CN110105665A - A kind of thermosetting/thermoplastic copoly type composite foam and its preparation method and application - Google Patents

Abstract

The invention relates to a thermosetting/thermoplastic copolymerization type composite foam and its preparation method and application. The preparation method: a. heating the hollow microspheres after mixing with the coupling agent; b. stirring and mixing the thermosetting resin matrix and the curing agent c. Stir the modified hollow microspheres and the resin matrix evenly to obtain the hollow microspheres/thermosetting resin; d. Stir and mix the foaming agent, the modified maleic anhydride grafted polypropylene and the thermoplastic resin matrix; e 1. Mix the mixed base material with hollow microspheres/thermosetting resin evenly; f. Put it into an extruder or injection molding machine to prepare a profile or sheet; g. Heat the profile or sheet to obtain a new type of thermosetting/thermoplastic copolymer composite foam. The composite foam of the present invention can be widely used in sandwich foam structures of thermoplastic and thermosetting composite materials, and is especially suitable for sandwich structures of thin-layer composite materials, including automotive interior parts, shells of various electronic products, shells of small ships, UAV composite structure and other fields.

Description

A kind of thermosetting/thermoplastic copolymerization composite foam and its preparation method and application

technical field

The invention relates to the technical field of resin-based composite materials, in particular to a thermosetting/thermoplastic copolymerized composite foam and its preparation method and application.

Background technique

Composite foam, also known as polymer composite foam and composite foam, is a kind of foam formed by combining light, high-strength hollow spheres such as glass microspheres or ceramic microspheres with matrix resin. This material is able to maintain adequate strength at lower densities, has high compressive strength/weight ratio, low creep and low water absorption. Thermosetting epoxy composite foam has been widely used in underwater equipment, so it is also called solid buoyancy material. It is also used as a structural foam core material in some high-performance thin-layer composite sandwich structures, and has been widely used in aerospace composite materials. Syntactic foams are much stiffer and stronger than conventional foams.

The low density of syntactic foam is mainly due to the large number of hollow spheres dispersed uniformly in the matrix material. The hollow microspheres used include glass microspheres, polymer microspheres, ceramic microspheres, carbon microspheres, metal microspheres and the like. Between 20 and 150 microns in diameter, the size of the hollow microspheres determines the cell size of the syntactic foam. After the surface treatment of the hollow microspheres with the coupling agent, the advanced molding process is used to organically fuse with the matrix resin to further strengthen the performance of the entire material. The requirements for the base material are strong adhesion, low water absorption, excellent thermal and electrical properties. The overall density of syntactic foam can be controlled between 0.40g/cm ³ and 0.65g/cm ³ .

The existing composite foam is divided into thermosetting type and thermoplastic type. The thermosetting foam core material can only be bonded with the thermosetting composite material surface layer. Similarly, the thermoplastic foam core material can only be bonded with the thermoplastic composite material surface layer. Otherwise, it is very likely that the interlayer delamination between the surface layer of the composite material and the core material will occur, which will lead to the failure of the sandwich structure of the composite material. Domestic and foreign patents on thermoplastic composite foam mainly involve glass microspheres filling thermoplastic resin matrix; while domestic and foreign patents on thermosetting composite foam mainly involve glass microspheres filling thermosetting resin matrix. The thermosetting/thermoplastic blended syntactic foam mentioned in this patent and its bonding method with the carbon fiber composite surface layer have not been mentioned in the relevant published patents and documents.

Contents of the invention

The purpose of the present invention is to solve the deficiencies of the above technical problems, to provide a thermosetting/thermoplastic copolymer composite foam and its preparation method and application, which can be widely used in the sandwich foam structure of thermoplastic and thermosetting composite materials, especially suitable for Thin-layer composite material sandwich structures, including automotive interior parts, various electronic product shells, small ship shells, composite material structures for drones, etc.

