Numerous publications are available on the structure and properties correlation of fibers spun from polymers with flexible chains such as polyethylene terephthalate (PET), nylon, polypropylene. Also considerable amount of work is reported in fibers spun from rigid rod polymers like poly(p-phenylene terephthalamide) due to their value in high performance fibers category. However, very limited literature is available on the structure-properties relationship in fibers manufactured from poly(phenylene sulfide) (PPS), a high performance polymer which possesses chain flexibility between above two classes of polymers. A few researchers have studied crystallization kinetics and the fibers by extruding the polymer using capillary rheometers. However, there is a lack of in-depth study of conversion of PPS into fibers through melt spinning and further enhancement of properties by drawing and annealing experiments. The purpose of the present research was to fill this void by systematically studying the fiber manufacture from PPS polymers. Four variances of proprietary Fortron® linear PPS resins differing in MW were analyzed for their characteristics such as molecular weight (MW) and MW distribution (MWD) using gel permeation chromatography (GPC), rheological properties using melt flow indexer (MFI) and capillary extrusion rheometer, and crystallization kinetics using differential scanning calorimetry (DSC). The fibers were spun on a pilot melt spinning facility, using a multi-hole spinneret, under different processing conditions. As-spun fibers were drawn and annealed subsequently by varying draw-annealing conditions. Thorough characterization of the as-spun and drawn-annealed fibers was carried out using various analytical techniques such as tensile testing, DSC, polarized light optical microscopy (POM), wide angle X-ray scattering (WAXS), and small angle X-ray scattering (SAXS). Relationship between polymer characteristics, process conditions and structure-properties in the fibers was analysed statistically. A strong correlationship between polymer molecular weight, processing conditions during melt spinning and draw-annealing, processing behavior during melt spinning and drawing, fiber tensile properties and fiber morphology is reported herein. Interaction effects of material and process variables in evolving fiber structure and properties are also discussed. Through optimal combination of material and process variables, PPS fibers of tenacity close to six gpd were obtained. With the help of several characterization tools listed earlier, melting behavior of PPS polymers and fibers is decoded, and probable structural model of high tenacity PPS fibers is proposed.

Rapid solidification experiment on Fe-Cr-Mo-Mn-Si-C alloy was performed to investigate metastable phases formed during the solidification. A wide range of cooling rate was used to analyse the sample from melt spinning technique (~107 K/s) to water quenching method (~102 K/s). A single phase featureless structure was obtaind initially in the melt spinning experiment for 77Fe-8Cr-6Mn-5Si-4C alloy. Reduction of C and addition of Mo led to form a complete featureless structure for 2.85 mm rod for 72.8Fe-8Cr-5Mo-6Mn-5Si-3.2C. Subsequent investigation of influence of Mo, Cr and Mn on the single phase featureless structure concludes that 7.5 mm thick complete featureless phase could be formed at 63.8Fe-15Cr-7Mo-6Mn-5Si-3.2C alloy composition. In a separate attempt, powder samples of 40 μm dia. size complete featureless powders were produced for three slightly different compostions for the same alloy system. Characterisation of the featureless phases reveals that it could be a single phase metastable structure of ε phase or austenitic solid solution with high amount of alloying element dissolved in it. Subsequent heat treatment of this featureless phase of the rod and the powder at different temperatures formed bainitic ferrite with fine carbides dispersed in the austenitic matrix. Hardness values measured on featureless phase found to have influenced by the alloying element specially Mo, Cr and Mn. In an attempet to improve clean melting condition to extend the featureless phase and to form amorphous, an elliptic short arc lamp vaccum furnace was designed with 10 kW lamp power. Around 30 g of iron based alloy system was melted and cast as a 7 mm rod sample in a copper mould. Design details of new mirror and the lamp furnace are presented. In a separate study, influence of the melt temperature on Al-Y and Al-Si alloys were investigated by levitaion casting in a silver mould at around 2000 K/s cooling rate. Plate like structure of Al8Y3 primary phase was observed at low melt temperature with small percentage of peritectic transformation of Al8Y3 and liquid melt into Al9Y2. A pre-dentritic star like crystal of Al3Y was observed in a fine eutectic matrix at very high melt temperature. Amount and number of primary Si crystals formed in a unit area during the solidification increases as the melt temperature increases. / QC 20100805

