RU2510408C1 - Polymer binder and prepreg based thereon - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of binder for polymer composite materials, used to make structures based on carbon fibre filler with operating temperature of 200-400°C, and can be used in aircraft, aerospace, motor car and ship-building and other industries. The polymer binder for composite materials consists of, pts.wt: tetranitrile of aromatic tetracarboxylic acid 100, polyester imide thermoplastic 2-10, amine curing agent 2-6. Also disclosed is a prepreg containing the disclosed polymer binder and fibre filler, with the following ratio of components, wt %: polymer binder 30.0-40.0, fibre filler 60.0-70.0. The fibre filler used is glass fibre or carbon fibre filler.

EFFECT: making high-strength articles at high temperature.

3 cl, 3 tbl

Description

The invention relates to the field of high molecular chemistry, in particular to the production of binders for polymer composite materials (PCM) used for the manufacture of structures based on fibrous carbon fillers with a working temperature of 200-400 ° C, and can be used in aviation, aerospace, automotive, shipbuilding and other industries.

Known binder for polymer composite materials having the following chemical composition, parts by weight:

4,4'-bismaleimide diphenylmethane 78-82 resorcinol 18-22 tribromophenylmaleimide 2-7 1,2-bis (hydroxymethyl) carboran 2-3 furfural 4-5

The prepreg is obtained by impregnating T-10-80 fiberglass on an impregnating machine or by applying a powder binder to a carbon filler in an electrostatic field, followed by drying at 100-110 ° C. The prepregs are pressed by direct compression at a temperature of 165-170 ° C. The obtained PCMs have a bending strength of 880-890 MPa and retain 80-85% of the initial strength at 300 ° C (RF patent No. 2052474).

The main disadvantages include the use of high-boiling organic solvents in the binder, which do not allow obtaining monolithic PCM samples, the toxicity of the components used in the binder, insufficient physical and mechanical properties of the PCM at 400 ° C from the initial properties at room temperature.

Known binders, formed by the interaction of phthalonitrile monomers in the molten state with halogen-containing aromatic amines, and polymer composite materials based on them with a working temperature of up to 400 ° C (US patents No. 5925475, No. 5389441; Sastri S., Armistead JP, Keller TM Polym. Compos. ., 1996, v.17, p. 816-822; Dominguez DD, Keller TM High Perform Polym., 2006, v. 18, p. 283-304).

The disadvantages of the known binders: low viability, which does not allow to process this material using autoclave-free technologies; high synthesis temperature up to 280 ° C.

The closest analogue adopted for the prototype is a polymer binder for composite materials having the following chemical composition, parts by weight:

3,3'-dicyano-4,4'-diaminodiphenylmethane 40.7 4,4 '- (m-phenylenedioxy) diphthalonitrile 53.3-59.3 1,2-bis (cyanoethyl) carboran 10-30

and a prepreg comprising a binder, fiberglass or carbon filler, in the following ratio of components in parts by weight:

polymer binder 24-42 fiberfill 58-76 (RF patent No. 2201423).

The disadvantages of the prototype binder for polymer composite materials is the presence of 1,2-bis (cyanoethyl) carborane in the composition, as a result of the interaction of which with other components of the binder, side reactions can occur during polymerization with the formation of low molecular weight products, which leads to high porosity of the polymer composite material based on it; low binder viability (15-30 min at the processing temperature), which does not allow to process this material using autoclave-free technologies.

An object of the invention is the creation of a polymer binder and a prepreg based on it for polymer composite materials with a working temperature of up to 400 ° C, with low porosity, increased viability, with physical and mechanical properties at the level of the prototype.

To solve the technical problem, a polymer binder for composite materials is proposed, obtained from aromatic tetracarboxylic acid tetranitrile, a thermoplastic polyesterimide and amine hardener, in the following ratio of components, parts by weight:

aromatic tetracarboxylic acid tetranitrile one hundred polyetherimide thermoplastic 2-10 amine hardener 2-6

A prepreg is also proposed, including the proposed polymer binder and fibrous filler in the following ratio of components, wt.%:

polymer binder 30.0-40.0 fiberfill 60.0-70.0

As the fibrous filler, fiberglass or carbon fiber filler is used.

It was found that the use of the amine hardener in the claimed amount slows down the vitrification of the polymer binder and promotes a smoother oligocyclotrimerization, almost completely eliminates side processes that increase porosity, which in turn leads to the production of monolithic defect-free matrices with low porosity.