In order to solve the deficiencies of the above-mentioned technical problems, the technical solution adopted by the present invention is: a preparation method of thermosetting/thermoplastic copolymerization type composite foam, comprising the following steps:

a. After mixing the hollow microspheres with the coupling agent, heat them to obtain the modified hollow microspheres, which are set aside;

b. Stir and mix the thermosetting resin matrix and curing agent, set aside;

c. Stir the modified hollow microspheres prepared in step a and the resin matrix prepared in step b evenly to obtain hollow microspheres/thermosetting resin, which are set aside;

d. Stir and mix the foaming agent, maleic anhydride grafted polypropylene and thermoplastic resin matrix to obtain a mixed base material for subsequent use;

e. Mix the mixed base material prepared in step d with the hollow microspheres/thermosetting resin prepared in step c to obtain a mixed prefabricated material for subsequent use;

f. Put the mixed preform prepared in step e into the hopper of an extruder or an injection molding machine to prepare a profile or sheet;

g. Heating the profile or sheet prepared in step f to fully cure the thermosetting resin in the material to obtain a novel thermosetting/thermoplastic copolymer composite foam.

As a further optimization of the preparation method of a thermosetting/thermoplastic copolymerized composite foam of the present invention: the hollow microspheres are glass microspheres, polymer microspheres, ceramic microspheres, carbon microspheres or metal microspheres, and the hollow microspheres The balls are baked to remove any remaining moisture before use. .

As a further optimization of the preparation method of a thermosetting/thermoplastic copolymerized composite foam of the present invention: the thermosetting resin matrix is epoxy resin, alkenyl ester resin, phenolic resin, unsaturated polyester resin or polyimide resin.

As a further optimization of the preparation method of a thermosetting/thermoplastic copolymer composite foam of the present invention: the thermoplastic resin is polypropylene resin, nylon, polyethylene, polyester, polyamide, polyoxymethylene or their copolymers.

As a further optimization of the preparation method of a thermosetting/thermoplastic copolymerized composite foam of the present invention: the foaming agent is expanded polymer microspheres, azodicarbonamide or hydrocarbon foaming agent.

As a further optimization of the preparation method of a thermosetting/thermoplastic copolymerized composite foam of the present invention: the ratio of the amount of hollow microspheres to the coupling agent in step a is 100:0.1-10, and in step b, the thermosetting resin matrix and The ratio of the addition amount of curing agent is 100:10-150, the ratio of the addition amount of modified hollow microspheres and resin matrix in step c is 100:80-150, in step d, foaming agent, thermoplastic resin matrix, Malay The ratio of the amount of the anhydride grafted polypropylene is 0.1-10:30-60:5-20, and the ratio of the amount of the mixed base material to the hollow microsphere/thermosetting resin in step e is 100:50-100.

As a further optimization of the preparation method of a thermosetting/thermoplastic copolymerized composite foam of the present invention: the temperature set in the molding process in step f is 190°C, and in step e, put the foam into a drying room or an oven and heat it to 120°C After 3 hours of heat preservation, it was gradually cooled to room temperature, and the heating and cooling speeds were both controlled at 1°C/min.

A thermosetting/thermoplastic copolymerized composite foam is prepared by the preparation method of the above composite foam.

The application of the above-mentioned thermosetting/thermoplastic copolymerization syntactic foam in the preparation of sandwich structure composite materials.

The application of the above-mentioned thermosetting/thermoplastic copolymerized syntactic foam in the preparation of sandwich structure composite materials: take polyester fiber fabric, carbon fiber/epoxy resin prepreg and syntactic foam, according to carbon fiber/epoxy resin prepreg-polyester Fiber fabric-composite foam-polyester fiber fabric-carbon fiber/epoxy resin prepreg are laid together in sequence, under the pressure of 1.0MPa, heat up to 150°C and keep it for 20min, cool naturally to 50°C, take it out, and you can get a sandwich Structural composites.

Beneficial effect

1. The thermosetting/thermoplastic copolymer composite foam prepared by the present invention can be widely used as a folder for thermoplastic and thermosetting composite materials by selecting both thermosetting resin and thermoplastic resin with specific content and combining specific content of hollow spheres. The core foam structure is especially suitable for thin-layer composite material sandwich structures, including automotive interior parts, various electronic product shells, small ship shells, composite material structures for drones, etc.;

Two, the composite foam prepared by the present invention can be bonded separately or simultaneously with the thermosetting and/or thermoplastic carbon fiber composite surface layer, and the bonding performance of the composite foam and the thermosetting and/or thermoplastic composite surface layer is good, and will not Delamination of the syntactic foam from the thermoset and/or thermoplastic composite facings occurs.

