RU2278028C1 - Prepreg and article made of the same - Google Patents

Abstract

FIELD: structural materials for airspace industry.

SUBSTANCE: claimed prepreg contains 24-50 mass % of polymer binder and 50-76 mass % of fibrous filler. As fibrous filler carbon, organic, glass bundles, fabrics and strips are used. Polymer binder contains (mass pts): N,N,N'N'-tentraglycidyldiamino-3,3'-dichlorodiphenyl methane as epoxy oligomere 100; 4,4'-diaminediphenyl sulfone as curing agent 44; fullerene C_2n, wherein n >= 30, 0.01-1.0; opened carbon nanotubes 0.1-1.5; fulleroidal multilayered nanomodifier 0.5-10, and fullerene amino derivative of general formula C₆₀(GA)₆. Said amino derivative represents reaction product of fullerene C₆₀ with hepthylamine (GA). Article from prepreg is obtained by extrusion.

EFFECT: prepreg with decreased flowability and gel-forming time; composites of increased degradation energy and rest compressive strength.

3 tbl, 9 ex

Description

The invention relates to the field of high-modulus polymer composite materials containing a polymeric binder and a fibrous filler, used as material of supporting structural elements of aircraft and space technology.

Epoxy binders for fiber composites are known. They do not give significant shrinkage phenomena during curing, have good adhesion to reinforcing fibers, including high-modulus carbon fibers with a passive surface.

In particular, binders based on diglycidyl ether of bisphenol A or N, N, N ', N'-tetraglycidyldiaminodiphenylmethane and hardeners - dicyandiamide or 4,4'-diaminodiphenylsulfone, used to produce heat-resistant polymer composites used in the aviation industry (Lee H. and Neivlle K., Handbook of Epoxy Resins, Me Graw-Hill, New York, 1967, p. 11, 48; Japanese Application No. 55-25217).

The multifunctionality of epoxy oligomers and hardeners provides developed spatial crosslinking and thermal stability of these compositions in the cured state.

However, at the same time, a high crosslinking density gives the thermoset matrix an increased fragility and deformability limited to 0.3-0.5%.

Plasticizers are used to increase the deformability, for example, diglycidyl ether of dimeralinolenic acid (Rinde J., Mones ET, Newey HA, "Flexible Epoxides for Wet Filament Winding", 32nd Annual Conference, Reinforced Plastics / Composites Institute, SPI, Washington, February 8-11, 1977, Section 11-D).

The plasticizer increases the elongation of the cured matrix by 8 times, but at the same time halves its strength.

Known epoxy binder based on diglycidyl ether of bisphenol A, hardener - 4,4'-diaminodiphenylsulfone and fullerenes C _2n , where n is not less than 30 (US patent No. 5281653).

The disadvantage of this binder is the increased fluidity to gel formation, which creates technological difficulties in the manufacture of prepregs and polymer composite materials with a normalized composition. In the resin-free polymer composite material, the level of realization of the strength of the reinforcing fiber is reduced, especially significantly during shear and longitudinal compression.

Known prepregs and the composite materials obtained from them are carbon, organo, and fiberglass containing continuous fibers and an epoxy binder consisting of diglycidyl ether of bisphenol A or N, N, N ', N'-tetraglycidyl diaminodiphenylmethane and diaminodiphenylsulfone (HANDBOOK OF COMPOSITES, Ed by George Lubin, Van Nostrand Reinhold Company Inc., New York, 1982, p. 107, 299).

Such composite materials and products made of them are heat-resistant up to 180 ° C, have high static strength in the direction of reinforcement, however, they show limited resistance to lateral and dynamic loading due to the accelerated development of microcracks in the epoxy matrix. Modeling of low-cycle fatigue of composite materials in order to determine the endurance limit of components and the fracture sequence of composite materials shows that the primary form of damage is the development of cracks in the polymer matrix. These damages always precede delamination and final destruction of composite materials and products from them due to pulling out and rupture of reinforcing fibers.

