The dissertation describes and assembles the building blocks for sound and accurate models for solid-state polymerization process systems of condensation polymers, particularly poly(ethylene terephthalate) and nylon-6. The work centers on an approach for modeling commercial-scale, as opposed to laboratory-scale, systems. The focus is not solely on coupled polymerization and diffusion, but extends to crystallization, physical properties, and phase equilibrium, which all enhance the robustness of the complete model. There are three applications demonstrating the utility of the model for a variety of real, industrial plant operations. One of the validated simulation models is for commercial production of three different grades of solid-state PET. There are also validated simulation models for the industrial leaching and solid-state polymerization of nylon-6 covering a range of operating conditions. The results of these studies justify our mixing-cell modeling approach as well as the inclusion of all relevant fundamental concepts. The first several chapters discuss in detail the engineering fundamentals that we must consider for modeling these polymerization process systems. These include physical properties, phase equilibrium, crystallization, diffusion, polymerization, and additional modeling considerations. The last two chapters cover the modeling applications. / Ph. D.

This thesis presents a multiscale model of an industrial nylon-6 leacher. We develop several models at various spatial scales and implement them together in a simplistic, efficient way to develop an overall leacher model. We solve dynamic transport differential equations using the finite-volume method and method of lines in an in-house-developed FORTRAN program. We use the ODEPACK package of ordinary differential equation (ODE) solvers to solve our system of coupled ODEs. Our multiscale model performs transport, thermodynamic, physical property, and mass-transfer calculations at a finite-volume scale. We introduce two additional scales: a mesoscale, in which we perform computational fluid dynamic (CFD) simulations, and a molecular scale. Our CFD simulations solve for turbulent properties of fluid flowing over a packed bed. We incorporate the turbulent diffusivity of the fluid into our finite-volume leacher model. We perform molecular simulations and use the conductor-like screening model-segment activity coefficient (COSMO-SAC) model to generate solubility predictions of small, cyclic oligomers in water and ε-caprolactam. Additionally, we develop an extension of COSMO-SAC to model polymer species, which we refer to as Polymer-COSMO-SAC, and apply it to solve liquid-liquid equilibrium equations. We present a unique methodology to apply COSMO-based models to polymer species, which shows reasonable results for nylon-6. Because of the computational intensity of our Polymer-COSMO-SAC liquid-liquid equilibrium algorithm, we generate pre-computed tables of equilibrium predictions that we may import into our leacher model. Our integration of multiscale models maximizes efficiency and feasibility with accuracy. We are able to use our multiscale models to estimate necessary parameters, but we need to fit two mass-transfer related parameters to industrial data. We validate our model against the plant data and find average-absolute errors in the final mass percent of ε-caprolactam and cyclic dimer in polymer chips of 25.0% and 54.7%, respectively. Several plant data sets are suspected outliers and we believe an unforeseen equilibrium limitation may cause this discrepancy. If we remove these outlying data sets, we then find average-absolute errors of 7.5% and 19.3% for ε-caprolactam and cyclic dimer, respectively. We then use our validated model to perform application and sensitivity studies to gain critical insight into the leacher's operating conditions. / Master of Science

No description available.

