Six poly(ether ketone ketone)/carbon composite panels were manufactured from powder coated towpreg. All six panels were initially processed using a hot press equipped with controlled cooling. Four of the panels were used to investigate the effect of cooling rate on crystallinity. A fifth panel was used to investigate the effect of annealing the composite after completion of the standard fabrication process. The sixth panel was used to investigate changes in toughness due to manufacturing towpreg with polymer that had been reclaimed from the towpreg fabrication system’s air cleaner. Cooling rates of 2°C/min, 4°C/min, 6°C/min, and 8°C/min resulted in composites with crystallinities of 33%, 27%, 24%, and 23%, respectively. The principal investigation of the effect of cooling rate on crystallinity and mode I and mode II strain energy release rates, G_Ic and G_IIc, respectively, showed that G_Ic and G_IIc values increase with increasing cooling rate. Comparison of the toughness values as a function of crystallinity showed that the dependence of toughness on crystallinity is approximately equivalent to the dependence of toughness on cooling rate. Comparison of the data from the annealed panel to that from the analogous principal panel showed that annealing increased the crystallinity and decreased the mode I strain energy release rate. There was no effect, however, on the mode II strain energy release rate. Comparison of the data from the panel made with reclaimed polymer to that from its analogous principal panel showed that the reclaimed polymer panel had equivalent crystallinity and G_Ic values. On the other hand, the G_IIc values in this panel were lower than in the analogous principal panel. / Master of Science

Polymeric materials have provided pathways to products that could not be manufactured otherwise. A new technology which merges the benefits of ceramics into these polymer products has created materials ideally suited to many different industries, like food packaging. Nano Scale Surface Systems, Inc. (NS3), a company which coats polymers with ceramic oxides like SiO2 through a process known as plasma enhanced chemical vapor deposition (PECVD), was interested in the feasibility of an in line measurement system for monitoring the deposited films on various polymer products. This project examined two different coated polymer products, polyethylene terephthalate (PET) beverage containers and biaxially oriented PET food packaging, commonly known as plastic wrap in an effort to determine the feasibility of an ellipsometry based measurement system for NS3’s purpose. Due to its extensive use in the semiconductor industry for monitoring films deposited on silicon, a measurement systems known as ellipsometry, adept at monitoring the thickness and refractive index of thin films deposited on various substrates, appeared to be an ideal system for the measurement of ceramic oxides deposited on various polymer substrates. This project set out to determine the feasibility of using an ellipsometry based measurement system to monitor ceramic films, specifically silicon oxides (SiOX), deposited on polymer products. A preliminary experiment determined linearly polarized light could induce a discernible change in polarized light traversing a coated beverage container relative to an uncoated container. However, the experiment lacked repeatability due to the measurement apparatus’ cheap setup, prompting the construction of a null (conventional) ellipsometer for further research. The curved surface of the beverage containers under study unnecessarily complicated the feasibility study so further research examined PECVD SiOX on biaxially oriented PET instead. Characterization of the PECVD SiOX-PET material was divided into three experiments, with the first two analyzing the SiOX film and PET substrate separately while the third analyzed them together. To assist with the characterization experiments, NS3 provided samples, both SiOX coated and uncoated, of various deposition thicknesses on silicon and biaxially oriented PET substrates. Null ellipsometry was used in conjunction with spectroscopic reflectometry to characterize the refractive index and thickness of the deposited films. The combined measurement systems found the refractive index of the deposited SiOX films to be between 1.461 and 1.465. The measured thicknesses resulting from the two measurement systems coincided well and were usually 10-20 nm thicker than the predicted thicknesses by the deposition processing parameters. Abeles’ method and monochromatic goniometry were attempted; however, the results had to be discarded due to irrecoverable errors discovered in the reflectance measurement. X-ray photoelectron spectroscopy (XPS) data provided by NS3 showed the deposited SiOX films to be homogeneous with stoichiometries between 2.15 and 2.23. Characterization of the uncoated biaxially oriented PET required numerous measurement systems. From spectroscopic transmission, trirefringent anisotropy was discovered, intertwined with thickness variations in the PET foil. Goniometry measurements displayed distinct interference curves resulting from rear interface reflections interfering with front interface reflections from the PET sample. Subsequent goniometric models produced multiple solutions due to an unknown optical phenomenon, probably scattering, which degraded the reflection measurements. However, a combined measurement technique utilizing goniometry and differential scanning calorimetry (DSC) determined the refractive indices of the polymer to be NX = 1.677, NY = 1.632 and NZ = 1.495 with a thickness of 11.343 μm and a volume fraction crystallinity of 35-41%. Utilizing the measured refractive indices, ellipsometric models produced only an adequate fit of the measured data due to the presence of depolarization caused by non-uniform PET thickness and scattering resulting from embedded microscopic crystallites. The majority of the error in the ellipsometric data was observed in the Δ measurement. XPS measurements of SiOX deposited on polypropylene (PP) provided by NS3 showed a heterogeneous interphase layer between the deposited oxide and the polymer substrate where the composition of the layer was continually changing. A similar region, which violates the homogenous assumption the ellipsometric model relied on, was anticipated for the SiOX-PET samples under investigation. The use of an effective medium approximation (EMA) to represent the interphase region was attempted, but failed to provide a decent model fit of the measured data. Depolarization and high optical anisotropy caused by the polymer substrate in combination with a heterogeneous interphase region and the effects of the deposited SiOX layer all interacted to prevent ellipsometric modelling of the null ellipsometry measurements conducted. Goniometry measurements were conducted on the thickest deposited SiOX film (approximately 100 nm) which allowed for the refractive index of the film to be approximated through Abeles’ method (n = 1.46); however the validity of this approximation was questionable given the presence of interference fringes resulting from interference between reflections at both the front and rear interfaces of the material. From the experiments conducted, it was concluded that null ellipsometry with conventional ellipsometric models could not adequately measure a SiOX film’s refractive index or thickness when deposited on biaxially oriented PET. The reasons for the failure were interactions between multiple sources of error which led to both measurement errors and inaccurate model assumptions. Use of generalized ellipsometry, possibly with spectroscopic ellipsometry, may overcome the failures of conventional ellipsometry when studying this complex optical material.

