CN109251412B - A kind of super-hydrophobic polytetrafluoroethylene/polymer material composite microcellular foam and preparation method thereof - Google Patents

Abstract

The invention discloses super-hydrophobic polytetrafluoroethylene/high polymer material composite microporous foam and a preparation method thereof. The invention adopts micrometer-scale and nanometer-scale polytetrafluoroethylene powder, and prepares the composite microporous foam material with a high polymer material through melt extrusion and supercritical fluid foaming processes. In the extrusion process, the micron-scale polytetrafluoroethylene powder can be subjected to in-situ fiber formation to form a nanofiber network structure in the polymer matrix, and the polytetrafluoroethylene nanoparticles are uniformly dispersed in the polymer material. And furthermore, microporous foaming is carried out through the supercritical fluid, a 10-50 mu m cellular structure can be formed in the composite material, and meanwhile, the polytetrafluoroethylene nanofiber network and the nano particles are exposed on the surface of material cells, so that the obtained foam material has good superhydrophobic performance. The preparation method is simple and easy to operate, and the prepared composite microporous foam has a water contact angle of more than 150 degrees and good stability.

Description

A superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam and its preparation method

technical field

The invention relates to the technical field of hydrophobic materials, and more particularly, to a super-hydrophobic polytetrafluoroethylene/polymer material composite microporous foam and a preparation method thereof.

Background technique

In recent years, with the increasing demand for energy saving and emission reduction, microcellular foam materials have received extensive attention in different fields. Polymer materials with a microporous structure can greatly reduce the demand for raw materials and the weight of products, and can maintain good mechanical properties and appearance dimensions, especially suitable for lightweight products, as well as some special applications of sound insulation and heat insulation . The preparation of polymer microcellular foams by supercritical fluid is a green, low-cost, and mass-produced production process, which has been widely promoted in practical production in recent years.

With the increasingly serious problems of oil leakage and water pollution, there is a higher market demand for high-performance superhydrophobic foams. The polymer microcellular foam with superhydrophobic properties not only has the properties of waterproof, anti-corrosion and self-cleaning, but also can selectively absorb oil pollution from water, thereby realizing water purification and oil pollution recovery.

However, traditional oil-absorbing materials have poor hydrophobicity, poor oil-water separation efficiency, and low adsorption rate, while the currently developed superhydrophobic modified foams or carbonized aerogels have superhydrophobic properties, but their preparation process is complex, high cost, and stable performance. It has poor performance and is not suitable for batch and large-scale production.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a super-hydrophobic polytetrafluoroethylene/polymer material composite microporous foam and a preparation method thereof, aiming at the shortcomings of the hydrophobic material performance and complex preparation process in the prior art.

The object of the present invention is achieved through the following technical solutions:

A super-hydrophobic polytetrafluoroethylene/polymer material composite microporous foam, the inner and outer surfaces of which are covered with multi-level rough polytetrafluoroethylene networks and particles, and the preparation steps include:

S1. Fully dry micron-scale PTFE, nano-scale PTFE and polymer materials;

S2. Mix evenly the micron-level polytetrafluoroethylene, nano-level polytetrafluoroethylene and macromolecular material described in step S1;

S3. the mixed material described in step S2 is granulated by an extruder;

S4. The pellets obtained in step S3 are foamed to prepare superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam.

Further, the diameter of the micro-scale polytetrafluoroethylene described in step S1 is 5-100 μm, and the diameter of the nano-scale polytetrafluoroethylene is 10-100 nm.

Further, the polymer material in step S1 includes one or more of polyethylene, polypropylene, polyurethane, polylactic acid, ABS, and polystyrene.

Further, the added amount of the micron-level polytetrafluoroethylene is 2-10% of the mass of the polymer material, and the added amount of the nano-level polytetrafluoroethylene is 1-5% of the mass of the polymer material.

Further, in step S2, one or more of antioxidants, heat stabilizers, reinforcing agents, toughening agents, and coupling agents may be added.

Further, the extrusion granulation in step S3 adopts a twin-screw or multi-screw extruder. The extruder temperature was set at 150 to 250° C. according to the polymer, and the screw speed was set at 80 to 150 rpm.

