Date : 2006
Editeur / Publisher : [Lieu de publication inconnu] : [éditeur inconnu] , 2006
Type : Livre / Book
Type : Thèse / ThesisLangue / Language : français / French
Résumé / Abstract : This work relates to the conception and the development of effective catalytic systems for the polycondensation of polyethylene terephtalate. This polymerization has the characteristic to proceed at high temperature and in mass. Under these conditions, many secondary reactions coexist. The principal consequence is a strong yellowing of the polymer. This phenomenon constitutes the major difficulty of the catalysis in polycondensation. So only the catalysts based on antimony and germanium are able to currently produce a polymer of quality. All the other catalysts show a low selectivity. However, suspicions on the toxicity of antimony involve a need for developing catalysts of substitution. Initially, the study of traditional catalysts showed the importance to develop thermostable ligands. Then, by studying synergistic effects, new systems were developed. Based on associations starting from aluminium and other specific elements, a new concept on the catalysis of polycondensation was born. These catalytic systems show an important activity and allow the formation of stable polymers oxidation. Lastly, their use in solid state polycondensation has been showed and their efficiency has been proved