RU2793864C1 - Carbon fibre polyesteretherketone composite and method for its production - Google Patents

Abstract

FIELD: polyether industry.

SUBSTANCE: products manufacture using additive techniques. The carbon fibre polyester ether ketone composite contains a filler and a polyether ether ketone. The filler is a carbon fibre finished with a mixture of dichlorobenzophenone and diaminodiphenylmethane. A method for producing a carbon fibre polyether ether ketone composite is also proposed.

EFFECT: improvement of the physical and mechanical properties of the carbon fibre composite.

2 cl, 1 tbl, 6 ex

Description

The invention relates to the field of polyetheretherketone composites with inorganic, in particular, carbon fibers as fillers and methods for their production, and can be used as structural polymeric materials for the production of special-purpose products in additive technologies

One of the ways to improve the performance of carbon fiber polyether ether ketone composites is to finish the carbon fiber surface, which makes it possible to modify the structure of the interfacial layer and increase intermolecular adhesive interactions at the polymer-filler interface.

Known polymer compositions containing polyetherketones.

Patent EP0224236A2 is devoted to the creation of polymer compositions with improved chemical resistance and stable molding for injection molding, which contain polyether ketone (PEK), (not polyether ether ketone (PEEK)) aromatic polysulfone, and fillers, including carbon fiber.

EP0316681A2 also describes fibrous composites of polyethersulfone, polyetherketone (not polyetherketone) and carbon fiber. Both patents provide composites obtained from a mixture of two polymers - polyethersulfone, polytherketone, filled with fibers. They do not provide information on the finishing of carbon fibers to obtain PCM with enhanced mechanical properties.

In the patent RU 2278126, publ. 06/20/2006, bull. No. 17 shows the compositions used for crosslinking chains. This paper proposes to use a blend of amino-terminated polyetherketone (not PEEK) and anhydride-terminated polyethersulfone-copolyethersulfone copolymers. The mixture is dissolved in a high-boiling solvent - N-methylpyrrolidone and carbon fibers are treated with it. The disadvantage of the solution is the use of a solvent with a high boiling point (203 °C), which is difficult to remove from the composition, and its residues at high operating temperatures of the products will lead to the appearance of bubbles in the castings, and as a result, to a decrease in operational properties.

From the prior art, various types of sizing additives are known that are used in the creation of polymer composite materials. So, in the patent for invention RU 2057767, a polymer composite material is given, which includes a polysulfone polymer and carbon fibers. Carbon fibers contain on the surface as a sizing layer a copolymer consisting of units of methacrylic acid, diethylene glycol and benzosulfonic acid in a molar ratio of 49.5:49.5:1 to 49:49:2 in an amount of 0.52-5.0% of fiber mass in the following ratio of components, wt. %: carbon reinforcing fibers containing a copolymer, 25-75; polysulfone matrix rest. According to the inventors, the use of said copolymer as a sizing layer makes it possible to increase the interlaminar shear strength of polysulfone carbon plastics by a factor of 1.8-2.2. The main disadvantage of the proposed solution is the use of an aqueous medium for applying a mixture of monomers to a carbon tape. Since carbon fibers and tapes are hydrophobic, it is difficult to achieve a uniform distribution of an aqueous solution of a mixture of monomers. As a result of polymerization, incomplete conversion of monomers is also possible, which can lead to the formation and release of water at other stages of obtaining a polymer composite, which will lead to the formation of pores and a decrease in strength characteristics. The presence of benzenesulfonic acid in an aqueous medium will contribute to the accumulation of ions, which will worsen the dielectric properties of materials.

According to the patent of the Russian Federation No. 2201423, polymer compositions were obtained from a polymer binder (sizing) and fiberglass or carbon filler. First, a binder is obtained - an oligomer by the reaction of aromatic tetracarboxylic acid tetranitrile and aromatic bis-o-cyanamine at temperatures of 170-180 ° C. The binder is obtained in the form of a powder. The main disadvantage of this solution is the complexity of the process of obtaining a binder. With incomplete conversion of monomers during synthesis, low molecular weight by-products of the reaction may be released during the combination of the binder with the filler at an elevated temperature, resulting in the formation of voids in the composite material. This will lead to a deterioration in the strength characteristics of the material. In addition, powdered finishes may not cover the surface of the filler evenly enough.