Process-induced Long-term Deformation Behavior of Injection Molded Semicrystalline Thermoplastics Injection molding is a very complex process because the polymer experiences a complex thermorheological history during molding that influences the molecular orientation, residual stresses, frozen-in free volume and crystallinity inside the part. These generally govern the final part properties. Therefore it is highly desirable to anticipate the effect of process parameters on the resulting microstructure and mechanical properties of the finished part in the long run. In the case of a semicrystalline thermoplastic part, the problem in understanding the deformation behavior arises from its two-phase structure and a tendency exists to concentrate primarily on the effect of the crystalline phase on the deformation behavior, while the contribution of the amorphous phase is less investigated. In this work, the influence of the processing parameters on the deformation behavior of injection molded semicrystalline thermoplastic parts, viz., syndiotactic Polystyrene (sPS) and Polybutylene terepthalate (PBT), has been monitored through creep. The resulting internal structures due to processing have been determined and the deformation behavior has been analyzed. It has been observed that only the rate of cooling shows a remarkable effect on the long-term viscoelastic behavior of an injection molded semicrystalline thermoplastic part as it influences not only the crystalline, but also the free volume fraction, whereas the different states of frozen-in orientations and pressure-induced densification have only a negligible effect. Besides, physical aging also plays an important role in the deformation behavior of the injection moldings which was manifested with the decrease in the tendency to creep. Therefore, it was suggested that the cooling rate during injection molding and the aging time can significantly affect the long-term deformation behavior of the injection molded semicrystalline thermoplastics. The results also showed that when no significant effect is observed in terms of short-term mechanical properties by changing the processing conditions, but while considering the long-term behavior they show a significant effect.

Η παρούσα διατριβή είχε ως σκοπό τη μελέτη της επίδρασης της επαναμορφοποίησης στις μηχανικές κυρίως ιδιότητες δυο πολύ κοινών πολυμερών, του πολυαιθυλενίου και του πολυπροπυλενίου. Τα πολυμερή αυτά, χρησιμοποιούνται σε πολλές εφαρμογές και για αυτό το λόγο ο όγκος των απορριμμάτων τους αποτελεί ένα σοβαρό περιβαλλοντικό πρόβλημα. Παρόλο που αποτελούν υλικά εύκολα ανακυκλώσιμα, πολύ μικρό ποσοστό από τα απορρίμματα τους ανακτώνται. Περιβαλλοντικοί αλλά και οικονομικοί λόγοι οδήγησαν στην ιδέα να κατασκευαστούν κάποια προϊόντα χαμηλών απαιτήσεων, τα οποία μέχρι τώρα κατασκευάζονται από καθαρά πολυμερή, από πλήρως ανακτημένη πρώτη ύλη. Η δυσκολία στην εφαρμογή των ανακτημένων υλικών έγκειται στο ότι αυτά περιέχουν διάφορα πρόσθετα, καταπονούνται αρκετά από την έκθεση τους σε περιβαλλοντικούς παράγοντες όσο διάστημα χρησιμοποιούνται ή βρίσκονται στους χώρους ενταφιασμού και οι πολλαπλές επαναμορφοποιήσεις τους είναι πιθανόν να προκαλέσουν υποβάθμιση του υλικού. Για αυτό το λόγο, μελετήθηκαν επαναμορφοποιημένα δείγματα από πολυαιθυλένιο και πολυπροπυλένιο άγνωστης προϊστορίας και καταπόνησης σε σύγκριση με τα αντίστοιχα καθαρά υλικά, προκειμένου να γίνει σύγκριση των ιδιοτήτων τους και κατ’ επέκταση μια εκτίμηση της επίδρασης του βαθμού επαναμορφοποίησης στη μηχανική τους συμπεριφορά. Παράλληλα, όλα τα δείγματα, επαναμορφοποιημένα και μη, μελετήθηκαν φασματοσκοπικά, ώστε να διαπιστωθεί αν η διαδικασία ανάκτησης έχει προκαλέσει μεταβολές στη χημική δομή των υλικών αυτών. Από τις τεχνικές χαρακτηρισμού που χρησιμοποιήθηκαν (φασματοσκοπία υπερύθρου και Raman, DSC και TGA) διαπιστώθηκε ότι δεν έχει επέλθει αλλαγή στη χημική δομή των ανακυκλωμένων υλικών. Όσον αφορά τις διαφοροποιήσεις που εκείνα παρουσίασαν σε σχέση με τα αντίστοιχα καθαρά υλικά, αποδίδονται στην παρουσία προσθέτων, χρωστικών ουσιών κυρίως, που τα ανακτημένα υλικά περιείχαν. Η μηχανική συμπεριφορά των επαναμορφοποιημένων, ιδιαίτερα στην περίπτωση του πολυαιθυλενίου ήταν παρόμοια με αυτή των καθαρών δειγμάτων και τα αποτελέσματα συγκρίσιμα. Αντίθετα, στην περίπτωση του πολυπροπυλενίου η διαδικασία ανάκτησης είχε υποβαθμίσει πολύ το υλικό με αποτέλεσμα να εμφανίζει πολύ κατώτερες μηχανικές ιδιότητες. Όλα τα επαναμορφοποιημένα υλικά είχαν υποστεί ως ένα βαθμό περιβαλλοντική γήρανση καθώς ήταν εκτεθειμένα για αρκετό χρονικό διάστημα σε περιβαλλοντικές συνθήκες. Η επίδραση της έκθεσης όμως δεν ήταν δυνατόν να αξιολογηθεί, αφού δε ήταν γνωστό το ακριβές χρονικό διάστημα καθώς και οι συνθήκες θερμοκρασίας, υγρασίας κ.