No laboratório de Análise, Processamento e Reologia de Materiais Poliméricos da Escola Politécnica da USP tem sido estudadas blendas de Poliamida-6 (PA-6) e filme de poli(vinil butiral) (PVB), como uma alternativa para reciclagem do filme de PVB oriundo do processo de separação dos componentes do vidro laminado pós-consumo. As propriedades mecânicas de uma blenda polimérica dependem da sua morfologia e, por sua vez, a morfologia depende das propriedades reológicas e da tensão interfacial entre os polímeros formadores da blenda, que para o caso de blendas envolvendo filme de PVB podem mudar em função da concentração de plastificante presente na composição do filme. Apesar da importância do seu conhecimento, a tensão interfacial entre PA-6 e filme de PVB não é conhecida. O presente trabalho teve como objetivo avaliar a tensão superficial do filme de PVB e da PA-6. O método utilizado foi o da gota pendente. Também estudou-se a influência da adição de plastificante na tensão superficial do filme de PVB. Os resultados mostraram que a tensão superficial dos polímeros estudados decresce com o aumento da temperatura (temperatura variando entre 240 e 260ºC). Em particular, para o filme de PVB a entropia de superfície ( (d/dT) ) apresentou um valor acima dos normalmente encontrados para polímeros fundidos. Este comportamento foi atribuído à estabilidade térmica do filme. O filme de PVB utilizado nos ensaios de tensão superficial foi caracterizado por Espectroscopia no Infravermelho (FTIR), Espectroscopia no Ultravioleta/Visível (UV-VIS), Espectroscopia Eletrônica para Análise Química (ESCA) e Análise Termogravimétrica (TG). Os resultados obtidos comprovaram que há mudanças na estrutura do PVB durante sua exposição a temperaturas elevadas, por longo período de tempo (condições do ensaio de tensão superficial). Foi observado, primeiramente, a evaporação do plastificante, seguida por perda de grupos polares (-OH, C=O e C-O-C) presentes na estrutura do PVB. A tensão superficial da Poliamida-6 foi determinada para temperaturas de 250 e 260ºC. Os resultados mostraram que a PA-6 manteve-se estável durante os ensaios. / In the Rheology and Polymer Processing Laboratory of Escola Politécnica of the University of São Paulo, Polyamide-6 / poly(vinyl butiral) film blends have been studied as an alternative for the recycling of post-consumption laminated glasses. The mechanical properties of these blends were studied and explained in light of their morphology. The morphology of polymer blends strongly depends on the rheological behavior of the blend and on the interfacial tension between the polymers forming the blend. In the case of Poliamide-6 (PA-6)/poly(vinyl butiral) (PVB) film blends, the interfacial tension depends on the plasticizer concentration present in PVB film. However, to our knowledge neither the PA-6/PVB film interfacial tension nor the surface tension of PVB film at temperatures above softening temperatures have been evaluated. In this work, the surface tension of poly(vinyl butyral) and polyamide was evaluated using the pendant drop method. Also it was tried to evaluate the surface tension of PVB film as a function of plasticizer content. The surface tension values obtained were in the same range as the ones obtained for other molten polymers: the surface tension decreases with increasing temperature (for temperatures ranging from 240 to 260°C). However, the value of PVB film surface entropy ((d/dT) where is the surface tension and T is the temperature) was much larger than values reported for other molten polymers. This result was attributed to thermal stability of PVB film during the surface tension measurement. The drops of PVB film after surface tension analysis were examined for any change in their functional groups using infrared spectroscopy (FITIR), ultraviolet-visible spectroscopy (UV/VIS), electron spectroscopy for chemical analysis (XPS/ESCA) and thermogravimetric analysis (TG). The results showed that changes in the chemical structure of PVB film occur during surface tension measurement. First, the plasticizer within the PVB film evaporates and, then, the PVB suffers reduction of polar units and creation of C=C bonds. The surface tension of PA-6 was evaluated for temperatures of 250 and 260°C. The PA-6 remained stable during tests.

The impact strength of Nylon 6 was improved by adding Ethylene- n-Butyl acrylate- maleic anhydride (E-nBA-MAH) terpolymer with various concentrations from 0% (w/w) to 15% (w/w). The bare interaction energy between two polymers was investigated by using melting point depression approach utilizing both the Flory-Huggins (FH) theory and the Sanchez-Lacombe Equation of State (SL EOS). The solution of the mixture was electrospun, and the effects of process parameters on the expected radii of nanofibers were investigated. The effects of process parameters such as polymer concentration in solution, electrical field, diameter of syringe needle, feed rate, and collector geometry on nanofibers were studied. The statistical analysis to relate these parameters on the diameter of nanofibers was carried out by using Johnson SB distribution. The ratio of elastic modulus to viscosity coefficient of nanofibers was worked out by using AFM and combined viscoelastic models. The experiments were carried out on single fiber. The ratio came out to be a function of nanofiber diameter and terpolymer concentration. Isothermal crystallization kinetics and WAXS diffraction patterns of blends revealed and also SEM images supported that after 5% addition of elastomeric terpolymer, the interaction between the components of the blend gets weaker. The elastic modulus of the blend with 5% of terpoymer was greater than that of the neat Nylon 6, but the elastic modulus decreased for the blends containing more than 5% terpolymer.

Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-10T16:31:48Z No. of bitstreams: 7 Marco 7.pdf: 246654 bytes, checksum: 0c5bf1d74df6ac0106a9cc8e1b18f21b (MD5) Marco 6.pdf: 1364038 bytes, checksum: 3b97a39e5bccbc78500a4c0afe8ac4fe (MD5) Marco 5.pdf: 1812363 bytes, checksum: 39cf3c9bb270b23b7d409571aad9c07f (MD5) Marco 4.pdf: 1290056 bytes, checksum: 92fadc3b1b5573893370bcf57e288326 (MD5) Marco 3.pdf: 1880966 bytes, checksum: ec424670898075ed2a402f4311c7ca2c (MD5) Marco 2.pdf: 545170 bytes, checksum: 798a1ca95b5a37fec7871bf3a5de5df5 (MD5) Marco 1.pdf: 564901 bytes, checksum: 4011e434981588d4b4b2a9e531286a8e (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-13T20:02:46Z (GMT) No. of bitstreams: 7 Marco 7.pdf: 246654 bytes, checksum: 0c5bf1d74df6ac0106a9cc8e1b18f21b (MD5) Marco 6.pdf: 1364038 bytes, checksum: 3b97a39e5bccbc78500a4c0afe8ac4fe (MD5) Marco 5.pdf: 1812363 bytes, checksum: 39cf3c9bb270b23b7d409571aad9c07f (MD5) Marco 4.pdf: 1290056 bytes, checksum: 92fadc3b1b5573893370bcf57e288326 (MD5) Marco 3.pdf: 1880966 bytes, checksum: ec424670898075ed2a402f4311c7ca2c (MD5) Marco 2.pdf: 545170 bytes, checksum: 798a1ca95b5a37fec7871bf3a5de5df5 (MD5) Marco 1.pdf: 564901 bytes, checksum: 4011e434981588d4b4b2a9e531286a8e (MD5) / Made available in DSpace on 2013-04-13T20:02:46Z (GMT). No. of bitstreams: 7 Marco 7.pdf: 246654 bytes, checksum: 0c5bf1d74df6ac0106a9cc8e1b18f21b (MD5) Marco 6.pdf: 1364038 bytes, checksum: 3b97a39e5bccbc78500a4c0afe8ac4fe (MD5) Marco 5.pdf: 1812363 bytes, checksum: 39cf3c9bb270b23b7d409571aad9c07f (MD5) Marco 4.pdf: 1290056 bytes, checksum: 92fadc3b1b5573893370bcf57e288326 (MD5) Marco 3.pdf: 1880966 bytes, checksum: ec424670898075ed2a402f4311c7ca2c (MD5) Marco 2.pdf: 545170 bytes, checksum: 798a1ca95b5a37fec7871bf3a5de5df5 (MD5) Marco 1.pdf: 564901 bytes, checksum: 4011e434981588d4b4b2a9e531286a8e (MD5) Previous issue date: 2006 / A pesquisa aqui apresentada teve como objetivo principal avaliar as propriedades mecânicas (resistência à tração, impacto e dureza) de compósitos produzidos com materiais residuais da indústria, constituídos por fase matriz de PVC reciclado e fase dispersa com frações volumétricas de 5, 10 e 20 % tanto de fibras de nylon 6 quanto de fibras de sisal. Objetivou, também, determinar em que medida o reforço de fibras curtas e orientadas aleatoriamente, poderia recuperar no PVC reciclado, as propriedades originais do PVC. Isto porque, sabe-se que os polímeros termoplásticos quando submetidos a processos de reciclagem tendem a apresentar perda nos valores de propriedades mecânicas, em virtude de rompimento de ligações entre suas cadeias moleculares. A pesquisa, ao usar materiais, resíduos e rejeitos industriais, notadamente o PVC e o sisal, visando futuro aproveitamento em novos materiais de construção, contribui não só para minimizar o impacto negativo do descarte de tais materiais nos resíduos sólidos urbanos, mas, também, para a busca do desenvolvimento sustentável. Apresenta revisão bibliográfica sobre pesquisas realizadas com compósitos similares além dos métodos seguidos para a produção e caracterização física e química dos compósitos, produzidos através de moldagem por injeção, e os procedimentos para realização dos ensaios mecânicos de tração direta, de impacto e de dureza. O PVC reciclado utilizado foi resultante de moagem e posterior pulverização de conexões produzidas com a mesma matéria prima utilizada para o PVC original As fibras de sisal, com comprimento médio de 3,5 cm, foram utilizadas nos compósitos, sem nenhum prévio tratamento térmico ou químico. As fibras de nylon, com comprimento médio de 2,5 cm, sendo rejeitos industriais, já possuíam um revestimento com um composto à base de látex, formaldeido e resorcinol. Os principais resultados da pesquisa foram: (i) o PVC reciclado teve desempenho mecânico semelhante ao do PVC original, em virtude de não ter passado por processo de envelhecimento acelerado, ou seja, praticamente manteve a mesma estrutura molecular do PVC original; (ii) entre as fibras, o sisal apresentou melhor desempenho que o nylon em todas as situações estudadas, pois além do seu módulo de elasticidade ser bastante superior que o do nylon 6, demonstrou ter havido, nas suas formulações, melhores coeficiente de forma e aderência na interface matriz-fibra. / Salvador