Further, the foaming method described in step S4 is a supercritical fluid extrusion foaming method or an intermittent foaming method.

Further, the supercritical fluid is nitrogen or carbon dioxide.

Further, in the process of supercritical fluid extrusion foaming, the extrusion temperature is set to 150-250°C according to the polymer, and single-screw or twin-screw supercritical fluid can be used for extrusion foaming, and the pressure in the barrel is 5-15 MPa.

Further, the intermittent foaming temperature is 150~200°C, the pressure is 8~20MPa, the soaking time of the supercritical fluid is 2~5h, and the foaming is carried out by a one-step pressure relief method.

Further, the cells of the prepared superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam are 10-50 μm.

Superhydrophobicity usually means that the water contact angle of the material surface is greater than 150°. There are two main reasons for the formation of superhydrophobicity: one is that the surface material has low surface energy, and the other is that the surface has a multi-level rough structure. PTFE has excellent chemical stability, corrosion resistance, high lubricity and non-stickiness, and PTFE itself is a low surface energy material, so for PTFE/polymer composites, only rough surfaces need to be constructed Superhydrophobicity can be achieved without further modification. In the invention, by adding micron-scale and nano-scale polytetrafluoroethylene into the polymer material, the micron-scale polytetrafluoroethylene particles can form a nanofiber network in situ during the twin-screw extrusion process, and combine the polytetrafluoroethylene nanoparticles and micron-scale polytetrafluoroethylene. The cellular structure forms a multi-level rough structure with low surface energy on the surface of the porous foam material, thereby endowing the foam material with superhydrophobic properties. Further preferably, the diameter of the micro-scale polytetrafluoroethylene is 50 μm, and the diameter of the nano-scale polytetrafluoroethylene is 50 nm.

The invention adopts the polytetrafluoroethylene powder of micrometer scale and nanometer scale, and prepares the composite material through twin-screw extrusion process and polymer material. Under the action of high temperature and strong shear during the mixing extrusion process, the micron-scale PTFE powder is in-situ fiberized, forming a nanofiber network structure in the polymer matrix, while the nano-scale PTFE particles It is uniformly dispersed in the polymer material. Further preferably, the added amount of the micron-level polytetrafluoroethylene is 10% of the mass of the polymer material, and the added amount of the nano-level polytetrafluoroethylene is 5% of the mass of the polymer material.

Supercritical fluid continuous extrusion foaming is a foaming technology that combines green foaming agent and direct extrusion processing. It shows the advantages of green, efficient and continuous in polymer foaming. At the same time, supercritical fluid is a green medium, which has both the mass transfer properties of liquid and the diffusion properties of gas, which can reduce the viscosity and processing temperature of polymers. It has the advantages of reducing energy consumption and reducing emissions for polymer processing. The supercritical fluid extrusion foaming process mixes the molten polymer material with supercritical nitrogen or carbon dioxide fluid in the barrel to form a single-phase fluid. Microcellular foam material. Preferably, the temperature in the extrusion foaming process of the supercritical fluid is 150-250° C., and the pressure is 5-15 MPa.

Intermittent foam molding has a high nucleation rate. The intermittent nature of the process ensures that the supercritical gas has sufficient time to penetrate into the interior of the composite material, and the two can be fully mixed to form a high-quality homogeneous system. After that, a large number of cell nuclei can be generated instantaneously. Batch foam molding can easily control the diameter and density of cells. Preferably, the intermittent foaming temperature is 150 ~ 200 ℃, the pressure is 8 ~ 20MPa, the supercritical fluid soaking time is 2 ~ 5h, and the one-step pressure relief method is adopted to foam.

The polymer material includes one or more of polyethylene, polypropylene, polyurethane, polylactic acid, ABS, and polystyrene. The polymer materials have a certain degree of hydrophobicity. The polytetrafluoroethylene/polymer material composite microporous foam material obtained by supercritical fluid foaming has a micron-level porous structure and the surface of the cell has a polytetrafluoroethylene nanometer. The low-surface-energy multi-level rough structure formed by the fiber network and nanoparticles makes the porous composite material superhydrophobic. According to the difference of the polymer material matrix, select the appropriate temperature to process the polymer material.