λπ. Για αυτό το λόγο, τόσο τα ανακτημένα όσο και τα καθαρά δείγματα, υπέστησαν τεχνητή επιταχυνόμενη περιβαλλοντική γήρανση, προκειμένου να μελετηθεί η επίδρασή της στις ιδιότητες των υλικών. Αυτό που παρατηρήθηκε και σε αυτές τις δοκιμές ήταν ότι, ανάλογα με τον βαθμό επαναμορφοποίησης στα μη γηρασμένα υλικά, η τεχνητή γήρανση επηρέασε κατά κύριο λόγο τις αντοχές των υλικών σε κάθε μηχανική καταπόνηση και δευτερευόντως τις φυσικές ιδιότητες τους. Σε γενικές γραμμές, διαπιστώθηκε ότι τα επαναμορφοποιημένα δείγματα HDPE δεν παρουσιάζουν μεταβολές ως προς τη χημική δομή τους, ενώ δίνουν συγκρίσιμα αποτελέσματα στις μηχανικές δοκιμές τόσο στο μέτρο ελαστικότητας όσο και στην αντοχή. Μετά τη γήρανση, η αντοχή τους μειώνεται σημαντικά παρόλα αυτά, η συνολική τους μηχανική απόκριση κρίνεται ικανοποιητική. Αντίθετα τα επαναμορφοποιημένα δείγματα ΡΡ, εμφάνισαν ακόμα και πριν την τεχνητή γήρανση, αισθητά χαμηλότερες μηχανικές ιδιότητες (χαμηλότερο μέτρο ελαστικότητας και αντοχή σε σχέση με τα παρθένα υλικά), παρόλο που δεν παρουσίασαν καμία αλλαγή στη χημική τους δομή. / Reforming effect on thermoplastics mechanical properties was the subject of this thesis. More specifically, samples of polyethylene and polypropylene were chosen to be tested, as they are widely used in many applications and consequently there is a large amount of municipal waste of this kind. Even though, these polymers are easily recyclable compared to other polymers, only 2% of this kind of municipal waste gets recycled in Greece nowadays. Economical and environmental reasons, researchers led to the idea of constructing products out of completely recycled materials. Recycling process faces many difficulties; the most important of these is the addition of pigments (additives) such as colors, coupling agents etc, which make polymer recycling heavier or even impossible in some cases. Moreover, these materials degrade signifantly because of their exposure to the environment while they are used in exterior application or get thrown in landfills after use. As the collection of completely recycled materials was quite impossible, virgin and reformed of known and unknown history samples of polyethylene and polypropylene, are examined, as for their chemical structure and mechanical properties, in order to get compared and finally reach a conclusion if reformed materials are appropriate for getting used in some applications. Through Raman and Infrared Spectroscopy, it was observed no change in reformed materials’ chemical structure before and after reforming process. Also, their thermal behavior appeared many similarities between virgin materials and reformed ones. However, these similarities did not appear in mechanical tests. Even though, reformed HDPE of known and unknown history showed comparable and very close properties with these of virgin, it is observed a lack of stability in their mechanical behavior, especially in case of reformed unknown history polyethylene. In the case of polypropylene, the reformed samples were always inferior to the virgin ones, in all tests, probably to its degradation during reforming process. In order to determine accurately, the weathering effect on samples behaviour, they were imposed to artificial ageing in oven, in controlled temperature, humidity etc. As in non aged samples, reforming ratio plays significant role in samples’ physical properties, which appear dominantly changed after ageing. As it was expected, mechanical behavior has changed after ageing, too. However, there were no significant reduce in moduli of elasticity in tensile, compression and flexural tests, a dramatic reduce in strength in every mechanical test was observed between samples before and after ageing.

