CC BY
97
https://doi.org/10.29013/AJT-19-11.12-38-44
Ismatova Rano Axadovna, Norov Ilgor Ilxomovich, Amonov Muxtor Raxmatovich, Ibragimova Feruza Baxriddinovna, Bukhara State University E-mail: [email protected]
SIZING POLYMER COMPOSITIONS ON THE BASE OF STARCH AND POLYVINYL ALCOHOL
Abstract. The article investigates the physicochemical properties of yarn depending on the concentration of starch and polyvinyl alcohol (PVA). It was revealed that the use of the developed polymer composition in the process of sizing cotton yarn made it possible to increase its strength, decrease the ultimate elongation and as the most important indicator contributes to the reduction of yarn breakage.
Keywords: Yarn, starch, PVA, properties, strength, composition, polymer, dressing (sizing solution), concentration, ultimate elongation.
Improving the quality and competitiveness of products is one of the key tasks in the textile industry, resolved by creating effective waste-free technologies that can significantly reduce or completely eliminate the use of expensive imported chemical materials.
Despite significant advances in the field of refinement of cotton fiber, successes in this area are far from exhausted. It remains a very urgent task to develop effective polymeric materials suitable for sizing yarn. Due to the availability of the raw material base, the specificity of the properties of polymeric materials makes it possible to purposefully use yarn in the sizing process, while significantly saving scarce expensive components and ensuring the rhythmic production of textile enterprises [1-4].
The main indicator that determines the quality of sizing in production is the thread breakage during weaving process. However, this indicator can only be determined under the conditions of a particular production, since the breakage is determined by the total influence of a number of factors, including factors not related to the quality of the dressing (yarn
quality, humidity in the weaving department, operating mode of the sizing machine, maintaining time of sized yarn before weaving, etc.). There are a number of indicators by which the suitability of the dressing can be determined without carrying out the sizing process. Such important indicators include viscosity, the degree of uncoupling of starch grains, the content of the water-soluble fraction and surface tension.
The main purpose of these studies is to identify the general trend of the influence of various factors on the properties of the dressing and the quality of the sized yarn according to the developed sizing polymer composition.
On this basis, the initial study was aimed at selecting the concentrations of starch, PVA in the composition.
The experiment results for the change in the physical and mechanical properties of the sized cotton yarn with starch and PVA are presented in (Table 1).
As can be seen from Table 1, the magnitude of bursting strength, bursting elongation and pick-
upconsiderably depend on the composition of the dressing. The use of the developed polymer composition on the basis of starch and PVA during sizing of
cotton yarn allowed to increase its strength, reduce bursting elongation, and this, in turn, helped to diminish the yarn breakage.
Table 1.- Changes in the physical and mechanical properties of yarn while taking in PVA into dressing
Sizing composition,% Ratio of starch and PVA in dressing,% Breaking load Р, Breaking elongation Е,%
Starch PVA from the weight of starch Pick-up R,%
- 100:0 256 10.7 3.7
5 1.0 97.5:2.5 264 9.1 4.6
2.0 95.0:5.0 314 6.4 5.1
3.0 93.0:7.0 321 5.2 6.8
- 100:0 265 10.4 3.6
6 1.0 97.5:2.5 286 9.0 5.0
3.0 95.0:5.0 332 5.7 5.2
3.0 93.0:7.0 354 4.3 5.4
- 100:0 282 9.7 3.5
7 1.0 97.5:2.5 310 8.1 5.6
3.0 95.0:5.0 336 5.2 5.8
3.0 93.0:7.0 361 4.1 5.9
Moreover, we can observe a significant change in the structural and mechanical properties of the system with an increase in the concentration of PVA from 1.0 to 3.0% in starch paste.
As can be seen from Table 1, not only the starch content, but also PVA has a significant effect on the breaking characteristics of the sized yarn. For instance, if the breaking load of cotton yarn is with 5% starch content, 1.0% PVA is 264 sN, with the same starch content and increase of PVA content to 3.0%, the breaking load will increase to 327 sN, i.e., it will upsurge by 23%.