The supercritical fluid extrusion foaming and intermittent foaming process produces a large number of micropores in the composite material, which on the one hand can greatly reduce the demand for raw materials, the weight of the product, and can maintain good mechanical properties and appearance size, On the other hand, the composite material has a three-dimensional porous structure, and the internal micropores can absorb a large amount of oily substances. Compared with the membrane structure, the oil absorption rate and oil absorption rate of the microcellular foam structure are higher and faster, which effectively improves the treatment efficiency. pollution efficiency.

Compared with the prior art, the beneficial effects are:

The invention creatively uses micron-scale polytetrafluoroethylene, nano-scale polytetrafluoroethylene and polymer materials to prepare composite porous foam with super-hydrophobic properties through high-shear screw extrusion and supercritical fluid microcellular foaming process . In the process of screw extrusion, the micron-sized PTFE particles can form a nanofiber network in situ. Combined with the PTFE nanoparticles and the micron-sized cellular structure, a multi-level rough structure with low surface energy is formed on the surface of the porous foam material. , which endows the foam with superhydrophobic properties.

The composite microporous foam prepared by the method of the present invention has PTFE nanofiber network and nanoparticles on the surface and inside of its cells, so both the inner and outer surfaces have super-hydrophobic properties, and the foam material is arbitrarily cut or brittle. After fracture, the cross section still has superhydrophobic properties. The present invention uses extrusion and foaming processes, so that composite microcellular foam sheets or blocks can be mass-produced.

The process for preparing the super-hydrophobic polytetrafluoroethylene/polymer composite microporous foam according to the invention is feasible, simple in operation and stable in quality. The superhydrophobic polytetrafluoroethylene/polymer composite microporous foam prepared according to the method has a water contact angle of more than 150° on the surface and the cross section, and realizes the superhydrophobicity.

Description of drawings

Fig. 1 is the scanning electron microscope photograph of the polytetrafluoroethylene/polypropylene composite microcellular foam prepared by using micron and nanoscale polytetrafluoroethylene;

Fig. 2 is the scanning electron microscope photograph of the polytetrafluoroethylene/polypropylene composite microcellular foam prepared by using micron and nanoscale polytetrafluoroethylene;

Fig. 3 is the scanning electron microscope photograph of the polytetrafluoroethylene/polypropylene composite microcellular foam prepared by using micrometer-scale polytetrafluoroethylene;

Fig. 4 is the scanning electron microscope photograph of the polytetrafluoroethylene/polypropylene composite microcellular foam prepared by using micron-scale polytetrafluoroethylene;

Fig. 5 is a scanning electron microscope photo of the teflon/polypropylene composite microcellular foam cut surface prepared by using micron and nano-scale teflon after 500 times of sandpaper rubbing;

Fig. 6 is a scanning electron microscope photo of the teflon/polypropylene composite microcellular foam section prepared by using micron and nanoscale teflon after 500 times of sandpaper rubbing;

Figure 7. Water contact angle of the cut surface of PTFE/polypropylene composite microcellular foam prepared by micro- and nano-scale PTFE;

Figure 8. The water contact angle of the brittle section of the PTFE/polypropylene composite microcellular foam prepared with micro- and nano-scale PTFE;

Figure 9. Water contact angle of the cut surface of PTFE/polypropylene composite microcellular foam prepared with micron-scale PTFE;

Figure 10. The water contact angle of the teflon/polypropylene composite microcellular foam section prepared by micro- and nano-scale teflon after 500 times of sandpaper rubbing;

Figure 11. The test results of the absorption rate of PTFE/polypropylene composite microcellular foam prepared by micro- and nano-scale PTFE to different organic solvents and oil stains.

Detailed ways

The following is further explained and illustrated in conjunction with the examples, but the specific examples do not limit the present invention in any form. Unless otherwise specified, the methods and equipment used in the examples are conventional methods and equipment in the art, and the raw materials used are conventional commercially available raw materials.

