The objective of this work was to examine the effect of thermal history during cooling from the melt on the degree of crystallinity, morphology and as well as the relationship between morphology/thermal history and mechanical properties of a 60:40 weight % mixture of woven glass fibres/PP composites. Mechanical properties studied include low velocity falling weight impact strength, flexural properties (modulus and strength) and interlaminar shear strength (ILSS). However the main focus was low velocity impact strength. The composite laminates were manufactured within a flat mould using a compression moulding press. Three thermal treatments were employed: isothermal crystallization from the melt in the range 106 to 156°C for 10, 30, 60 and 240 minutes in an oven; non-isothermal crystallization from the melt at rates varying from 0.67°C/Min. to 62.4°C/Min; and quenching from 190°C to rzooc and then annealing at 155, 160 and 165°C for one hour. The degree of crystallinity developed in the matrix polymer was determine using differential scanning calorimetry (DSC) and the matrix morphology was examined by reflected light microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). TEM was used for quenched and annealed specimens.

The morphological investigation of AFR-PEPA-N and the development of a new polyimide have been established herein. AFR-PEPA-N is an imide oligomer that was created out of the need to attain a high temperature polyimide that is also resistant to hygrothermal and thermooxidative degradation. Previously, AFR700B was implemented in aerospace applications, but it was found to be hygrothermally unstable. It experienced a severe drop in its glass transition temperature and composite blistering. AFR700B was improved upon, by altering the chemical structure of the polyimide. The nadic end-cap was removed and replaced by a more hydrolytically stable end-cap. However this phenylethynyl-terminated end-group could possibly create semi-crystallinity or liquid-crystalline characteristics within the polymer. Previous research suggests further study of the relationships between AFR-PEPA-N's oligomer crystallinity and the properties of phenylethynyl-terminated polyimides. This understanding is valuable in processing AFR-PEPA-N by resin transfer molding (RTM) to obtain its optimum properties. The investigation included the identification of a processing window, temperature overlap between the melting of residual crystals and crosslinking reactions, and liquid crystallinity behavior. These reactions were investigated primarily through birefringence. The residual crystals were found to be innate in the oligomer powder and not created by preliminary thermal processing. Therefore a reasonable processing window was found based upon the reduction of crystal size by appropriate dissolution techniques. Possible nematic liquid-crystalline characteristics were found to be present at 360oC. A new imide oligomer, which was based upon AFR-PEPA-N's original structure, was synthesized. The non-linear, flourinated backbone of AFR-PEPA-N was replaced with a co-linear backbone, pyromellitic dianhydride (PMDA). These modifications were made in hopes to improve upon the network structure by it becoming more regular and resistance to nano-sized defects in the final crosslinked structure. The initial characterization found that the new polyimide, AFR-P3, displayed a cure temperature at 350oC. The degree of cure reaches about 80 to 90 percent complete based upon the consumption of the carbon-triple bond. AFR-P3 did not show signs of liquid-crystalline behavior. However, there will be future work in creating a more rigid-rod, self-assembling oligomer that can attain optimum thermal and mechanical properties.

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Biomass conversion technologies are receiving increasing attention due to global climate change and most recently plans from the President of the United States to reduce fossil fuel consumption. The MixAlco process converts a variety of feedstocks, such as agricultural residues, municipal solid waste, and sewage sludge, into mixed alcohols via microbial fermentation, which can then be used as fuel additives or independently as an alternative fuel. Optimizing the pretreatment step of this process is critical to improving product yields. The process uses lime pretreatment, which can be enhanced using new decrystallization pretreatment methods, namely hydrodynamic cavitation and shock tube pretreatment.Previous studies on biomass decrystallization showed an increase in biomass digestibility when hydrodynamic cavitation was utilized as a pretreatment step. This previous work was expanded by studying both acoustic and hydrodynamic cavitation. Computational fluid dynamics (CFD) was used to model the cavitator to improve its efficiency. The crystallinity before and after pretreatment was analyzed. A new laboratory-scale MixAlco lime-pretreatment system was developed to produce greater quantities of lime-pretreated biomass that could be subjected to decrystallization experiments. The length of pretreatment, water loading, and bagasse loadings were varied for the shock tube experiments. After each pretreatment, enzymatic hydrolysis was performed, and the equivalent glucose yield was measured by the DNS (dinitrosalicylic acid) assay. Additionally, mixed-acid fermentation was performed to show the benefits of reduced crystallinity on the MixAlco fermentation. The acoustic and hydrodynamic cavitation pretreatments had a modest effect on crystallinity. In contrast, the shock tube pretreatment shows greater promise as an effective decrystallization pretreatment, even for lime-treated bagasse. Repeated shocks had little effect on digestibility and the crystallinity; however, the water temperature used in shock tube pretreatment played an important role in bagasse digestibility and crystallinity.