MCM-22 is a typical representative of the MWW family zeolite being obtained from laminated precursor MCM-22 (P) after calcination process having high surface area and high thermal stability. In this work, we carried out an optimization of the synthesis process of MCM-22 zeolite, in order to reduce the amount of reactants used and the crystallization time. The zeolite was synthesized using three different sources of silicon (Aerosil silica, silica gel and Ultrasil 60) and static hydrothermal treatment; in order to evaluate the influence of silicon source on the formation of the structure and physicochemical properties. The syntheses were performed without aging and with aging at room temperature and at 40 ° C for each source of silicon. It was also a study on the influence of calcination on the formation of MCM-22 structure. The materials (MCM-22 (P) and MCM-22) were characterized by X-ray diffraction (XRD); textural analysis of nitrogen adsorption at low temperature; scanning electron microscopy (SEM); spectroscopy in the infrared (FT-IR); thermogravimetry / derivative thermogravimetry (TGA / DTG) and determination of acidity termoprogramada desorption of NH3 (NH3-TPD). The X-ray diffraction showed that the synthesis of the materials has been successful, with the characteristic peaks of the MWW topology. In the conditions proposed in this work it was possible to optimize the synthesis of MCM-22 zeolite, which is obtained in a short time of 4 days without aging, for the sources of silica and Aerosil Ultrasil, and 3-day aging at 40 ° C for source of Aerosil silica. Unable to the formation of MCM-22 zeolite with silica gel within 8 days. The X-ray diffraction confirmed the obtaining of MCM-22 with high purity and crystallinity without the presence of any contaminant phase in a short time (4 days) in the absence of aging. Through the analysis (FT-IR) was confirmed the presence of the intrinsic vibrations of TO4 tetrahedrons that provide internal and external bands characteristics of these materials. Through the thermogravimetric analysis (TGA / DTG) it was found that higher weight loss occurred between 180 and 530 ° C and corresponds to the output of most of the organic driver. The results of BET showed that the textural properties of MCM-22 zeolite were heavily dependent on silicon source and treatment of synthesis gel. Generally, the samples showed a surface area higher than 500 m2 / g. From acid analysis by NH3-TPD it was observed that acid sites present in the samples were predominantly mild and strong acid sites. The source of silicon and the aging of the gel did not influence the acidity of the material. The evaluation method of calcination showed that the form of calcination used to obtain MCM-22 influences the textural properties of the zeolite. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A MCM-22 é uma zeólita típica representante da família MWW, sendo obtida a partir do precursor lamelar MCM-22(P) após processo de calcinação possuindo elevada área superficial e alta estabilidade térmica. Neste trabalho, realizou-se uma otimização do processo de síntese da zeólita MCM-22, com a finalidade de reduzir a quantidade de reagentes utilizados e o tempo de cristalização. A zeólita foi sintetizada empregando três diferentes fontes de silício (Sílica Aerosil, Ultrasil e Sílica gel 60) e tratamento hidrotérmico estático; com o objetivo de avaliar a influência da fonte de silício sobre a formação da estrutura e propriedades físico-químicas. As sínteses foram realizadas sem envelhecimento e com envelhecimento a temperatura ambiente e a 40°C, para cada fonte de silício. A influência do processo de calcinação sobre a formação da estrutura da MCM-22 também foi estudada. Os materiais obtidos (MCM-22 (P) e MCM-22) foram caracterizados por difração de raios-X (DRX); análise textural por adsorção de nitrogênio a baixa temperatura; microscopia eletrônica de varredura (MEV); espectroscopia na região do infravermelho (FT-IR); termogravimetria/termogravimetria derivada (TG/DTG), e determinação de acidez por dessorção termoprogramada de NH3 (TPD-NH3).Os difratogramas de raios-X comprovaram que a síntese dos materiais foi bem sucedida, apresentando os picos característicos da topologia MWW. Nas condições propostas neste trabalho foi possível otimizar a síntese da zeólita MCM-22, em um tempo curto de 4 dias sem envelhecimento, para as fontes de sílicas Aerosil e Ultrasil, e com 3 dias com envelhecimento a 40°C para a fonte de sílica Aerosil.Não foi possível a formação da zeólita MCM-22 com a sílica gel no período de 8 dias. Os difratogramas de raios-X comprovaram a obtenção da MCM-22 com alta pureza e cristalinidade, sem a presença de nenhuma fase contaminante, em um tempo reduzido (4 dias), e na ausência de envelhecimento. Por meio das análises (FT-IR) foi possível confirmar a presença das vibrações intrínsecas dos tetraedros TO4 que fornecem as bandas internas e externas características desses materiais. Através das análises termogravimétricas (TG/DTG) verificou-se que a maior perda de massa ocorreu entre 180 e 530 °C, e corresponde à saída da maior parte do direcionador orgânico. Os resultados de BET mostraram que as propriedades texturais da zeólita MCM-22 foram fortemente dependentes da fonte de silício e do tratamento do gel de síntese. De uma forma geral, as amostras apresentaram área superficial superior a 500 m2/g. A partir das análises de acidez por TPD-NH3 observou-se que os sítios ácidos presentes nas amostras foram, predominantemente, sítios ácidos moderados e fortes. A fonte de silício e o envelhecimento do gel não influenciaram na acidez do material. A avaliação do método de calcinação revelou que a forma de calcinação empregada para a obtenção da MCM-22 influencia nas propriedades texturais da zeólita.