Closest to the claimed invention, adopted as a prototype, is a prepreg made of a polymer binder, including, by weight: epoxy oligomer - N, N, N ', N'-tetra-glycidyl diamino-3,3'-dichlorodiphenylmethane - 100, hardener -4,4'-diaminodiphenylsulfone - 44, fullerene C _2n , where n is not less than 30 - 0.01-1.0, open carbon nanotubes - 0.1-1.5, and fulleroid multilayer nanomodifier Astralen - 0.5-10 , and fibrous filler.

The prepreg contains, wt.%: The specified binder is 24-50 and carbon, organo and fiberglass filler (bundles, ribbons, fabrics) is 50-76 (RF patent No. 2223988).

Nanostructural modification of interphase boundaries provides an increase in the transverse (transverse and interlayer) strength of known composite materials. However, they have not high enough indicators of residual compressive strength and specific fracture energy and, therefore, insufficiently high crack resistance.

The technical task of the invention is to reduce the fluidity and gelation time of the prepregs and increase the specific fracture energy and residual compressive strength of composite materials.

To solve the technical problem proposed:

A prepreg made of a polymeric binder including an epoxy oligomer - N, N, N ', N'-tetraglycidyldiamino-3,3'-dichlorodiphenylmethane, hardener - 4,4'-diaminodiphenylsulfone, fullerene C _2n , where n is not less than 30, open carbon nanotubes and fulleroid multilayer astralen nanomodifier, and a fibrous filler, in which the polymer binder additionally contains amino derivatives of fullerene - the products of the chemical interaction of fullerene C ₆₀ with heptylamine (GA) gross formula C ₆₀ (GA) ₆ , in the following ratio, wt.h. :

N, N, N ', N'-tetraglycidyldiamino-3,3'-dichlorodiphenylmethane  one hundred 4,4'-diaminodiphenylsulfone  44 fullerene C _2n , where n is not less than 30  0.01-1.0 open carbon nanotubes  0.1-1.5 fulleroid multilayer nanomodifier Astralen  0.5-10 The above amino derivative of fullerene C ₆₀  0.02-0.5

The prepreg, in which the polymeric binder and fiber filler - carbon, organic, glass tows, fabrics, ribbons - are taken in the following ratio, wt.%:

polymer binder  24-50 fiberfill  50-76

Products obtained by molding said prepreg.

A significant difference of the present invention is the introduction of amino derivatives of Fullerene C ₆₀ in the binder to increase the fracture toughness of the matrix and to increase the adhesive strength of the “reinforcing fiber-polymer matrix” interface, which, in turn, leads to an increase in the specific fracture energy and residual compressive strength of composite materials.

The introduction of amino derivatives of fullerenes into a polymer binder together with other nanoparticles makes it possible to mobilize their potential for targeted interaction with the objects of modification — the “dispersed phase-dispersion medium” interface in the supramolecular structure of the polymer matrix and the interface “reinforcing fiber-polymer matrix”. It is these interphase boundaries that are responsible for the mechanical properties of polymers, polymer composite materials and, accordingly, for the endurance and survivability of products made from them. The formation of covalent bonds between the amino derivatives of fullerene and the polymer matrix, as well as the presence of a very mobile system of T-localized electrons in fullerenes and other nanoparticles due to Van der Waals forces, allows overlapping interphase boundaries and removing the free excess energy of the system, i.e. makes the composite material system more stable .

The proposed technical solution provides: uniform distribution of carbon nanoparticles in the volume of the binder and on the surface of the reinforcing fibers; preservation of the electronic potential of carbon nanoparticles during the storage period of the prepreg, mobilization of the individual nanostructured and electronic potential of the carbon nanoparticle for targeted interaction with nanomodification objects (the “dispersed phase-dispersion medium” boundary in the supramolecular structure of the polymer matrix, the “reinforcing fiber-polymer matrix” boundary), creation in the polymer composite material of the nanoscale system of stoppers of microcracks of carbon nanoparticles, which provides an increase in elm fracture bone composites.

An amino derivative of fullerene C _{60 of the} formula C ₆₀ (HA) _{6 is} obtained by reacting fullerene with n. Heptylamine with an excess of the latter with stirring on a magnetic stirrer. The fullerene amino derivatives are then extracted with chloroform and precipitated with hexane. The resulting substance was washed with methanol and dried in vacuum at a temperature of 60-80 ° C.

