Polystyrene membrane material and preparation method thereof

Abstract

The invention discloses a polystyrene membrane material and a preparation method thereof. A penetrating network structure is provided; the porosity is 12 to 75 percent. The preparation method is simple, high in yield and rich in pore volume, and is different from the traditional method from top to bottom or from bottom to top, an intermediate transition array structure is prepared, deformation is generated through polymer thermal induction, and therefore a penetrating network structure is obtained. The method has good expansibility and controllability, the method is suitable for materials such as styrene, styrene-diethylene benzene copolymers and low-crosslinking-degree phenolic resin, and the pores of the obtained penetrating network can be changed by adjusting the conditions such as the particle size of the microemulsion, the pores in the particles, the thermal induction temperature, the thermal induction time and the solid content of the microemulsion.

Description

Technical Field

[0001] The present application relates to a polystyrene film material and a preparation method thereof, belonging to the field of organic film materials. Background Art

[0002] Polystyrene (PS) is a polymer made of styrene. Its main chain is a saturated hydrocarbon and its side chain is a rigid benzene ring structure. PS has the characteristics of high transparency, low price, low hygroscopicity, good shrinkage, easy processing, firmness and electrical insulation. It is widely used in packaging, construction, separation and other fields. It is the third largest resin plastic after polyethylene and polyvinyl chloride. Its main products can be divided into general-purpose polystyrene (GPPS), expanded polystyrene (EPS), high-impact polystyrene (HIPS), and syndiotactic polystyrene (SPS). Different types of PS have different characteristics and are used in different fields. PS has a relatively low heat deformation temperature (70-98°C), which is conducive to plasticization through melting in industrial production on the one hand, and limits the scope of use of PS on the other hand. PS with high porosity has light weight, good cushioning and shock absorption performance and corrosion resistance, and is widely used in cushioning packaging, thermal insulation materials, and sports toys.

[0003] The methods for synthesizing high-porosity polymers can be divided into soft and hard template methods and non-template methods. The template method includes solidifying a two-phase mixture of a pore source template and a polymer precursor, and then removing the pore source template, thereby leaving pores. For example, CN103204965B discloses a "Preparation Method and Application of Ultra-Low Density Porous Polystyrene Block Material", in which a W / O type gel emulsion obtained by using a small molecule gelling agent as a stabilizer is used as a template to initiate polymerization to obtain an ultra-low density porous polystyrene block material. The preparation process is simple, and only requires reaction stirring at room temperature, simple washing and drying at room temperature. However, the porous polymer obtained by the hard template method generally has larger pores at the micron level. The material obtained using a soft template can obtain small channels, but the production cost is relatively high. CN108948236B discloses "A polystyrene macro-shaped block and its preparation method", using persulfate as an initiator, deionized water as a medium, anionic surfactant as an emulsifier, and styrene as a monomer, to carry out emulsion polymerization to obtain a polystyrene microsphere emulsion, and then add a water-soluble organic solvent thereto to demulsify and precipitate the polystyrene microsphere emulsion, and obtain a polystyrene shaped block after drying, but the block obtained by this method is dense and non-porous. CN103374143B discloses "A super-large porous polymer sphere and its preparation method", using a two-step emulsification method to prepare a water-in-oil-in-water emulsion as a template for super-large porous microspheres, and then using a solvent removal method to solidify the oil phase to form super-large microspheres with internal and external through-holes. The porosity of the microspheres prepared by this method is as high as 10-90%, but the emulsification operation involves a complex liquid flow process, which is not conducive to large-scale production, and the pores of the obtained samples are all macroporous. Summary of the invention

[0004] Based on the technical defects existing in the background technology, the purpose of the present invention is to provide a polystyrene through-network with easily controllable pores. The method has simple process, low production cost, strong controllability, high scalability, and is easy to achieve large-scale production.

[0005] According to one aspect of the present application, a polystyrene film material is provided, wherein the polystyrene film material has a through-network structure;

[0006] The porosity of the polystyrene membrane material is 12-75%.

