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Textile Waste from Woollen Yarn Production as Raw Materials for Thermal Insulation Products

Sigitas Vėjelis
Sigitas Vėjelis
, 
Saulius Vaitkus
Saulius Vaitkus
, 
Audronė Sankauskaitė
Audronė Sankauskaitė
, 
Arūnas Kremensas
Arūnas Kremensas
 and 
Jurga Šeputytė Jucikė
Jurga Šeputytė Jucikė
   | Dec 22, 2022
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Article Category: Research Article
Published Online: Dec 22, 2022
Page range: 8 - 16
DOI: https://doi.org/10.2478/ftee-2022-0039
Keywords
© 2022 Sigitas Vėjelis et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Dependence of thermal conductivity on the density of specimens of 100% polylactide fibres (PLA): ○ – experimental data; (──) – regression line (equation (3)); and woollen yarn waste (Table 1, mixture No 1): ◊ – experimental data; (─ ─ ─) – regression line (equation (4))
Dependence of thermal conductivity on the density of specimens of 100% polylactide fibres (PLA): ○ – experimental data; (──) – regression line (equation (3)); and woollen yarn waste (Table 1, mixture No 1): ◊ – experimental data; (─ ─ ─) – regression line (equation (4))

Fig. 2

Relationship between thermal conductivity and density: a) composite without added yarns (Table 1, mixture No 2); ○, □ – experimental data; (──) – thermally untreated specimen (regression line according to equation (5)); (- - -) – thermally treated specimen (regression line according to equation (6)); b) composite with added yarns (Table 1, mixture No 3); ○, □ – experimental data; (──) – thermally untreated specimen (regression line according to equation (7)); (- - -) – thermally treated specimen (regression line according to equation (8))
Relationship between thermal conductivity and density: a) composite without added yarns (Table 1, mixture No 2); ○, □ – experimental data; (──) – thermally untreated specimen (regression line according to equation (5)); (- - -) – thermally treated specimen (regression line according to equation (6)); b) composite with added yarns (Table 1, mixture No 3); ○, □ – experimental data; (──) – thermally untreated specimen (regression line according to equation (7)); (- - -) – thermally treated specimen (regression line according to equation (8))

Fig. 3

Structure of fibres and contact zones of thermally treated composite (Table 1, mixture No 2): a – sheep wool fibres; b – general view of interconnected fibres of composite; c – network of interconnected polylactide fibres; d – network of interconnected sheep wool and polylactide fibres
Structure of fibres and contact zones of thermally treated composite (Table 1, mixture No 2): a – sheep wool fibres; b – general view of interconnected fibres of composite; c – network of interconnected polylactide fibres; d – network of interconnected sheep wool and polylactide fibres

Quantity of non-fibrous matter in long and medium length fibres

No. of specimen Non-fibrous matter, mass %
Quantity of oils, fats, and waxes Salts and etc.
1 1.1 2.7
2 1.0 2.8
Mean value 1.1 2.8

Compositions of mixtures for the production of thermal insulation

Mixture No. Weight percentage of input components, %
Waste from woollen yarn production PLA Waste from defibered woollen yarn
1 100 - -
2 87 13 -
3 74 11 15

Results of the statistical processing of the thermal conductivity of PLA fibres and woollen yarn waste

Number of regression equation Number of tests (estimations) Values of constant coefficients Sr, W/(m·K) R2λ10·φ
b0 b1 b2
3 18 0.0223 0.000069 0.3813 0.000168 0.998
4 24 0.0258 0.000041 0.2818 0.000170 0.995

Quantity of fibrous matter in long and medium length fibres

No. of specimen Fibres, mass %
Sheep wool fibres Polyamide Wood resins and fibres polyester Cellulose fibres (grass, wood pieces and etc.)
1 94.7 0.5 0.1 0.9
2 95.3 0.4 0.1 0.4
Mean value 95.0 0.4 0.1 0.6

Quantity of fibrous matter in short length fibres

No. of specimen Fibre content, mass %
Sheep wool fibres Wood resins, polyester fibres, and polyamide fibres Cellulose fibres (grass, wood pieces and etc.)
1 91.2 1.4 7.4
2 91.6 1.2 7.2
3 93.0 0.6 6.4
Mean value 91.9 1.1 7.0

Results of the statistical processing of the thermal conductivity of composites

Number of regression equation Number of tests (estimations) Values of constant coefficients Sr, W/(m·K) R2λ10 ·φ
b0 b1 b2
5 12 0.0242 0.000124 0.305 0.000354 0.993
6 12 0.0189 0.000206 0.412 0.000276 0.997
7 12 0.0183 0.000240 0.398 0.000173 0.998
8 12 0.0145 0.000320 0.486 0.000566 0.988

Composition of woollen yarn waste

Amount, mass %
Long fibres (>30 mm) Average fibres (10÷30 mm) Short fibres and dusts (< 10 mm)
47.7 26.3 26.0
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