Known polyetherimide composites according to US patent No. 4049613. To increase the wettability of carbon fiber polymer matrix, the authors propose to withstand the filler in hot nitric acid for three days, which is technologically and economically unfavorable.

The next patent provides a method for sizing carbon fiber according to RF patent No. 2054015 "Method for sizing carbon fiber for the production of polysulfone carbon fiber." According to the proposed method, the block copolymer is mixed with a solvent. A block copolymer consisting of units of bismethacryloyloxydiethylene glycol phthalate and bismethacryloyloxy triethylene glycol phthalate is used to impregnate the carbon filler, followed by drying to remove the solvent and polymerize the sizing film on the fiber, characterized in that the mixing is carried out in water with simultaneous exposure to ultrasonic radiation at a frequency of 15 to 44 kHz and duration exposure from 5 to 14 minutes. The disadvantages of this method are the use of aqueous solutions of block copolymers for wetting hydrophobic surfaces of carbon fiber and the need for further polymerization on the surface of the filler. The result may be uneven wetting of the filler, and, consequently, a decrease in the properties of the resulting carbon fiber.

The closest analogue is the patent of the Russian Federation No. 2743995, "A polymer composite based on polyetheretherketone reinforced with carbon fiber, and a method for its production." The disadvantages of the patent include not too high values of the given physical and mechanical parameters of polymer composites and the duration of the process of obtaining finished fibers.

The objective of the present invention is to obtain a polyether ether ketone composite with higher tensile strength values based on a polyether ether ketone (PEEK) matrix polymer filled with sized carbon fiber (CF) and to develop a method for its production.

This task is achieved by the fact that carbon fiber polyesteretherketone composites are obtained by pre-treatment of carbon fiber with a sizing composition, which is a mixture of dichlorobenzophenone (CBF) and diaminodiphenylmethane (DFM).

In this case, the following ratios (wt. %) of the components in the filler are taken:

carbon fiber 97.5; HBF 2.46 ÷ 2.08; DFM 0.04 ÷ 0.42.

The amount of sizing composition to carbon fiber corresponds to 2.5%. The amount of finished carbon fiber in the composite material corresponds to 20 wt. %. Treatment with such a sizing composition increases the wettability of the carbon fiber with polyesterimide, and allows repeated, if necessary, heat treatment of the resulting product without changing the properties of the sizing composition.

Finished fibers are obtained by treating carbon fiber with a sizing composition in an ultrasonic bath CD-4820 with an operating frequency of 46 kHz.

Polyether ether ketone composites of the present invention are obtained by pre-mixing the polymer matrix and sized carbon fiber using a high speed homogenizer Multi function disintegrator VLM-40B. Then the polymer mixture is extruded using a laboratory twin-screw extruder with three heating zones at processing temperatures of 200 °C, 315 °C, 355 °C.

Used carbon fiber brand RK-306 (IFI Technical Production), matrix polyester ether ketone, which is an industrial polymer PEEK 450, which is a polycondensation product of 1,4-dioxibenzene and 4,4'-difluorobenzophenone of the formula:

chloroform, dichlorobenzophenone, and diaminodiphenylmethane brand "HCh".

Below are examples illustrating a method for obtaining sizing carbon fibers using a sizing composition, and the sizing is applied from a solution with a mass concentration of 0.3 wt. % in an organic solvent.

Example 1. Obtaining finished CF with 2.46 wt. % CBF and 0.04 wt. % DFM.

