Estudo teórico e experimental da despolimerização de poliuretanos: uma nova visão para reciclagem química

• Autor(a) principal: Uliana, Fabricio
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/7353
• topic: Chemical recycling; Polyurethanes; Chemical kinetics; Molecular modeling; Reciclagem química; Poliuretanos; Cinética química; Modelagem molecular; Química; 54

The increasing demand for polymeric materials in various industrial sectors and even in everyday life, results in a large volume of waste generated. Chemical recycling methods are an option to reduce the impact caused by improper disposal of these materials. The study of kinetic and thermodynamic parameters of the depolymerization reactions can help optimize existing processes as well as assist in the development and feasibility study of new processes. Another tool with great potential for studies of chemical recycling processes is molecular modeling. Through computational calculations it is possible to identify previously the products generated in a chemical reaction, the reaction mechanism for the process besides determining the kinetic and thermodynamic parameters. In the present work, a new methodology for the depolymerization of polyurethane is proposed. For this process the reaction mechanism was determined and performed kinetic and thermodynamic study using molecular modeling tools. The experimental data obtained in the depolymerization process of post-consumption polyurethane (PU) were compared with theoretical data and it was possible to show a good correlation between the activation energy values (93.37 kJ?mol-1) experimentally obtained and 96.51 kJ?mol-1 through theoretical calculations) and enthalpy of activation (experimental of 89.77 kJ?mol-1 and theoretical 93.19 kJ?mol-1 ). In addition, through semi-empirical calculations, the reaction products in addition to the proposed mechanism in which the reaction occurs.