It is known that under the conditions of complex formation of starch and PVA, significant changes occur in the rheological properties of the system.
It will be possible to significantly modify the physical and mechanical properties of starch dressing by adding PVA in it.
The advantage of PVA compositions as a sizing preparation lies in its high adhesive ability.
The strength properties of yarn sized with the proposed compounds have shown that the strength properties of yarn sized with a 5-7% starch dressing differ significantly from those without PVA (Table 2). In addition, the use of a water-soluble PVA polymer as a part of starch dressing contributes to the maximum decrease in the surface tension of the system and the improvement of the physical and mechanical characteristics of the yarn. Furthermore, in order to let dressing remain on the surface of the fiber in the form of an adhesive film, it must have sufficient viscosity and meet numerous production requirements.
Based on the scientific data and theoretical and experimental research, highly effective dressing polymer compositions consisting of starch and PVA have been developed for various types ofyarn (18.5; 20 and 29.4).
Table 2.- Physical and mechanical characteristics of sized and unsized cotton yarn
Dressing Breaking load Р, sN Breaking elongation (mm)
Unsized 220 ± 5.5 98 ± 1.0
Starch% PVA,,% of dry weight of starch
4 - 256 93
5 - 265 87
6 - 282 82
4 1.0 264 78
2.0 314 72
3.0 321 66
5 1.0 286 75
2.0 332 69
3.0 254 61
6 1.0 310 72
2.0 335 64
3.0 361 56
The properties of dressing and the sized cotton starch and helps to increase the breaking strength
yarn are presented in Table 3. of the system. For example, at a yarn density of
From Table 3 it is seen that the presence of PVA 29.4, the breaking load of the sized polymer com-
in the dressing composition based on starch, it has positions is 328.3 sN versus 291.7 sN of sized corn
a positive effect on the process of gelatinization of starch.
Table 3.- Properties of dressing made of polymer materials and sized yarn of various types
Parameters Sizing polymer compositions Dressing on the basis of starch
Yarn density, textile
18,5 20 29,4 18,5 20 29,4
Dressing viscosity 2.7 4.4 7.1 1.6 4.2 6.1
Concentration of adhesive mate-rial,% 1.5 3.0 4.2 1.6 4.0 4.4
Real pick-up,% 2.1 3.6 4.1 1.8 2.5 3.8
Breakage 0.27 0.29 0.32 0.32 0.41 0.52
Degree of dressing wear,% 96.3 87.2 81.7 78.3 66.4 63.2
Breaking strength, sN 314.5 326.7 328.3 266.7 284.6 291.7
Breaking elongation,% 5.6 4.8 4.4 8.1 7.5 6.8
Breaking yarn length, km 12.7 15.3 16.7 15.1 17.2 18.1
Linear deviation density,% 7.4 7.9 8.6 8.1 8.9 9.5
Deviation of breaking strength,% 9.6 13.4 14.7 12.6 14.0 14.2
Abrasion resistance, sN 1910 2570 3170 2540 3010 3070
In the (Table 3) it is shown that sizing polymer compositions significantly increase the efficiency of a number of technological processes, in particular, sizing. At the same time, it was revealed that the breaking elongation of the sized yarn is inversely proportional to the amount of PVA. The optimal PVA ratio was found, providing breaking strength and elongation corresponding to the production requirements. It has been established that the introduction of low concentrations, up to 5% and PVA up to 3.0% from the weight of starch into starch solutions favorably improve the adhesion of
the system to cotton fibers. The degree of dressin-gwear reaches up to 96.3%. In addition, the use of polymer compositions helps to increase labor productivity by improving a number of technological characteristics, in particular, reducing the thread breakage.
Thus, the study of the dependence of the physi-cochemical and mechanical properties of sized substrates on the chemical nature and concentration of the dressing components showed that starch and PVA compositions satisfy the requirements for adhesive and film-forming dressing components.
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