A GPC METHOD TO DETERMINE THE AMOUNT OF COMONOMER IN AN ETHYLENE-NORBORNENE-COPOLYMER

The overall composition of an ethylene-norbornene-copolymer can be det ermined by measuring the GPC-peak area, normalizing it according to sa mple weight and using a calibration curve established on the basis of C-13-NMR measurements. The normalized GPC-peak area decreases with inc reasing norbornene content up to 29-30 mol% when it disappears. At hig her norbornene contents the polarity of the signal changes but the cor relation with norbornene content is still valid. This phenomenon is du e to refractive index changes caused by the comonomer. GPC is therefor e a very practical tool for characterizing COC which has recently appe ared on the market. (C) 1996 Elsevier Science Ltd.