[0007] According to another aspect of the present application, a method for preparing the above-mentioned polystyrene film material is provided, comprising the following steps:

[0008] The raw materials containing styrene, a surfactant, an initiator and a solvent are mixed, reacted in an inert gas atmosphere to obtain a microemulsion containing polystyrene, filtered / evaporated to obtain a polystyrene array, and thermally induced to obtain the polystyrene membrane material.

[0009] The surfactant is selected from at least one of ionic surfactants, nonionic surfactants and zwitterionic surfactants;

[0010] Optionally, the surfactant is selected from at least one of polypyrrolidone, polyvinyl alcohol, and sodium lauryl sulfate;

[0011] The initiator is selected from at least one of potassium persulfate, benzoyl peroxide, and azobisisobutyronitrile;

[0012] The solvent is selected from water and / or ethanol.

[0013] In the raw materials, the mass ratio of the styrene to the solvent is 3 to 15;

[0014] Optionally, the mass ratio of the styrene to the solvent is 6 to 10;

[0015] The mass content of the surfactant is 0.1 to 3 wt%;

[0016] Optionally, the mass content of the surfactant is 0.15 to 1.5 wt%;

[0017] The mass of the initiator is 0.5 to 5 wt% of the mass of the styrene;

[0018] Optionally, the mass of the initiator is 0.65 to 2.5 wt% of the mass of the styrene;

[0019] Optionally, the raw material further contains a pore-forming agent;

[0020] The pore-forming agent is selected from at least one of silicon oxide or alkane;

[0021] In the raw materials, the mass content of the pore-forming agent is 0.01 to 20 wt %.

[0022] The inert gas atmosphere is selected from at least one of nitrogen, argon and helium.

[0023] The reaction temperature is 60-120°C;

[0024] The reaction time is 6 to 24 hours.

[0025] In the microemulsion containing polystyrene, the particle size of the polystyrene is 30 nm to 3 μm;

[0026] Optionally, in the microemulsion containing polystyrene, the particle size of the polystyrene is 50 to 800 nm.

[0027] The polystyrene can be swollen by chloroform.

[0028] The microemulsion may also contain at least one of poly(divinyl benzene), phenolic resin and styrene-divinyl benzene copolymer;

[0029] The microemulsion containing polystyrene has a solid content of 0.5 to 60 wt %;

[0030] Optionally, the microemulsion containing polystyrene has a solid content of 1 to 30 wt %.

[0031] The thickness of the polystyrene array is 0.1 mm to 10 cm;

[0032] Optionally, the thickness of the polystyrene array is 1 mm to 5 cm.

[0033] The heat-induced atmosphere is an atmosphere containing nitrogen and / or hydrogen;

[0034] Optionally, the thermal induction is performed in a vacuum;

[0035] The heat-induced temperature is 60 to 230°C;

[0036] Optionally, the heat-induced temperature is 80 to 200°C;

[0037] The heat-induced heating rate is 0.5 to 20°C / min;

[0038] Optionally, the heat-induced heating rate is 1 to 15°C / min;

[0039] The heat induction time is 0.1 to 15 hours;

[0040] Optionally, the thermal induction time is 0.3 to 12 hours.

[0041] Specifically,

[0042] The following steps are involved:

[0043] Step 1: dissolve the surfactant in deionized water or ethanol as a continuous phase, remove air with nitrogen or argon, use styrene and / or other monomers as a dispersed phase, use silicon oxide or alkane as a pore-forming agent, add an initiator under a nitrogen or argon atmosphere, react at 60 to 120° C. for 6 to 24 hours, and cool to room temperature to obtain polystyrene microemulsions of different sizes;

[0044] Step 2, the polystyrene microemulsion is filtered or evaporated to obtain a polystyrene array;

[0045] Step 3: Heat the array obtained in step 2 to 60-230° C. at 0.5-20° C. / min under air, nitrogen, hydrogen or vacuum conditions and maintain for 0.1-15 h.

[0046] The beneficial effects of this application include:

[0047] The invention develops a new, simple and effective method for preparing a novel polystyrene through-network. The preparation method is simple, the yield is high, the porosity is as high as 75%, and the network uniformity is good.