23.4 g (97.5 wt.%) of HC with a fiber length of 0.2 mm is placed in a three-necked reaction flask and a solution obtained by dissolving 0.59 g (2.46 wt.%) of CBF and 0.01 g ( 0.04 wt.%) DPM in 137 ml of chloroform (0.3 wt.% solution). The flask is placed in a water bath of an ultrasonic bath at a temperature of 20 °C, the ultrasound is turned on and incubated for 5 minutes. After that, a stirrer is placed in the flask, a direct condenser is connected, and the supply of gaseous nitrogen is turned on. The stirrer is turned on, and the contents of the flask are heated and chloroform is distilled off according to the regime: 44 ° C - 2 minutes; 54 °С - 2 min.; 60 °С - 2 min.; 63 °С - 2 min.

The finished fiber is dried in an oven under vacuum at 70-72 °C for 65 minutes.

Example 2. Obtaining finished HC with 2.38 wt. % CBF and 0.12 wt. % DFM.

23.4 g (97.5 wt. %) of HC with a fiber length of 0.2 mm is placed in a three-necked reaction flask and a solution obtained by dissolving 0.57 g (2.38 wt. %) of CBF and 0.03 g ( 0.12 wt.%) DPM in 137 ml of chloroform (0.3 wt.% solution). The flask is placed in a water bath of an ultrasonic bath at a temperature of 20 °C, the ultrasound is turned on and incubated for 5 minutes. After that, a stirrer is placed in the flask, a direct condenser is connected, and the supply of gaseous nitrogen is turned on. The stirrer is turned on, and the contents of the flask are heated and chloroform is distilled off according to the regime: 44 ° C - 2 minutes; 54 °С - 2 min.; 60 °С - 2 min.; 63 °С - 2 min.

The finished fiber is dried in an oven under vacuum at 70-72 °C for 65 minutes.

Example 3. Obtaining finished HC with 2.29 wt. % CBF and 0.21 wt. % DFM.

23.4 g (97.5 wt. %) of HC with a fiber length of 0.2 mm is placed in a three-necked reaction flask and a solution obtained by dissolving 0.55 g (2.29 wt. %) of CBF and 0.05 g ( 0.21 wt.%) DPM in 137 ml of chloroform (0.3 wt.% solution). The flask is placed in a water bath of an ultrasonic bath at a temperature of 20 °C, the ultrasound is turned on and incubated for 5 minutes. After that, a stirrer is placed in the flask, a direct condenser is connected, and the supply of gaseous nitrogen is turned on. The stirrer is turned on, and the contents of the flask are heated and chloroform is distilled off according to the regime: 44 ° C - 2 minutes; 54 °С - 2 min.; 60 °С - 2 min.; 63 °С - 2 min.

The finished fiber is dried in an oven under vacuum at 70-72 °C for 65 minutes.

Example 4. Obtaining finished HC with 2.21 wt. % CBF and 0.29 wt. % DFM.

23.4 g (97.5 wt. %) of HC with a fiber length of 0.2 mm is placed in a three-necked reaction flask and a solution obtained by dissolving 0.53 g (2.21 wt. %) of CBF and 0.07 g ( 0.29 wt.%) DPM in 137 ml of chloroform (0.3 wt.% solution). The flask is placed in a water bath of an ultrasonic bath at a temperature of 20 °C, the ultrasound is turned on and incubated for 5 minutes. After that, a stirrer is placed in the flask, a direct condenser is connected, and the supply of gaseous nitrogen is turned on. The stirrer is turned on, and the contents of the flask are heated and chloroform is distilled off according to the regime: 44 ° C - 2 minutes; 54 °С - 2 min.; 60 °С - 2 min.; 63 °С - 2 min.

The finished fiber is dried in an oven under vacuum at 70-72 ^° C for 65 minutes.

Example 5. Obtaining finished HC with 2.12 wt. % CBF and 0.38 wt. % DFM.

23.4 g (97.5 wt.%) of HC with a fiber length of 0.2 mm is placed in a three-necked reaction flask and a solution obtained by dissolving 0.51 g (2.12 wt.%) of CBF and 0.09 g ( 0.38 wt.%) DPM in 137 ml of chloroform (0.3 wt.% solution). The flask is placed in a water bath of an ultrasonic bath at a temperature of 20 °C, the ultrasound is turned on and incubated for 5 minutes. After that, a stirrer is placed in the flask, a direct condenser is connected, and the supply of gaseous nitrogen is turned on. The stirrer is turned on, and the contents of the flask are heated and chloroform is distilled off according to the regime: 44 ° C - 2 minutes; 54 °С - 2 min.; 60 °С - 2 min.; 63 °С - 2 min.

