018] The advantages of the present application are as follows:

[0019] 1. The preparation method of the polystyrene resin with ultra-high molecular weight in the method of the present application is simple, the raw materials are cheap and easy to obtain, and it is suitable for industrial large-scale production.

[0020] 2. The polystyrene resin with ultra-high molecular weight in the method of the present application has higher toughness, and at the same time, the thermal performance and tensile performance are more excellent than those of general-purpose polystyrene.

[0021] 3. The solution gas-jet spinning fiber membrane of the polystyrene with ultra-high molecular weight in the method of the present application has high hydrophobicity, the preparation method of the fiber membrane is simple and easy to operate, and the controllability is strong, and the hydrophobicity can be simply controlled by different boiling points and polar solvents. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a comparison chart of the tensile performance, impact resistance and thermal performance of the ultra-high molecular weight polystyrene resin (PS-1) and the general-purpose polystyrene resin in Example 1.

[0023] Figure 2 It is a static water contact angle chart of the fiber membrane prepared by 1wt% PS-DMF solution gas-jet spinning in Example 1.

[0024] Figure 3 It is a static water contact angle chart of the fiber membrane prepared by 3wt% PS-DMF solution gas-jet spinning in Example 2.

[0025] Figure 4 It is a static water contact angle chart of the fiber membrane prepared by 5wt% PS-DMF solution gas-jet spinning in Example 3.

[0026] Figure 5 Static water contact angle and SEM image of the fiber membrane prepared by solution air-jet spinning of 1 wt% PS-DCM solution in Example 1 at a solution advancing speed of 1.5 mL / min.

[0027] Figure 6 Static water contact angle and SEM image of the fiber membrane prepared by solution air-jet spinning of 1 wt% PS-DCM solution in Example 1 at a solution advancing speed of 3 mL / min.

[0028] Figure 7 Static water contact angle and SEM image of the fiber membrane prepared by solution air-jet spinning of 2 wt% PS-THF solution in Comparative Example 2.

[0029] Figure 8 Static water contact angle of the fiber membrane prepared by solution air-jet spinning of 5 wt% GP525-DMF solution in Comparative Example 3.

[0030] Figure 9 Static water contact angle of the fiber membrane prepared by solution air-jet spinning of 25 wt% GP525-DMF solution in Comparative Example 3.

[0031] Figure 10 Static water contact angle of the film prepared by hot pressing with a flat plate vulcanizer in Comparative Example 4.

[0032] Figure 11 Static water contact angle of the sample prepared by injection molding with a micro injection molding machine in Comparative Example 5.

[0033] Figure 12 Structural morphology of the fiber membrane prepared by electrospinning. DETAILED DESCRIPTION

[0034] The present application is further illustrated by the following examples, which are not intended to limit the scope of the present application.

[0035] Example 1

[0036] In a Schlenk single-necked reaction flask equipped with a magnetic stirrer, sodium dodecyl sulfate (4.1660 g, 0.014 mol) and deionized water (333.2800 g, 4 m. St), and after a period of time with stirring until it is fully dissolved, styrene (83.3200 g, 0.800 mol) is added, and stirred until a uniform white emulsion is formed (pre-emulsification). After pre-emulsification, the ice water bath is removed, and the oxygen is removed by vacuum and replaced with argon. This is repeated three times, and then potassium persulfate (2.1626 g, 0.008 mol) is added under argon. The reaction is allowed to proceed for 8 h at 25 °C in a constant temperature water bath. After the reaction is complete, a sample is taken, and the emulsion is broken with anhydrous ethanol. The polymer is washed with water to remove the emulsifier, and then washed with anhydrous ethanol to remove unreacted monomer. The resulting high molecular weight polystyrene is filtered, and dried in an 80 °C forced air oven until a constant weight is achieved. The conversion of styrene monomer is determined to be 93.5%, and the resulting ultra-high molecular weight polystyrene (PS-1) has a relative weight average molecular weight of Mw= 3,260,000 g / mol, and a molecular weight distribution of Mw / Mn= 1.06. w.SEC The tensile strength of the sample bars obtained by injection molding of the ultra-high molecular weight polystyrene resin and general purpose polystyrene (GP525) are 60.63 MPa and 56.94 MPa, respectively, and the Izod impact strength (notched) are 3.51 kJ / m2and 1.68 kJ / m2, respectively. The glass transition temperature is 108.4 °C. The comparison of the mechanical properties and thermal properties of the ultra-high molecular weight polystyrene resin and general purpose polystyrene (GP525) are shown in FIG. 1 of the drawings. 2 2 Figure 1 The PS-1 (0.5 g) and N,N-dimethylformamide (DMF, 49.5 g) are added to a single neck flask with a magnetic stir bar to make a 1 wt% PS-DMF solution. The solution is stirred for 3 h until it is fully dissolved, and the viscosity of the solution is 185 Pa-s. The solution is then electrospun at a feed rate of 3 mL / min and a receiving distance of 20 cm. After the electrospinning is complete, the resulting fiber membrane is placed in a vacuum oven at 30 °C until a constant weight is achieved. The resulting ultra-high molecular weight polystyrene electrospun fiber membrane has a water contact angle of 134°, a tensile strength of 0.92 MPa, and an elongation at break of 78.89%. Figure 2