In this study, we developed the manufacturing pathways of carbon nanofibers (CNF) and activated carbon nanofibers (ACNF) via the ¡§melt-spinning¡¨ method. A novel route based on the solvent-free core/sheath melt-spinning of polypropylene/ (phenol formaldehyde-polyethylene) (PP/(PF-PE)) to prepare CNF. The approach consists of three main steps: co-extrusion of PP (core) and a polymer blend of PF and PE (sheath), followed by melt-spinning, to form the core/sheath fibers; stabilization of core/sheath fibers to form the carbon fiber precursors; and carbonization of carbon fiber precursors to form the final CNF. Both scanning electron microscopy and transmission electron microscopy images reveal long and winding CNF with diameter 100 - 600 nm and length greater than 80 £gm. With a yield of ~ 45 % based on its raw material PF, the CNF exhibits regularly oriented bundles which curl up to become rolls of wavy long fibers with clean and smooth surface. Results from X-ray diffractometry, energy dispersive X-ray, Raman spectroscopy, and selected area electron diffraction patterns further reveal that the CNF exhibits a mixed phase of carbon with graphitic particles embedded homogeneously in an amorphous carbon matrix. The carbon atoms in CNF are evenly distributed in a matrix having a composition of 90 % carbon element and 10 % in oxygen element. A series of ACNF have also been prepared based on the chemical activation on the thus-prepared CNF; their morphological and microstructure characteristics were analyzed by scanning electron microscopy, atomic force microscopy (AFM), Raman spectroscopy, and X-ray diffractometry, with particular emphasis on the qualitative and quantitative AFM analysis. The effect of activating agent, potassium hydroxide and phosphorous acid, is compared; factors affecting the surface morphology and microstructure of ACNF are analyzed. The ACNF also exhibits a mixed phase of carbon with graphitic particles embedded homogeneously in an amorphous carbon matrix. The resulting ACNF consists of 73 % C element and 27 % O element. The total pore volume of the all activated ACNF is larger than that of un-activated CNF. It can be inferred that chemical activation by KOH results in increased micropore volume in carbon nanofibers; while the micropores produced by the chemical activation of H3PO4 may further be activated and then enlarged to become the mesopores at the expense of micropore volume. For the concentration effect of KOH on ACNF, it can be inferred that high concentration KOH activation results in increased SBET and micropore volume in carbon nanofibers. The average pore diameter of ACNF gradually decreases as the KOH concentration increases.

The thesis deals with the principal heating design of the electrospinning electrode. These electrodes are fed with high voltage (tens of kV), which is an essential part of the device for the nanofibres production. This thesis presents the research of possible solutions of the heating and also it analyzes some principles of the nanofibre production. Furthermore, the work presents electrical schematics and PCB of the heating module. The aim of this work is to propose such a solution of heating that makes spinning from melt realizable in the device for 4SPIN ® nanofibres production.

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京都大学 / 新制・課程博士 / 博士(工学) / 甲第25016号 / 工博第5193号 / 新制||工||1991(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)准教授 谷口 貴志, 教授 大嶋 正裕, 教授 古賀 毅 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

One interesting approach is the development of conductive polymer composite fibers for innovative textile applications such as in sensors, actuators and electrostatic discharge. In this study, conductive polymer composite fibers were prepared using several different blends containing conductive components: a conjugated polymer (polyaniline-complex) and/or carbon nanotubes. Different factors such as processing parameters, the morphology of the initial blends and the final fibers, fiber draw ratio and material selection were studied separately to characterize their effects on the fiber properties. In binary blends of PP/polyaniline-complex, the processing conditions, the matrix viscosity and the fiber draw ratio had substantial effects on the electrical conductivity of the fibers and linearity of resistance-voltage dependence. These factors were associated with each other to create conductive pathways through maintaining an appropriate balance of fibril formation and breakage along the fiber. The blend morphology was defined as the initial size of the dispersed conductive phase (polyaniline-phase), which depended on the melt blending conditions as well as the PP matrix viscosity. Depending on the initial droplet phase size, an optimum draw ratio was necessary to obtain maximum conductivity by promoting fibril formation (sufficient stress) and preventing fibril breakage (no excess stress) to create continuous pathways of conductive phase. Ternary blend fibers of PP/PA6/polyaniline-complex illustrated at least three-phase morphology with matrix/core-shell dispersed phase style. When ternary fibers were compared to binary fibers, the former could combine better mechanical and electrical properties only at a specific draw ratio; this showed that draw ratio was a more determinant factor for the ternary fibers, as both conductivity and tensile strength depended on the formation of fibrils from the core-shell droplets of the PA6/polyaniline-complex through the polypropylene matrix. The achieved maximum conductivity so far was in the range of 10 S/cm to 10 S/cm, which for different samples were observed at different fiber draw ratios depending on the mixing conditions, the matrix viscosity or whether the fiber was a binary or ternary blend. To improve the properties, PP/polyaniline-complex blends were filled with CNTs. The CNTs and the polyaniline-complex both had an increasing effect on the crystallization temperature and the thermal stability of PP. Furthermore, the maximum conductivity was observed in samples containing both CNTs and polyaniline-complex rather than the PP with either one of the fillers. Although increasing the content of CNTs improved the conductivity in PP/CNT fibers, the ease of melt spinning, diameter uniformity and mechanical properties of fibers were adversely affected. Diameter variation of PP/CNT as-spun fibers was shown to be an indication of hidden melt-drawings that had occurred during the fiber extrusion; this could lead to variations in morphology such as increases in the insulating microcracks and the distance between the conductive agglomerates in the drawn parts of the fiber. Variations in morphology result in variations in the electrical conductivity; consequently, the conductivity of such inhomogeneous fiber is no longer its physical property, as this varies with varying size. / Thesis to be defended in public on Friday, May 20, 2011 at 10.00 at KC-salen, Kemigården 4, Göteborg, for the degree of Doctor of Philosophy.

