RU2067597C1 - Polymeric composition - Google Patents

Abstract

FIELD: manufacture of components and constructional articles. SUBSTANCE: polymeric composition comprises (wt parts): 70-96 aliphatic polyamide or polyolefin; carbon fiber based on hydrocellulose having linear density of 205-320 tex and twisting of 100-180 tw/m. The fiber has the following properties: parameter of crystallite orientation 0.5-0.8, interplanar distance between carbon layers 0.34-0.35, crystallite width to height ratio 1.0-4.0 to 0.25-28.5 and untwisted carbon fiber based on polyacrylonitrile. The fiber has the following properties: fineness 130-410 tex, parameter of crystallite orientation 0.2-0.5, interplanar distance between carbon layers 0.36-0.39 nm and crustallite width to height ratio 1.5-2.0 to 0.25- 28.5. EFFECT: improved properties of the polymeric composition. 24 cl, 2 tbl

Description

 The invention relates to polymer composite materials, in particular to polymer compositions based on thermoplastics, and can be used for the manufacture of parts and products for structural purposes.

A known polymer composition containing a thermoplastic polymer (60 to 90 wt.), Carbon fiber (5 to 30 wt.) And single crystals of titanate (5 to 30 wt.) Potassium. Products obtained from this composition have a bending strength of 1820 kgf / cm ² , impact strength 31 kgf / cm / cm ² and an elastic modulus of 74500 kgf / cm ² .

 A disadvantage of the known polymer compositions is that the products obtained from them, despite the high physical, mechanical and tribological properties, have high creep.

The closest technical solution is a polymer composition containing thermoplastic material (100 parts by weight), carbon fiber treated with chromium chloride (2 to 10 parts by weight), low-modulus carbon fiber treated with a mixture of sodium tetraborate and diammonium phosphate (2 to 70 parts by weight) hours) and fluorinated high-modulus graphitized fiber (1 30 wt. hours). As a low-modulus carbon fiber, fibers based on hydrated cellulose fiber (HZ), polyacrylonitrile (PAN), pitch and heat-treated at 800 1600 ^° C and having a strength of 0.2 1.5 GPA and a modulus of 6 80 GPa are used. As a high-modulus graphitized carbon fiber, fibers based on PAN or HZ are used, heat-treated at 1800 - 2500 ^o C and having a module of 800 600 GPa and a strength of 1.5 to 5.0 GPa.

Products obtained from this composition have a friction coefficient of 0.16 0.26 and a wear rate of 0.52 0.78 • 10 ^-6 mm ³ / nm.

 However, as a result of carbon fiber treatments, the elastic-strength properties of the products are reduced and the products have increased creep.

 The purpose of the invention is the reduction of creep while maintaining high physical and mechanical properties of products obtained from polymer compositions.

 The goal is achieved in that the polymer composition, including aliphatic polyamide or polypropylene, low-modulus carbon fiber and high-modulus carbon fiber, as proposed, as a low-modulus carbon fiber contains carbon fiber based on hydrocellulose linear density 205 520 tex, with a twist of 100 180 cr / m characterized by the following structure: crystallite orientation parameter equal to 0.5 0.8, interplanar spacing between carbon layers 0.34 - 0.35 nm, width to height ratio e crystallite 1.0 4.0, and as a high-modulus crystalline fiber, the composition contains an untwisted carbon fiber based on polyacrylonitrile fineness 130 410 tex, characterized by a crystallite orientation parameter of 0.2 0.5, an interplanar distance between carbon layers of 0.36 0.39 nm, and a ratio of width to height of crystallite equal to 1.5 2.0, in the following ratio of components of the composition, wt. including aliphatic polyamide or polypropylene 70 96; carbon fiber based on cellulose hydrate of the above structure 0.25 - 28.5; polyacrylonitrile-based carbon fiber of the above structure 0.25 28.5.

