Polyamide 6 fibre recycling by twin-screw melt extrusion of mixed thermoplastic polymers
Textile wastes consist of multi-component materials are hardly recycled due to challenge to sort and separate the waste into a single component. Textile products dominantly produced from a non-renewable source that can be recycled several times before the end of life. Mixed-waste can be recycled...
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Main Author: | |
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Format: | Thesis |
Language: | English |
Published: |
2019
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Subjects: | |
Online Access: | http://eprints.uthm.edu.my/10777/1/24p%20SITI%20ZAHARAH%20KUNCHI%20MON.pdf |
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Summary: | Textile wastes consist of multi-component materials are hardly recycled due to
challenge to sort and separate the waste into a single component. Textile products
dominantly produced from a non-renewable source that can be recycled several
times before the end of life. Mixed-waste can be recycled together without sorting by
thermo-mechanical process to produce hybrid fibres. The aim of this study was to
investigate the potential on upcycling polyamide 6 (PA6) polymer mixed with
secondary polymers via one-step twin-screw melt extrusion. Three secondary
polymers were chosen in this study; thermoplastic polyurethane (TPU) which has
interaction with PA6, and two polymers which do not have interaction with PA6;
polyethylene terephthalate (PET) and polypropylene (PP). Different blending
composition was prepared between PA6 and secondary polymers before being
extruded into hybrid fibres through melt extrusion. The secondary polymers were then
removed from the hybrid fibres to investigate the properties of the leftover of PA6
component. The fibres were characterised using attenuate total reflectance Fourier
Transform Infrared Spectroscopy (ATR-FTIR) and microscopy techniques, the
mechanical and thermal properties were investigated via tensile strength and
differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The
results showed that the blending of PA6 with interacting polymer TPU creates novel
fibres morphology with multi-connected porous fibres. The mean diameter of
PA6:TPU hybrid fibres when the PA6 content at 50% and 80% are 136 and 126 μm,
respectively. Thermal and chemical results demonstrated strong interaction happen
between PA6 and TPU. Meanwhile, the co-extrusion of PA6 with non-interacting
polymer PP and PET formed PA6 micro and nanofibres in the blend, respectively. In
PA6:PP blend, the SEM images show the PA6 microfibres with mean diameters of
0.76 μm and 1.13 μm developed in the hybrid fibres with PA6 content 50% and 60%,
respectively. The phase inversion between PA6 and PP happened at the composition
of 65% of PA6 showing the development of PA6 microfibres in a unique fibre
morphology. In PA6:PET blend, PA6 nanofibres with mean diameter of 532 nm to
1026 nm were obtained. The diameter of PA6 nanofibres increase when PA6 content
increase in the blend. Later, single jersey knitted fabric was produced from PA6:PP
60:40 blend composition and was treated later to remove the PP component. The
treatment process exposed the development of PA6 microfibres fabric which has
excellent behaviour in wicking and improved in ball burst strength compared to the
untreated fabric. The success of upcycling PA6 fibres with value added properties
through single-step melt extrusion can be applied to other mixed polymer waste. |
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