The use of a polyetherimide thermoplastic in the invention makes it possible to obtain a polymer binder, prepregs and composite materials based on it with enhanced physical and mechanical properties at the prototype level and an operating temperature of up to 400 ° C. Being in the binder system, thermoplastic polyetherimide during curing does not integrate into the polymer structure, but forms a separate phase. When loading materials and products made on the basis of the proposed polymer binder, growing microcracks, meeting the plastic phase of the thermoplastic in the matrix, are braked and more energy is required for their further advancement, which ultimately increases the total energy expenditure required for the complete destruction of the material.

The introduction of thermoplastic polyetherimide into a polymer binder helps to increase its thermomechanical characteristics, the strength of materials and products based on it under shear at quasistatic loading speeds and significantly increases their compressive strength.

As the tetranitrile of aromatic tetracarboxylic acid, 4.4 '- (m-phenylenedioxy) diphthalonitrile, 4.4' - (2,2-propylidene-bis (p-phenylenedioxy) diphthalonitrile, 4.4 '- (2.2 -sulfo-bis (p-phenylenedioxy) diphthalonitrile (TU 2472-001-12669346-05).

The invention uses a thermoplastic polyetherimide grades Ultem® PEI 1000 (GM GMP.PEI.001), Skybond 700, LARC-TPI.

A complex of boron trifluoride with benzylamine (TU 2494-664-11131395-2010), 4,4-diaminodiphenylmethane (TU 6-14-415-80), 4,4-diaminodiphenylsulfone (TU 6-14-17- 95).

UT-900 fabric (TU 916-155-05763346-95), carbon tape of the LU-24P brand (TU 6-06-31-560-86) or carbon tape UOL-300 (TU 1916-167- 05763346-96), aluminoborosilicate fiberglass with a satin structure (GOST 19170-73), quartz fiberglass with a satin structure (TU 6-11-216-71).

Examples of carrying out the invention

Example 1

Getting a binder

100 parts by weight were loaded into a reactor equipped with a mechanical stirrer, heating and cooling. 4,4 '- (m-phenylenedioxy) -diphthalonitrile and was melted in a stream of inert gas. Then downloaded 2 wt.h. a thermoplastic polyetherimide Ultem ^® PEI 1000 and fusion was performed. After that, 2 wt.h. complex of boron trifluoride with benzylamine. The mixture was stirred, then the melt was drained. After cooling the melt, the polymer binder was crushed to a fine powder with a particle size of not more than 500 microns.

Getting glass

A prepreg was prepared by spraying 30 wt.% Of a powdery polymer binder onto an alumina-borosilicate glass cloth of a satin structure in an amount of 70 wt.%, Followed by reflow.

Getting coal shatter

The prepreg was obtained by spraying 40 wt.% Of a powdery polymer binder onto a carbon tape LU-24P in an amount of 60 wt.%, Followed by reflow.

Example 2

Getting a binder

100 parts by weight were loaded into a reactor equipped with a mechanical stirrer, heating and cooling. 4.4 '- (2,2-propylidene-bis (p-phenylenedioxy) diphthalonitrile was melted in an inert gas stream. Then 10 parts by weight of LARC-TPI polyetherimide thermoplastic were loaded and fusion was performed. After that, 2 parts by weight were loaded. 4,4-diaminodiphenylmethane. The mixture was stirred, then the melt was drained. After cooling the melt, the polymer binder was ground to a fine powder with a particle size of not more than 500 microns.

Getting glass

Analogously to example 1 receive glass reinforcement with the following ratio of components, wt.%:

binder thirty fiberglass 70

Getting coal shatter

Analogously to example 1 get uglerepreg using as a carbon filler fabric brand UT-900 with the following ratio of components wt.%:

binder 40 carbon fiber filler 60

Example 3

Getting a binder

100 parts by weight were loaded into a reactor equipped with a mechanical stirrer, heating and cooling. 4.4 '- (2,2-sulfo-bis (p-phenylenedioxy) diphthalonitrile was melted in an inert gas stream. Then 10 parts by weight of a Skybond 700 polyetherimide thermoplastic were loaded and fused. After that, 2 parts by weight of 4 , 4-diaminodiphenylsulfone. The mixture was stirred, then the melt was poured. After cooling the melt, the polymer binder was ground to a fine powder with a particle size of not more than 500 microns.