 The weight ratio of carbon fiber based on hydrocellulose to carbon fiber based on polyacrylonitrile is from 5 95 to 95 5. The weight ratio of aliphatic polyamide or polypropylene with a total amount of carbon fibers is from 70 30 to 95 5, respectively.

Hydrocellulose-based carbon fiber (URAL-N-24) is obtained by treating a hydracellulose fiber with a strength of 34.5 gf / tex with an extension of 12 with a catalyst, followed by relaxation in the following mode: heating from 20 to 120 300 ^o C for 0.4 2, 0 h, cooling to room temperature for 0.05 0.2 h and again warming to room temperature to 120 - 300 ^o C for 0.4 2.0 h with a total degree of deformation of 0 (-10) Then the fiber is carbonized while in the temperature range 300 - 400 ^o C carry out deformation with a degree of (-25) (+30) Graphitization is carried out by When 900 2800 ^o C and the degree of deformation (-10) (+25) The result is a carbon fiber, characterized by the above properties.

Carbon fiber based on polyacrylonitrile (UKN) is obtained by oxidation of untwisted polyacrylonitrile fiber with a strength of 450 Mn / tex and an elongation of 18 in several stages according to the following regime: the first stage 1 cycle with heating temperatures of 165 250 ^o C and cooling of 20 26 ^o C with drawing on ( -3) (+170) heating time per cycle 1.5 6 min and cooling 11.7 46.8 min, the second stage of 5 cycles with a total stretch of (+0.1) 15 of them: 1 4 cycles with heating temperatures in each cycle of 180 240 ^o C, the heating time per cycle of 3.3 min and 13.2 1.5 cooling 6 minutes 5 minutes with the temperature cycle hEAT and 180 240 ^o C for 3.3 to 13.2 minutes and cooling at a temperature of 165 225 ^o C for 1.5 6 min and then at 20 ^o C for 26 13,5 54 min, the third stage of 11 cycles, of which 5 cycles with heating temperatures in each cycle of 210 250 ^o С and cooling of 165 235 ^o С, heating time per cycle of 3.3 13.2 min and cooling of 1.5 5 min, 3 cycles with heating temperatures of 235 300 ^o С and cooling of 165 285 ^o With a heating time of 1 cycle 3.3 13.2 minutes and cooling 1.5 6 minutes, the fourth stage - keeping at a temperature of 165 265 ^o C for 4.0 16.2 minutes The total drawing in the third fourth stages is (-5) (+10). Further, the oxidized fiber is carbonized in an inert medium. The treatment is carried out by low temperature and / or high temperature carbonization. The low-temperature treatment is carried out at 350 800 ^o C in one or two stages in the temperature range of the stages respectively 350 600, 350 - 800 ^o C. The processing time at each stage of 1.5 to 20 minutes High-temperature processing is carried out at 1200 2480 ^o C for 1 to 5 minutes With this processing method, carbon fiber with the above properties is obtained.

где λ длина волны рентгеновского излучения;
q угол отражения соответствующей плоскости кристаллита;
b полуширина рефлекса рентгеновского рассеяния, полученного при отражении от плоскостей кристаллита с индексом hkl соответственно 002 и 100 (см. Жумалиева К. Усенбаев К. Касаточкин В. И. Химия твердого топлива. 1974, N 4, с. 104 110) или "Термо-, жаростойкие и негорючие волокна". Под ред. А. А. Конкина. М. Химия. 1978, с. 222 235).The interplanar spacing d _{002 is} calculated from X-ray data according to the Wulf-Bragg formula, and the height L _c and the crystallite width L _a according to the Selyakov-Scherrer formula:
λ = 2d • sinθ

where λ is the x-ray wavelength;
q angle of reflection of the corresponding crystallite plane;
b the half-width of the X-ray scattering reflection obtained by reflection from the crystallite planes with the hkl index of 002 and 100, respectively (see Zhumalieva K. Usenbaev K. Kasatokin V. I. Chemistry of solid fuels. 1974, N 4, p. 104 110) or Thermo -, heat-resistant and non-combustible fibers. " Ed. A.A. Konkin. M. Chemistry. 1978, p. 222 235).

