Possibility and conditions for optimal re-processing of plasticized poly(vinyl butyral) (PVB) were tested. The aim of the work was to determine degradation of PVB sheet at different kneading conditions and to estimate an influence of temperature, air oxygen content and mechanical stress on the course of degradation process. In order to confirm the influence of humidity on the PVB properties during reprocessing, the sheets with the humidity content of 0.5 and 8.0 % were tested. The PVB degradation was determined from the changes of melt flow index, mechanical properties in terms of stress at break and strain, yellowness and molecular weight distribution. The optimal re-processing conditions for PVB were estimated from the evaluation of all the studied properties and their changes.P(ED2.1.00/03.0111
