Beitrag zur verfolgung des abbaues von polyäthylen während der verarbeitung

Abstract

The degradation of low‐density polyethylene under thermal stress in a quiet state and during processing from the melt was investigated. It was found that the limiting viscosity value decreases in both cases and the gel content increases, reaching a maximum in the range of 140–160°C. The molecular weight distribution broadens mostly toward the low fractions at the expense of the middle fractions. The main factors in the destruction are temperature and oxygen. The influence of frictions is not important.

Photodegradation kinetics of poly(para-substituted styrene) in solution

“…Although the presence of oxygen molecules in irradiated polymer solution can quench the excited polymer chromophores, we found that the difference between the intensities of excimer fluorescence of polymeric solutions in the presence and absence of oxygen molecules is not very affective. Therefore, the presence of oxygen will accelerate the photodegradation and photo-oxidation of polymeric materials through the formation of proxy radicals and hydro peroxides, which can generate more free radical reactions [29,30].…”