[0048] The polystyrene through-network prepared by the present invention has abundant pore volume. Different from the traditional top-down or bottom-up method, the present invention adopts the method of preparing an intermediate transition array structure to induce self-deformation through thermal induction of the polymer, thereby obtaining a through-network structure.

[0049] The preparation method of the present invention has good scalability and controllability. The method is applicable to materials such as styrene, styrene-diethylbenzene copolymer, and phenolic resin with a low degree of crosslinking, and the obtained through-network pores can be changed by adjusting conditions such as the microemulsion particle size, the pores in the particles, the thermal induction temperature, the thermal induction time, and the microemulsion solid content. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a cross section of the polystyrene through-network prepared in Example 1, Figure 1 The scale is 1 μm;

[0051] Figure 2 A high-magnification scanning electron micrograph (SEM) of a cross section of the polystyrene through-network prepared in Example 1, Figure 2 The scale is 100nm;

[0052] Figure 3These are photos of the plane and cross-section layered structure of the polystyrene array prepared in Example 1. Figure 3 The scale is 400nm;

[0053] Figure 4 These are SEM morphology photos of the plane and cross-section layered structure of the polystyrene array prepared in Example 1. Figure 4 The scale is 400nm;

[0054] Figure 5 This is a photo of a polystyrene interpenetrating network prepared by heat induction using the polystyrene array prepared in Example 1. Figure 5 The scale is 1 μm.

[0055] Figure 6 This is a SEM morphology photograph of a polystyrene interpenetrating network prepared by thermal induction of the polystyrene array prepared in Example 1. Figure 6 The scale is 100nm. DETAILED DESCRIPTION

[0056] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0057] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0058] Example 1

[0059] (1) Preparation of microemulsion or suspension

[0060] First, 50 mL of styrene was thoroughly washed with 10 mL of 10 wt.% NaOH solution and deionized water in order to remove the stabilizer. The washed styrene was added to a three-necked round-bottom flask containing 250 mL of deionized water and 1.2 g of polypyrrolidone. After bubbling with nitrogen for 15 minutes, it was preheated at 75°C for 30 minutes.

[0061] Subsequently, 20 mL of aqueous solution of 0.4 g of KSO was quickly added to the flask to initiate the polymerization reaction of styrene. After stirring at 70°C for 24 hours, the mixture was cooled to obtain a monodisperse polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. Polystyrene or other microemulsions / suspensions with a particle size of 30 nm to 3 um were obtained by other synthesis methods.

[0062] (2) Array preparation

[0063] The obtained microemulsion was filtered to obtain an intermediate transition polystyrene array with a thickness of 0.5 cm.

[0064] (3) The dried polystyrene array was heated to 130° C. at 5° C. / min in air and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 67%.

[0065] Figure 1 , 2 The cross section of the polystyrene through-network prepared in Example 1 and its high-magnification scanning electron micrograph (SEM), Figure 1 The scale is 1 μm. Figure 2 The scale is 100nm, which means that the interior of the sample is a network structure with through-holes, and the network is connected by interconnected 10nm filaments, thus producing a large number of pores.

[0066] Figure 3 , 4 These are SEM morphology photos of the plane and cross-section layered structure of the polystyrene array prepared in Example 1. Figure 3 The scale is 400nm, Figure 4 The scale is 400nm; it is its intermediate transition state structure.

[0067] Figure 5 , 6 The polystyrene array prepared in Example 1 ( Figure 2 ) SEM morphology of the polystyrene interpenetrating network prepared by thermal induction, Figure 5 The scale is 1 μm. Figure 6 The scale is 100nm. The sample has an obvious layered structure.

[0068] The characterization results of other embodiments are similar to those of Embodiment 1.

[0069] Example 2

[0070] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 50 nm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 25%.

[0071] Example 3

[0072] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 100 nm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 27%.

[0073] Example 4

[0074] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 340 nm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 54%.

[0075] Example 5

[0076] A 0.7 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 40% and a particle size of 50 nm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 20%.

[0077] Example 6

[0078] A 0.7 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 40% and a particle size of 100 nm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 25%.

