Copoliesteres amorfos derivados del poli(etilen-co-1,4-ciclohexilen dimetilen tereftalato) para aplicaciones industriales

Laburpena

Amorphous poly(ethylene-co-1,4-cyclohexylene dimethylene terephthalate) (PECT) copolyesters and their derivatives, with 30 mole-% of 1,4- cyclohexanedimethanol (CHDM), have been studied in the presented Thesis. These copolyesters have been prepared by bulk polycondensation using terephthalic acid (TPA) as a raw feedstock in a batch laboratory pilot plant, which has been designed, built-up and put into operation in order to operate closer to the industrial conditions. The reactor, which the polymerizations take place, try to simulate the industrial process carried out in batch stirred tank reactors, these kind of reactors were originally designed to produce poly(ethylene terephthalate)(PET) with modest molecular weight (intrinsic viscosity about 0.6 dL/g). Disadvantages concerned to the use of this reactor type has been overcoming in order to produce high molecular weight amorphous PECT copolyesters. The work presented can be divided into three blocks. The first block is dedicated to understanding the polymerization of TPA with ethylene glycol (EG) and CHDM. Both the relative reactivity of both diols against TPA and the effect on polycondensation step of the size of oligomers formed at the end of the esterification stage have been evaluated. The second block describes the two strategies studied in order to prepare amorphous copolyesters PE70C30T with a high molecular weight. First strategy study the effect on molecular weight of introduction of small amounts of a third diol (of aliphatic nature) during the polymerization of PE70C30T. Basically, we would verify if the results obtained in our previous studies on the polymerization of dimethyl terephthalate (DMT) with EG, CHDM and 1,4- butanediol (BD), which demonstrate that the substitution of a small amount of EG by BD increase the molecular weight, could be reproduced when the feedstock is TPA. The second strategy was the preparation of branched copolymers using polyfunctional commoners as trimesic acid (TMS) or pentaerythritol (PER). The synthesis, characterization and thermal, mechanical and rheological properties of these branched PECT copolyesters have been studied. The occurrence of flow induced crystallization in some of these amorphous copolyesters is reported. The modification of PECT copolyesters with isosorbide is carried out in the last block. Determination of thermal properties and crystallization of these terpolyesters have been studied in depth.