Poly(urethane)s and poly(urethane-urea)s (PUU) are nearly ubiquitous, having been in existence since before the Second World War. Spandex, a poly(urethane-urea) elastomeric fiber, is found in nearly all articles of apparel as well as in an increasing array of other consumer items. The technology and chemistry of spandex is largely unchanged since its inception in the late 1950s, with the majority of spandex employing poly(tetramethylene ether glycol) as soft segments. Recent developments in catalyst technology have resulted in the production of ultra-low monol content poly(propylene glycol) (PPG), which is nearly difunctional (f=1.95+). This enhancement in difunctionality has potentially enabled the use of PPG as a spandex soft segment with potential spandex processing, performance, and economic benefits. PPG-based spandex elastomers were evaluated in both film and fiber form for the purpose of investigating morphological, orientational, mechanical, and thermal properties with the goal of understanding relationships between chemistry, morphology and properties. Key variables of interest were soft segment molecular weight (MW), molecular weight distribution (MWD), and composition, and hard segment content and composition. Of those, the influence of the molecular weight distribution of the polyol used for soft segments was of foremost interest and had previously been largely neglected during the course of poly(urethane) and poly(urethane-urea) research. It was found that over the range of PUU compositions suitable for production of spandex, that hard segment content and composition had little effect upon the morphology and thermal and mechanical properties. Appreciable trends as functions of soft segment molecular weight were observed. The soft segment MWD was adjusted through the addition of a low molecular weight homolog of PPG, tri(propylene glycol) (TPG), decreasing the number average soft segment MW. The results of these experiments were contrary to those for variation of soft segment molecular weight. It was determined that the low MW portion of the polyol MWD contributes to the building of hard segments in addition to or in lieu of soft segments. Incorporation of TPG in the PUUs resulted in larger, presumably less cohesive, hard domains and increased hard segment content. The TPG containing materials had enhanced tensile properties, less permanent set, and less residual orientation after deformation. These materials proved quite comparable to those using PTMEG soft segments. Comparison of film and fiber PUUs revealed only minor differences, implying that the trends and conclusions drawn from the study of films with spandex-like compositions would also hold for fibers. The key difference between films and fibers is that fibers maintain some residual ordering and orientation due to drawing of the fibers during processing. Of the processing variables investigated, none impacted the morphology as determined from small angle x-ray scattering. It was concluded, that of the various compositional variables germane to spandex, the polyol MW and MWD played key roles in development of morphology, and hence properties. The role of polyol MWD had been woefully neglected during the development of spandex previously, and was observed to be a critical variable. / Ph. D.

De senaste decennierna har visat på en stor ökning av den textila konsumtionen som följd av efterfrågan, samtidigt som den textila återvinningen idag är nästintill obefintlig. Detta leder till att mycket av det textila materialet deponeras istället för att återvinnas, vilket innebär ett stort slöseri av redan befintlig råvara som skulle kunna användas till att skapa nytt textilt material. Genom att undersöka olika återvinningsmetoder och -processer skulle denna råvara kunna användas på nytt. Examensarbetet är en del av forskningsprojektet ”Från spill till guld” som leds av forskningsinstitutet Swerea IVF. Forskningsprojektets utgångspunkt är att minimera produktionsspill och att höja dess värde inom bland annat textilindustrin. Examensarbetet syftar till att undersöka termomekanisk återvinning av plagg gjorda av polyamid 6.6 (PA6.6) och elastan, smältspinna filament samt formspruta provstavar från denna nya polymerblandning utan att separera fibrerna. Andra syftet är att även hitta en lösning för produkterna som undersöks i detta examensarbete kan återvinnas i sin helhet, så att ingen demontering av produkterna ska behövas. Fyra olika plagg undersöktes i examensarbetet bestående av materialblandningen PA6.6 och elastan. Analyser av de fyra olika plaggen genomfördes för att fastställa materialen. Hela plagg tillverkade i de olika materialen klipptes eller maldes ned och smältes sedan om genom kompoundering, därefter tillverkades granulat. Materialen testades i spinnbarhet genom smältspinningsförsök, sedan smältspanns eller formsprutades materialen. Resultaten från smältspinningsförsöken analyserades i ljusmikroskop för att avgöra om elastanen är termoplastiskt eller inte då detta är en avgörande faktor vid smältspinning. Olika tester gjordes på materialen för att undersöka deras eventuella kemiska nedbrytning som resultat av kompoundering. Resultatet visade att smältspinning och formsprutning inte är möjligt från denna polymerblandning. Ett antagande kan göras att återvinningen inte fungerade på grund av PA6.6:s höga smälttemperatur, då elastanen antagligen bryts ned vid denna höga temperatur, vilket förstör materialet. Slutsatsen blir då att smältspinning och formsprutning inte är möjligt utifrån denna polymerblandning, men återvinning till plastdetaljer kan produceras vid kompounderingsstadiet och återanvändas i annan industri än textilindustrin. Potential finns för återvinning av plagg till plagg om ändringar görs under processens gång och om elastanen identifieras som termoplastisk eller inte. / The latest decades have shown a large increase in textile consumption as a result of demand, at the same time the textile recycling today is almost non-existent. This means that much of the textiles are used for landfill rather than being recycled, which generates a large waste of raw material that could be used to create new textiles. By exploring various recycling methods and processes this raw material could be used again. This thesis is part of a research project, “From Waste To Gold”, which is led by the research institute Swerea IVF. The research projects foundation is to minimize production waste and to increase its value in areas such as textile industries. This thesis’ foundation is to examine the mechanical recycling of garments made by polyamide 6.6 (PA6.6) and spandex, melt spin filaments and produce injection moulded samples from this new polymer blend, without separating the fibres. The other foundation is to find a solution for the products that are examined in this thesis so they could be recycled as a unit, no disassembly of the products would be necessary Four different garments was examined in this thesis, the materials were a combination of PA6.6 and spandex. Different analyses were made on the four different garments. Whole garments from the different materials were cut or milled and then re melted through compounding, after compounding granulates was made. The materials spin ability was tested through melt spinning trials, then the materials were either melt spun or injection moulded. The results from the spinning trials was analysed in a light microscope to examine if the spandex were thermoplastic or not, as this is a crucial factor when melt spinning. Various tests were conducted to analyse their chemical degradation after the compounding. The results from the melt spinning and injection moulding showed that it was not possible to recycle this polymer combination this way. An assumption can be made that the recycling methods did not work because of the high melt temperature of PA6.6, the spandex assumes to decompose at this high temperature and therefore destroys the material. The conclusion is that melt spinning and injection moulding is not possible to conduct with this polymer combination, but recycling to plastic details could be done at the compound stage and then be used in some other industry, not in the textile industry. There are potential for garment-to-garment recycling if changes are made during the recycling processes and if the spandex could be identified as a thermoplastic or a non-thermoplastic.

