Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low polydispersity and controlled molecular weights, and on the other hand, on studying their thermal properties. In the first project, well-defined poly (N-octyl-p-aminobenzoate) and poly (N-butyl-p-aminobenzoate) were synthesized, and for the first time, their thermal properties were studied. In the second project, ethyl4-aminobenzoate, ethyl 4-octyl aminobenzoate and 4-(hydroxymethyl) benzoic acid were used as novel efficient initiators of ε-caprolactone with t-BuP2 as a catalyst. Macroinitiator and Macromonomer of poly (ε-caprolactone) were synthesized with ethyl 4-octyl aminobenzoate and ethyl 4-aminobenzoate as initiators to afford polyamide-block-poly (ε-caprolactone) and polyamide-graft-poly (ε-caprolactone) by chain growth condensation polymerization (CGCP). In the third project, a new study has been done on chain growth condensation polymerization to discover the probability to synthesize new polymers and studied their thermal properties. For this purpose, poly (N-cyclohexyl-p-aminobenzoate) and poly (N-hexyl-p-aminobenzoate) were synthesized with low polydispersity and controlled molecular weights.

Este trabalho apresenta uma extensiva série de resultados experimentais da condutividade induzida por radiação X contínua, durante e após a irradiação, em amostras de PET e Kapton. As medidas foram realizadas variando-se uma série de parâmetros, tais como: o campo elétrico aplicado, a taxa de exposição, a espessura da amostra, o tipo de eletrodo, a energia da radiação e as condições ambientes. Foram feitas ainda medidas da corrente termo-estimulada em amostras irradiadas e não irradiadas, que permitiram verificar a presença de armadilhas nos materiais. Medidas da corrente fotônica com diferentes eletrodos e espessuras das amostras, constataram a influência do eletrodo no valor dessa corrente. Finalmente um modelo teórico foi desenvolvido, baseado na teoria de balanço dos portadores generalizada, com a inclusão do efeito do campo elétrico na taxa de geração de portadores (efeito Onsager). O ajuste teórico-experimental permitiu a determinação numérica dos principais parâmetros de condução, tais como, mobilidade dos portadores, coeficiente de recombinação e densidade de armadilhas, para os dois materiais estudados. / In this work we present extensive results of measurements of the prompt and delayed radiation-induced conductivity of samples of PET and Kapton. Experimental parameters, such as the effective energy of the radiation, the exposure rate, the total dose, the value of the applied electric field, the nature of the electrodes, and the ambienta1 conditions were changed within wide limits. We also report measurement of thermally stimulated currents for non-irradiated and for irradiated samples which allowed us to investigate the trap-structure of the materials. Measurements of photo-Compton currents with different electrode materials and sample thicknesses gave information about the relation between the nature of the electrodes and the amplitudes of the currents. Based on the generalized rate theory of radiation-induced conduction we developed a theoretical model which includes the effect of the applied electric field on the carrier generation yield (geminate recombination, Onsager effect). Comparison of experimental and theoretical curves allowed us to determine the values of the main conduction parameters, such as carrier mobility, recombination coefficient, trap densities, for the materials under investigation.

Este trabalho apresenta uma extensiva série de resultados experimentais da condutividade induzida por radiação X contínua, durante e após a irradiação, em amostras de PET e Kapton. As medidas foram realizadas variando-se uma série de parâmetros, tais como: o campo elétrico aplicado, a taxa de exposição, a espessura da amostra, o tipo de eletrodo, a energia da radiação e as condições ambientes. Foram feitas ainda medidas da corrente termo-estimulada em amostras irradiadas e não irradiadas, que permitiram verificar a presença de armadilhas nos materiais. Medidas da corrente fotônica com diferentes eletrodos e espessuras das amostras, constataram a influência do eletrodo no valor dessa corrente. Finalmente um modelo teórico foi desenvolvido, baseado na teoria de balanço dos portadores generalizada, com a inclusão do efeito do campo elétrico na taxa de geração de portadores (efeito Onsager). O ajuste teórico-experimental permitiu a determinação numérica dos principais parâmetros de condução, tais como, mobilidade dos portadores, coeficiente de recombinação e densidade de armadilhas, para os dois materiais estudados. / In this work we present extensive results of measurements of the prompt and delayed radiation-induced conductivity of samples of PET and Kapton. Experimental parameters, such as the effective energy of the radiation, the exposure rate, the total dose, the value of the applied electric field, the nature of the electrodes, and the ambienta1 conditions were changed within wide limits. We also report measurement of thermally stimulated currents for non-irradiated and for irradiated samples which allowed us to investigate the trap-structure of the materials. Measurements of photo-Compton currents with different electrode materials and sample thicknesses gave information about the relation between the nature of the electrodes and the amplitudes of the currents. Based on the generalized rate theory of radiation-induced conduction we developed a theoretical model which includes the effect of the applied electric field on the carrier generation yield (geminate recombination, Onsager effect). Comparison of experimental and theoretical curves allowed us to determine the values of the main conduction parameters, such as carrier mobility, recombination coefficient, trap densities, for the materials under investigation.