No laboratório de Análise, Processamento e Reologia de Materiais Poliméricos da Escola Politécnica da USP tem sido estudadas blendas de Poliamida-6 (PA-6) e filme de poli(vinil butiral) (PVB), como uma alternativa para reciclagem do filme de PVB oriundo do processo de separação dos componentes do vidro laminado pós-consumo. As propriedades mecânicas de uma blenda polimérica dependem da sua morfologia e, por sua vez, a morfologia depende das propriedades reológicas e da tensão interfacial entre os polímeros formadores da blenda, que para o caso de blendas envolvendo filme de PVB podem mudar em função da concentração de plastificante presente na composição do filme. Apesar da importância do seu conhecimento, a tensão interfacial entre PA-6 e filme de PVB não é conhecida. O presente trabalho teve como objetivo avaliar a tensão superficial do filme de PVB e da PA-6. O método utilizado foi o da gota pendente. Também estudou-se a influência da adição de plastificante na tensão superficial do filme de PVB. Os resultados mostraram que a tensão superficial dos polímeros estudados decresce com o aumento da temperatura (temperatura variando entre 240 e 260ºC). Em particular, para o filme de PVB a entropia de superfície ( (d/dT) ) apresentou um valor acima dos normalmente encontrados para polímeros fundidos. Este comportamento foi atribuído à estabilidade térmica do filme. O filme de PVB utilizado nos ensaios de tensão superficial foi caracterizado por Espectroscopia no Infravermelho (FTIR), Espectroscopia no Ultravioleta/Visível (UV-VIS), Espectroscopia Eletrônica para Análise Química (ESCA) e Análise Termogravimétrica (TG). Os resultados obtidos comprovaram que há mudanças na estrutura do PVB durante sua exposição a temperaturas elevadas, por longo período de tempo (condições do ensaio de tensão superficial). Foi observado, primeiramente, a evaporação do plastificante, seguida por perda de grupos polares (-OH, C=O e C-O-C) presentes na estrutura do PVB. A tensão superficial da Poliamida-6 foi determinada para temperaturas de 250 e 260ºC. Os resultados mostraram que a PA-6 manteve-se estável durante os ensaios. / In the Rheology and Polymer Processing Laboratory of Escola Politécnica of the University of São Paulo, Polyamide-6 / poly(vinyl butiral) film blends have been studied as an alternative for the recycling of post-consumption laminated glasses. The mechanical properties of these blends were studied and explained in light of their morphology. The morphology of polymer blends strongly depends on the rheological behavior of the blend and on the interfacial tension between the polymers forming the blend. In the case of Poliamide-6 (PA-6)/poly(vinyl butiral) (PVB) film blends, the interfacial tension depends on the plasticizer concentration present in PVB film. However, to our knowledge neither the PA-6/PVB film interfacial tension nor the surface tension of PVB film at temperatures above softening temperatures have been evaluated. In this work, the surface tension of poly(vinyl butyral) and polyamide was evaluated using the pendant drop method. Also it was tried to evaluate the surface tension of PVB film as a function of plasticizer content. The surface tension values obtained were in the same range as the ones obtained for other molten polymers: the surface tension decreases with increasing temperature (for temperatures ranging from 240 to 260°C). However, the value of PVB film surface entropy ((d/dT) where is the surface tension and T is the temperature) was much larger than values reported for other molten polymers. This result was attributed to thermal stability of PVB film during the surface tension measurement. The drops of PVB film after surface tension analysis were examined for any change in their functional groups using infrared spectroscopy (FITIR), ultraviolet-visible spectroscopy (UV/VIS), electron spectroscopy for chemical analysis (XPS/ESCA) and thermogravimetric analysis (TG). The results showed that changes in the chemical structure of PVB film occur during surface tension measurement. First, the plasticizer within the PVB film evaporates and, then, the PVB suffers reduction of polar units and creation of C=C bonds. The surface tension of PA-6 was evaluated for temperatures of 250 and 260°C. The PA-6 remained stable during tests.