The invention utilizes micron-scale and nano-scale polytetrafluoroethylene and macromolecular materials to prepare composite porous foam with superhydrophobicity through twin-screw extrusion and supercritical fluid microcellular foaming process. Combined with PTFE nanoparticles and micro-scale cell structure, a multi-level rough structure with low surface energy is formed on the surface of the porous foam material, thus endowing the foam material with superhydrophobic properties. A super-hydrophobic polytetrafluoroethylene/polymer composite microporous foam, the preparation steps of which include:

S1. Fully dry the polytetrafluoroethylene and polymer materials;

S2. Mix the polytetrafluoroethylene and the polymer material described in step S1 uniformly through a high-speed mixer;

S3. the mixed material described in step S2 is granulated by an extruder;

S4. The pellets obtained in step S3 are foamed to prepare superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam.

Further, the polytetrafluoroethylene described in step S1 includes micro-scale polytetrafluoroethylene and nano-scale polytetrafluoroethylene; the diameter of the micro-scale polytetrafluoroethylene is 5-100 μm, and the diameter of the nano-scale polytetrafluoroethylene is 10~100nm.

Further, the polymer material in step S1 includes one or more of polyethylene, polypropylene, polyurethane, polylactic acid, ABS, and polystyrene.

Further, the added amount of the micron-level polytetrafluoroethylene is 2-10% of the mass of the polymer material, and the added amount of the nano-level polytetrafluoroethylene is 1-5% of the mass of the polymer material.

Further, the extrusion granulation in step S3 adopts a twin-screw or multi-screw extruder. The extruder temperature is 150~250℃, and the screw speed is 80~150rpm.

Further, the foaming method described in step S4 is a supercritical fluid extrusion foaming or intermittent foaming process.

Further, the supercritical fluid is nitrogen or carbon dioxide.

Further, the extrusion temperature in the supercritical fluid extrusion foaming process is 150-250 ° C, and the single-screw or twin-screw supercritical fluid can be used for extrusion foaming, and the pressure in the barrel is 5-15 MPa; the intermittent foaming temperature is 150~200℃, the pressure is 8~20MPa, the soaking time of supercritical fluid is 2~5h, and the foaming is carried out by one-step pressure relief method.

Further, the cells of the prepared superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam are 10-50 μm.

Example 1

The present embodiment uses polypropylene as the base material to provide a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 50 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 50 nm polytetrafluoroethylene with 1 kg of polypropylene pellets uniformly;

S3. Granulate the mixed material described in step S2 by a twin-screw extruder, and the temperature of the extruder is set to 170°C, 210°C, 200°C, 200°C, 190°C, and the extruder screw speed is 100rpm;

S4. the pellet obtained in step S3 is subjected to microcellular foaming by a supercritical fluid extruder, and the temperature of the superfluid extruder is set to 170° C., 210° C., 200° C., 190° C., 190° C., and the control barrel The inner pressure is about 10MPa, and the polytetrafluoroethylene/polypropylene composite microcellular foam is extruded.

Example 2

The present embodiment uses polypropylene as the base material to provide a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam, and the preparation steps are as follows:

S1. Dry 5μm polytetrafluoroethylene and 10nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 5 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 10 nm polytetrafluoroethylene with 1 kg of polypropylene pellets uniformly;

S3. The mixed material described in step S2 is granulated by an extruder, and the temperature of the extruder is set to 170°C, 210°C, 200°C, 200°C, 190°C, and the extruder screw speed is 80rpm;

S4. the pellet of step S3 gained is carried out microcellular foaming by supercritical fluid extruder, the temperature of superfluid extruder is set to 190 DEG C, and the pressure in the control material barrel is about 15MPa, extruded to obtain polytetrafluoroethylene Ethylene/polypropylene composite microcellular foam.

Example 3

The present embodiment uses polypropylene as the base material to provide a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam, and the preparation steps are as follows:

S1. Dry 100μm PTFE and 100nm PTFE and polypropylene pellets at 60°C for 24h;

S2. Mix 20 g of 100 μm polytetrafluoroethylene dried as described in step S1 and 10 g of 100 nm polytetrafluoroethylene with 1 kg of polypropylene pellets uniformly;

S3. the mixed material described in step S2 is granulated by an extruder, the temperature of the extruder is set to 170°C, 210°C, 200°C, 200°C, 190°C, and the extruder screw speed is 150rpm,;

S4. the pellet obtained in step S3 is subjected to microcellular foaming by a supercritical fluid extruder, and the temperature of the superfluid extruder is set to 170° C., 210° C., 200° C., 200° C., 190° C., and the control barrel The inner pressure is about 10MPa, and the polytetrafluoroethylene/polypropylene composite microcellular foam is extruded.

