13C NMR sequence determination and modelling of polypropylene oils

Propylene can be polymerized using a variety of catalysts under different reaction conditions. In the general case, the polymer may exhibit both stereochemistry (tacticity) and regiochemistry (normal and inverted propylene enchainment). When the molecular weight is low, chain ends also become important. The NMR spectra of the resulting polymers can be very complex. In this work, the spectra are studied with the help of analytical (model fitting) and synthetic (computer simulation) approaches in conjunction with a tetrapolymerization model. The approaches described herein are applied to regioirregular polypropylene, particularly low‐molecular‐weight irregular polypropylene samples (polypropylene oils) made with homogeneous catalysts. Complete spectral assignments and analyses are provided for these oils. Studies of polymer main chain structure provide information on polymer chain propagation; analyses of chain ends provide information on initiation, chain transfer, and termination.