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No. of bitstreams: 2 Tese - Aline Mendonça Pascoal - 2014.doc: 4428288 bytes, checksum: 759c80688c07f85efa0d5d3663f7dbec (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-03-28 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / This study was conducted to evaluate the chemical, physical-chemical, biochemical and rheological properties of starch from Solanum lycocarpum. The pulp from Solanum lycocarpum fruits was used as raw material for extraction of starch, resulting in a yield of 51%. The starch granules were heterogeneous in size, presenting a conical appearance, very similar to those from high-amylose cassava starch. The elemental analysis (CHNS) revealed 64.33% carbon, 7.16% hydrogen and 0.80% nitrogen. FT-IR spectroscopy showed the peaks characteristic of polysaccharides and NMR analysis confirmed the presence of the α-anomer of D-glucose. The S. lycocarpum starch was characterized by high value of intrinsic viscosity (3515 mPa s) and estimated molecular weight around 645.69 kDa. Furthermore, this starch was classified as a C-type and high amylose content starch, presenting 34.66% of amylose and 38% crystallinity. Endothermic transition temperatures (To = 61.25°C; Tp = 64.5°C; Tc = 67.5°C), gelatinization temperature (∆T = 6.3°C) and enthalpy changes (∆H= 13.21 J g−1) were accessed by DCS analysis. The thermogravimetric analysis of S. lycocarpum starch showed a typical three-step weight loss pattern. Microscopy revealed significant changes in the granule morphology after thermal treatment. Samples treated at 50°C for 10 min lost 52% of their crystallinity, which was partially recovered after storage for 7 days at 4°C. However, samples treated at 65°C for 10 min became were totally amorphous. This treatment was sufficient to completely disrupt the starch granule, as evidenced by the absence of an endothermic peak in the DSC thermogram. The RVA of S. lycocarpum starch revealed 4440.7 cP peak viscosity, 2660.5 cP breakdown viscosity, 2414.1 cP final viscosity, 834.3 cP setback viscosity, and a pasting temperature of 49.6°C. The low content of resistant starch (10.25%) and high content of digestible starch (89.78%) in S. lycocarpum suggest that this starch may be a good source for the production of hydrolysates, such as glucose syrup and its derivatives. These results make the S. lycocarpum fruit a very promising source of starch for biotechnological applications. / Este trabalho foi realizado para avaliar as propriedades químicas, físico- químicas, bioquímicas e reológicas do amido de Solanum lycocarpum. Polpas dos frutos de Solanum lycocarpum foram utilizadas como matéria-prima para a extração de amido, resultando em um rendimento de 51%. Os grânulos de amido apresentaram tamanho heterogêneo, com aparência cônica, muito semelhante ao amido de mandioca, com alto teor de amilose. A análise elementar (CHNS) revelou 64,33% de carbono, 7,16% de hidrogênio e 0,80% de nitrogênio. A espectroscopia FT-IR revelou picos característicos de polissacarídeos e a análise de RMN confirmou a presença do carbono αanomérico da D-glicose. O amido de S. lycocarpum apresentou elevada viscosidade intrínseca (3515 mPa s) e peso molecular estimado de 645,69 kDa. Além disso, este amido foi classificado como um amido do tipo C, apresentando 34,66% de amilose e 38% de cristalinidade. Através de análises por DCS determinou-se as temperaturas de transição endotérmica (To = 61,25°C; Tp = 64,5°C; Tc = 67,5°C), a variação da temperatura de gelatinização (∆T = 6,3°C) e a variação de entalpia (∆H = 13,21 J g-1). A análise termogravimétrica do amido de S. lycocarpum apresentou um padrão típico de perda de peso de três etapas. A microscopia revelou alterações significativas na morfologia dos grânulos após o tratamento térmico. As amostras tratadas a 50°C, durante 10 minutos, perderam 52% de sua cristalinidade, a qual foi parcialmente recuperada após armazenamento a 4°C, por 7 dias. No entanto, as amostras tratadas a 65°C, por 10 minutos, perderam totalmente sua cristalinidade, apresentando estrutura totalmente amorfa. Este tratamento foi suficiente para romper completamente o grânulo de amido, conforme evidenciado pela ausência do pico endotérmico na curva do DSC desta amostra. O RVA do amido de S. lycocarpum revelou um pico de viscosidade de 4440,7 cP, quebra de viscosidade 2660,5 cP, viscosidade final 2414,1 cP, tendência a retrogradação 834,3 cP e temperatura de pasta de 49,6°C. O baixo teor de amido resistente (10,25%) e o elevado teor de amido digerível (89,78%) sugerem que este amido pode ser uma boa fonte para a produção de hidrolisados, tais como xarope de glicose e seus derivados. Os resultados obtidos neste estudo fazem do fruto de S. lycocarpum uma fonte promissora de amido para aplicações biotecnológicas.