Example 4

The present embodiment uses polypropylene as the base material to provide a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 50 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 50 nm polytetrafluoroethylene with 1 kg of polypropylene pellets uniformly;

S3. Granulate the mixed material described in step S2 through a twin-screw extruder, and the temperature of the extruder is set to 170°C, 210°C, 200°C, 200°C, and 190°C;

S4. the pellets obtained in step S3 are subjected to intermittent foaming through an autoclave, the temperature of the foaming kettle is 180° C., the pressure in the kettle is 15MPa, the immersion time of the supercritical fluid is 3h, and the pressure is relieved for foaming to obtain polytetrafluoroethylene. / Polypropylene composite microcellular foam.

Example 5

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam with polyurethane as the matrix material, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 50 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 50 nm polytetrafluoroethylene with 1 kg of polyurethane pellets uniformly;

S3. The mixed material described in step S2 is granulated by an extruder, and the temperature of the extruder is set to 180°C, 190°C, 200°C, 210°C, 200°C, and the extruder screw speed is 80rpm;

S4. the pellet obtained in step S3 is subjected to microcellular foaming by a supercritical fluid extruder, and the temperature of the superfluid extruder is set to 180° C., 190° C., 200° C., 210° C., 200° C., and the control barrel The inner pressure is about 15MPa, and the polytetrafluoroethylene/polyurethane composite microcellular foam is extruded.

Example 6

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam with polyurethane as the matrix material, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 50 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 50 nm polytetrafluoroethylene with 1 kg of polyurethane pellets uniformly;

S3. The mixed material described in step S2 is granulated by an extruder, and the temperature of the extruder is set to 180°C, 190°C, 200°C, 210°C, 200°C, and the extruder screw speed is 100rpm;

S4. the pellets obtained in step S3 are subjected to intermittent foaming through an autoclave, the temperature of the foaming kettle is 180° C., the pressure in the kettle is 15MPa, the immersion time of the supercritical fluid is 3h, and the pressure is relieved for foaming to obtain polytetrafluoroethylene. /Polyurethane composite microcellular foam.

Example 7

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam with polyurethane as the matrix material, and the preparation steps are as follows:

S1. Dry 100μm PTFE and 100nm PTFE and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 100 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 100 nm polytetrafluoroethylene with 1 kg of polyurethane pellets uniformly;

S3. The mixed material described in step S2 is granulated by an extruder, and the temperature of the extruder is set to 180°C, 190°C, 200°C, 210°C, 200°C, and the extruder screw speed is 100rpm;

S4. the pellet of step S3 gained is carried out intermittent foaming by autoclave, foaming still temperature is 190 DEG C, and the pressure in the still is 15MPa, and the supercritical fluid soaking time is 5h, and the pressure relief is foamed to obtain polytetrafluoroethylene Vinyl/polyurethane composite microcellular foam.

Example 8

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microcellular foam with polyurethane as the matrix material, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 50 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 50 nm polytetrafluoroethylene with 1 kg of polyurethane pellets uniformly;

S3. Granulate the mixed material described in step S2 by a twin-screw extruder, the temperature of the extruder is set to 180°C, 190°C, 200°C, 210°C, 200°C, and the extruder screw speed is 100rpm;

S4. the pellet of step S3 gained is carried out intermittent foaming by autoclave, foaming kettle temperature is 200 DEG C, and pressure in the kettle is 15MPa, and the supercritical fluid soaking time is 2h, and the pressure relief is foamed to obtain polytetrafluoroethylene Vinyl/polyurethane composite microcellular foam.

Example 9

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microporous foam with polyethylene as the base material, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 50 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 50 nm polytetrafluoroethylene with 1 kg of polyethylene pellets uniformly;

S3. Granulate the mixed material described in step S2 by a twin-screw extruder, the temperature of the extruder is set to 150°C, 170°C, 200°C, 200°C, 170°C, and the extruder screw speed is 100rpm;

S4. the pellet obtained in step S3 is subjected to microcellular foaming by a supercritical fluid extruder, and the temperature of the superfluid extruder is set to 150 ℃, 170 ℃, 200 ℃, 200 ℃, 170 ℃, and the control barrel The inner pressure is about 5MPa, and the polytetrafluoroethylene/polyethylene composite microcellular foam is extruded.