 The invention is illustrated by the following examples and tables.

 Example 1

 The polymer composition contains polyamide-6 (OST 6-060-9-85) 70 wt. and carbon fiber filler 30 wt. consisting of a mixture of the following composition: 3.0 wt. including carbon fiber based on hydrocellulose URAL-N-24 and 27 wt. including carbon fiber based on polyacrylonitrile (UKN). The mass ratio of fibers is 10 90. URAL-N-24 has 205 tex, a twist of 100 cr / m and a fiber structure and is characterized by a crystallite orientation parameter of 0.5, an interplanar distance between carbon layers of 0.34 nm, a ratio of width to height of crystallite of 1.0 . The UKN fiber has a linear density of 410 tex and its structure is characterized by an orientation parameter of 0.2, an interplanar distance between carbon layers of 0.39 nm and a ratio of width to height of crystallite of 1.5.

The thermoplastic polyamide and the filler are mixed on a ZSK-30 twin screw extruder. Nine UKN coils and two URAL-N-24 coils are installed on the creel. The processing temperature is 220 250 ^o C. Composite material is obtained in the form of granules, which can be processed by all traditional methods of processing thermoplastics.

Samples for testing were made by injection molding on a KVASSY injection molding machine at a temperature of 220 260 ^o C and a pressure of 100 MPa.

 The tests are carried out according to current standards on the VTS universal tensile testing machine and the KM-05 pendulum head.

 The test results are given in table. 2.

 Examples 2 to 7.

 The composition is obtained analogously to example 1, but the ratio of the carbon fibers and the filler mixture is changed, the ratio of the thermoplastic polymer and the carbon fiber filler, as well as the carbon fibers are used with different structures. The properties of carbon fibers are given in table. 1. The composition and properties are given in table. 2. Samples for testing receive analogously to example 1.

 Example 8

 The composition contains 80 wt. polypropylene (PP 2160, GOST 26996-86) and 20 wt. carbon fiber filler, representing a mixture of 50 wt. including UKN and 15 wt. h. URAL-N-24. The properties of the filler are given in table. 1.

The mixing of polypropylene with a fibrous filler is carried out on a 2-screw extruder ZSK-30. 5 coils of UKN and 4 coils of URAL-N-24 are installed on the creel. The processing temperature is 190 240 ^o C. The properties of the product obtained analogously to example 1 are shown in table. 2.

 Using the claimed composition can reduce creep, characterized by initial deformation, while maintaining high physical and mechanical properties of products obtained from this composition.

Claims (2)

 1. A polymer composition comprising an aliphatic polyamide or polypropylene, a low-modulus carbon fiber and a high-modulus fiber, characterized in that the low-modulus carbon fiber contains a carbon fiber based on hydrated cellulose with a linear density of 205,520 tex, with a twist of 100,180 cr / m, characterized by the following structure - a crystallite orientation parameter equal to 0.5 0.8, an interplanar distance between carbon layers of 0.34 0.35 nm, a ratio of width to crystallite height of 1.0 4.0, and as a high-modulus crystalline fiber composition contains untwisted carbon fiber based on polyacrylonitrile fineness 130 410 tex, characterized by a crystallite orientation parameter of 0.2 0.5, an interplanar distance between carbon layers of 0.36 0.39 nm and a ratio of width to crystallite height of 1.5 - 2.0, in the following ratio of components of the composition, parts by weight Aliphatic polyamide or polypropylene 70 96
Carbon fiber based on cellulose hydrate of the above structure 0.25 28.5
Carbon fiber based on polyacrylonitrile of the above structure - 0.25 28.5
2. The composition according to p. 1, characterized in that the mass ratio of carbon fiber based on cellulose hydrate to carbon fiber based on polyacrylonitrile is from 5 95 to 95 5.  3. The composition according to p. 1, characterized in that the mass ratio of aliphatic polyamide or polypropylene and the total amount of carbon fibers is from 70 30 to 95 5, respectively.

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