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2016-10-10T18:10:31Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Vania Zanela Pinto.pdf: 3876720 bytes, checksum: a2458e7baefb3806f5f42a1803a8a8b1 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-10-11T20:56:35Z (GMT) No. of bitstreams: 2 Tese Vania Zanela Pinto.pdf: 3876720 bytes, checksum: a2458e7baefb3806f5f42a1803a8a8b1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-11T20:56:35Z (GMT). No. of bitstreams: 2 Tese Vania Zanela Pinto.pdf: 3876720 bytes, checksum: a2458e7baefb3806f5f42a1803a8a8b1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-08-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Os amidos mais comumente utilizados industrialmente, são o amido de milho, o de trigo, o de batata e o de mandioca. No entanto, amidos oriundos de fontes não convencionais têm despertado grande interesse de indústrias e cientistas. Isso, associado a possibilidade de expandir e modificar as propriedades do amido por tratamentos físicos, conferem aos amidos de pinhão e de feijão vantagens para o uso na indústria de alimentos. Outra possibilidade para a aplicação de amidos é a utilização destes como matéria-prima alternativa na produção de embalagens e compósitos poliméricos, bem como a produção de nanocristais (SNCs). O estudo foi composto damodificação (pré-tratamentos) e caracterização dos amidos de pinhão e feijão Carioca e subsequente hidrólise dos mesmos para a produção de nanocristais. Os pré-tratamentos com tratamento térmico de baixa umidade (TTBU), annealing (ANN)ultrassom (SNT) e hidrólise enzimática (ENZ) empregados objetivaram diminuir o tempo e/ou aumentar o rendimento de hidrólise, bem como alterar e/ou melhorar as propriedades dos nanocristais a serem produzidos. Os amidos apresentaram alterações nas propriedades de pasta, térmicas e mudança no padrão de difração de raio-X, variando conforme a modificação aplicada. Os nanocristais foram produzidos através de hidrólise ácida (H2SO4 3,0 M) por 5 e 7 dias à 40°C. O rendimento após a hidrólise variou entre 10,2-14,7 % para o amido de pinhão e 35,2-42,3 % para o amido de feijão o que aumentou a cristalinidade relativa. O TTBU e o SNT aumentam o rendimento dos SNCs mas promovem perdas na cristalinidade relativa dos mesmos, enquanto que, o ANN promove melhor estabilidade térmica dos SNCs. O amido de feijão se mostrou promissor para a produção de SNCs, principalmente pelo elevado rendimentoapós 5 dias de hidrólise com ácido sulfúrico. / The most common industrially used starches come from corn, wheat, potato, and cassava. Nevertheless, starches from non-conventional botanical origins are receiving more attention of industries and researchers. Associated with this interest, the possibility of expand and modify the starch properties through physical modifications provide for pinhão and Carioca beans advantages in food industry purposes. The use of theses starches as an alternative to raw materials derived from petroleum for packaging and polymer composites is another possible application. Also included in this possibility, there is the production of starch nanoparticles and nanocrystals (SNCs). This study consisted in modifications (pretreatment), characterization and subsequent hydrolysis of pinhão and Carioca bean starches to produce starch nanocrystals. The starch pretreatments of heat-moisture-treatment (HMT), annealing (ANN), sonication (SNT) and mild enzymatic hydrolysis (ENZ) were used to improve the starch nanocrystals characteristics, as well as decrease the acid hydrolysis time and/or increase the hydrolysis final yield. The pretreatments changed the paste, thermal, and crystallinity properties of the starches, which changed according to the modification applied (HTM, ANN, SNT and ENZ). The SNCs were made by 3 M H2SO4 at 5 and 7 days at 40°C and obtained from the resulted removal of the amorphous lamella from the starch granules, what increased the relative crystallinity. The achieved hydrolysis yields were between 10.2 to 14.7% for pinhão starch and 35.2 to 42.3% for Carioca bean. HMT and SNT pretreatments increased the SNCs yield, but they promote a decrease on the SNCs relative crystallinity, whereas the ANN promotes a better thermal stability, mainly due to the high yield after 5 days of sulfuric acid hydrolysis.

