The purpose of this research has been to develop a textile finish based on chitosan that is a biopolymer. A fiber-reactive chitosan derivative was synthesized from chitosan with a low molecular weight and a high degree of deacetylation. The synthesis was composed of two steps. As a first step, a water-soluble chitosan derivative was prepared by introducing quaternary ammonium salt groups on the amino groups of chitosan. The derivative was further modified by introducing functional groups (acrylamidomethyl) on the primary alcohol groups of the chitosan backbone, which can form covalent bonds with cotton. The fiber-reactive chitosan derivative (NMA-HTCC) itself showed complete bacterial reduction against Staphylococcus aureus and Escherichia coli at the concentration of 10 ppm. The NMA-HTCC was applied to cotton fabrics by a pad-batch method in the presence of an alkaline catalyst. The 1% NMA-HTCC treated cotton showed 100% bacterial reduction against S. aureus. The fabric maintained over 99% of bacterial reduction even after 50 home launderings. The NMA-HTCC cotton was dyed with direct and reactive dyes without addition of salt. The color yield was higher than that of untreated cotton, which required a large amount salt for dyeing. The NMA-HTCC cotton showed better washfastness than untreated cotton, but the lightfastness was inferior to that of untreated cotton. The antimicrobial activity of the NMA-HTCC cotton was considerablely decreased after dyeing due to the blocking of the cationic groups of the NMA-HTCC by dye molecules.

Poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT), poly(ethylene isophthalate) (PEI), and poly(trimethylene isophthalate) (PTI) were synthesized in a Parr reactor and melt-spun. Thermal and physical properties of the as-synthesized polymers and melt-spun fibers were determined. As-synthesized PEI and PTI were amorphous polymers and did not show any melting peaks by DSC analysis. All the polymers were thermally stable (TGA analysis). Amorphous films were made by a melt-press method with PET and PEI for determination of CO2 gas barrier properties. PEI, which has the meta-linkage of ester groups on the phenyl ring, had much lower CO2 gas permeability around one tenth that of PET, which has the para-linkage of ester groups on the phenyl ring. This is because in PET the phenyl rings are substituted in the para (1,4) positions, which allows for their facile flipping, effectively permitting gases to pass through. However, the meta-substituted phenyl rings in PEI do not permit such ring flipping, and thus PEI may be more suitable for barrier applications. The coalesced PEI was prepared from the inclusion compound of PEI with ?×-cyclodextrin. The coalesced PEI may have retained partially highly extended and parallel chains from the narrow channels of the inclusion compound, resulting in better/tighter packing among the PEI chains and exhibited a higher glass-transition temperature. Cyclic oligoesters of PET, PTT, PEI, and PTI were prepared by cyclo-depolymerization of these polyesters. The cyclic oligoesters were mixtures of different sized cyclic oligomers. PET cyclic oligomers showed four melting peaks at 59, 122, 194, and 276 o C. The cyclic oligomers of PTT, PEI, and PTI showed single melting peaks at 241, 335o C and 147o C, respectively. The cyclic oligoesters could be converted to linear polyesters by ring-opening polymerization. PTT was also prepared by ring-opening polymerization of its cyclic dimer obtained as a by-product in the conventional manufacturing plant. Antimony, tin, and titanium catalysts were used with various concentrations. The highest molecular weight, 40,000 g/mol was obtained when 0.25 mol% of titanium(IV) butoxide was used.

<p>HUANG, WENSHENG. Online Characterization of Fabric Compressional Behavior. (Under the direction of Tushar K. Ghosh and Winser E. Alexander)Response of a fabric to applied forces normal to its plane is known as fabric compressional behavior. It is one of the important properties that determine fabric performance in many applications. The principle of a system used to measure fabric compressional characteristics, online, is proposed in this paper. A controllable nip formed by a pair of rollers is employed to apply compressional deformation to a moving fabric while the compression force and displacement are continuously recorded. The influence of various system parameters on the sensitivity of the system has been analyzed. By assuming a stepwise anisotropic behavior in the thickness direction, Incremental Differential Algorithm (IDA) is developed to calculate the pressure-displacement relationship from the measured force-displacement data obtained from the online system. A prototype online measurement system has been developed based on this principle. A number of woven and nonwoven fabrics have been evaluated using the online system as well as a number of other commercially available fabric compression testers. The compressional characteristics obtained from the online measurement system compare well with the same parameters measured using the other commercially available compressional testers.<P>