Bilayer embedded proteins are affected by stress. This general affirmation is, in this thesis, embodied by two types of proteins: membrane spandex and voltage-gated sodium channels. In this work, we essentially explore, using methods from physics, the theoretical consequences of ideas drawn from experimental biology. Membrane spandex was postulated to exist and we study the theoretical implications and possible benefits for a cell to have such proteins embedded in its bilayer. There are no specific membrane spandex proteins, rather any protein with a transition involving a large enough area change between two non-conducting states could act as spandex. Bacterial cells have osmovalve channels which open at near-lytic tensions to protect themselves against rupture. Spandex expanding at tensions just below the osmovalves’ opening tension could relieve tension enough as to avoid costly accidental osmovalve opening due to transient bilayer tension excursions. Another possible role for spandex is a tension-damper: spandex could be used to maintain bilayer tension at a fixed level. This would be useful as many bilayer embedded channels are known to be modulated by tension. The Stress/shear experienced in traumatic brain injury cause an immediate (< 2 min) and irreversible TTX-sensitive rise in axonal calcium. In situ, this underlies an untreatable condition, diffuse axonal injury. TTX sensitivity indicates that leaky voltage-gated sodium (Nav) channels mediate the calcium increase. Wang et al. showed that the mammalian adult CNS Nav isoform, Nav1.6, expressed in Xenopus oocytes becomes “leaky” when subjected to bleb-inducing pipette aspiration. This “leaky” condition is caused by a hyperpolarized-shift (left-shift or towards lower potentials, typically 20 mV) of the kinetically coupled processes of activation and inactivation thus effectively degrading a well-confined window conductance into a TTX-sensitive Na leak. We propose experimental protocols to determine whether this left-shift is the result of an all-or-none or graded process and whether persistent Na currents are also left-shifted by trauma. We also use modeling to assess whether left-shifted Nav channel kinetics could lead to Na+ (and hence Ca2+ ) loading of axons and to study saltatory propagation after traumatizing a single node of Ranvier.

Bilayer embedded proteins are affected by stress. This general affirmation is, in this thesis, embodied by two types of proteins: membrane spandex and voltage-gated sodium channels. In this work, we essentially explore, using methods from physics, the theoretical consequences of ideas drawn from experimental biology. Membrane spandex was postulated to exist and we study the theoretical implications and possible benefits for a cell to have such proteins embedded in its bilayer. There are no specific membrane spandex proteins, rather any protein with a transition involving a large enough area change between two non-conducting states could act as spandex. Bacterial cells have osmovalve channels which open at near-lytic tensions to protect themselves against rupture. Spandex expanding at tensions just below the osmovalves’ opening tension could relieve tension enough as to avoid costly accidental osmovalve opening due to transient bilayer tension excursions. Another possible role for spandex is a tension-damper: spandex could be used to maintain bilayer tension at a fixed level. This would be useful as many bilayer embedded channels are known to be modulated by tension. The Stress/shear experienced in traumatic brain injury cause an immediate (< 2 min) and irreversible TTX-sensitive rise in axonal calcium. In situ, this underlies an untreatable condition, diffuse axonal injury. TTX sensitivity indicates that leaky voltage-gated sodium (Nav) channels mediate the calcium increase. Wang et al. showed that the mammalian adult CNS Nav isoform, Nav1.6, expressed in Xenopus oocytes becomes “leaky” when subjected to bleb-inducing pipette aspiration. This “leaky” condition is caused by a hyperpolarized-shift (left-shift or towards lower potentials, typically 20 mV) of the kinetically coupled processes of activation and inactivation thus effectively degrading a well-confined window conductance into a TTX-sensitive Na leak. We propose experimental protocols to determine whether this left-shift is the result of an all-or-none or graded process and whether persistent Na currents are also left-shifted by trauma. We also use modeling to assess whether left-shifted Nav channel kinetics could lead to Na+ (and hence Ca2+ ) loading of axons and to study saltatory propagation after traumatizing a single node of Ranvier.

