Análise de envelhecimento do polipropileno submetido à radiação ultravioleta

Abstract

Polypropylene is a polymer chemically neutral, 100% recyclable, high temperature resistant, waterproof , durable, which offers a fantastic combination of physical, chemical, mechanical, thermal and electrical properties (electrical insulator). Polypropylene is one of the biggest selling plastic and shows the highest annual growth rate in the world, due to their exceptional properties and versatility of application and use. Due to the wide use of polymers in various outdoor applications, the need arose to study its weather resistance, not only for aesthetic aspects, such as discoloration or fading, but also by changes in their properties. The polymers when exposed to sunlight in the presence of oxygen are degraded, however the rates of photo-oxidative degradation strongly depend on the chemical nature of the polymer. During the process of degradation of the physical and chemical changes occur that lead to polymer discoloration, cracking, loss of gloss and decrease of mechanical strength. Such phenomena are almost always associated with processes of chain scission and in some cases also occur crosslinks. To assess the stability or evaluate the efficiency of a polymer is necessary to subject them to tests simulating the conditions to which he was exposed during its lifetime. In that contest an assessment of the degradation of polypropylene exposed to ultraviolet radiation will be presented.