Description of drawings

Fig. 1 is the schematic flow chart diagram of composite foam preparation process of the present invention;

Fig. 2 is the connection mechanism schematic diagram of each component of composite foam of the present invention;

Fig. 3 is the schematic diagram of the preparation process of composite foam of the present invention;

Fig. 4 is the schematic diagram of the preparation process of the sandwich structure composite material of the present invention;

Fig. 5 is the scanning electron micrograph of composite foam of the present invention;

Fig. 6 is the scanning electron micrograph of sandwich structure composite material of the present invention;

Fig. 7 is the test diagram of bonding strength between surface layer and core material;

Fig. 8 is a three-point bending test diagram of the sandwich structure composite material of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with specific embodiments.

Example 1

A method for preparing a thermosetting/thermoplastic copolymerized composite foam, the preparation process and process are shown in Figure 1 and Figure 3, comprising the following steps:

The list of raw materials is as follows:

a. Take 100Kg of hollow glass microspheres K20, carry out surface treatment with 1Kg of coupling agent KH560, heat and bake, remove the surface solvent, obtain modified hollow glass microspheres, and set aside;

b. Take 100Kg of epoxy resin, add 80Kg of acid anhydride curing agent, stir evenly, remove air bubbles by vacuum method, and set aside;

c. Take 100Kg of modified hollow glass microspheres prepared in step a and 107.8Kg of resin matrix prepared in step b and stir evenly to obtain hollow glass microspheres/thermosetting resin for subsequent use;

d. Take 2Kg of expanded polymer microspheres, 80Kg of polypropylene, and 80Kg of maleic anhydride grafted polypropylene and stir and mix to obtain a mixed base material for subsequent use;

e. Mix 100Kg of the mixed base material prepared in step d with 86Kg of hollow glass microspheres/thermosetting resin prepared in step c to obtain a mixed prefabricated material for subsequent use;

f. Put the mixture prepared in step e into the hopper of an extruder or injection molding machine, set the temperature of the machine to 190°C, and prepare molding materials or sheets;

g. Put the profile or sheet prepared in step f into a drying room or an oven, heat it to 120°C for 3 hours, and then gradually cool it to room temperature. Thermosetting/thermoplastic copolymer syntactic foam (Figure 5 is a SEM photo of syntactic foam).

The chemical reaction mechanism of each component in the syntactic foam is shown in Figure 2. The hydroxyl group in methyltetrahydrophthalic anhydride can react with the siloxy group in the hollow glass microspheres to form a chemical bond, and at the same time it can cure the epoxy resin, and the epoxy resin can react with the maleic anhydride-modified polypropylene Chemical bonding and physical entanglement between the two polypropylenes make the syntactic foam an effective monolithic structure.

Example 2

A preparation method of thermosetting/thermoplastic copolymerization type composite foam, comprising the following steps:

a. Take 100Kg of hollow glass microspheres K20, use 5Kg of coupling agent KH560 to carry out surface treatment, heat and bake, remove the surface solvent, obtain modified hollow glass microspheres, and set aside;

b. Take 100Kg of epoxy resin, add 10Kg of acid anhydride curing agent, stir evenly, remove air bubbles by vacuum method, and set aside;

c, get the modified hollow glass microspheres 100Kg prepared in step a and the resin matrix 80Kg prepared in step b and stir evenly to obtain hollow glass microspheres/thermosetting resin for subsequent use;

d, get foaming agent 10Kg, epoxy resin matrix 160Kg, maleic anhydride grafted polypropylene 120Kg and stir and mix, obtain mixed base material, for subsequent use;

e, take 100Kg of the mixed base material prepared in step d and mix evenly with 100Kg of hollow microspheres/thermosetting resin prepared in step c to obtain a mixed prefabricated material for subsequent use;

f. Put the mixture prepared in step e into the hopper of an extruder or injection molding machine, set the temperature of the machine to 190°C, and prepare molding materials or sheets;

g. Put the profile or sheet prepared in step f into a drying room or an oven, heat it to 120°C for 3 hours, and then gradually cool it to room temperature. Thermoset/thermoplastic copolymer syntactic foam.