Getting glass

Analogously to example 1, a glass reinforcement is prepared using a satin structure with a quartz glass fabric as a filler with the following ratio of components, wt.%:

binder thirty fiberglass 70

Getting coal shatter

Analogously to example 1 get uglerepreg using as a carbon filler tape brand UOL-300 with the following ratio of components wt.%:

binder 40 carbon fiber filler 60

The properties of the polymer binder according to the invention and the prototype are shown in table 1, the properties of the prepregs according to the invention and the prototype are shown in table 2, the properties of the products according to the invention and the prototype are shown in table 3.

The thermal stability of the cured polymeric binder was determined by the method of thermomechanical analysis according to MM 1.595-11-246-2005 on the Netzsch DMA 242 C thermoanalytical installation.

Determination of the strength characteristics of the obtained composite materials: compressive strength - according to GOST 25.602-80, interlayer shear strength using the short beam method - according to OST 190199-75.

Comparative data from table 1 show that the proposed polymer binder is operable at temperatures up to 400 ° C, and also has increased viability (gelation time at 230 ° C 5-35 times higher) during processing compared to the prototype binder.

Comparative data from table 3 show that the obtained composite material based on the proposed polymer binder has a low porosity of 0.6-0.8%, high physical and mechanical properties at the level of the prototype at an operating temperature of up to 400 ° C, while maintaining strength 80- 90% of the original.

The composition of the proposed binder does not include a scarce and expensive 1,2-bis (cyanoethyl) carborane, the use of which in the composition of the prototype binder can lead to an uncontrolled exothermic reaction.

The proposed binder has universality in the choice of processing technology: it can be processed both by pressure impregnation using rigid mold punches, and its varieties - vacuum impregnation, as well as by powder technology, by spraying it onto a filler in an electrostatic field, followed by drying, or by prepreg technology. The polymer binder for composite materials at a processing temperature (190 ° C) has a low viscosity, not more than 0.15 Pa · s, and homogeneity, which contribute to an easy and uniform distribution of the binder between the filler particles.

The developed polymer binder, prepregs made on its basis, make it possible to create high-strength products with improved physical and mechanical characteristics, and maintaining strength of 80-90% of the original at elevated temperatures up to 400 ° C.

Table number 1 Name of the properties of the binder Example Properties Prototype one 2 3 Gelation time at 230 ° С, min 276 117 37 8 Temperature 10% mass loss in air 560 540 530 550 Glass transition temperature, ° С 500 490 470 490 The compressive strength, σ _-in , MPa 300 310 330 280 Impact strength, kJ / m twenty 22 25 twenty

Table number 2 Name of properties of prepregs Example Properties Prototype one 2 3 Surface density, g / m ² carbon repreg 328 317 324 302 Gelation time at 230 ° С, min fiberglass 83.51 31.64 12.03 2.43 carbon repreg 82.68 31.34 11.10 2.11 The temperature of the onset of an active reaction (heating rate 10 ° C / min), T _onset , ° C fiberglass 218.2 215.6 210.1 196.7 carbon repreg 212.1 210.0 204.3 188.6 The temperature of the reaction maximum (heating rate 10 ° C / min), Tm, ° C fiberglass 270,0 268.6 266.7 242.2 carbon repreg 261.2 259.2 255.1 238.4

Table number 3 Name of the properties of polymer composite materials Test temperature, ° С Properties examples by Prototype one 2 3 Carbon fiber monolayer thickness, mm twenty 0.174 0.171 0.173 0.173 The density of carbon plastics, g / cm ³ twenty 1,587 1,582 1,585 1,451 Carbon porosity twenty 0.63 0.57 0.78 1.8 Strength in the interlayer shear of carbon plastics according to the examples τ _1.3 , MPa twenty 51 55 56 54 400 45 fifty 49 43 Tensile strength under static bending of fiberglass according to examples, σ _VI , MPa twenty 871 894 886 863 400 785 811 808 726

Claims (3)

1. A polymer binder for composite materials obtained from aromatic tetracarboxylic acid tetranitrile, a thermoplastic polyesterimide and amine hardener, in the following ratio, wt.h:
aromatic tetracarboxylic acid tetranitrile one hundred polyetherimide thermoplastic 2-10 amine hardener 2-6 2. A prepreg comprising a polymeric binder and a fibrous filler, characterized in that the binder according to claim 1 is used as the polymeric binder in the following ratio of components, wt.%:
polymer binder 30.0-40.0 fiberfill 60.0-70.0 3. The prepreg according to claim 2, characterized in that fiberglass or carbon fiber filler is used as the fibrous filler.