Poly(ethylene succinate) (PES), poly(trimethylene succinate) (PTS) and their copolyesters (PETSAs) with various compositions were used to investigate the structure-property relationship. The results of intrinsic viscosity and GPC have proven successful in preparing high molecular weight polyesters. The chemical compositions and the sequence distribution of co-monomers in the copolyesters were determined by NMR spectroscope. The distributions of ES unit and TS unit were found to be random. Their thermal properties were characterized using differential scanning calorimeter (DSC). The thermal stability of polyesters was analyzed by thermogravimeter (TGA) and polarized light microscope (PLM) under nitrogen. The results of TGA show that all of the samples have similar thermal stability (Tstart : 246¡Ó3 ¢XC), but the thermal degradation temperature of PES and PETSA(95/05) are 213 and 200 ¢XC, respectively, estimated from the isothermal growth rates after pre-melting at various temperatures. The degradation temperature analyzed by PLM is more sensitive than that obtained from TGA. The incorporation of 5 mol% of TS units into PES significantly reduces the thermal stability of PES. In addition, wide-angle X-ray diffractograms (WAXD) were obtained for polyesters which were crystallized isothermally at a temperature 5~10 ¢XC below their melting temperatures. The results of WAXD and DSC indicate that the incorporation of TS units into PES significantly inhibit the crystallization behavior of PES. In the second part of this study, PES and PETSA(95/05) were studied in detail. The crystallization kinetics and the melting behavior were investigated by using DSC in both conventional mode and modulated mode (TMDSC). The reversing, total, and non-reversing heat flow curves were analyzed. The Hoffman-Weeks plots gave an equilibrium melting temperature of 112.7 and 108.3 ¢XC for PES and PETSA(95/05), XI respectively. Only one crystal form was found from WAXD for specimens crystallized isothermally at various temperatures. Based on the WAXD patterns, DSC and TMDSC thermograms, multiple endothermic melting peaks can be explained by two mechanisms, melting-recrystallization-remelting and dual morphologies. PLM was used to study the growth rates and morphology of the spherulites. The growth rates measured in isothermal conditions were very well comparable with those measured by the non- isothermal procedure. In addition, the temperature range of growth rates detected by the non- isothermal procedure is wider than that by the isothermal method, which is time consuming. The regime II®III transition of PES was estimated at ~ 71 ¢XC which is very close to the literature values, and that of PETSA(95/05) was found at ~ 65 ¢XC.

This thesis contains two parts of materials characterization. Part I is a poly(butylene succinate) copolymer with minor amount of 2-methyl-propylene succinate. In the second part, six kinds of implant crowns made from five dental casting alloys and one Zircoina ceramic are studied. Copolyester was synthesized and characterized as having 89.0 mol% butylene succinate units and 11.0 mol% 2-methyl-propylene succinate units in a random sequence, revealed by NMR. Isothermal crystallization kinetics was studied in the temperature range (Tc) from 75 to 91 ¢XC using differential scanning calorimeter (DSC). The melting behavior after isothermal crystallization was studied by using DSC by varying the Tc, the crystallization time and the scanning rate. DSC curves showed triple melting peaks. Multiple melting behaviors indicate that the upper melting peaks are associated with the primary and the recrystallized crystals, or the crystals with different lamellar thickness. As the Tc increases, the contribution of recrystallization slowly decreases and finally disappears. A Hoffman-Weeks linear plot gives an equilibrium melting temperature of 118.4 ¢XC. The spherulitic growth rates of this copolyester were measured at Tc between 69 and 91 ¢XC using an optical microscope equipped with a CCD camera. The kinetic analysis of the growth rates gave a regime II-III transition temperature at about 77.2 ¢XC. Rectangular specimens of 10 ¡Ñ 9 ¡Ñ 4 mm were made of five kinds of casting alloys, separately. They were treated in the same procedures as crowns did. Their surfaces after oxidation were analyzed using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Rectangular specimens after applying porcelains were ~5.5 mm thick. The cross-section areas were studied by electron probe micro analyzer (EPMA). Standardized maxillary premolar crowns were fabricated with five different alloys and one Zircoina ceramic. The crown specimens were positioned in a custom testing apparatus and vertically loaded on the middle of the occlusal surface with a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Mean values of load at fracture were calculated in each alloy and compared with a one-way analysis of variance and Tukey test (£\=0.05). The fracture surfaces were examined using SEM. The results of XPS, SEM and EPMA indicate that on the surface there was an oxidation layer (or interface between metal and ceramic) of indium (or/and tin, zinc, etc.). The concentration of oxide metal increased, whereas that of precious metal decreased, from bulk to interface. The fracture strength and the fracture path of the crowns were correlated with the metal-ceramic interface of the rectangular specimens that was characterized using XPS, SEM and EPMA.

No description available.