Le procédé d'injection soufflage est rendu accessible aux presses d'injection standard à travers le procédé d'injection soufflage cycle chaud, sans stockage puis réchauffe de la préforme. Le but étant de rendre accessible la production de petites séries de pièces creuses à des entreprises possédant un parc machine de presse à injecter. Les pièces sont réalisées en polypropylène et sont soufflées juste après avoir été injectées. Ce processus implique que la préforme se doit d'être suffisamment malléable pour être soufflée mais suffisamment visqueuse pour éviter de se rompre durant la phase de soufflage. Ces contraintes conduisent à une fenêtre de mise en oeuvre réduite, comprise entre la température de fusion du polymère et la température de cristallisation, soit le domaine ou le polypropylène est à l'état amorphe et suffisamment froid pour avoir une viscosité conséquente sans cristalliser. Ce procédé cycle chaud implique des gradients de température, de grands taux d'étirages et d'importantes cinétiques de refroidissement. Des mesures de rhéométrie à l'état fondu sont réalisées pour identifier le comportement de la matière dans la plage de température du procédé, de même que des tests de calorimétrie différentielle. L'observation du procédé et l'étude de la cristallisation du matériau permettent de supposer que ce dernier reste à l'état fondu durant la phase de soufflage. Un modèle rhéologique de Cross est utilisé, avec la dépendance thermique prise en compte par une loi d'Arrhénius. Le procédé est simulé à l'aide d'un logiciel de calcul par éléments finis dédié aux écoulements de fluides complexes (POLYFLOW) dans l'espace de travail ANSYS Workbench. La géométrie autorise une approche axisymétrique, facilitant ainsi la modélisation. Le calcul transitoire est lancé sous conditions anisothermes et l'auto-échauffement est considéré. Des études de sensibilité sont réalisées et révèlent l'influence de paramètres procédé tels que le comportement du matériau, la pression de soufflage et le champ de température initial. Des mesures d'épaisseurs sont réalisées en utilisant une méthode de traitement d'image permettant l'analyse des images numérisées de pièces découpées et des images issues de tomographie X des pièces. Les résultats simulés sont comparés aux mesures expérimentales. Le modèle présente les mêmes tendances que les mesures. L'existence de déformations élongationnelles, mais aussi par cisaillement lors du soufflage après contact avec le moule, est discutée. Une boucle d'optimisation est mise en place afin de déterminer numériquement la géométrie optimale de préforme. Des points de contrôle sont placés le long de la préforme et l'algorithme d'optimisation modifie les épaisseurs à ces points. / Single stage injection blow molding process, without preform storage and reheat, could be run on a standard injection molding machine, with the aim of producing short series of specific hollow parts. The polypropylene bottles are blown right after being injected. The preform has to remain sufficiently malleable to be blown while being viscous enough to avoid being pierced during the blow molding stage. These constraints lead to a small processing window, and so the process takes place between the melting temperature and the crystallization temperature, where the polypropylene is in his molten state but cool enough to enhance its viscosity without crystallizing. This single stage process introduces temperature gradients, molecular orientation, high stretch rate and high cooling rate. Melt rheometry tests were performed to characterize the polymer behavior in the temperature range of the process, as well as Differential Scanning Calorimetry. A viscous Cross model is used with the thermal dependence assumed by an Arrhenius law. The process is simulated through a finite element code (POLYFLOW) in the Ansys Workbench framework. The geometry allows an axisymmetric approach. The transient simulation is run under anisothermal conditions and viscous heating is taken into account. Thickness measurements using image analysis are done and the simulation results are compared to the experimental ones. The experimental measurements are done by analizing tomography datas. The simulation shows good agreements with the experimental results. The existence of elongational strain as well as shear strain during the blowing after contact with the mold is discussed. An optimization loop is run to determine an optimal initial thickness repartition by the use of a Predictor/Corrector method to minimize a given objective function. Design points are defined along the preform and the optimization modifies the thickness at these locations. This method is compared to the Downhill Simplex Method and shows better efficiency.

Abstract Wood powders are used in numerous applications such as thermoplastics and filters, and a lot of research effort has been put into developing novel ways of utilising them. The mechanical processing of wood powders, especially at particle sizes below 100 µm, has been reported in several studies, but they lack information on the effect of fine grinding conditions on the particle morphology and cellulose crystallinity, both of which are important parameters in the further processing of wood powders and in their various applications. This makes it very difficult to design and optimise fine grinding processes with different applications in mind. The aim of this thesis was to study the dry fine grinding of wood in several impact-based fine grinding mills in order to find out their effect on the properties of the wood and to study the energy required for the mechanical processing of the resulting powders. The effect of the main operational parameters on the properties of dried Norway spruce wood and the energy consumption was studied using three impact-based fine grinding mills that were capable of pulverising the wood down to a median particle size of less than 25 µm. It was found that the impact events occurring in media mills can be used for the production of very fine wood powders with lower cellulose crystallinity and rounder shaped particles having more