h. Prepare two layers of polyester fiber fabric with an area density of 30g/m2, ^two layers of carbon fiber/epoxy resin prepreg with an area density of 155 g/ ^m2 , and one layer of epoxy modified composite material with a thickness of 1.0mm , and lay it out in the manner shown in Figure 4;

I. Heat up the sandwich composite materials placed in order under a pressure of 1.0MPa to 150°C for 20 minutes, cool naturally to 50°C, and take them out to obtain a sandwich composite structure with a thickness of about 1.5mm and an overall density of about 0.8g /cm ³ . Figure 6 is a metallographic photograph of a sandwich composite structure.

Example 3:

A preparation method of thermosetting/thermoplastic copolymerization type composite foam, comprising the following steps:

a. Take 100Kg of hollow glass microspheres K20, use 0.5Kg of coupling agent KH560 to carry out surface treatment, heat and bake, remove the surface solvent, obtain modified hollow microspheres, and set aside;

b. Take 100Kg of epoxy resin, add 20Kg of acid anhydride curing agent, stir evenly, remove air bubbles by vacuum method, and set aside;

c, get the modified hollow microspheres 100Kg prepared in step a and the resin matrix 150Kg prepared in step b and stir evenly to obtain hollow microspheres/thermosetting resin, and set aside;

d, take foaming agent 2Kg, thermoplastic resin matrix 80Kg, maleic anhydride grafted polypropylene 80Kg and stir and mix to obtain the mixed base material for subsequent use;

e, take 100Kg of the mixed base material prepared in step d and mix evenly with 50Kg of hollow microspheres/thermosetting resin prepared in step c to obtain a mixed prefabricated material for subsequent use;

f. Put the mixture prepared in step e into the hopper of an extruder or injection molding machine, set the temperature of the machine to 190°C, and prepare molding materials or sheets;

g. Put the profile or sheet prepared in step f into a drying room or an oven, heat it to 120°C for 3 hours, and then gradually cool it to room temperature. Thermoset/thermoplastic copolymer syntactic foam.

h. Prepare two layers of carbon fiber/epoxy resin prepreg with an area density of 155 g/m ² and one layer of composite foam with a thickness of 1.0mm, sandwich the composite foam between two layers of carbon fiber/epoxy resin prepreg laying;

1. Under the pressure of 1.0 MPa, the composite materials placed in order are heated up to 150° C. for 20 minutes, cooled naturally to 50° C., and taken out to obtain a composite material without the transition layer polyester fabric.

Take the composite material prepared in Example 2 and the composite material prepared in Example 3, and use the pull-out method to compare and test the bonding strength between the surface layer and the core material. The test chart is shown in Figure 7 (a is before the pull-out test. , b is after drawing composite material with transition layer, c is after drawing composite material without transition layer). The distribution of test results is that the pull-out force with transition layer is 3.3MPa, and the pull-out force without transition layer is 0.5MPa. After adding the bonding transition layer between the core material and the surface layer composite material, the bonding effect between the two is obviously improved.

Reference standard GB/T 1449-2005 Fiber Reinforced Plastics Bending Performance Test Method Three-point bending test is performed on the sandwich composite structure with and without transition layer PET fabric, and the bending test strength of the sandwich structure composite material after adding the transition layer is 650.7 MPa, there is no delamination phenomenon in the damaged part, and the bending strength of the sandwich composite material without adding layers is 243.4MPa, and obvious delamination phenomenon can be seen between the core material and the carbon fiber surface layer in the damaged part.

Embodiment 4-7:

A preparation method of thermosetting/thermoplastic copolymerization composite foam, other conditions are the same as in Example 1, and the epoxy resin is replaced by alkenyl ester resin, phenolic resin, unsaturated polyester resin and polyimide resin respectively.

Embodiment 8-12:

A preparation method of thermosetting/thermoplastic copolymerization composite foam, other conditions are the same as in Example 1, and the polypropylene resin is replaced by nylon, polyethylene, polyester, polyamide and polyoxymethylene respectively.