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.

Ce travail a été réalisé en collaboration avec EDF R&D, dans le cadre d’une convention CIFRE-ANRT, l’objectif étant d’améliorer le coefficient de performance de pompes à chaleur thermoélectriques (PACTEs) pour des "Bâtiments Basse Consommation". Les PACTEs présentent de nombreux avantages environnementaux, le désavantage étant leur faible performance. Ainsi l'objectif de ce travail a été d'examiner la possibilité d'améliorer, par nanostructuration les performances des semi-conducteurs utilisés dans les modules thermoélectriques des PACTEs. Nos travaux se sont concentrés sur les solutions solides à base de Sb2-xBixTe3, celles-ci étant, selon l’état-de-l’art, les plus performantes pour l’application visée. La nanostructuration a été réalisée par la technique de trempe sur roue (technique de refroidissement rapide de liquides) de matériaux synthétisés auparavant à l'état liquide dans des tubes en quartz. Les moyens de caractérisation (DRX, MEB, MET, METHR) ont permis de corréler les changements structurels avec la variation des propriétés thermiques et électriques (le pouvoir thermoélectrique, la résistivité électrique, l'effet de Hall, la conductivité thermique) mesurées sur de larges gammes de température (5-460 K). L'influence favorable de la nanostructuration par la diminution de conductivité thermique a été prouvée. Nous avons montré la forte dépendance des propriétés thermoélectriques des matériaux étudiés avec la concentration de défauts et la stœchiométrie. Le dopage avec du Te a été examiné comme une possibilité de contrôler le niveau de la concentration des porteurs de charge. L'idée de créer des niveaux d'impuretés résonantes par un dopage au Sn s’est montrée infructueuse, vraisemblablement en raison de la structure de bande complexe du composé ternaire. Néanmoins, des valeurs du facteur de mérite adimensionel ZT de près de 1,2 ont été obtenues pendant ce travail / This work results from the collaboration between IJL and EDF R&D performed under a CIFRE-ANRT convention, in order to improve the coefficient of performance of thermoelectric heat pumps (THPs). THPs attracted attention of EDF due to its numerous environmental advantages, but the main drawback remains its low performance. The objective of our work was thus to investigate the possibility to enhance the performance of the semiconductors used in the thermoelectric modules of the THPs, by nanostructuration. The research was concentrated on the Sb2-xBixTe3-based solid solutions, the most effective materials for the application sought. The nanostructuration was performed by applying the melt-spinning technique (rapid quenching from a melt on a water-cooled cupper wheel) to the material synthesised beforehand from liquid state in quartz tubes. The means of characterisation (XRD, SEM, TEM, HRTEM) gave the possibility to correlate the structural changes with the variation of the thermal and electrical properties (thermoelectric power, electrical resistivity, Hall effect, thermal conductivity) measured over a wide temperature range (5-460 K). The favourable influence of nanostructuration through the decreasing of thermal conductivity was proved. A high dependence of the thermoelectric efficiency of the studied materials on the concentration of defects and stoichiometry is shown. Doping with Te was investigated as a possibility to control the resulting level of the charge carrier concentration. The idea of creating resonant impurity levels by Sn-doping was shown to be non-conclusive presumably due to the complex band structure of the ternary compounds. Nevertheless, relatively high values of the dimensionless TE figure of merit, close to 1.2, were obtained during this work

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