[0037] Example 2

[0038] ​​​​PS-1 (1.5 g) and N,N-dimethylformamide (DMF, 48.5 g) obtained in Example 1 were added to a single-neck flask equipped with a magnetic stirrer to prepare a 3 wt% mass percentage PS-DMF solution, and stirred for 4 hours. After the solution was completely dissolved, the viscosity of the solution was 190 Pa-s, and the solution was subjected to solution gas-jet spinning at a feed rate of 3 mL / min and a receiving distance of 20 cm. After the spinning was completed, the obtained fiber membrane was dried in a vacuum drying oven at 30°C until the weight was constant, thereby obtaining a solution gas-jet spun fiber membrane of ultrahigh molecular weight polystyrene. The water contact angle of the prepared fiber membrane was 132°, the tensile strength was 0.43 MPa, and the elongation at break was 18.94%, as shown in FIGS. 1A and 1B. Figure 3 .

[0039] Example 3

[0040] PS-1 (2.5 g) and N,N-dimethylformamide (DMF, 47.5 g) obtained in Example 1 were added to a single-neck flask equipped with a magnetic stirrer to prepare a 5 wt% mass percentage PS-DMF solution, and stirred for 6 hours. After the solution was completely dissolved, the viscosity of the solution was 200 Pa-s, and the solution was subjected to solution gas-jet spinning at a feed rate of 3 mL / min and a receiving distance of 20 cm. After the spinning was completed, the obtained fiber membrane was dried in a vacuum drying oven at 30°C until the weight was constant, thereby obtaining a solution gas-jet spun fiber membrane of ultrahigh molecular weight polystyrene. The water contact angle of the prepared fiber membrane was 126°, the tensile strength was 0.61 MPa, and the elongation at break was 17.44%, as shown in FIGS. 2A and 2B. Figure 4 .

[0041] Comparative Example 1

[0042] PS-1 (0.5 g, 1.5 g, 2.5 g) and dichloromethane (0.5 g, 1.5 g, 2.5 g) obtained in Example 1 were added to a single-neck flask equipped with a magnetic stirrer to prepare 1 wt%, 3 wt%, and 5 wt% mass percentage PS-DCM solutions, and stirred for a certain period of time until the solutions were completely dissolved. When the mass percentage of the PS-DCM solution was higher than 3 wt%, the viscosity of the spinning solution was sharply increased to 586 Pa-s, which was too large to perform spinning. When the mass percentage of the PS-DCM solution was 1 wt%, the solution was successfully spun into a polystyrene fiber membrane at a feed rate of 1.5 mL / min or 3 mL / min and a receiving distance of 20 cm. The obtained fiber membrane was dried in a vacuum drying oven at 30°C until the weight was constant, thereby obtaining a solution gas-jet spun fiber membrane of ultrahigh molecular weight polystyrene. The water contact angle of the prepared fiber membrane was 117° and 113°, the tensile strength was 0.31 MPa, and the elongation at break was 6.67%, as shown in FIGS. 3A and 3B. Figure 5 and Figure 6 .

