No description available.

The objective of this project was to develop blends based upon post consumer RPET and N6, and to evaluate the suitability of these blends to form fibres for the end use in carpet fibre. In the work carried out it was found it is possible to spin RPET/N6 biconstituent fibres over a wide range of blend ratios. All the blends studied have diminished physical properties when compared to those of pure RPET and N6. The processability of these blends also deteriorated due to the large increases in normal forces which manifests in extrusion equipment as die swell that often results in melt fracture. It has been shown that the morphology of the fibre controls the degree of decay in properties and die swell at the spinnerette. The blends that are rich in one phase, with the secondary phase distributed as elongated fibrils have shown better physical performance and improved processing compared to the blends 70/30 � 30/70, which have poorer properties and increased die swell due to there co-continuous morphology. In quiescent studies, the physical properties of the blends have had little deviation from those predicted using a rule of mixtures line. In and around the 50% RPET blend, die swell was observed to be extreme and this makes fibre spinning difficult. It was found that this was caused by a loss in viscosity in the blends and a general increase in normal forces in response to applied shear. The die swell phenomenon is a rheological characteristic of the blends, which was inevitably caused by internal capillary flow of one component in the other. IR spectroscopy has shown that there is little to no in-situ compatibilisation occurring during simple melt processing. However, it was found that significant interfacial compatibilisation could be achieved through solid stating N6/RPET blends. The FTIR spectra for solid state blends in figure 4.51 has shown absorbency in the 3300 cm-1 region after all free N6 was removed. This indicates that in-situ compatibilisation has occurred between the phases in the solid stating process and it is a time dependent reaction. The Burgers and Koltunov models can be used to predict the creep behaviour of the fibre blends studied. The Burgers model provides greater accuracy for longer-term exposure to stress. From the thermal results, the solid stating process significantly affects the melting and crystallisation out of the melt and the ultimate level of crystallinity. The contribution of the copolymer in these changes appears to be small. The physical strength of the fibres made on the laboratory line was only marginally lower than those made on a factory line. The morphology of the mid-range blends is co-continuous and that of the N6 and RPET rich blends is dispersed droplet morphology. Based on the finding, a N6 rich blends and in particular the 10% RPET blend is the most suitable for further commercial development as its processing, physical performance and post spinning processing closely resemble the pure N6 currently in use. It has provided performance and consistency throughout the processing and testing we have conducted.

No description available.

A kaolinite-nylon 6 composite was prepared by a polycondensation reaction from 6-aminohexanoic acid (AHA) intercalated in the kaolinite interlayer space. The basal spacing of kaolinite-AHA was 1.47 nm and the basal spacing of the heated products decreased to 1.16 nm. The signals attributed to nylon 6 were detected in the 13C CP/MAS NMR spectra of the heated products. Formation of nylon 6 in kaolinite was confirmed by appearance of IR band due to amide I and amide II. Sarcosine was intercalated in kaolinite for the first time by guest displacement with methanol from the kaolinite-methanol precursor. The basal spacing of kaolinite-sarcosine was 1.27 nm. This intercalation compound was characterized by NMR, TGA, XRD, and IR. The physical and chemical properties of natural clay sample from Mirandela formation (Portugal) were determined in terms of external skin treatment. The low CEC 4,45meq/100g is consistent with high content of kaolinite in the sample

A kaolinite-nylon 6 composite was prepared by a polycondensation reaction from 6-aminohexanoic acid (AHA) intercalated in the kaolinite interlayer space. The basal spacing of kaolinite-AHA was 1.47 nm and the basal spacing of the heated products decreased to 1.16 nm. The signals attributed to nylon 6 were detected in the 13C CP/MAS NMR spectra of the heated products. Formation of nylon 6 in kaolinite was confirmed by appearance of IR band due to amide I and amide II. Sarcosine was intercalated in kaolinite for the first time by guest displacement with methanol from the kaolinite-methanol precursor. The basal spacing of kaolinite-sarcosine was 1.27 nm. This intercalation compound was characterized by NMR, TGA, XRD, and IR. The physical and chemical properties of natural clay sample from Mirandela formation (Portugal) were determined in terms of external skin treatment. The low CEC 4,45meq/100g is consistent with high content of kaolinite in the sample

This research explores various immobilized enzyme support materials, including the novel nylon-6 fiber membrane (NFM), observing the increase of surface area and what effect that has on enzyme binding potential. This study also manipulates incubation and reaction conditions and observes what affect that has on activity and stability of β-galactosidase comparing various solid support materials and free enzyme. Nylon-6 fiber membranes were created using the process of electrospinning and were compared with other materials as solid support materials for enzyme binding. The other materials included polyvinylidene fluoride 5 kD nanofiltration dairy membranes, nylon-6 pellets, silica glass beads, and free—dissolved—enzyme. Scanning electron microscopy images exposed the nylon-6 fiber membrane’s large amount of surface area which coordinated with greater enzyme activity as compared to the relatively flatter surfaces of the other solid support materials. Enzyme activity was measured spectrophotometrically with the color-changing substrate ortho-Nitrophenyl-β-galactoside. NFM had greater maximum enzyme binding potential than the other solid supports. Across pH conditions ranging from 3.5 to 6.0., enzyme activity was maintained on the membrane immobilized samples whereas free enzyme did not maintain activity. Altering storage temperature (4, 22, and 50 °C) affected enzyme stability, the ability of the enzyme to maintain activity over time, of free and polyvinylidene fluoride membrane samples. However, nylon-6 fiber membrane samples maintained stability across the varying storage temperatures. Increasing the immobilization solution enzyme concentration above maximum enzyme binding capacity had no significant effect on enzyme stability for membrane immobilized samples. Although, both had lower mean stability than free enzyme by approximately 74% percent. With further development, β-galactosidase immobilized on nylon-6 fiber membranes, or other membranes, could be used in continuous processing in the dairy industry for a combination of filtration and lactose hydrolysis—creating products reduced in lactose and increased in sweetness with no “added sugars” requirement for a nutrition label and no enzyme listed as final product ingredient.