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Submitted by Juliana Aparecida Marques Eburneo null (julianaeburneo@gmail.com) on 2017-03-27T19:09:19Z No. of bitstreams: 1 Dissertação Final Versão Impressão.pdf: 1337107 bytes, checksum: a68b8582ead29404b314742e523864b0 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-29T19:40:50Z (GMT) No. of bitstreams: 1 eburneo_jam_me_bot.pdf: 1337107 bytes, checksum: a68b8582ead29404b314742e523864b0 (MD5) / Made available in DSpace on 2017-03-29T19:40:50Z (GMT). No. of bitstreams: 1 eburneo_jam_me_bot.pdf: 1337107 bytes, checksum: a68b8582ead29404b314742e523864b0 (MD5) Previous issue date: 2017-01-30 / A batata é a hortaliça com maior área cultivada no Brasil, sendo que sua produção se concentra nos estados da região sul e sudeste. Na cultura da batata o manejo inadequado da adubação nitrogenada pode causar crescimento exagerado da parte aérea, reduzir a qualidade de tubérculos e aumentar o custo de produção. Além disso, as condições de cultivo também podem influenciar as características do amido, principal carboidrato de reserva da batata, o que pode levar a interferências na aplicabilidade deste pelas indústrias alimentícias. Frente ao exposto, este trabalho teve por objetivo caracterizar amidos extraídos de batata cv Ágata cultivada sob diferentes doses de adubação nitrogenada e avaliar a possível interferência desta prática sobre a morfologia e distribuição de tamanho dos grânulos de amido, teor de amilose, teores de fósforo, cálcio, potássio e magnésio, composição físico-química, propriedades de pasta e térmicas; parâmetros estes determinantes para o estabelecimento das potencialidades de aplicabilidades do amido pelas indústrias. Para o alcance deste objetivo foram utilizados tubérculos de batata resultantes da colheita de ensaio experimental com adubação nitrogenada instalado em propriedade rural na região da cidade de Avaré, estado de São Paulo. Após o cultivo de 117 dias, as batatas foram colhidas, lavadas e processadas para a extração e análise do amido. Os resultados obtidos mostram que o amido de batata extraído de plantas cultivadas sem a aplicação de adubo nitrogenado apresentou grânulos redondos e ovalados, com predomínio de diâmetro maior na faixa de 26 a 50μm, padrão de difração de raio X do tipo B, 22,16% de cristalinidade relativa, elevada pureza, presença de 1090 ppm de fósforo, 893 ppm de potássio, 200 ppm de cálcio e 88 ppm de magnésio. Temperatura de pasta de 67,94°C, pico de viscosidade de 796,88 RVU, quebra de viscosidade de 622,03 RVU, viscosidade final de 236,28 RVU e tendência a retrogradação de 65,76 RVU. A gelatinização iniciou em 65,85°C, com pico em 68,03°C e final em 70,79°C, com variação de entalpia de 9,92 J g-1. A análise dos dados mostrou interferência da adubação nitrogenada sobre as características do amido de batata cv Ágata, sendo que o incremento nas doses de nitrogênio levou a obtenção de amidos com menor cristalinidade relativa, menores teores de fósforo, cálcio e magnésio, menor resistência à temperatura e agitação e menores temperaturas de gelatinização. Estes resultados indicam que o manejo cultural pode afetar importantes propriedades determinantes de aplicabilidade do amido de batata. / Potato is a vegetable with the largest cultivated area in Brazil and its production is concentrated in the states of the southeast region. In potato cultivation nitrogen fertilization management can cause overgrown growth, reduce the quality of tubers and increase the cost of production. In addition, the cultivation conditions may also influence the characteristics of the starch, main reserve carbohydrate of the potato, which can lead to interference in applicability of starch by industries. In view of the above, the objective of this work was to characterize starches extracted from Ágata cultivar cultivated under different rates of nitrogen fertilization, and to evaluate possible interference on morphology and size distribution of starch granules, amylose content, phosphorus, calcium, potassium and magnesium, physical-chemical composition, pasting and thermal properties, important characteristics for establishing the potential of starch application by industries. In order to reach this objective was analyzed tubers obtained from experimental area in the region of the Avaré city, state of São Paulo. After cultivation of 117 days potatoes were harvested, washed and processed for extraction and analysis of the starches. The results obtained show that potato starch extracted from plants cultivated without a nitrogen fertilizer application showed round and oval granules, with a larger diameter in the range of 26 to 50μm, pattern type B of X-ray diffraction, 22,16% of relative crystalline, high purity, presence of 1090 ppm of phosphorus, 893 ppm of potassium, 200 ppm of calcium and 88 ppm of magnesium. The pasting temperature was 67.94°C, viscosity peak was 796.88 RVU, viscosity breakdown was 622.03 RVU, final viscosity was 236.28 RVU and seatback was 65.76 RVU. The gelatinization of starch granules started at 65.85°C, with peak at 68.03°C, and final at 70.79°C, with enthalpy variation of 9.92 J g-1. The analysis of the data showed the interference of nitrogen fertilization on the characteristics of Ágata potato starch. The increase in nitrogen rates led to the obtaining of starches with lower relative crystalline, lower phosphorus, calcium and magnesium contents, lower resistance to temperature and agitation and lower gelatinization temperatures. These results indicate that cultural management can affect important determining properties of potato starch application, which is of great interest to the food industry.

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Linear polyamides, commonly known as Nylons, are widely used for their high melting temperatures, heat stability, toughness and abrasion resistance, allowing diverse commercial applications such as carpets, nylon stockings and automotive parts. The work here has possible ramifications for membrane production and drug delivery systems and makes a scientific contribution to the area of binary polymer/diluent systems where the polymer is semicrystalline and the diluent crystallises at a quite different temperature to the polymer. Melt blended crystalline/crystalline systems have, so far, not received the attention that amorphous/amorphous or crystalline/amorphous systems have, perhaps due to the complexity of the morphology that often results within such systems.