Examples 13-14:

A preparation method of a thermosetting/thermoplastic copolymerization type composite foam, other conditions are the same as in Example 1, and the expanded polymer microspheres are replaced by azodicarbonamide and a hydrocarbon foaming agent respectively.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but if they do not depart from the technical solution of the present invention, according to this Technical Essence of the Invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (10)

1. a preparation method of thermosetting/thermoplastic copolymerization type composite foam, is characterized in that: comprise the following steps: a. After mixing the hollow microspheres with the coupling agent, heat them to obtain the modified hollow microspheres, which are set aside; b. Stir and mix the thermosetting resin matrix and curing agent, set aside; c. Stir the modified hollow microspheres prepared in step a and the resin matrix prepared in step b evenly to obtain hollow microspheres/thermosetting resin, which are set aside; d. Stir and mix the foaming agent, maleic anhydride grafted polypropylene and thermoplastic resin matrix to obtain a mixed base material for subsequent use; e. Mix the mixed base material prepared in step d with the hollow microspheres/thermosetting resin prepared in step c to obtain a mixed prefabricated material for subsequent use; f. Put the mixed preform prepared in step e into the hopper of an extruder or an injection molding machine to prepare a profile or sheet; g. Heating the profile or sheet prepared in step f to fully cure the thermosetting resin in the material to obtain a novel thermosetting/thermoplastic copolymer composite foam. 2. A kind of preparation method of thermosetting/thermoplastic copolymerization composite foam as claimed in claim 1, is characterized in that: described hollow microsphere is glass microsphere, polymer microsphere, ceramic microsphere, carbon microsphere or Metal microspheres and hollow microspheres are baked to remove residual moisture before use. 3. a kind of preparation method of thermosetting/thermoplastic copolymerization type composite foam as claimed in claim 1, is characterized in that: described thermosetting resin matrix is epoxy resin, alkenyl ester resin, phenolic resin, unsaturated polyester resin or polyimide resin. 4. A kind of preparation method of thermosetting/thermoplastic copolymerization type composite foam as claimed in claim 1, is characterized in that: described thermoplastic resin is polypropylene resin, nylon, polyethylene, polyester, polyamide, polyoxymethylene or their copolymers. 5. A kind of preparation method of thermosetting/thermoplastic copolymerization type composite foam as claimed in claim 1, is characterized in that: described blowing agent is macromolecule expanded microsphere, azodicarbonamide or hydrocarbon blowing agent . 6. A kind of preparation method of thermosetting/thermoplastic copolymerization type composite foam as claimed in claim 1, is characterized in that: the ratio of the addition of hollow microspheres and coupling agent in step a is 100:0.1-10, step The ratio of the addition of thermosetting resin matrix and curing agent in b is 100:10-150, the ratio of the addition of modified hollow microspheres and resin matrix in step c is 100:80-150, foaming agent, The ratio of the addition of thermoplastic resin matrix, maleic anhydride grafted polypropylene is 0.1-10:30-60:5-20, and the ratio of the addition of mixed base material and hollow microsphere/thermosetting resin is 100 in step e: 50-100. 7. A method for preparing thermosetting/thermoplastic copolymerization type composite foam as claimed in claim 1, characterized in that: the temperature set during the molding process in the step f is 190°C, and the foam is put into the drying room in the step e Or heat the oven to 120°C for 3 hours, then gradually cool to room temperature, and control the heating and cooling speed at 1°C/min. 8. A thermosetting/thermoplastic copolymerized composite foam, characterized in that the composite foam is made by the method for preparing composite foam according to any one of claims 1-7. 9. Application of a thermosetting/thermoplastic copolymerization syntactic foam in the preparation of sandwich structure composite materials. 10. the application of thermosetting/thermoplastic copolymerization type composite foam as claimed in claim 9 in the preparation of sandwich structure composite material, is characterized in that: get polyester fiber fabric, carbon fiber/epoxy resin prepreg and composite foam, according to Carbon fiber/epoxy resin prepreg-polyester fiber fabric-composite foam-polyester fiber fabric-carbon fiber/epoxy resin prepreg is laid together in sequence, under a pressure of 1.0MPa, the temperature is raised to 150°C for 20min, Cool naturally to 50°C and take it out to obtain a sandwich structure composite material.