Bilayer embedded proteins are affected by stress. This general affirmation is, in this thesis, embodied by two types of proteins: membrane spandex and voltage-gated sodium channels. In this work, we essentially explore, using methods from physics, the theoretical consequences of ideas drawn from experimental biology. Membrane spandex was postulated to exist and we study the theoretical implications and possible benefits for a cell to have such proteins embedded in its bilayer. There are no specific membrane spandex proteins, rather any protein with a transition involving a large enough area change between two non-conducting states could act as spandex. Bacterial cells have osmovalve channels which open at near-lytic tensions to protect themselves against rupture. Spandex expanding at tensions just below the osmovalves’ opening tension could relieve tension enough as to avoid costly accidental osmovalve opening due to transient bilayer tension excursions. Another possible role for spandex is a tension-damper: spandex could be used to maintain bilayer tension at a fixed level. This would be useful as many bilayer embedded channels are known to be modulated by tension. The Stress/shear experienced in traumatic brain injury cause an immediate (< 2 min) and irreversible TTX-sensitive rise in axonal calcium. In situ, this underlies an untreatable condition, diffuse axonal injury. TTX sensitivity indicates that leaky voltage-gated sodium (Nav) channels mediate the calcium increase. Wang et al. showed that the mammalian adult CNS Nav isoform, Nav1.6, expressed in Xenopus oocytes becomes “leaky” when subjected to bleb-inducing pipette aspiration. This “leaky” condition is caused by a hyperpolarized-shift (left-shift or towards lower potentials, typically 20 mV) of the kinetically coupled processes of activation and inactivation thus effectively degrading a well-confined window conductance into a TTX-sensitive Na leak. We propose experimental protocols to determine whether this left-shift is the result of an all-or-none or graded process and whether persistent Na currents are also left-shifted by trauma. We also use modeling to assess whether left-shifted Nav channel kinetics could lead to Na+ (and hence Ca2+ ) loading of axons and to study saltatory propagation after traumatizing a single node of Ranvier.

Bilayer embedded proteins are affected by stress. This general affirmation is, in this thesis, embodied by two types of proteins: membrane spandex and voltage-gated sodium channels. In this work, we essentially explore, using methods from physics, the theoretical consequences of ideas drawn from experimental biology. Membrane spandex was postulated to exist and we study the theoretical implications and possible benefits for a cell to have such proteins embedded in its bilayer. There are no specific membrane spandex proteins, rather any protein with a transition involving a large enough area change between two non-conducting states could act as spandex. Bacterial cells have osmovalve channels which open at near-lytic tensions to protect themselves against rupture. Spandex expanding at tensions just below the osmovalves’ opening tension could relieve tension enough as to avoid costly accidental osmovalve opening due to transient bilayer tension excursions. Another possible role for spandex is a tension-damper: spandex could be used to maintain bilayer tension at a fixed level. This would be useful as many bilayer embedded channels are known to be modulated by tension. The Stress/shear experienced in traumatic brain injury cause an immediate (< 2 min) and irreversible TTX-sensitive rise in axonal calcium. In situ, this underlies an untreatable condition, diffuse axonal injury. TTX sensitivity indicates that leaky voltage-gated sodium (Nav) channels mediate the calcium increase. Wang et al. showed that the mammalian adult CNS Nav isoform, Nav1.6, expressed in Xenopus oocytes becomes “leaky” when subjected to bleb-inducing pipette aspiration. This “leaky” condition is caused by a hyperpolarized-shift (left-shift or towards lower potentials, typically 20 mV) of the kinetically coupled processes of activation and inactivation thus effectively degrading a well-confined window conductance into a TTX-sensitive Na leak. We propose experimental protocols to determine whether this left-shift is the result of an all-or-none or graded process and whether persistent Na currents are also left-shifted by trauma. We also use modeling to assess whether left-shifted Nav channel kinetics could lead to Na+ (and hence Ca2+ ) loading of axons and to study saltatory propagation after traumatizing a single node of Ranvier.