Since the commercialization of Ziegler-Natta process of polypropylene synthesis, this technology was for decades almost the only source of all grades of polypropylene (PP). Only at the end of the last century a new process was developed, based on metallocene catalysis. This process provides new types of metallocene PP (m-PP) different from previous Ziegler Natta PP types (ZN-PP), the main difference consisting in the production of grades with different stereoregularity (isotactic, syndiotactic, hemi-isotactic, atactic) [1] or narrow polydispersity of the polymer chains, compared to Ziegler-Natta catalysts, which produces only highly polydisperse isotactic polymers. The tacticity of isotactic (i) m-PP and ZN-PP is virtually the same (98% of isotactic diads), though the configurational defects are more frequent in m-iPP [2]; this might be reflected in a lower melting temperature of m-iPP in comparison with ZN-iPP. Comparing to ZN-iPP, m-iPP offers a unique balance of stiffness, transparency, and organoleptic properties which is not achievable with ZN-iPP. On the other hand, m-iPP is usually less rigid than ZNiPP homopolymers. Thus, any additional information on similarity or differences in m-iPP vs. ZNiPP behaviour seems to be of scientific as well as Abstract. The high-resolution solid-state 13 C NMR spectra were recorded for metallocene (m) and Ziegler-Natta (ZN) isotactic polypropylenes (iPP) in pelletized form using cross polarization (CP) and magic angle spinning (MAS) techniques within the temperature range of 20-160°C. Besides the CP MAS experiments also the MAS 13 C NMR spectra (without CP), MAS 1 H NMR spectra and rotating frame spin-lattice relaxation times T 1" ( 13 C) were measured at elevated temperatures. With the rise of temperature the splitting of CH 2 , CH and CH 3 signals into two components was detected in 13 C NMR spectra and assigned to amorphous and crystalline phases. The temperature dependences of chemical shifts and integral intensities obtained from the deconvoluted spectra provided information on the main chain and CH 3 groups motions in amorphous and crystalline regions of studied samples. While T 1" ( 13 C) values show that the rate of segmental motion in amorphous regions in m-iPP and ZN-iPP is virtually the same, larger linewidths in 13 Vol.6, No.3 (2012) 204-212 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2012.23 * Corresponding author, e-mail: olga.fricova@tuke.sk © BME-PT commercial importance. NMR investigation is considered to be one of the basic relevant methods. The high-resolution solid-state 13 C NMR studies of iPP reported NMR spectra recorded with combination of magic angle spinning (MAS), cross polarisation (CP) and dipolar decoupling (DD) techniques [3][4][5][6][7][8][9][10][11][12][13][14]. Since iPP can crystallize in several crystalline forms, depending on the crystallization temperature and on the presence of specific nucleating agents, the shape of the spectra was found to depend strongly on the physical treatment of the sa...

The paper deals with a method for the estimation of the degree of crystallinity for partially-crystalline isotacticpolypropylenes (i-PP) using high-resolution solid-state 13 C NMR. For this purpose direct polarization 13 C MAS NMR spectra were measured for i-PP samples with dierent degrees of crystallinity at 98• C. The areas beneath the resonance lines in these spectra correspond to the number of carbons in particular functional groups, while the widths and shapes of the lines reect the degree of crystallinity, crystalline modications, distribution of chain conformations and the chain mobility. The 13 C MAS NMR spectra, measured using appropriate combination of delay time and high proton decoupling eld, made it possible to detect only amorphous domains in the sample. This enabled identication of the lines associated with the amorphous domains in the complete 13 C MAS NMR spectra and provided sucient information for reliable estimation of the degree of crystallinity. The heteronuclear Overhauser enhancement of the 13 C NMR signals due to short delay time was taken into account in our calculations.