Time-domain NMR in polyolefin research

Polyethylene's and polypropylenes are most studied polymers by different solid-state NMR methods. Among various NMR methodologies used, time-domain proton NMR (TD-NMR) has been extensively applied for the characterization of physical structures in polyolefins. Despite many publications, obtained pieces of information are scattered in the polymer literature. This review provides a comprehensive source of information on appli-cations of TD-NMR for studying polyolefins with different chemical structures, polyolefin blends, films, and fi-bres. After an introduction to TD-NMR, capabilities of the method are illustrated on the following topics: (1) analysis of phase composition and molecular mobility; (2) determination of the size of crystalline and amorphous domains, and the crystal-amorphous interface; (3) the effect of crystallization conditions - namely crystallization from a melt, dilute solutions and during synthesis of nascent powders -on the phase composition and molecular mobility; (4) estimation of the entanglement density and the relative density of interlamellar links (so-called tie molecules) in the amorphous phase; (5) crystallization and melting phenomena; (6) the effect of melting on the entanglement density in low-entangled polyolefins; (7) the effect of deformation, annealing and aging on the physical structures; (8) applications of the method for quality control in polyolefins production; and (9) the use of Rheo-NMR and NMR-MOUSE for studying flow-induced phenomena and surface analyses, respectively. The given examples prove that TD-NMR is a mature and powerful tool for establishing structure-processing-property relationships in polymers.