PEREIRA, J. S.; http://lattes.cnpq.br/3241544996400278; PEREIRA, Jaedson dos Santos.
Résumé:
Polymer degradation is a change in the tensile strength and properties of a polymer or polymer based product under the influence of one or more environmental factors such as heat, light or
chemicals. Within such a process, for example, biodegradation is desirable, deliberately by
lowering the molecular weight of a polymer for recycling, or decomposing it into the
environment. The present work presents a simple experimentation sequence, using a heat source
as the main experimental activity. In addition, it uses the thermal degradation process of
Polyethylene Terephthalate (PET) as a subsidy to obtain kinetic parameters. Based on
numerical calculations and mainly the Arrhenius equation, it was possible to determine the pre exponential factors (A) and the activation energies (Ea) involved in this process. As a means of
comparison, the same tests were performed with pure PET and after that, with the addition of
two catalysts specific to the MCM-41, Al-MCM-41 and La-MCM-41 mesostructured catalysts,
through comparisons in the (Al3 +) and (La3 +) cations belong to the same valence layer, the
aluminum catalyst favored the process by decreasing the activation energy due to the presence
of aluminum (trivalent ion, Al 3 + ) by isomorphic substitution to silicon (tetravalent ion, Si4)
in the MCM-41 structure to generate Bronsted acid sites. However the catalyst with Lanthanum
was not satisfactory to the process, since it increases the activation energy involved, since the
presence of available f orbitals makes the rare earth with properties / chemical behavior very
characteristic to the lanthanide elements.
