| 1. |
- Guo, Zengwei, et al.
(författare)
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An efficient recycling process of glycolysis of PET in the presence of a sustainable nanocatalyst
- 2018
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 135:21
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the catalyst Perkalite F100 efficiently works as a nanocatalyst in the depolymerization of poly(ethylene terephthalate) (PET). After depolymerization of PET in the presence of ethylene glycol and the Perkalite nanocatalyst, the main product obtained was bis(2-hydroxylethyl) terephthalate (BHET) with high purity, as confirmed by Fourier transform infrared spectroscopy and NMR. The BHET monomers could serve directly as starting materials in a further polymerization into PET with a virgin quality and contribute to a solution for the disposal of PET polymers. Compared with the direct glycolysis of PET, the addition of a predegradation step was shown to reduce the reaction time needed to reach the depolymerization equilibrium. The addition of the predegradation step also allowed lower reaction temperatures. Therefore, the strategy to include a predegradation step before depolymerization is suitable for increasing the efficiency of the glycolysis reaction of PET into BHET monomers.
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| 2. |
- Guo, Zengwei, et al.
(författare)
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Development of Circularly Recyclable Low Melting Temperature Bicomponent Fibers toward a Sustainable Nonwoven Application
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society. - 2168-0485. ; 9:49, s. 16778-16785
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable low melting temperature bicomponent polyester fibers that can be circularly recycled were developed. The potentially biobased poly(hexamethylene terephthalate) (PHT), acting as the low melting temperature sheath material in the designed bicomponent fibers, was synthesized in a pilot scale. The obtained PHT with an intrinsic viscosity of 0.47 dL/g showed suitable processability when it was processed together with a poly(butylene terephthalate) (PBT) core in a melt-spinning process of bicomponent fibers. Compared with the commercial low melting temperature terephthalate-isophthalate copolyester LMP-160, PHT showed superior mechanical properties according to DMA analysis. The low melting temperature bicomponent fibers with a ratio of the PBT core and PHT sheath at 70:30 were produced smoothly at 290 °C in a pilot melt-spinning line. Preliminary chemical recycling investigations by methanolysis revealed that PHT/PBT bicomponent fibers were completely depolymerized within 2 h at 200 °C, yielding pure terephthalate, which could be conveniently separated and recycled. This indicated the feasibility of circular recycling, which will greatly improve the sustainability of nonwovens thermally bonded by these new bicomponent fibers. © 2021 The Authors.
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| 3. |
- Guo, Zengwei, et al.
(författare)
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Melt spinning of PVDF fibers with enhanced β phase structure
- 2013
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 130:4, s. 2603-2609
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Tidskriftsartikel (refereegranskat)abstract
- Polyvinylidene fluoride (PVDF) fibers with a high amount of β phase crystal structure were prepared by melt spinning. With this technique, the cold drawing process is critical and efficient when aiming for a high amount of β phase. During the cold drawing process, more than 80% of the originally formed α phase crystal structure was converted into the β phase structure. In addition, the incorporation of 0.01 wt % of amino-modified double wall carbon nanotube (NH2-DWCNT) could further enhance the β phase content in the PVDF fibers. FTIR and DSC studies showed that the addition of NH2-DWCNT to PVDF fibers could increase both the total crystallinity and β phase fraction in PVDF. The addition of nanoclay was found to be less efficient in this respect.
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| 4. |
- Guo, Zengwei, et al.
(författare)
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Nanostructured micro particles as a low-cost and sustainable catalyst in the recycling of PET fiber waste by the glycolysis method
- 2021
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Ingår i: Waste Management. - : Elsevier Ltd. - 0956-053X .- 1879-2456. ; 126, s. 559-566
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic Mg-Al-O@Fe3O4 micro particles were synthesized by coating nanosized Mg-Al double oxides onto Fe3O4 micro particles. The formed hierarchical structure gave Mg-Al-O@Fe3O4 micro particles a high active surface area, which enabled these micro particles to work efficiently as a catalyst in the glycolysis of poly(ethylene terephthalate) (PET). The bis(hydroxyethyl) terephthalate (BHET) yield reached above 80 mol% in the presence of 0.5 wt% of Mg-Al-O@Fe3O4 micro catalyst in the reaction system within 90 min at 240 °C. After the reaction, Mg-Al-O@Fe3O4 micro catalyst was easily retrieved by a magnetic decantation and can be repetitively used for two times with a high catalytic efficiency. After that, the deactivated Mg-Al-O@Fe3O4 micro catalyst can be regenerated by heat treatment. The regenerated Mg-Al-O@Fe3O4 micro catalyst displays a comparable catalytic performance as that of the virgin catalyst. In addition, the Mg-Al double oxides and Fe3O4 micro particles are low-cost and environmentally benign. Therefore, the Mg-Al-O@Fe3O4 micro catalyst may contribute to an economically and environmentally improved large-scale circular recycling of PET fiber waste. © 2021 The Author(s)
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| 5. |
- Guo, Zengwei, et al.
