PROBABILITY MODEL TREATMENT OF REGIO-IRREGULAR AND STEREO-IRREGULAR POLYMERS

A general analytical approach is devised to treat the NMR data of stereoirregular and regioirregular homopolymers. The methodology is based on the four-component copolymerization model, treating normal and inverted monomer and the levo and dextro configurations as ''comonomers''. In this way, the effects of monomer inversion and tacticity can be separately deduced. The analytical approach has been computerized. From the conditional probabilities, information on propagation mechanism (chain-end or catalytic-site control) can be obtained. The model has been used to analyze the NMR data of poly(propylene) samples made with titanium, vanadium and group IV metallocene catalysts. Comparisons have been made between model parameters and polymer microstructure.