<p>IKIZ, YUKSEL. Fiber Length Measurement by Image Processing. (Under the direction of Dr. Jon P. Rust.) This research studied the accuracy and feasibility of cotton fiber length measurement by image processing as an alternative to existing systems. Current systems have some weaknesses especially in Short Fiber Content (SFC) determination, which is becoming an important length parameter in industry. Seventy-two treatments of five factors were analyzed for length and time measurements by our own computer program. The factors are: Sample preparation (without fiber crossover and with fiber crossover), lighting (backlighting and frontlighting), resolution (37-micron, 57-micron, 106-micron, and 185-micron), preprocessing (4-neighborhood and 8-neighborhood), and processing (outlining, thinning, and adding broken skeletons). The best results in terms of accuracy, precision and analysis time for images without fiber crossovers were: 106-micron resolution with frontlighting using an 8-neighborhood thresholding algorithm and using an outline algorithm for length determination. With fiber crossovers, 57-micron resolution with backlighting using an 8-neighborhood thresholding algorithm and using a thinning algorithm combined with an adding algorithm for combining broken skeletons. Using the above conditions, 1775 area can be analyzed using our current equipment in 15 seconds. In the case of images with crossovers, only 117 can be analyzed in 15 seconds. This research demonstrates that successful sample preparation without fiber crossovers would create the best fiber length measurement technique, however with fiber crossovers the system efficiency has been proven as well.<P>

<p>Bauer-Kurz, Ina. Fiber Crimp and Crimp Stability in Nonwoven Fabric Processes. (Under the direction of Dr. William Oxenham and Dr. Donald A. Shiffler.)In nonwovens, crimp characteristics of synthetic fibers are, along with finish, major contributors to processing efficiency, web cohesion, fabric bulk and bulk stability. However, the meaning of measurable crimp parameters and their influence on processing and fabric characteristics has not been quantified. The purpose of this study is to quantify the mechanical fiber behavior during crimp removal, and relate it to fundamental fiber properties, nonwoven fabric properties, and processibility in nonwoven equipment.Single fiber tensile tests in the crimp removal region have been performed on various fibers with the Textechno FAVIMAT and have also been monitored optically. Based on empirical evidence, a basic understanding of the physical crimp removal mechanism is obtained. A methodology is developed, to identify the true crimp removal region of the whole single fiber load-extension curve during a tensile test. A mechanical model accounting for the nonlinear load-deflection behavior during crimp removal is developed. According to this model, a logarithmic function can be used to describe the material behavior in the crimp node during crimp removal. This function is fit to experimental data and delivers two fitting parameters that characterize the shape of the experimental load-extension curve in the crimp region.The extracted characteristic crimp parameters are being evaluated in terms of fiber material characteristics, such as fiber type, crimp processing settings and carding performance during nonwoven production. A dependence of the shape of the crimp removal curve on crimping settings during crimp production is established. The characteristic crimp parameters are also correlated to the sequence of processing stages during nonwoven production and cylinder speed during carding.<P>