(författare)
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Preparation of polypropylene/nanoclay composite fibers
- 2013
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Ingår i: Polymer Engineering and Science. - : Wiley. - 0032-3888 .- 1548-2634. ; 53:10, s. 2035-2044
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Tidskriftsartikel (refereegranskat)abstract
- Melt spinning of nanoclay (NA)/polypropylene (PP) composites into textile fibers is studied. The synthetic NA Perkalite F100 is prone to be exfoliated in PP matrix. With the help of a maleic anhydride-grafted low-molecular-weight PP as compatibilizer (Epolene E43), a highly exfoliated PP/NA composite was successfully prepared. However, the prepared PP/NA composite shows a poor spinnability because of the phase separation between Epolene E43 and PP matrix. The combination of two different groups of compatibilizers, which are Polybond 1001 (acrylic acid-grafted PP) for the dispersion of NA and Epolene G3216 (maleic anhydride-grafted PP-based copolymer) for the exfoliation of NA, can solve this problem. The PP/NA composite prepared by these two compatibilizers can be smoothly spun into fiber at the NA concentration below 1.9 wt%, which is found to be the percolation concentration of formation of NA network structure in PP matrix.
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| 6. |
- Junker, Katja, et al.
(författare)
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Mechanistic aspects of the horseradish peroxidase-catalysed polymerisation of aniline in the presence of AOT vesicles as templates
- 2012
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 2:16, s. 6478-6495
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism of the horseradish peroxidase (HRP)-H2O 2-catalysed polymerisation of aniline in the presence of AOT vesicles was investigated. AOT (= bis-(2-ethylhexyl)sulfosuccinate) served as vesicle-forming surfactant and dopant for obtaining at pH = 4.3 and room temperature within 24 h under optimal reaction conditions the green emeraldine salt form of polyaniline in 90-95% yield. Based on UV/VIS/NIR and EPR measurements carried out during the polymerisation reaction, and based on changes in aniline and H2O2 concentrations and HRP activity, a mechanism is proposed. According to this "radical cation mechanism" chain growth occurs on the vesicle surface through addition of aniline radical cations to the growing polymer chain. H2O2 plays two essential roles, to oxidise the heme group of HRP, and to oxidise the growing polymer chain for allowing the stepwise addition of new aniline radical cations. The entire reaction can be divided into three kinetically distinct phases. In the first rapid phase (5-10 min), the actual polymer formation takes place to yield the emeraldine salt form of polyaniline in its bipolaron state. In the second and third slower phases (1-2 days) the bipolarons transform into polarons with unpaired electrons. During the reaction, the HRP activity is decreasing until the enzyme becomes inactive after polymer formation. Reactions carried out with partially deuterated anilines were analysed by 2H magic-angle spinning (MAS) NMR spectroscopy to demonstrate the regioselectivity of the chain growth: para-coupling of the aniline units clearly dominates. Association of the formed polyaniline with the vesicle membrane is evident from cryo-TEM and SANS measurements.
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| 7. |
- Jönsson, Christin, et al.