[0079] Example 7

[0080] The 1.0 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 60% and a particle size of 320 nm. The temperature was raised to 120° C. at 5° C. / min and maintained for 12 hours to obtain a polystyrene interpenetrating network with a porosity of 45%.

[0081] Example 8

[0082] A 0.5 mm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 1% and a particle size of 50 nm. The temperature was raised to 125°C at 5°C / min and maintained for 9 hours to obtain a polystyrene interpenetrating network with a porosity of 53%.

[0083] Example 9

[0084] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 50 nm. The temperature was raised to 115°C at 20°C / min and maintained for 14 hours to obtain a polystyrene interpenetrating network with a porosity of 17%.

[0085] Example 10

[0086] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 50 nm. The temperature was raised to 120° C. at 1° C. / min and maintained for 14 hours to obtain a polystyrene interpenetrating network with a porosity of 12%.

[0087] Embodiment 11

[0088] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. The temperature was raised to 135° C. at 10° C. / min and maintained for 1 hour to obtain a polystyrene interpenetrating network with a porosity of 45%.

[0089] Example 12

[0090] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. The array was immersed in silicone oil and heated by raising the temperature to 130°C at 10°C / min and maintaining it for 3 hours to obtain a polystyrene interpenetrating network with a porosity of 67%.

[0091] Embodiment 13

[0092] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. Water vapor at a temperature of 130° C. was introduced for 3 hours to obtain a polystyrene interpenetrating network with a porosity of 43%.

[0093] Embodiment 14

[0094] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. Under a nitrogen atmosphere, the temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 70%.

[0095] Embodiment 15

[0096] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. Under vacuum conditions, the temperature was raised to 130° C. at 5° C. / min and maintained for 3 hours to obtain a polystyrene interpenetrating network with a porosity of 65%.

[0097] Example 16

[0098] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. Under hydrogen conditions, the temperature was raised to 130°C at 5°C / min and maintained for 3 hours to obtain a polystyrene interpenetrating network with a porosity of 43%.

[0099] Embodiment 17

[0100] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. Under argon conditions, the temperature was raised to 130°C at 5°C / min and maintained for 3 hours to obtain a polystyrene interpenetrating network with a porosity of 57%.

[0101] Embodiment 18

[0102] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 350 nm. Hexane was added to the microemulsion as a pore-forming agent. Under argon conditions, the temperature was raised to 120°C at 5°C / min and maintained for 4 hours to obtain a polystyrene permeable network with a porosity of 75%.

[0103] Embodiment 19

[0104] A 0.5 cm thick array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. After swelling with chloroform at room temperature for 2 hours, the swollen polystyrene array was filtered out. Under vacuum conditions, the temperature was raised to 120°C at 5°C / min and maintained for 4 hours to obtain a polystyrene permeable network with a porosity of 58%.

[0105] Embodiment 20

[0106] A 0.5 cm thick array was obtained by filtering a microemulsion of styrene divinyl benzene polymer with a solid content of 5% and a particle size of 170 nm and a crosslinking degree of 20%. The temperature was raised to 130°C at 5°C / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 45%.

[0107] Embodiment 21

[0108] A 0.5 cm thick array was obtained by filtering a phenolic resin dispersion with a solid content of 21% and a particle size of 150 nm. The temperature was increased to 230° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 34%.

[0109] Embodiment 22

[0110] A 0.3 cm thick array was obtained by filtering a poly(divinylbenzene) microemulsion with a solid content of 5% and a particle size of 550 nm. The temperature was raised to 180° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 45%.

[0111] Embodiment 23

[0112] The 1.0 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 40% and a particle size of 800 nm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 58%.

[0113] Embodiment 23

[0114] A 1.0 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 40% and a particle size of 1.2 μm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 61%.

[0115] Embodiment 24

[0116] A 1.0 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 40% and a particle size of 3.0 μm. The temperature was raised to 130° C. at 5° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 64%.

[0117] Comparative Example 1

[0118] The 0.5 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. The temperature was raised to 180°C at 5°C / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 4%.

[0119] The temperature was too high and the polystyrene melted quickly, which was found to have caused the structure to collapse.