Example 10

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microporous foam with polyethylene as the base material, and the preparation steps are as follows:

S1. Dry 100μm PTFE and 100nm PTFE and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 100 μm polytetrafluoroethylene dried as described in step S1 and 50 g of 100 nm polytetrafluoroethylene with 1 kg of polyethylene pellets uniformly;

S3. The mixed material described in step S2 is granulated by an extruder, and the temperature of the extruder is set to 150°C, 170°C, 200°C, 200°C, 170°C, and the extruder screw speed is 80rpm;

S4. the pellet of step S3 gained is carried out intermittent foaming by autoclave, foaming still temperature is 150 DEG C, and the pressure in the still is 8MPa, and the supercritical fluid soaking time is 3h, and the pressure relief is foamed to obtain polytetrafluoroethylene Ethylene/polyethylene composite microcellular foam.

Example 11

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microporous foam with polystyrene as the base material, and the preparation steps are as follows:

S1. Dry 50μm polytetrafluoroethylene and 50nm polytetrafluoroethylene and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of dried 50 μm polytetrafluoroethylene and 50 g of 50 nm polytetrafluoroethylene described in step S1 with 1 kg of polystyrene pellets uniformly;

S3. Granulate the mixed material described in step S2 by a twin-screw extruder, and the temperature of the extruder is set to 180°C, 220°C, 230°C, 250°C, 240°C, and the extruder screw speed is 100rpm;

S4. the pellet obtained in step S3 is subjected to microcellular foaming by a supercritical fluid extruder, and the temperature of the superfluid extruder is set to 180° C., 220° C., 230° C., 250° C., 240° C., and the control barrel The inner pressure is about 10MPa, and the polytetrafluoroethylene/polystyrene composite microcellular foam is extruded.

Example 12

The present embodiment provides a super-hydrophobic polytetrafluoroethylene/polymer composite microporous foam with polystyrene as the base material, and the preparation steps are as follows:

S1. Dry 100μm PTFE and 100nm PTFE and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of 100 μm polytetrafluoroethylene dried in step S1 and 50 g of 100 nm polytetrafluoroethylene with 1 kg of polystyrene pellets uniformly;

S3. The mixed material described in step S2 is granulated by an extruder, and the temperature of the extruder is set to 180°C, 220°C, 230°C, 250°C, 240°C, and the extruder screw speed is 100rpm;

S4. the pellet of step S3 gained is carried out intermittent foaming by autoclave, foaming kettle temperature is 200 DEG C, and the pressure in the kettle is 20MPa, and the supercritical fluid soaking time is 2h, and the pressure relief is foamed to obtain polytetrafluoroethylene Ethylene/polystyrene composite microcellular foam.

Comparative Example 1

S1. Dry 50μm PTFE and polypropylene pellets at 60°C for 24h;

S2. Mix 100 g of the dried 50 μm polytetrafluoroethylene described in step S1 with 1 kg of polypropylene pellets uniformly;

S3. Granulate the mixed material described in step S2 by a twin-screw extruder, and the temperature of the extruder is set to 170°C, 210°C, 200°C, 200°C, 190°C, and the extruder screw speed is 100rpm;

S4. the pellet obtained in step S3 is subjected to microcellular foaming by a supercritical fluid extruder, and the temperature of the superfluid extruder is set to 170° C., 210° C., 200° C., 190° C., 190° C., and the control barrel The inner pressure is about 10MPa, and the polytetrafluoroethylene/polypropylene composite microcellular foam is extruded.

The invention utilizes micron-level and nano-level polytetrafluoroethylene and macromolecular materials to obtain super-hydrophobic composite foam materials through extrusion and super-fluid foaming processes, utilizes micron-level polytetrafluoroethylene to form fibers in situ, and nano-level polytetrafluoroethylene Tetrafluoroethylene and micron-sized PTFE form a multi-level rough structure to achieve the super-hydrophobicity of the syntactic foam. The raw material required by the invention is single and the cost is low. The preparation process of the invention is simple, the super-hydrophobic composite microporous foam material can be prepared only by extrusion and superfluid foaming process, and the composite microporous foam board or block can be produced in large quantities.

