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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Research of the developing strategy of the Taiwan nylon synthetic filament industry toward globalization

Chen, Evalon 01 August 2005 (has links)
It is quite a decisive role for the Taiwan¡¦s relevant sector to play in the nylon synthetic filament industry of the world on both quality and quantity. Their accomplishments ever included the significant contributions on a favorable balance of trade with the noticeable amount of foreign currency making for the Taiwan government. However, The business management of the connected industry in Taiwan is encountering the numerous dilemmas due to the Taiwanese currency appreciation in the recent decade, The globalization trend, And cost advantage of the emerging country. Through the profound interview approaches with the local nylon filament manufacturers in respects of the current business strategy and the coming developing tendency under the globalization circumstances, This research classified all the information available from the interviews, as a result, and sought for the persistent development prospects for the Taiwan nylon synthetic filament industry, both adaptable and successful, to the worldwide competent markets.
2

Convenient synthesis of caprolactam from lysine alternative of current benzene-based caprolactam production /

Yang, Jinsong. January 2007 (has links)
Thesis (PH. D.)--Michigan State University. Dept. of Chemistry, 2007. / Title from PDF t.p. (viewed on Sept. 8, 2009) Includes bibliographical references. Also issued in print.
3

Extraction of caprolactam in a rotating disk contactor extractor

Cato, David A. January 1900 (has links)
Master of Science / Department of Chemical Engineering / Larry E. Erickson / Caprolactam (C₆H₁₁NO) is produced in industry primarily as a monomer to be converted to nylon-6 via a polymerization reaction. More demanding purity requirements for nylon-6 have increased the performance requirements of extraction columns in the purification train of caprolactam production. Caprolactam is produced by performing a Beckmann Rearrangement on cyclohexanone oxime followed by a neutralization of the excess oleum post reaction. The resulting side product is ammonium sulfate in water with a residual amount of caprolactam that has to be extracted with benzene from the aqueous ammonium sulfate solution to reduce product losses. The aqueous caprolactam liquor is extracted in another column into benzene which purifies the product from water soluble impurities. The resulting caprolactam dissolved in benzene is back extracted into water where the final purification steps are completed prior to storage. Rotating disk contactor (RDC) extraction columns were invented by Royal Dutch Shell in the early 1950’s. The columns have a rotor in the center that is driven by an electric motor to rotate equally spaced flat disks inside the column. There are equally spaced annulus shaped stators that serve to provide mixing-separation compartments for each of the mounted disks on the rotor. Of the variables to consider for the optimum performance of the extraction in the RDC extraction column is the rotor speed. Rotor speed curves are generated for the 3 RDC extraction columns of the caprolactam purification as well as calculations of the number of theoretical stages for each of the columns based on actual performance data. Benzene is the solvent of choice in this purification process however recent push by environmental groups and agencies as well as tightening regulations have driven a desire to find a more benign alternative to benzene for this process. A review of the research and literature on potential alternative solvents for caprolactam purification is summarized with positives and drawbacks for each possible alternative.
4

Potential migration of [epsilon]-caprolactam to water and wine as affected by transportation and storage a thesis /

Ianneo, J. Chad. Brown, J. Wyatt. January 1900 (has links)
Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on March 25, 2009. Major professor: J. Wyatt Brown. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Agriculture with specialization in Crop Science." "March, 2009." Includes bibliographical references (p. 30-32). Also available on microfiche.
5

Towards renewable commodity chemicals biosynthesis of phloroglucinol and chemoenzymatic synthesis of caprolactam /

Cox, Brad M. January 2008 (has links)
Thesis (Ph. D.)--Michigan State University. Dept. of Chemistry, 2008. / Title from PDF t.p. (viewed Sept. 10, 2009). Includes bibliographical references. Also issued in print.
6

Anionic polymarisation of caprolactam : an approach to optimising thr polymerisation condition to be used in the jetting process

