Stabilisation and Degradation of Polymers

The laboratory examines the stability of polymers, kinetics of degradation, behaviour of additives in polymers and develops stabilising formulations.

Processing stability is evaluated by either multiple extrusion technique (polypropylene) or by measurement of torque necessary for extrusion or kneading of the molten material (HDPE).

Thermooxidative stability (accelerated tests) is examined either in open test tubes or in an oven with forced air circulation at temperatures 50-150°C depending on the kind of examination and type of the polymer. To a limited extent the oxygen absorption method may be used or OIT measured.

Light stability is assessed in accelerated ageing tests or by exposure under natural weathering conditions at the PIB weathering station with the option of terrestrial light intensity monitoring.

The chemical and physical behaviour of additives in polymer may be studied by measuring the diffusion kinetics, exudation rate and solubility of additives in the polymer matrix and by following the chemical changes of the additives in the course of stabilisation process. The nucleation, antistatic and optical brightening effects as well as mutual interactions of particular additives in the package and phenomena connected with water carry-over during the production of oriented slit-tapes can also be assessed.

The group has been involved in the development of stabiliser formulations for polyolefins, additive masterbatches and has extensive experience in production plant trouble-shooting.