Evaluation of Thermal Degradation of High Density Polyethylene by Principal Component Analysis <sup></sup>

Abstract

Principal components analysis (PCA) is a data analysis and reduction technique widely used in the method of statistical analysis,elucidation of the variation of five mechanical properties (tensile strength, bending strength, impact strength, tensile modulus and bending modulus) and five microstructure properties (carbonyl index, hydroxyl index, branching degree, chain scission degree and unsaturated value) that taken place when subjected to ultraviolet (UV) aging of high density polyethylene (HDPE) used as rotational packaging case by using PCA. The information of main components were extracted and studied. Also the relationships between performance properties were considered. Finally, the combined evaluating parameter Z was established and analyzed. The results show that the first and second components extracted by PCA can be determined on behalf of all components. Among the 10 performance parameters, tensile strength, bending strength and impact strength are strongly correlated, carbonyl index, hydroxyl index, branching degree and chain scission degree are strongly correlated, and the tensile modulus is non-correlated to other performance parameters. The trendy of the evaluating parameter Z show that the HDPE aged quickly in the first 20 days and leveled off in the following days.