De modo geral, os materiais termoplásticos são sensíveis à radiação ultravioleta (UV), a qual provoca mudanças em suas estruturas químicas, afetando suas propriedades, principalmente as mecânicas, e características de aparência. A radiação ultravioleta (10-400 nm), em especial na faixa entre 290- 400 nm, é bastante agressiva aos materiais plásticos resultando na quebra de cadeias e/ou reticulação. Para aplicações agrícolas, são fatores críticos para envelhecimento: a radiação solar total, temperatura, umidade relativa do ar, esforço mecânico, presença de agroquímicos, poluição do ar e a combinação desses fatores. Os aditivos estabilizantes de luz são adicionados aos plásticos para aumentar a durabilidade do produto final. Existem diversos sistemas estabilizantes de luz, desenvolvidos de acordo com a resina, aplicação final, tipo de cultivo e outras características. Além dos estabilizantes convencionais, como por exemplo, benzofenona, benzotriazol e as moléculas do tipo aminas estericamente bloqueadas (HALS), existem também aditivos inorgânicos baseados em nanotecnologia. Este estudo avalia diferentes sistemas de aditivos: HALS, nano carbonato de cálcio (nCaCO3 ou NPCC), nano óxido de zinco (nZnO) e nano dióxido de titânio (nTiO2), aplicados a 0,25 % e 0,75 % (em massa) em polietileno de baixa densidade linear (PEBDL) e copoliéster alifático aromático. As amostras foram envelhecidas em QUV-B simulando 6 meses de exposição à intempérie. Foram realizados testes de resistência à tração, termogravimetria (TG), calorimetria exploratória diferencial (DSC), índice de carbonila, espectroscopia na região do infravermelho com transformada de Fourier (FT-IR), microscopia eletrônica de varredura (MEV), microscopia de força atômica (AFM) e espectroscopia de absorção na região de ultravioleta e visível (UV-VIS). As propriedades das amostras não envelhecidas foram comparadas as envelhecidas para avaliar o desempenho dos vários sistemas de aditivos sobre o comportamento da degradação das amostras. Como resultado deste estudo, concluiu-se que há viabilidade da aplicação de nanopartículas como aditivos estabilizantes de luz (anti-UV), em especial o nZnO. Contudo, a aditivação do tipo HALS ainda mostrou-se mais eficaz, considerando os polímeros, sistemas de aditivação e proporções utilizadas. / Usually, the thermoplastic materials are sensitive to ultraviolet radiation (UV), which produces changes in their chemical structures, affecting their mechanical properties and appearance characteristics. Ultraviolet radiation (10- 400 nm), in particular range between 290-400 nm, is extremely aggressive to plastic materials resulting in breaking chains and/or crosslinking. For agricultural applications, are critical factors for aging: the total solar radiation, temperature, air relative humidity, mechanical stress, agrochemicals presence, air pollution, and combinations of these factors. Light stabilizers additives are added to plastics to increase the durability of the final product. There are several light stabilizers systems, developed according with the resin, final application, the type of plantation and other factors. In addition to the conventional stabilizers, such as benzophenone, benzotriazole and molecules like hindered amine light stabilizer (HALS), there are also inorganic additives based on nanotechnology. This study evaluates different additive systems: hindered amine light stabilizer (HALS), nano calcium carbonate (nCaCO3 or NPCC), nano zinc oxide (nZnO) and nano titanium dioxide (nTiO2), applied 0.25 % and 0.75 % (in mass) in linear low density polyethylene (LLDPE) and aliphatic-aromatic copolyester. The samples were aged in QUV-B simulating 6 months of exposure to weather. Tests of tensile strength, thermogravimetry (TG), differential scanning calorimetry (DSC), carbonyl index, spectroscopy in the infrared Fourier transform (FT-IR), scanning electron microscopy (SEM), force microscopy atomic (AFM) and absorption spectroscopy in the ultraviolet and visible region (VIS-UV) were carried out. The properties of non aged samples were compared with aged samples in order to evaluate the performance of various additive systems on behavior of samples degradation. As result of this study, it was concluded that there is viability of nanoparticles application as light stabilizers additives (anti-UV), in particular the nZnO. However, the properties of HALS still showed to be more effective, considering the polymers, additives systems and proportions used.