(författare)
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Återvinning av textilier : Hur säkerställer man giftfria flöden i relation till textilåtervinning
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Huvudsyftet med arbetet var att främja ökad återvinning av textilt spill utan ökad spridning av giftiga ämnen eller minskad kvalitet. Arbetet har till stor del utförts genom fallstudier men även genom myndighetsdialoger, underlag till myndigheter och företag samt initiering av nya relevanta forskningsstudier.Målet i arbetspaket 3 Textil var att ta fram ett kvalificerat underlag för ökad användning av giftfri återvunnen textilråvara genom att studera och beskriva kunskapsläget samt ta fram ny kunskap och driva en aktiv dialog med relevanta aktörer inom fyra fokusområden:1. Spårbarhet2. Minskning av spill3. Teknikutveckling för återvinning av textil4. Återvinning på den svenska marknadenMålet har väl uppfyllts och projektet har bidragit till ökad kunskap om möjligheter för ökad användning av giftfri återvunnen textilråvara. Framförallt har fallstudier genererat detaljerad förståelse för vilka specifika utmaningar som är kopplade till olika textila material och fiberslag.Arbetet har utförts i tät samverkan och dialog med parter från textilbranchen: Boob, Filippa K, Gudrun Sjöden, Fjällräven och WRSD, Swegmarks, Ragnsells, Re:Newcell, samt några av deras leverantörer och flera medlemmar i Kemikaliegruppen på Swerea IVF.Projektet visar att materialspecifik kunskap och teknik är det viktigaste steget mot ökad återvinning av industriella restprodukter. Detta är således en förutsättning för att den sekundära råvaran ska ha ett tillräckligt värde och ändamålsenlig kvalitet. Dessa specifika aspekter kommer att studeras vidare inom efterföljand
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| 8. |
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| 9. |
- Warlin, Niklas, et al.
(författare)
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Synthesis and melt-spinning of partly bio-based thermoplastic poly(cycloacetal-urethane)s toward sustainable textiles
- 2021
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Ingår i: Polymer Chemistry. - 1759-9954. ; 12:34, s. 4942-4953
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Tidskriftsartikel (refereegranskat)abstract
- A rigid diol with a cyclic acetal structure was synthesized by facile acetalation of fructose-based 5-hydroxymethyl furfural (HMF) and partly bio-based di-trimethylolpropane (di-TMP). This diol (Monomer T) was copolymerized with potentially biobased flexible polytetrahydrofuran and diisocyanates to prepare thermoplastic poly(cycloacetal-urethane)s. A modified one step solution polymerization protocol resulted in relatively high molecular weights (Mn ~ 41.5 -98.9 kDa). All the obtained poly(cycloacetal-urethane)s were amorphous with tuneable glass transition temperatures up to 104 °C. Thermogravimetric analysis indicated that these polymers were thermally stable up to 253 °C and had a relatively high pyrolysis char residue, which may indicate potential inherent flame resistance. Melt rheology measurements were performed to determine a suitable processing window between 165-186 °C, after which the polymer was successfully melt-spun into ~150 meters of homogeneous fibres at 185 °C. The resulting fibres could be readily hydrolysed under acidic conditions, resulting in partialrecovery of the original chemical building blocks.
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| 10. |
- Warlin, Niklas, et al.
(författare)
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Synthesis and melt-spinning of partly bio-based thermoplastic poly(cycloacetal-urethane)s toward sustainable textiles
- 2021
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry. - 1759-9954 .- 1759-9962. ; 12:34, s. 4942-4953
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Tidskriftsartikel (refereegranskat)abstract
- A rigid diol with a cyclic acetal structure was synthesized by facile acetalation of fructose-based 5-hydroxymethyl furfural (HMF) and partly bio-based di-trimethylolpropane (di-TMP). This diol (Monomer T) was copolymerized with potentially bio-based flexible polytetrahydrofuran and diisocyanates to prepare thermoplastic poly(cycloacetal-urethane)s. A modified one-step solution polymerization protocol resulted in relatively high molecular weights (Mn ∼ 41.5-98.9 kDa). All the obtained poly(cycloacetal-urethane)s were amorphous with tuneable glass transition temperatures up to 104 °C. Thermogravimetric analysis indicated that these polymers were thermally stable up to 253 °C and had a relatively high pyrolysis char residue, which may indicate potential inherent flame resistance. Melt rheology measurements were performed to determine a suitable processing window between 165-186 °C, after which the polymer was successfully melt-spun into ∼150 meters of homogeneous fibres at 185 °C. The resulting fibres could be readily hydrolysed under acidic conditions, resulting in partial recovery of the original chemical building blocks.
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