Examples of implementation.

Example 1

Obtaining a polymer binder.

Fullerene C ₆₀ (0.01 parts by weight), open carbon nanotubes NTA (0.1 parts by weight), fulleroid multilayer nanomodifiers NTC - Astralen (0.5 parts by weight) according to TU 2166-001-13800624- 2003 and the amino derivative of fullerene C ₆₀ (0.02 parts by weight) were dispersed in an organic diluent and the resulting suspension was subjected to ultrasonic treatment (frequency - 35 kHz, duration - 30 minutes) in an external radiation bath UZU 025 (TU 1-01-05- 79-79). Next, the resulting suspension of carbon nanoparticles was introduced in 100 wt.h. epoxyamine resin ECD (N, N, N ', N'-tetraglycidyl diamino-3,3'-dichlorodiphenylmethane (TU 6-05-1725-75), 44 parts by weight of a hardener, 4,4'-diaminodiphenylsulfone, were added to the mixture TU 6-02-1188-79, was mixed and in this way a polymer binder was obtained.

Obtaining a prepreg and products from it.

The finished ELUR-P carbon tape (GOST 28006-88) was dried in air at 45-55 ° C for 1-1.5 hours and impregnated with a polymer binder prepared according to Example 1 to obtain a prepreg. Next, the prepreg was dried and laid, and the glider casing element was molded according to the stepwise temperature-time regime with the final stage at 175 ° С and Руд. = 0.5 MPa for 4 hours. Next, carbon fiber samples with an artificial crack were made (d / β = 5/40) and subjected to a test for residual compressive strength σ _tr according to MP 65-82 and specific fracture energy G _IC , which characterizes the crack resistance of the material under normal stresses. For this, carbon fiber samples 200 × 20 × 3.0 mm in size were layered according to the double-beam method. During loading, the dependence of the force F on the movement of the clamps D was determined. The distance between the clamps was equal to the distance between the ends of the consoles. The number of loading-unloading cycles ranged from 7 to 10. At the end of each loading, the crack length l was fixed. Due to the considerable thickness of the sample, the angle between the consoles did not exceed 20–25 degrees, which allowed us to use the “compliance method” when calculating the values of G _1c , according to which the relation is: G _1c l = 3F ² C / 2b, where b is the width of the sample , C is the flexibility of the consoles (C = D / F; D is the distance between the attachment points of the clamps to the beam consoles; F is the force at which the crack begins to move). In this case, G _1c can be calculated as the tangent of the slope of the line in coordinates 3FD / (2b-l).

The preparation of the binder, the manufacture of prepregs and products from them according to examples 2-6 were carried out analogously to example 1. The compositions of the binder and prepregs are given in table 1, the compositions of the prepregs are given in table 2, the properties of the prepregs and composite materials are given in table 3. According to examples 2-4 various elements of the airframe linings were made; according to examples 5.6, elements of the power set (spars).

Examples 7-9 are a prototype.

Example 7

Fullerene C ₆₀ (1.0 parts by weight), open carbon nanotubes NTA (1.5 parts by weight), fulleroid multilayer nanomodifier NTC-Astralen (0.5 parts by weight) according to TU 2166-001-13800624- 2003 was dispersed by ultrasonic treatment of their suspensions in acetone using a submersible emitter UZSN-A (TU 25-7401.0027-88). A suspension of nanomodifiers was introduced in 100 weight. including epoxyamine resin ECD (N, N, N ', N'-tetraglycidyldiamino-3,3'-dichlorodiphenylmethane (TU 6-05-1725-75). 44 parts by weight of hardener - 4.4' were introduced into the mixture. -diaminodiphenylsulfone (DADFS) (TU 6-02-1188-79) to obtain a polymer binder.

Getting prepreg and carbon fiber (prototype).