[0120] Comparative Example 2

[0121] The 0.5 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. The temperature was raised to 250° C. at 20° C. / min and maintained for 8 hours to obtain a polystyrene interpenetrating network with a porosity of 0.5%.

[0122] The temperature was too high and the heating rate was too fast, causing the polystyrene to melt quickly. Testing found that this caused the structure to collapse.

[0123] Comparative Example 3

[0124] The 0.5 cm array was prepared by filtering a polystyrene microemulsion with a solid content of 16% and a particle size of 500 nm. The temperature was raised to 130°C at 140°C / min and maintained for 36 hours to obtain a polystyrene interpenetrating network with a porosity of 3%.

[0125] The heat treatment time was too long and the polystyrene crystallized completely. Testing found that this led to structural collapse.

[0126] Comparative Example 4

[0127] The 12 cm array obtained by filtration of a polystyrene microemulsion with a solid content of 70% and a particle size of 500 nm was prepared by heating to 130°C at 30°C / min and maintaining it for 8 hours. It was loose and did not form lumps.

[0128] Thick arrays are heated unevenly, which was found to result in non-uniform structures.

[0129] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A polystyrene film material, characterized in that: The polystyrene film material has a through-network structure; The porosity of the polystyrene membrane material is 12-75%.

2. A method for preparing the polystyrene film material according to claim 1, characterized in that: The following steps are involved: Raw materials containing styrene, a surfactant, an initiator and a solvent are mixed and reacted in an inert gas atmosphere to obtain a microemulsion containing polystyrene, obtain a polystyrene array, and thermally induce to obtain the polystyrene film material.

3. The preparation method according to claim 2, characterized in that: The surfactant is selected from at least one of ionic surfactants, nonionic surfactants and zwitterionic surfactants; Preferably, the surfactant is selected from at least one of polypyrrolidone, polyvinyl alcohol and sodium lauryl sulfate; The initiator is selected from at least one of potassium persulfate, benzoyl peroxide, and azobisisobutyronitrile; The solvent is selected from water and / or ethanol.

4. The preparation method according to claim 2, characterized in that: In the raw material, the mass ratio of the styrene to the solvent is 3 to 15; Preferably, the mass ratio of the styrene to the solvent is 6 to 10; The mass content of the surfactant is 0.1 to 3 wt%; Preferably, the mass content of the surfactant is 0.15 to 1.5 wt%; The mass of the initiator is 0.5 to 5 wt% of the mass of the styrene; Preferably, the mass of the initiator is 0.65 to 2.5 wt% of the mass of the styrene; Preferably, the raw material also contains a pore-forming agent; The pore former is selected from at least one of silicon oxide or alkane; In the raw materials, the mass content of the pore-forming agent is 0.01 to 20 wt %.

5. The preparation method according to claim 2, characterized in that: The inert gas atmosphere is selected from at least one of nitrogen, argon and helium.

6. The preparation method according to claim 2, characterized in that: The reaction temperature is 60-120°C; The reaction time is 6 to 24 hours.

7. The preparation method according to claim 2, characterized in that: In the microemulsion containing polystyrene, the particle size of the polystyrene is 30 nm to 3 μm; Preferably, in the microemulsion containing polystyrene, the particle size of the polystyrene is 50 to 800 nm.

8. The preparation method according to claim 2, characterized in that: The microemulsion containing polystyrene has a solid content of 0.5 to 60 wt %; Preferably, the microemulsion containing polystyrene has a solid content of 1 to 30 wt%.

9. The preparation method according to claim 2, characterized in that: The thickness of the polystyrene array is 0.1 mm to 10 cm; Preferably, the thickness of the polystyrene array is 1 mm to 5 cm.

10. The preparation method according to claim 2, characterized in that: The heat-induced atmosphere is an atmosphere containing nitrogen and / or hydrogen; Preferably, the thermal induction is performed in a vacuum; The heat-induced temperature is 60 to 230° C. Preferably, the heat-induced temperature is 80-200°C; The heat-induced heating rate is 0.5 to 20°C / min; Preferably, the heat-induced heating rate is 1 to 15°C / min; The heat induction time is 0.1 to 15 hours; Preferably, the thermal induction time is 0.3 to 12 hours.

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