MLE3102 Degradation and Failure of Materials
Lab Report for the Experiment: Degradation of Polymers
Department of Materials Science and Engineering, Faculty of Engineering, National University of Singapore, Singapore 117574.
Lab Group 9
Neo Chi Jin Darren (U084552E)
See Yi Sian (U084514U)
Sim Zhen Hao (U084502Y)
Date of Experiment: 2 and 9 of September 2010
1. Aims and Objectives
* To study the thermal oxidation and thermal degradation of polyvinyl chloride (PVC) with time
* To compare the various differences between the changes in PVC during thermal oxidation and those induced by thermal degradation
* To learn how to use the Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectrometers to obtain information on the changes in the molecule structures over degradation time.
Degradation of polymers includes all the changes in the chemical structure and physical properties of the polymers due to external chemical or physical stresses caused by chemical reactions, involving bond scissions in the backbone of the macromolecules that lead to materials with characteristics different from (usually worse than) those of the starting material. Polymer degradation in broader terms includes biodegradation, pyrolysis, oxidation, and mechanical, photo- and catalytic degradation. According to their chemical structure, many polymers are vulnerable to harmful effects from the environment. This includes attack by chemical deteriogens – oxygen, its active forms, humidity, harmful anthropogenic emissions and atmospheric pollutants such as nitrogen oxides, sulfur dioxide and ozone and physical stresses such as heat, mechanical forces, radiation and ablation. While trying to elucidate the general features of polymer degradation, including the mechanism of elementary reactions, it is important to consider the effects of various physical factors on the reactions. The degradation of materials could either...