Khodabakhshi, Khosrow January 2011 (has links)
The main aim of this project was to investigate the possibility of manufacturing 3D parts of polyamide (nylon or PA) 6 by inkjetting its monomer caprolactam (CL). The principle of this process was similar to the other rapid prototype (RP) and rapid manufacturing (RM) processes in which a 3D part is manufactured by layer on layer deposition of material. PA6 was used as the thermoplastic polymer in this work because of its good properties and also because PA6 can be produced by heating its monomer (i.e. plus catalyst and activator) in a short time. Two polymerisation mixtures of CL-catalyst (mixture A) and CL-activator (mixture B) are intended to be jetted separately using conventional jetting heads and polymerise shortly after heating. Anionic polymerisation of CL (APCL) was investigated in the bulk and on a smaller scale. Sodium caprolactamate (CLNa and C10) and caprolactam magnesium bromide (CLMgBr) were used as catalysts and N-acetylcaprolactam (ACL) and a di-functional activator (C20) were used as activators. The influence of polymerisation conditions was investigated and optimised. These were catalyst-activator concentration, polymerisation temperature and the influence of the polymerisation atmosphere. The physical properties (monomer conversion, crystallinity, and viscosity average molecular weight) of PA6 samples produced using each catalyst-activator combinations were measured and compared. Small scale polymerisation was carried out using a hotplate, by hot stage microscopy and using differential scanning calorimetry (DSC). The influence of heating strategy on small scale polymerisation was studied using DSC. The polymerisation mixture compositions were characterised using rheometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and optical microscopy to investigate their suitability in jetting for using the available jetting heads. It was shown that the combination of CLMgBr-ACL resulted in fast polymerisation which was not sensitive to moisture. The C10-C20 combination resulted in fast polymerisation with the best properties in a protected environment (nitrogen); however, the polymerisation was affected by moisture in air and the properties of polymer produced and rate of polymerisation decreased in air. Polymers produced using CLNa-ACL had the poorest properties and polymerisation did not occur in air. Material characterisation showed that micro-crystals of CLMgBr existed in CLMgBr-CL mixture at the jetting temperature (80oC) which were too large to be jetted. However, the mixture of C10 in CL could be partially jetted. The activator mixtures had similar properties to CL and were easily jetted. Drop on drop polymerisation was carried out by dripping droplets of mixtures A and B (at 80oC) on top of each other on a hotplate at the polymerisation temperature. Small scale polymerisation in a DSC showed that the monomer conversion increased with increase in polymerisation temperature from 140oC to 180oC and decreased from 180oC to 200oC. The crystallinity of the polymer produced in the DSC decreased with increase in polymerisation temperature. Hot stage microscopy produced evidence for simultaneous polymerisation and crystallisation processes on heating. Small scale polymerisation in an oven and analysed by DSC showed that increasing catalystactivator concentration resulted in increasing monomer conversion and decrease in crystallinity. Monomer conversion also increased with increase in polymerisation temperature and polymerisation time. Comparison between small scale and bulk polymerisations shows a good agreement between the two polymerisation rates. This shows that the polymerisation mechanism did not change significantly when the quantity of materials was reduced to less than 20mg. Finally, the polymerisation was carried out in a DSC after jetting C10-CL and C20-CL mixtures into a DSC pan using a jetting system, which was made in another work.
7

Associations tanins-bore pour des produits de protection du bois à faible impact environnemental / Tannins-boron networks for long-term and low-environmental impact wood preservatives

