Pos-condensação em estado solido de poli(etileno tereftalato)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

In this work it was studied the solid state post condensation of poly( ethylene terephtalate) (PET), which is required to obtain good plastics packs as well as for engineering applications. PET with a high molecular weight and with a minimum amount of by-products, such as water, acetaldehyde and ethylene glycol, that are generated by the polymeric degradation of the own in subject during its synthesis, is necessary for such applications. The water and the acetaldehyde are removed by diffusion with a initial heating at 170 °C and the ethylene glycol is also removed by diffusion, at temperatures 5 to 40 °C below the melting point of the polymer (240 °C). Additionally, the end groups are free to react with other, allowing the increase ofthe molecular weight ofthe polymer. The PET polymer used was supplied by Rhodia-ster Fibras e Resinas Ltda. and the equipment used to run the reactions of post condensation is an auto clave made by LECO@ Corporation, model RA - IA-I. The experiments were performed under vacuum below 200 miliTorr and amorphous and crystalline type polymer, both with and without thermal impact with liquid nitrogen. This thermal impact was utilized for creating micropores or crazing, in order to diffusion of by-products to pellets surface. The vacuum was utilized in order to remove byproducts inside the reaction vessel, so that, the equilibrium among the pellets surface and the inside of reaction vessel is prevented. Methods of characterization such SEM, DSC, TGA, W AXS, lntrinsic Viscosity, density and cristalinity were employed to observe how the differences in the initial morphology of PET influence the final viscosity after the solid state postcondensation reaction. The experimental results were satisfactory. It was obtained an intrinsic viscosity around 0,800:i 0,020 d1.g-1 in a period of 8 hours of reaction

ASSUNTO(S)

difusão viscosidade peso molecular polimeros

ACESSO AO ARTIGO

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