THERMAL ANNEALİNG AND REFRACTIVE INDEX MONITORING OF POLYPROPYLENE FİLM

Özet

Öz Isothermal annealing technique was used to accelerate the ageing process on prefabricated highly crystalline polypropylene thin films to investigate the specification failure of such films. Samples were held at a constant temperature of 125 °C, for different periods of titne ranging from 1 to 10 hours. A mechanism to describe the observed variations has been proposed. A model for the macrostructure is introduced which explains the observed data. The suggested model helps to identify the role o f relaxation processes by ageing. The periodic changes of the polymer structure were proven by infra-red technique. Infra-red dispersion properties of the samples were measured in the vvavelength range 2-6.5 micron. The technique exhibited a structural periodic time of 4 hours.