Thermoplastic films for packaging applications

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In this work, the influence of aromatic structures on drug encapsulation, self-assembly and hydrogel formation was investigated. The physically crosslinked gelling systems were characterized and optimized for the use in biofabrication and applied in initial (bio)printing experiments. Chapter I: The cytocompatible (first in vitro and in vivo studies) amphiphile PMeOx-b-PBzOx-b- PMeOx (A-PBzOx-A) was used for the solubilization of PTX, schizandrin A (SchA), curcumin (CUR), niraparib and HS-173. Chapter II: Compared to the polymers A-PPheOx-A, A-PBzOx-A and A-PBzOzi-A, only the polymer A-PPheOzi-A showed a reversible temperature- and concentration-dependent inverse thermogelation, which is accompanied by a morphology change from long wormlike micelles in the gel to small spherical micelles in solution. The worm formation results from novel interactions between the hydrophilic and hydrophobic aromatic polymer blocks. Changes in the hydrophilic block significantly alter the gel system. Rheological properties can be optimized by concentration and temperature, which is why the hydrogel was used to significantly improve the printability and stability of Alg in a blend system. Chapter III: By extending the side chain of the aromatic hydrophobic block, the inverse thermogelling polymer A-poly(2-phenethyl-2-oxazoline)-A (A-PPhenEtOx-A) is obtained. Rapid gelation upon cooling is achieved by inter-correlating spherical micelles. Based on ideal rheological properties, first cytocompatible bioprinting experiments were performed in combination with Alg. The polymers A- poly(2-benzhydryl-2-oxazoline)-A (A-PBhOx-A) and A-poly(2-benzhydryl-2-oxazine) (A-PBhOzi-A) are characterized by two aromatic benzyl units per hydrophobic repeating unit. Only the polymer A- PBhOzi-A exhibited inverse thermogelling behavior. Merging micelles could be observed by electron microscopy. The system was rheologically characterized and discussed with respect to an application in 3D printing. Chapter IV: The thermogelling POx/POzi system, in particular the block copolymer PMeOx-b- PnPrOzi, was used in different applications in the field of biofabrication. The introduction of maleimide and furan units along the hydrophilic polymer part ensured additional stabilization by Diels-Alder crosslinking after the printing process. / In dieser Arbeit wurde der Einfluss von aromatischen Strukturen auf die Wirkstoffeinkapselung, der Selbstassemblierung und die Hydrogelbildung untersucht. Die physikalisch vernetzten Gele wurden für den Einsatz in der Biofabrikation charakterisiert und optimiert und fanden ersten (Bio)druckversuchen Anwendung. Kapitel I: Das zytokompatible (erste in vitro und in vivo Studien) Amphiphil PMeOx-b-PBzOx-b- PMeOx (A-PBzOx-A) eignet sich hervorragend für die Solubilisierung von PTX, Schizandrin A (SchA), Curcumin (CUR), Niraparib und HS-173. Kapitel II: Ausschließlich das Polymer A-PPheOzi-A zeigt im Vergleich zu den Polymeren A-PPheOx- A, A-PBzOx-A und A-PBzOzi-A eine reversible temperatur- und konzentrationsabhängige inverse Thermogelierung, welche durch eine Morphologie-Änderung von langen wurmartigen Mizellen im Gel zu kleinen sphärischen Mizellen in Lösung begleitet wird. Die Wurmbildung entsteht durch neuartige Wechselwirkungen zwischen den hydrophilen Polymerblöcken und den hydrophoben aromatischen Polymerblöcken. Veränderungen der hydrophilen Blöcke verändert signifikant das Gelsystem. Die rheologischen Eigenschaften können durch Konzentration und Temperatur optimiert werden, weshalb in einem Blendsystem die Druckbarkeit und Stabilität von Alginat signifikant verbessert wurde. Kapitel III: Durch Verlängerung der Seitenkette des aromatischen hydrophoben Blocks erhält man das inverse thermogelierende Polymer A-Poly(2-phenethyl-2-oxazolin)-A (A-PPhenEtOx-A). Die schnelle Gelierung bei Abkühlung wird durch miteinander korrelierende sphärische Mizellen erzielt. Auf Grundlage idealer rheologischer Eigenschaften, konnten erste zytokompatible Biodruckversuche in Kombination mit Alginat durchgeführt werden. Die Polymere A-Poly(2-benzhydryl-2-oxazolin)-A (A- PBhOx-A) und A-Poly(2-benzhydryl-2-oxazine) (A-PBhOzi-A) sind durch zwei aromatische Benzyl- Einheiten pro hydrophober Wiederholungseinheit charakterisiert. Nur das Polymer A-PBhOzi-A zeigt inverses thermogelierendes Verhalten. Durch Elektronenmikroskopie konnten verschmelzende Mizellen beobachtet werden. Das System wurde hinsichtlich einer Anwendung im Bereich des 3D- Drucks rheologisch charakterisiert und diskutiert. Kapitel IV: Das thermogelliernde POx/POzi System, insbesondere das Blockcopolymer PMeOx-b- PnPrOzi, wurde in weiterführenden Studien im Bereich der Biofabrikation genutzt. Durch die Einführung von Maleimide- und Furan-Einheiten entlang des hydrophilen Polymerteil konnte eine zusätzliche Stabilisierung durch Diels-Alder-Vernetzung nach dem Druckprozess realisiert werden.

No description available.

No description available.