Hu, Jinbo 01 September 2015 (has links)
Étant donné son origine, le bois reste biodégradable et a besoin d'être protégé contre les agents abiotiques et biotiques afin d'avoir une longue durée de service. Les associations entre les tanins et l'acide borique peuvent être considérés comme un traitement innovant et respectueux de l'environnement. Ces formulations aqueuses de tannins et d'acide borique augmentent la rémanence du bore dans le bois traité. De plus, le bore est partiellement fixé au réseau polymère de tannins autocondensés dans le bois et garde suffisamment de mobilité pour garder son efficacité biologique. Ces associations ont été testées pour une application en extérieur, au-dessus et dans le sol, et pour leurs propriétés ignifugeantes. Une première formulation de tannin-hexamine et acide borique a montré une efficacité certaine face aux dégradations biologiques et au feu. Le comportement au vieillissement naturel et artificiel, au lessivage à l'échelle du laboratoire, ainsi que l'efficacité biologique résultante, de bois traité par ces associations a été étudié. Les résultats montent que ces trois vieillissements mènent à des performances biologiques différentes, toutes liées à la teneur en bore résiduelle. Une formulation tannin-bore dite améliorée, contenant du ɛ-caprolactame pour rendre le réseau polymère plus flexible (et éviter les craquelures comme dans la première formulation) a été étudiée pour les mécanismes chimiques mis en jeu, la résistance biologique au-dessus et dans le sol, et la résistance au feu. Le polymère à base de tannin acquiert une structure plus élastique après incorporation de ɛ-caprolactame, comme démontré par des analyses FT-IR. La résistance biologique du bois traité procure une résistance à long terme en extérieur, même dans le sol. L'effet de protection au feu est moins intéressant que pour la première formulation, mais reste toute de même plus important que pour le témoin. Afin d'améliorer l'efficacité des associations entre bore et tannins, l'élaboration de bois contenant un polymère nano-composite (Wood Tannin NanoComposite, WTNC) utilisant tannins, acide borique et montmorillonite a été étudiée. Des analyses FT-IR et XRD on permit d’identifier des nanoparticules d'argiles dans le WTNC. Par ailleurs, des traces de montmorillonite dans les parois du bois ont été observées en microscopie électronique à balayage. Par comparaison avec des témoins, la résistance à la compression du WTNC est plus importante, l'absorption d'eau et l'aptitude au collage du WTNC dépend de l'essence utilisée (pin sylvestre vs. Hêtre), la stabilité dimensionnelle du WTNC est légèrement abaissée et sa mouillabilité significativement réduite. La résistance à l'attaque de champignons et termites est améliorée dans des proportions variables selon que l'on utilise du pin sylvestre ou du hêtre. Les performances anti-feu des WTNC sont affectées différemment en fonction de l'essence de bois utilisée et des paramètres considérés. Cette étude analyse aussi les impacts environnementaux de la production de produit de préservation tannin-bore (pour la première formulation) et compare aussi les impacts du berceau à la tombe dans le cadre d'une analyse de cycle de vie de bois traité par cette formulation, en comparaison avec 2 formulations industrielles et du béton. Il apparaît que même si ces associations tannin-bore peuvent être encore étudiées plus avant et plus finement du point de vue chimique, pour leurs performances biologiques (vis-à-vis d'insectes coléoptères, essais de champ avec des termites, moisissures…), ainsi que pour leur profil éco-toxicologique, elles ont montré de réelles améliorations du bois dans les domaines de la résistance biologique et de la résistance au feu. / Due to its origins, wood remains biodegradable and needs to be protected against abiotic and biotic agents for a long service life. Tannin-boron associations can be considered as an innovative preservative formulation and environmentally-friendly treatment. These waterborne associations of tannins and boric acid increase the permanence of boron in the wood. Furthermore, boric acid is partly fixed to the network of autocondensed tannin in the wood and keeps sufficient mobility to maintain its biological action. These associations have been investigated for their outdoor applications, both above and in-ground, as well as for their ability for fire protection. An original formulation of tannin-hexamine and boric acid, has shown efficiency against biological attack and fire degradation. The natural and artificial weathering behaviour, and laboratory scale leaching, of such treated wood have been investigated, and followed by biological tests. The results showed that the weatherings led to different performances, always linked with the amount of remaining boron. An advanced tannin-boron formulation including ɛ-caprolactam to make the polymer network more flexible (and avoiding cracks as noticed for the original formulation) was studied for the chemical mechanisms, biological resistance above and in-ground, fire retardancy. The tannin polymer acquires a more elastic structure after adding ɛ-caprolactam, as seen with FT-IR analyses. The biological resistance of the treated wood provided a long lasting protection against degradation in outdoor exposures, and even in ground contact. However, fire retardant effect of this advanced tannin-boron preservative was negatively influenced with comparison to the original tannin-boron formulation, but still better than control. In order to improve the associations between boron and tannin for wood protection, the conception of wood polymer nanocomposite using tannin, boric acid and montmorillonite tentatively carried out. The analyses of FT-IR and XRD have investigated to identify nanoclay in Wood Tannin Nanocomposite (WTNC). Meanwhile, the trace of montmorillonite in wood cell is also captured by SEM. By comparison with control, compression strengths of WTNC samples increase; water absorption and gluing ability of WTNC depend on the wood species used (Scot Pine vs. Beech); dimensional stability of WTNC is slightly decreased, and wettability was significantly decreased. Fungal and termite resistance of WTNC are improved to different extends if Scots pine or beech samples are used. Fire performances of WTNC is affected differently depending on the wood species used and the parameters considered. This study also analyses the environmental impacts of producing tannin-boron (TB) preservative (the original formulation) and comparatively introduces the cradle-to-grave life cycle environmental impacts (LCA) of TB-treated timber as landscaping materials, compared with 2 industrial formulations and concrete.Even if all these tannin-boron association systems developed still need to be improved for some point of their chemistry, biological performances (coleoptera insects, field tests with termites, molds…), as well as for their eco-toxicological profile, they have shown to improve the biological and fire resistance of the wood.
8

Neue Copolyesteramide für die Anwendung als Biomaterial : Synthese, Charakterisierung, Degradation und Zytokompatibilität /

Schillings, Jörg Andreas. January 2003 (has links)
Thesis (doctoral)--Techn. Hochsch., Aachen, 2003.
9

HYDRATE PARTICLES ADHESION FORCE MEASUREMENTS: EFFECTS OF TEMPERATURE, LOW DOSAGE INHIBITORS, AND INTERFACIAL ENERGY

Taylor, Craig J., Dieker, Laura E., Miller, Kelly T., Koh, Carolyn A., Sloan, E. Dendy 07 1900 (has links)
Micromechanical adhesion force measurements were performed on tetrahydrofuran (THF) hydrate particles in n-decane. The experiments were performed at atmospheric pressure over the temperature range 261–275 K. A scoping study characterized the effects of temperature, anti-agglomerants, and interfacial energy on the particle adhesion forces. The adhesion force between hydrate particles was found to increase with temperature and the interfacial energy of the surrounding liquid. The adhesion force of hydrates was directly proportional to the contact time and contact force. Both sorbitan monolaurate (Span20) and poly-N-vinyl caprolactam (PVCap) decreased the adhesion force between the hydrate particles. The measured forces and trends were explained by a capillary bridge between the particles.
10

Synthesis and characterization of alternating poly(amide urethane)s

Sharma, Bhaskar. Unknown Date (has links) (PDF)
Techn. Hochsch., Diss., 2004--Aachen.

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