De modo geral, os materiais termoplásticos são sensíveis à radiação ultravioleta (UV), a qual provoca mudanças em suas estruturas químicas, afetando suas propriedades, principalmente as mecânicas, e características de aparência. A radiação ultravioleta (10-400 nm), em especial na faixa entre 290- 400 nm, é bastante agressiva aos materiais plásticos resultando na quebra de cadeias e/ou reticulação. Para aplicações agrícolas, são fatores críticos para envelhecimento: a radiação solar total, temperatura, umidade relativa do ar, esforço mecânico, presença de agroquímicos, poluição do ar e a combinação desses fatores. Os aditivos estabilizantes de luz são adicionados aos plásticos para aumentar a durabilidade do produto final. Existem diversos sistemas estabilizantes de luz, desenvolvidos de acordo com a resina, aplicação final, tipo de cultivo e outras características. Além dos estabilizantes convencionais, como por exemplo, benzofenona, benzotriazol e as moléculas do tipo aminas estericamente bloqueadas (HALS), existem também aditivos inorgânicos baseados em nanotecnologia. Este estudo avalia diferentes sistemas de aditivos: HALS, nano carbonato de cálcio (nCaCO3 ou NPCC), nano óxido de zinco (nZnO) e nano dióxido de titânio (nTiO2), aplicados a 0,25 % e 0,75 % (em massa) em polietileno de baixa densidade linear (PEBDL) e copoliéster alifático aromático. As amostras foram envelhecidas em QUV-B simulando 6 meses de exposição à intempérie. Foram realizados testes de resistência à tração, termogravimetria (TG), calorimetria exploratória diferencial (DSC), índice de carbonila, espectroscopia na região do infravermelho com transformada de Fourier (FT-IR), microscopia eletrônica de varredura (MEV), microscopia de força atômica (AFM) e espectroscopia de absorção na região de ultravioleta e visível (UV-VIS). As propriedades das amostras não envelhecidas foram comparadas as envelhecidas para avaliar o desempenho dos vários sistemas de aditivos sobre o comportamento da degradação das amostras. Como resultado deste estudo, concluiu-se que há viabilidade da aplicação de nanopartículas como aditivos estabilizantes de luz (anti-UV), em especial o nZnO. Contudo, a aditivação do tipo HALS ainda mostrou-se mais eficaz, considerando os polímeros, sistemas de aditivação e proporções utilizadas. / Usually, the thermoplastic materials are sensitive to ultraviolet radiation (UV), which produces changes in their chemical structures, affecting their mechanical properties and appearance characteristics. Ultraviolet radiation (10- 400 nm), in particular range between 290-400 nm, is extremely aggressive to plastic materials resulting in breaking chains and/or crosslinking. For agricultural applications, are critical factors for aging: the total solar radiation, temperature, air relative humidity, mechanical stress, agrochemicals presence, air pollution, and combinations of these factors. Light stabilizers additives are added to plastics to increase the durability of the final product. There are several light stabilizers systems, developed according with the resin, final application, the type of plantation and other factors. In addition to the conventional stabilizers, such as benzophenone, benzotriazole and molecules like hindered amine light stabilizer (HALS), there are also inorganic additives based on nanotechnology. This study evaluates different additive systems: hindered amine light stabilizer (HALS), nano calcium carbonate (nCaCO3 or NPCC), nano zinc oxide (nZnO) and nano titanium dioxide (nTiO2), applied 0.25 % and 0.75 % (in mass) in linear low density polyethylene (LLDPE) and aliphatic-aromatic copolyester. The samples were aged in QUV-B simulating 6 months of exposure to weather. Tests of tensile strength, thermogravimetry (TG), differential scanning calorimetry (DSC), carbonyl index, spectroscopy in the infrared Fourier transform (FT-IR), scanning electron microscopy (SEM), force microscopy atomic (AFM) and absorption spectroscopy in the ultraviolet and visible region (VIS-UV) were carried out. The properties of non aged samples were compared with aged samples in order to evaluate the performance of various additive systems on behavior of samples degradation. As result of this study, it was concluded that there is viability of nanoparticles application as light stabilizers additives (anti-UV), in particular the nZnO. However, the properties of HALS still showed to be more effective, considering the polymers, additives systems and proportions used.

Thermal and morphological studies of the segmented multiblock copolyesters containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and dimethyl-1,4-cyclohexane dicarboxylate were carried out using differential scanning calorimetry, small angle X-ray scattering, wide angle X-ray diffraction and dynamic mechanical analysis. Molecular origins of the thermal transitions appearing in copolyesters were assigned by the copolyester analysis at different temperatures. The hard segments in copolyesters underwent short-range and long-range ordering (crystallization) during cooling or annealing above glass transition temperature, as concluded from thermal and wide angle X-ray diffraction analysis. Annealing process affected the ordering in hard segments and annealing temperatures of 160 °C and above led to increased microphase mixing. The small angle X-ray scattering studies confirmed the microphase separated morphology of copolyesters and supported the argument of increased microphase mixing in copolyesters annealed at higher temperatures. The amount of sulfonate containing co-monomer and its presence in either hard or soft microphase affected the morphology of the copolyesters. Introduction of the sulfonate groups led to increased microphase mixing in copolyesters as well as destruction of long-range order in the hard segments. / Master of Science

This thesis is an investigation of the fabrication and assembly methodologies employed in the development of a proof-of-principle prototype electric guitar composed of laminated copolyester. The objective of the project was to develop the processes and procedures to create an optimized physical and visual bond between layers to minimize vibratory dissipation, thus maximizing sustain. A high speed CNC router, abrasive waterjet, laser engraver-cutter, as well as various manual fabrication and assembly methods were investigated in the construction of the guitar prototypes. The lamination processes explored include low-temperature, heat-assisted pressure bonding, solvent and chemical welding, and contact adhesives. The project concluded with the completion of a working guitar comprised of a laminated copolyester body and a traditional bolton wooden neck.