uniform shape distribution than powders pulverised to a similar size range by means of impact events in non-media mills. A practical estimate was obtained for the minimum specific energy consumption in fine grinding in mills involving grinding media that could be utilised as a target for optimisation. Impact-based media milling under cryogenic conditions can be used to obtain different Norway spruce wood powders from those produced under ambient grinding conditions, i.e. without the freezing effect of nitrogen liquid. The energy efficiency of fine grinding can be enhanced by choosing cryogenic rather than ambient conditions. The moisture content of the wood has greater influence on the size and shape of the particles when milling is accomplished under ambient conditions. Torrefaction can reduce the energy consumption in impact-based media mills for median particle sizes over 17.4 µm (± 0.2 µm), while the shape and cellulose crystallinity of the particles are not significantly affected by torrefaction pretreatment as a function of energy consumption. / Tiivistelmä Puujauheita käytetään laajalti erilaisissa sovelluksissa, kuten esimerkiksi biokomposiiteissa ja suodattimissa. Tämän lisäksi on olemassa paljon tutkimustietoa siitä, kuinka puujauheita voitaisiin hyödyntää laajemminkin. Puu voidaan mekaanisesti prosessoida alle 100 µm:n kokoluokkaan, mutta yksityiskohtaista tietoa kuivahienojauhatuksen olosuhteiden vaikutuksesta jauheiden morfologiaan ja selluloosan kiteisyyteen ei ole saatavilla. Puujauheen morfologialla ja selluloosan kiteisyydellä on kuitenkin merkittävä vaikutus sovelluksia ja jatkojalostusta ajatellen. Puun kuivahienojauhatuksen tiedon puute hankaloittaa merkittävästi prosessin suunnittelua ja optimointia erilaisia sovelluksia varten. Tämän väitöskirjan tavoitteena on selvittää iskuihin perustuvien hienojauhimien vaikutukset puun ominaisuuksiin ja tutkia mekaanisen prosessoinnin energiatehokkuutta hienojauhatuksessa. Tutkimuksessa selvitettiin kolmen erilaisen iskuun perustuvan hienojauhatusmyllyn pääasiallisten operointiparametrien vaikutusta kuivatun metsäkuusen ominaisuuksiin ja energiankulutukseen. Jokaisella hienojauhimella onnistuttiin tuottamaan puujauhoja, joiden mediaanikoko oli alle 25 µm. Iskuihin perustuvalla jauhinkappalemyllyllä saatiin tuotettua puujauhoa, jonka selluloosan kiteisyys on alhaisempi ja partikkelimuodot pyöreämpiä verrattuna samankokoisiin puujauhoihin, jotka on tuotettu iskuihin perustuvilla jauhinkappaleettomilla hienojauhatusmyllyillä. Työssä saatiin käytännöllinen arvio kuivatun metsäkuusen hienojauhatuksen minimienergiankulutukselle iskuihin perustuville jauhinkappalemyllyille, mitä voidaan käyttää kyseisten myllytyyppien optimoinnin tavoitteena. Työssä havaittiin lisäksi, että kryogeenisiä jauhatusolosuhteita käyttämällä voidaan tuottaa erilaisia puujauhoja verrattuna puujauhoihin, jotka prosessoidaan ilman nestetyppijäädytystä, kun jauhatus suoritetaan iskuihin perustuvalla jauhinkappalemyllyllä. Ilman nestetyppijäädytystä puun kosteuspitoisuudella on merkittävämpi vaikutus puujauhojen ominaisuuksiin kuin kryogeenisissä olosuhteissa jauhetuilla. Kryogeenisillä jauhatusolosuhteilla voidaan parantaa myös jauhatuksen energiatehokkuutta. Torrefioinnilla voidaan vähentää hienojauhatuksen energiankulutusta iskuihin perustuvilla jauhinkappalemyllyillä, kun tavoitekoon mediaani on yli 17,4 µm (± 0,2 µm). Torrefioinnilla ei ole vaikutusta selluloosan kiteisyyteen tai partikkeleiden muotoon energiankulutuksen funktiona.

[pt] Sintetizar Bi-2223 por decomposição peritética com posterior recristalização para estudar a cristalinidade e o efeito da fase líquida na formação de amorfo é de suma importância em pesquisas de fitas supercondutoras 1G (1ª geração) de Bi-2223. Tal rota de tratamento de fitas 1G de fase Bi-2223 já foi demonstrada, mas ainda há desafios devido à sua estreita região de estabilidade, lenta formação e a volatilização de chumbo durante a decomposição. No presente trabalho, amostras de (Bi, Pb)-2223 com 6 porcento de fração de PbO (adicionados aos reagentes) foram aquecidas a temperaturas acima da decomposição peritética e resfriadas lentamente. Empregaram-se análises de DTA/TGA, MEV/EDS, DRX e Análise quantitativa (com uso do método de Rietveld, V(I) e R(T). Os resultados mostram que o balanço de fases e a microestrutura dependem da temperatura de decomposição para fita comercial e caseira e da fração de PbO somente para a fita caseira. Uma investigação sistemática por DRX foi realizada, a fim de elucidar tal processo. Foi observada uma recuperação parcial de Bi-2223 nas fitas estudadas e os resultados indicaram que a decomposição e a recristalização da fase Bi-2223, fase amorfa e fases secundárias geraram mudanças na microestrutura e nas propriedades elétricas da fita 1G seja monofilamentar ou multifilamentar. / [en] Synthesize Bi-2223 by peritectic decomposition with subsequent recrystallization to study the crystallinity and the effect of the liquid phase in the formation of amorphous is very important in research of superconducting tapes 1G Bi-2223. Such a route of treatment tapes 1G phase Bi-2223 has been demonstrated, but there are still challenges due to its narrow region of stability, and slow formation of lead volatilization during decomposition. In this work, samples of (Bi, Pb) -2223 with 6 percent PbO fraction (added to the reactants) were heated to temperatures above the peritectic decomposition and cooled slowly. Analyzes were employed DTA / TGA, SEM / EDS and DRX Quantitative analysis (using the Rietveld method, V (I) and R (T). Results show that the balance of phases and microstructure depend on the decomposition temperature for commercial and homemade ribbon and the fraction of PbO only homemade tape. a systematic investigation by DRX was performed in order to elucidate this process. was observed a partial recovery of Bi-2223 and studied the tapes results indicate that the decomposition and recrystallization of the phase Bi-2223 phase amorphous and secondary phases generate changes in microstructure and electrical properties of the tape 1G be monofilament or multifilament.