No description available.

This dissertation concerns the development of simulation and optimization technology for industrial, hydrolytic nylon-6 polymerizations. The significance of this work is that it is a comprehensive and fundamental analysis of nearly all of the pertinent aspects of simulation. It steps through all of the major steps for developing process models, including simulation of the reaction kinetics, phase equilibrium, physical properties, and mass-transfer- limited devolatization. Using this work, we can build accurate models for all major processing equipment involved in nylon-6 production. Contributions in this dissertation are of two types. Type one concerns the formalization of existing knowledge of nylon-6 polymerization mixtures, mainly for documentation and teaching purposes. Type two, on the other hand, concerns original research contributions. Formalizations of existing knowledge include reaction kinetics and physical properties. Original research contributions include models for phase equilibrium, diffusivities of water and caprolactam, and devolatization in vacuum-finishing reactors. We have designed all of the models herein to be fundamental, yet accessible to the practicing engineer. All of the analysis was done using commercial software packages offered by Aspen Technology, Cambridge, MA. We chose these packages for two reasons: (1) These packages enable one to quickly build fundamental steady-state and dynamic models of polymer trains; and (2) These packages are the only ones commercially available for simulating polymer trains. / Ph. D.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nanocompósitos de poliamida 6 (PA6) e montmorilonita modificada com sal de amônio quaternário têm sido estudados, visando melhorar as propriedades térmicas e mecânicas. De fato os efeitos da nano-escala e da interação carga-matriz resultam em maior módulo de elasticidade e resistência à tração, porém a deformação é reduzida. Assim, nesse trabalho, optou-se por adicionar elastômeros, terpolímero de etileno-propileno-dieno (EPDM) e terpolímero de etileno-propileno-dieno modificado com anidrido maleico (EPDM-MA), ao sistema PA 6/argila organofílica para recuperar os valores de deformação. Foi utilizada montmorilonita modificada com cloreto de dimetildioctadecil amônio. A intercalação por fusão foi realizada em câmara interna de mistura. Além das propriedades mecânicas, térmicas e reológicas, foram investigadas as modificações na cristalinidade da fase PA-6 em função da adição da argila modificada, EPDM e EPDM-MA, detectando-se as variações no grau de cristalinidade e nas temperaturas de fusão e cristalização. Os difratogramas de raios-x revelaram ocorrência de intercalação/esfoliação e também modificação da forma cristalina da PA 6, indicando a formação do cristal gama / Nanocomposites of polyamide 6 and montmorillonite modified with alquil-ammonium salts have been studied, searching for the improvement of mechanical and thermal properties. In fact the effects of the nano-scale and the interaction matrix-filler result in larger module of elasticity and tensile strength. However, the elongation at break was greatly reduced. Therefore, in this work, it has been decided to add elastomers, ethylene-proplene-diene terpolymer (EPDM) and ethylene-proplene-diene terpolymer funcionalized with maleic anhydride (EPDM-MA), to the system PA6/organoclay, using modified montmorillonite with ditallowdimethylammonium chloride. The nanocomposites were prepared by melt intercalation technique in a mix internal chamber. Besides the mechanical, thermal and rheological properties, the modifications in the crystallinity of PA6 phase were investigated, being detected the variations in the degree of crystallinity and in the melt temperature and crystallization. The diffractograms of x-ray (XRD) revealed occurrence of intercalation/exfoliation as well as modification of the crystalline form of PA 6, indicating the formation of  crystals

A fracture mechanics protocol appropriate for small fibers (35 micron diameter) is presented, which allows for the determination of the strength limitations of high performance nylon 6,6 fibers. Specifically, linear elastic fracture mechanics (LEFM) techniques are employed in addition to elastic-plastic fracture mechanics (EPFM) theories to achieve this. We assume that a minute semi-elliptical flaw of an unknown size exists in the specimen, as a result of the detrimental effects of the manufacturing process (melt spinning). Next, we seek to propagate this flaw in a stable manner through an ancillary process such as high cycle or low cycle fatigue (load-unload). After propagation, uniaxial tensile experiments are performed on the fatigued samples, by which the crack growth eventually becomes catastrophic during the process. After performing scanning electron microscopy (SEM) techniques and reviewing fractography, we are able to determine the critical flaw size and ligament length that leads to unstable crack propagation. These results are substituted into the appropriate LEFM equations and are in close agreement with material properties for nylon 6,6. A discussion is provided that draws parallel to the topics discussed in the literature investigation and the experimental results of this study.