SPECTROSCOPIC, VISCOMETRIC AND MECHANICAL CHARACTERIZATION OF GAMMA-IRRADIATED ISOTACTIC POLYPROPYLENE SYRINGES

FTIR spectrometry, UV-vis spectrophotometry, viscosimetry and static m echanical test methods were applied to freshly irradiated and aged ipp syringes. Qualitative and quantitative analysis of post irradiation p roducts were performed by FTIR spectroscopy. The depth, dose and aging time dependencies of radiochemical yield values for carbonyl and hydr oxyl groups were determined. For the whole syringe barrels radiochemic al yields were found to be G(C=O) = 6.1 and G(OH) = 1.23. The same G v alues were found to change between 34.8-13.5 and 5.8-2.9 respectively from outer surface of the barrel towards inner surface. The sum of the se two G values were found to be in close agreement with the G(S) valu es determined from molecular weight measurements. Further cross sectio nal characterization of syringe barrels were carried by W-vis spectros copy of solutions of ipp flakes obtained from microtomed sections. The above mentioned experimental work and compressive tests have been app lied to the samples aged under normal conditions for 3 years.