Abstract
The high-resolution solid-state 13 C NMR spectra were recorded for metallocene (m) and Ziegler-Natta (ZN) iso- tactic 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 T1 ( 13 C) were measured at elevated temperatures. With the rise of temperature the splitting of CH2, CH and CH3 signals into two components was detected in 13 C NMR spec- tra and assigned to amorphous and crystalline phases. The temperature dependences of chemical shifts and integral intensi- ties obtained from the deconvoluted spectra provided information on the main chain and CH3 groups motions in amorphous and crystalline regions of studied samples. While T1 ( 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 C and 1 H NMR spectra indicate somewhat larger restraints of the motion in amorphous regions of ZN-iPP.
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