No description available.

yes / Novel natural fibre composites of nylon-6 reinforced with coconut shell (CS) particles and empty fruit bunch (EFB) fibres have been investigated. Fillers were alkali treated before melt compounding with nylon-6. Mechanical, thermal and rheological properties of composites were measured. Tensile modulus was found to improve with both fillers up to 16% for nylon-6/CS composite and 10% for nylon-6/EFB composite, whereas a moderate increase in tensile strength was observed only with CS composites. Differences in the strengthening mechanisms were explained by the morphology of the two fillers, empty fruit bunch fibres having a weaker cellular internal structure. Observation of composite morphology using SEM showed that both fillers were highly compatible with nylon-6 due to its hydrophilic nature. Both fillers were found to cause a slight drop in crystallinity of the nylon matrix and to lower melt viscosity at typical injection moulding strain rates. Moisture absorption increased with addition of both fillers.

The catalytic depolymerization/pyrolysis of nylon 6 and 66 were investigated with the prospect of helping to curb the amount of carpet landfilled. Thermogravimetric analysis was used to determine which catalysts (and their nylon/catalyst ratio) were most suited for the depolymerization. By adding bases, the onset of degradation for some bases was 100 aC lower than that of the pure nylons. Potassium hydroxide and sodium hydroxide were found to be the most effective catalysts at a catalyst ratio of 100:1 of nylon 6 and nylon 66 to catalyst, respectively. After determining the most efficient catalyst, kinetic models/parameters from the TGA data were determined. These parameters were used in a reactive extrusion model for depolymerizing nylon 6 in carpet. Data from the model was then used to do cost analysis for the process. It was found that to get a Present Value Ratio greater than 1, the flow rate has to be greater than or equal to 500 lb/hr. At even higher flow rates up to the model¡¦s limit (1500 lb/hr), the Net Present Value shows that this process is economically viable. Extrusion of a 100:1 ratio of pure N6 and KOH was done in a 30 mm counter-rotating non-intermeshing twin screw extruder. The material collected from the vents of the extruder was tested with a gas chromatograph- mass spectrum (GC-MS) in tandem. There was only one significant peak from the GC and the primary molecular weight on the MS was 113, the molecular weight of caprolactam. This shows that the process could be profitable and require little purification if done industrially.