Application: Plastics/Polymer

Polymers are used in a wide range of fields such as food wrapping materials, medicine packing, and industrial materials and products. Properties and functionalities of polymer materials are dependent on various factors, including molecular weight, molecular weight distribution, molecular chemical structures (primary structures), morphology of molecular chains (secondary structures) depending on the spinning angles ofchemical bonds, and crystalline or non-crystalline structures of inner-molecules and inter-molecules, as well as spherulite structure aggregates, phase separation structures and orientations (higher-order structures).It is of prime importance to analyze and evaluate the structures and properties of polymers as well as the correlation between these two factors, and to feed these analysis and evaluation results to the development and manufacturing sites for the enhancement of the performance and quality control of polymer materials and polymer products. On the other hand, industry in Japan is supported by functional molecules, which are becoming more advanced and more complicated. This makes it more difficult to characterize such polymers, there by increasing the importance of multiple analyses that combine a variety of analytical methods.

Acknowledgements: Samples were provided by courtesy of the Council for PET Bottle Recycling for the degradation evaluation of PET bottles through outdoor exposure testing.

The components, which are reaction pyrolysis products derived from the PET main chain were strongly detected. These were common components before and after UV irradiation. As a result of the difference analysis of the outdoor exposure test between 0 year and 2 years, a component characteristic of the outdoor exposure test was observed at a retention time of 11.37 minutes in the total ion current chromatogram (TICC). The components of the peak that increased from the outdoor exposure test were the same as those which increased due to UV irradiation onto the PET fi lm described on page 36. An EIC was created at the base peak of component ★to confi rm the change of area value with respect to UV irradiation time (average value of n = 3). As a result, it was found that there was a rapid increase within one year of outdoor exposure, and the increase rate became gradual after that.

Before the outdoor exposure testing, a series derived from the cyclic oligomer of PET was mainly observed. After the outdoor exposure testing, the series COOX/COOX terminus (X = H, Na), which was presumed to have carboxy terminus derived from the photooxidation reaction, was observed. These were identical to the series observed by UV irradiation onto PET reported on page 36. When the ion intensity ratio of the series with the cyclic oligomer and the carboxy terminal was determined, the carboxy terminal series increased. It was found that the rate of increase during the second year was less than that of the first year.