A inflamabilidade de polímeros como tema motivador para o ensino de termoquímica

Abstract

The objective of this study was to develop a learning tool for thermochemistry concepts using flammability, combustion of polymers and the action of a class of flame-retardant additives, metal hydroxides, as theme generator. To achieve this objective, two short videos were prepared. The first video lasted 8 minutes and addressed the flammability of polymers, real cases involving fires, the burning process of a polymer and the importance of developing flameretardant polymeric materials, always correlating these topics with thermochemistry. The second video, lasting 12 minutes, covered the tests for evaluating flame retardancy: cone calorimetry, limiting oxygen index (LOI), vertical burning technique (UL-94) and glow-wire. After production, these two educational products were presented to 3rd year high school students from two schools in the state education network of Rio de Janeiro, through a one hour and thirty-minute workshop. The meeting was divided into 6 stages. Initially, a general presentation of the activity was made, and a questionnaire was administered with 10 multiplechoice questions covering the main thermochemistry concepts seen in high school and 3 discursive questions about polymers and flame retardants. Afterwards, the first video was presented, “The chemistry behind a fire”, followed by a presentation on the concepts of thermochemistry, in the form of a dialogued class. Next, participants watched the second video, “Evaluation of the flame-retardant properties of polymeric materials”. The workshop concluded with the application of a second questionnaire to verify the learning gains achieved after carrying out the activity. The study showed that videos can be important facilitating resources in the learning process, including the concepts of thermochemistry, a subject considered difficult by most high school students. In addition to chemical concepts, the tool can bring chemistry teaching closer to the daily lives of this generation and the role of chemistry in the development of materials with flame retardant properties. It is possible to conclude that students gained knowledge, showed curiosity about flame retardant materials and were interested in getting to know the laboratories where tests with flame retardant materials are carried out.