[0043] Comparative Example 2

[0044] In a single-neck flask equipped with a magnetic stirrer, PS-1 (0.5 g, 1.0 g, 1.5 g) and tetrahydrofuran (THF, 49.5 g, 49.0 g, 48.5 g) were added to prepare a 1 wt%, 2 wt% and 3 wt% mass percentage PS-THF solution, respectively. After stirring for a period of time until it was fully dissolved, solution gas-jet spinning was performed. When the mass percentage of the PS-THF solution was 1 wt%, the viscosity of the spinning solution was 110 Pa·s, which was too low to spin. When the mass percentage of the PS-THF solution was 3 wt%, the viscosity was too high to spin. When the mass percentage of the PS-THF solution was 2 wt%, the viscosity was 180 Pa·s. The push speed was set to 3 mL / min and the receiving distance was 20 cm. After spinning, the obtained fiber membrane was placed in a 30 °C vacuum drying oven to dry to constant weight, thereby obtaining a ultrahigh molecular weight polystyrene solution gas-jet spinning fiber membrane. The water contact angle of the fiber membrane was 121°, the tensile strength was 0.40 MPa, and the elongation at break was 7.73%, as shown in the accompanying drawings. Figure 7

[0045] Comparative Example 3

[0046] In a single-neck flask equipped with a magnetic stirrer, GP525 (relative weight average molecular weight M w.SEC = 220000 g / mol) (0.5 g, 1.5 g, 2.5 g, 12.5 g) and N,N-dimethylformamide (DMF, 49.5 g, 48.5 g, 47.5 g, 37.5 g) were added to prepare a 1 wt%, 3 wt%, 5 wt% and 25 wt% mass percentage GP525-DMF solution, respectively. After stirring for a period of time until it was fully dissolved, solution gas-jet spinning was performed. When the mass percentage of the GP525-DMF solution was less than 5 wt%, the viscosity of the spinning solution was less than 120 Pa·s, which was difficult to spin. For the spinning solution with a mass percentage of 5 wt% and 25 wt% of the GP525-DMF solution, the solution viscosities were 185 Pa·s and 200 Pa·s, respectively. The push speed was set to 3 mL / min and the receiving distance was 20 cm. After spinning, the obtained fiber membrane was placed in a 30 °C vacuum drying oven to dry to constant weight, thereby obtaining a polystyrene solution gas-jet spinning fiber membrane. The water contact angles of the fiber membranes were 118° and 117°, respectively. The tensile strength of the fiber membrane prepared from the 25 wt% mass percentage GP525-DMF solution was 0.16 MPa, and the elongation at break was 2.31%, as shown in the accompanying drawings. Figure 8 Figure 9

[0047] Comparative Example 4 ​​​

[0048] The ultra-high molecular weight polystyrene (PS-1, M) obtained in Example 1 was used... w.SEC =3260000g / mol, Ultra-high molecular weight polystyrene (UHMWPE) films are obtained by hot pressing using a flat vulcanizing machine. The water contact angle of the produced film is 80°. The film contact angle is shown in the attached instruction manual. Figure 10 As shown.

[0049] Comparative Example 5

[0050] The ultra-high molecular weight polystyrene (PS-1, M) obtained in Example 1 was used... w.SEC =3260000g / mol, Ultra-high molecular weight polystyrene (UHMWPE) strips were obtained by injection molding using a micro-injection molding machine. The water contact angle of the prepared strips was 88°. The membrane contact angle is shown in the attached instruction manual. Figure 11 As shown.

Claims

1. A method for producing a high tenacity hydrophobic fiber membrane under the action of an electric field-free force, characterized by: The method of room temperature emulsion polymerization is used to prepare ultrahigh molecular weight polystyrene, which is precipitated by demulsification, dissolved in a polar solvent to form a uniform, stable and viscous solution, and then the solution is spun into a high-toughness and high-hydrophobicity ultrahigh molecular weight polystyrene fiber membrane by microfluidic nanobubble jet spinning technology; wherein the relative weight average molecular weight of the polystyrene is higher than 1000000 g / mol. The viscosity of the solution is 180-200 Pa·s, the water contact angle of the fiber membrane is 126°-134°, and the elongation at break of the fiber membrane is 17.44%-78.89%. The mass percentage of the super high molecular weight polystyrene and the polar solvent is 1%-5%; the polar solvent is N , N dimethylformamide (DMF).

2. The method for preparing a high tenacity hydrophobic fiber membrane under the action of an electric field-free force according to claim 1, characterized in that, The receiving distance in the process parameters of the microfluidic nanobubble jet spinning technology is 10 cm-30 cm.

3. The method for preparing a high-toughness hydrophobic fiber membrane without the action of an electric field according to claim 1, characterized in that, The membrane method is microfluidic nanobubble jet spinning technology, and the advancing speed of spinning is 0.5 cm / min-3 cm / min.

4. The method of claim 1, wherein the hydrophobic fiber film has a high toughness under the action of an electric field force. The demulsification precipitant is anhydrous ethanol.

5. A high-toughness and high-hydrophobicity fiber membrane prepared by the method according to any one of claims 1-4.

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