RU2277548C1 - Polymer composition preparation method - Google Patents

Abstract

FIELD: polymer materials.

SUBSTANCE: invention aims at creating biological protection against radioactive emissions employed in nuclear power plants and provides a method for preparing polymer composition involving operation of mixing tungsten powder, iron powder, and powdered polypropylene. Prior to be mixed, tungsten powder is subjected to mechanical treatment for 3-5 h on ball mixer at weight ratio of metallic balls to tungsten powder between 5:1 and 7:1.

EFFECT: enabled manufacture of part from composition without stratification and imperfections.

2 tbl, 12 ex

Description

The invention relates to the field of processing polymer compositions based on tungsten, iron and polypropylene powder, which are used to protect against radioactive emissions during the operation of nuclear power plants.

The properties of the filled polymer material are determined by the properties of the polymer matrix and fillers, the nature of the distribution of the latter, the nature of the adhesive interaction at the polymer-filler interface. The properties of the polymeric material substantially depend on the shape of the filler particles ("Encyclopedia of Polymers" ed. "" Soviet Encyclopedia ", Moscow, vol. 2, p. 327).

A known method of preparing mixtures based on a polymer matrix, including mixing powdered materials for a certain time in apparatuses of various designs with air or gas using the parts themselves, as well as various mixing devices ("Equipment for the processing of plastics", Reference manual for calculation and design, under edited by V.K. Zavgorodnogo. - M.: Mechanical Engineering, 1976, p. 82).

However, the known method does not allow to change the structure of solid particles in the mixing process in order to improve the technological properties of the polymer composition and its structure.

The closest in technical essence to the invention is a method of preparing a polymer composition, in which powder tungsten, iron are mixed with powdered polypropylene (technological instruction "Production and processing of PVZH material, 0556.2529100488 RFNC VNIIEF, Sarov, Gorky region, 2003).

Compositions based on tungsten, iron and polypropylene are shown in table 1.

Table 1 The composition of the polymer composition Material grade The content of components,% Tungsten Powder Powder Iron Powdered Polypropylene PVZH-2 49.7-51.8 6.8-7.1 43.6-41.2 PVZH-4 71.7-72.2 9.8-10.0 18.6-18.0

The preparation of the composition includes the following operations:

- loading components into a ball mixer in a certain ratio (see table 1);

- loading of metal balls in relation to the total mass of components from 2: 1 to 3: 1;

- mixing for 4 ÷ 6 hours.

However, the polymer composition made in a known manner has low fluidity, since tungsten powder is a solid material with a developed specific surface of ≈10 m ² / g.

Studies of tungsten particles with a MBS-9 binocular stereoscopic microscope showed that the particles have sharp edges. The presence of such a filler in the polymer dramatically increases the effective melt viscosity of the composition during processing. On the surface of pressed products from a polymer composition containing such tungsten, loosening, shells, and delamination are observed.

An object of the invention is to prepare a polymer composition based on tungsten powder, iron and polypropylene powder, which would allow to extrude products without defects from it.

The task is achieved in that before mixing the powder tungsten is subjected to mechanical treatment in a ball mixer for 3 ÷ 4 hours at a ratio of the weight of metal balls to the weight of powder tungsten - 5: 1 ÷ 7: 1.

Only tungsten powder is subjected to mechanical processing in a ball mixer, since it is the hardest component.

The application of the operation of machining particles of tungsten powder in a ball mixer allows these particles to be run in, round sharp edges, bringing them closer to a spherical shape. The presence of such particles of tungsten powder in the polymer composition can improve its rheological properties. In the claimed technical solution, the proposed method for producing a polymer composition allows to make parts from it without defects.

The proposed method for preparing the polymer composition is implemented as follows.

To prepare the composition, powder tungsten can be used according to TU48-19-72-92, powder iron according to GOST13084-88, powdered polypropylene according to TU2211-015.002.03521-99.

Powder tungsten before mixing is subjected to mechanical processing in a ball mixer. The diameter of the metal balls is 20-30 mm, the mixing time is 3-4 hours.

The processing modes of tungsten powder, the composition and surface condition of the parts are shown in table 2, examples 1 ÷ 10.

table 2 Tungsten powder processing modes, composition and surface condition of parts №№ Tungsten Powder Processing Technology Composition of DRI The fluidity of the composition according to Rashig, mm Part surface condition The ratio of the weight of the balls to the weight of tungsten Processing time, hour The content of tungsten powder,% The rest of the composition (iron + polypropylene)% one 4: 1 3 49.7 50.3 90 ± 2 Are available 2 4: 1 four 72,2 27.8 69 ± 2 minor shells, bundles 3 5: 1 3 49.7 50.3 127 ± 2 No defects four 5: 1 3 72,2 27.8 112 ± 2 5 6: 1 four 49.7 50.3 139 ± 2 6 6: 1 3 72,2 27.8 128 ± 2 7 7: 1 four 49.7 50.3 147 ± 2 8 7: 1 3 72,2 27.8 132 ± 2 9 8: 1 four 72,2 27.8 138 ± 2 10 9: 1 3 72,2 27.8 141 ± 2 eleven According to the prototype 49.7 50.3 52 ± 2 There are shells, bundles 12 72,2 27.8 43 ± 2 Note: The fluidity is determined according to GOST5689-79

The analysis of table 2 shows that when preparing the composition of the DRI composition, wt.%:

tungsten powder 49.7 ÷ 72.2 powder iron 6.8 ÷ 10.0 polypropylene powder 18.0 ÷ 43.6

the mechanical processing of tungsten powder in a ball mixer must be carried out at a ratio of the weight of metal balls to the weight of tungsten powder 5: 1 ÷ 7: 1 for 3 ÷ 4 hours.

An increase in this ratio is not economically feasible.

The proposed method for producing a polymer composition allows to produce parts from it without defects.

Claims (1)

A method of preparing a polymer composition composition, wt.%: Tungsten Powder 49.7 ÷ 72.2 Powder Iron 6.8 ÷ 10.0 Powdered Polypropylene 18.0 ÷ 43.6 comprising the operation of mixing the components, characterized in that before mixing the powder tungsten is subjected to mechanical processing in a ball mixer with a ratio of the weight of metal balls to the weight of powder tungsten 5: 1 ÷ 7: 1 for 3 ÷ 4 hours