SOLID-STATE H-1-NMR STUDIES OF POLYPROPYLENE

Two samples of isotactic polypropylene (PP), with different treatment histories, were studied by carrying out a number of proton n.m.r. meas urements, namely free induction decay (FID) and spin-lattice relaxatio n in both the laboratory and rotating frames. The results were subject ed to detailed mathematical analysis, and are shown to yield informati on about the domain structure and intrinsic relaxation parameters. Inv ersion-nulled FID analysis shows that the samples contain a spatially resolved distribution of crystallinities, which is responsible for bi- exponential spin-lattice relaxation.