The carbon tape UOL-300-1 (TU) was saponified with a solution of fullerene C ₆₀ in toluene. The finished tape was impregnated with a binder made according to Example 7. The prepreg was dried, the prepreg packages were laid out (laying [0]), and the carbon fiber was molded by the press method according to the step temperature-time regime with the final stage at 175 ° C and Ore. = 0.5 MPa for 4 hours. The carbon fiber samples were tested for residual compressive strength σ _tr (MP 65-82) and specific fracture energy G _IC . In example 8, we used the binder of example 7 and fiberglass T-10-80 (GOST 19170-73), in example 9 - CBM fabric art. 56313 (GOST 17-62-9575-80).

A comparison of the test results shows that the proposed technical solution provides a 10-40% reduction in the prepreg fluidity, a 5-10-fold reduction in gelation time, a 10-15% increase in the residual compressive strength, and a 40-50% increase in the specific fracture energy - indicators characterizing the crack resistance of composite materials. As a result, their fracture toughness, endurance, and survivability increase. Improving the reliability of composite materials allows you to increase the service life of products and structural elements of aviation and space technology.

Table 1 Name of components Content, parts by weight, by examples one 2 3 four 5 6 N, N, N ', N'-tetraglycidyldiamino-3,3'-dichlorodiphenylmethane one hundred one hundred one hundred one hundred one hundred one hundred 4,4'-diaminodiphenylsulfone 44 44 44 44 44 44 fullerene C _2n , where n is not less than 30 0.01 0.05 1,0 0.05 0.05 0.05 open carbon nanotubes 0.1 0.75 1,5 0.75 0.75 0.75 fulleroid multilayer nanomodifier Astralen 0.5 5,0 10.0 5,0 5,0 5,0 Fullerene C ₆₀ amino derivatives 0.02 0.25 0.5 0.25 0.25 0.25 table 2 Name of components Content, wt.%, According to examples one 2 3 four 5 6 Binder 24.0 40.05 50,0 40.05 40.05 40.05 Carbon tape ELUR-P 76.0 59.95 50,0 - - - Carbon tape UOL-300-1 - - - 59.95 - - Fiberglass T-10-80 - - - - 59.95 - CBM fabric - - - - - 59.95

Table 3 Properties According to the invention Prototypes one 2 3 four 5 6 Tape UOL-300-1 Fiberglass T-10-80 CBM fabric Prepreg Properties: Vitality, days 45 45 45 45 45 45 thirty thirty thirty Fluidity,% eighteen 13 16 fifteen 13 fifteen twenty 22 23 The gelation time, min 35 27 eighteen 27 27 26 180 180 230 Properties of composite materials: Residual compressive strength, σ _t , MPa 697 712 686 718 675 647 630 615 580 The specific energy of destruction, G _1s , kJ / m ² 214 212 219 234 221 185 148 139 135

Claims (4)

1. A prepreg made of a polymeric binder including an epoxy oligomer - N, N, N ', N'-tetraglycidyl diamino-3,3'-dichlorodiphenylmethane, hardener - 4,4'-diaminodiphenylsulfone, fullerene C _2n , where n is not less than 30, open carbon nanotubes and a fulleroid multilayer nanomodifier Astralen, and a fibrous filler, characterized in that the polymer binder further comprises an amino derivative of fullerene - the product of the chemical interaction of Fullerene C ₆₀ with heptylamine (HA) gross formula C ₆₀ (HA) ₆ , in the following ratio entov, parts by weight: N, N, N ', N'-tetraglycidyldiamino-3,3'-dichlorodiphenylmethane one hundred 4,4'-diaminodiphenylsulfone 44 Fullerene C _2n , where n is not less than 30 0.01-1.0 Open carbon nanotubes 0.1-1.5 Fulleroid multilayer nanomodifier Astralen 0.5-10 The above amino derivative of fullerene C ₆₀ 0.02-0.5 2. The prepreg according to claim 1, characterized in that the polymer binder and the fibrous filler are taken in the following ratio, wt.%: Polymer binder 24-50 Fiberfill 50-76 3. The prepreg according to claims 1 and 2, characterized in that it contains carbon, organic, glass tows, fabrics, ribbons as a fibrous filler. 4. The product, characterized in that it is made by molding the prepreg according to claims 1 to 3.