The finished fiber is dried in an oven under vacuum at 70-72 ^° C for 65 minutes.

Example 6. Obtaining finished HC with 2.08 wt. % CBF and 0.42 wt. % DFM.

23.4 g (97.5 wt.%) of HC with a fiber length of 0.2 mm is placed in a three-necked reaction flask and a solution obtained by dissolving 0.5 g (2.08 wt.%) of CBF and 0.1 g ( 0.42 wt.%) DPM in 137 ml of chloroform (0.3 wt.% solution). The flask is placed in a water bath of an ultrasonic bath at a temperature of 20°C, the ultrasound is turned on and incubated for 5 minutes. After that, a stirrer is placed in the flask, a direct condenser is connected, and the supply of gaseous nitrogen is turned on. The stirrer is turned on, and the contents of the flask are heated and chloroform is distilled off according to the regime: 44 ° C - 2 minutes; 54 °С - 2 min.; 60 °С - 2 min.; 63 °С - 2 min.

The finished fiber is dried in an oven under vacuum at 70-72 °C for 65 minutes.

Composites containing 20 wt. % finished with a mixture of CBF and DFM carbon fibers.

Table 1 presents the compositions, as well as the physical and mechanical properties of polyetheretherketone composites, according to examples 1-6, containing various amounts of sizing composition.

Table 1 Compound А _r , kJ/m²
11 J, s/n E izg,
GPa E growth, GPa σ grow,
MPa ε, % PEEK 450 + 20% HC 0.2 mm 7.0 13.6 8.75 132.2 3.7 According to example 1 7.4 13.8 9.02 135.2 3.74 According to example 2 7.6 14.1 9.16 136.3 3.76 According to example 3 8.1 14.3 9.27 137.2 3.78 According to example 4 8.3 14.4 9.46 139.5 3.82 According to example 5 7.9 14.5 9.51 140.7 3.87 According to example 6 7.8 14.5 9.50 140.4 3.85

where A _p - impact strength with a notch, E izg - modulus of elasticity in bending, E rast - modulus of elasticity in tension, σ razr - tensile strength, ε, % - relative elongation.

As can be seen from the data presented, carbon fiber polyesteretherketone composites containing sized CFs (nos. 1–6) in almost all cases exhibit higher physical and mechanical properties compared to a composite containing untreated carbon fiber.

The technical result of the invention is to improve the physical and mechanical properties of the created carbon fiber polyether ether ketone composites by introducing a sizing composition - dichlorobenzophenone and diaminodiphenylmethane, which increases the wettability of the filler and increases the boundary interactions between the filler and the polyesterimide matrix.

Claims (3)

1. Carbon fiber polyesteretherketone composite based on polyetheretherketone and carbon fiber, intended as a structural polymeric material, containing 20 wt.% filler and polyetheretherketone, characterized in that it contains as a filler a carbon fiber finished with a mixture of dichlorobenzophenone (CBF) and diaminodiphenylmethane (DFM) filler consists of the following components, wt. %: carbon fiber 97.5 HBF 2.46-2.08 DFM 0.04-0.42 2. A method for producing a carbon fiber polyetheretherketone composite intended as a structural polymer material according to claim 1, including sizing carbon fiber by applying a sizing composition from a solution followed by drying, characterized in that the sizing is applied from a solution with a mass concentration of 0.3 wt. % in an organic solvent chloroform, where a carbon fiber polyesteretherketone composite is obtained by mixing polyetheretherketone and finished carbon fiber, after which the polymer mixture is subjected to extrusion, then the organic solvent is heated and distilled off under the action of ultrasound with an operating frequency of 46 kHz according to the mode: 44 ° C - 2 min; 54°C - 2 min; 60°C - 2 min; 63°C - 2 min.