Through the comparison of Figure 1, Figure 2 and Figure 3, Figure 4, on the surface of the microcellular foam material, the surface of the micro-scale and nano-scale polytetrafluoroethylene added is rougher, forming a multi-level rough structure, which is beneficial to the material. Hydrophobic properties. From Figures 7 to 9, it can be seen that the PTFE/polypropylene composite microcellular foam prepared by micro- and nano-scale PTFE has super-hydrophobic properties, and the water contact angle is greater than 150°. The hydrophobic properties of the PTFE/PP composite microcellular foam are better. It can be seen from Figure 5, Figure 6 and Figure 10 that the PTFE/polypropylene composite microcellular foam that has been polished for 500 times still has good hydrophobic properties. It can be seen from Fig. 11 that the polytetrafluoroethylene/polypropylene composite microcellular foam prepared by the present invention can well adsorb various organic substances. Therefore, the polytetrafluoroethylene/polymer composite microporous foam prepared by the method of the present invention has the effects of super-hydrophobicity, high adsorption and strong practicability.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (8)

1. a preparation method of super-hydrophobic polytetrafluoroethylene/polymer material composite microcellular foam, it is characterized in that, the inner and outer surfaces of described super-hydrophobic polytetrafluoroethylene/polymer material composite microcellular foam are covered with multi-level roughness The polytetrafluoroethylene network and particles, the preparation steps of which include: S1. Dry the micron-scale PTFE and nano-scale PTFE and polymer materials; S2. Mix the micron-level polytetrafluoroethylene, nano-level polytetrafluoroethylene and macromolecular material described in step S1 uniformly; S3. the mixed material described in step S2 is granulated by an extruder; S4. prepare superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam by foaming the pellets obtained in step S3; The diameter of the micro-scale PTFE in step S1 is 5-100 μm, and the diameter of the nano-scale PTFE is 10-100 nm; the polymer material described in step S1 includes polyethylene, polypropylene, polyurethane, polylactic acid, ABS , one or more of polystyrene. 2. the preparation method of super-hydrophobic polytetrafluoroethylene/polymer material composite microcellular foam according to claim 1, is characterized in that, the addition of described micron-level polytetrafluoroethylene is 2～10% of macromolecular material quality %, the addition amount of nano-polytetrafluoroethylene is 1~5% of the mass of the polymer material. 3. the preparation method of super-hydrophobic polytetrafluoroethylene/polymer material composite microcellular foam according to claim 1, is characterized in that, in step S2, also add antioxidant, heat stabilizer, reinforcing agent, toughening agent , one or more coupling agents. 4. the preparation method of super-hydrophobic polytetrafluoroethylene/polymer material composite microcellular foam according to claim 1, is characterized in that, the described extrusion granulation of step S3 adopts twin-screw or multi-screw extruder, extruding The outlet temperature is 150~250℃, and the screw speed is 80~150rpm. 5. the preparation method of superhydrophobic polytetrafluoroethylene/polymer material composite microcellular foam according to claim 1, is characterized in that, the foaming method described in step S4 is supercritical fluid extrusion foaming method or intermittent foaming Law. 6. the preparation method of the superhydrophobic polytetrafluoroethylene/polymer material composite microcellular foam according to claim 5, is characterized in that, the supercritical fluid in described supercritical fluid extrusion foaming method is nitrogen or carbon dioxide. 7. the preparation method of the superhydrophobic polytetrafluoroethylene/polymer material composite microcellular foam according to claim 5, is characterized in that, in the supercritical fluid extrusion foaming process, extrusion temperature is 150～250 ℃, adopts single Screw or twin-screw supercritical fluid extrusion foaming, the pressure in the barrel is 5~15MPa; the intermittent foaming temperature is 150~200℃, the pressure is 8~20MPa, the soaking time of the supercritical fluid is 2~5h, and one-step unloading is adopted. foaming by pressing. 8. the preparation method of the superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam according to claim 1, is characterized in that, the cell of the prepared superhydrophobic polytetrafluoroethylene/polymer composite microcellular foam is 10~50μm.

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