Influence of the chemical nature of cross-links on the local dynamics of bulk poly(ethylene oxide) networks as studied by carbon-13 NMR at temperatures well above the glass-transition temperature

Abstract

13 C spin-lattice relaxation time measurements have been performed on cyclosiloxane cross-linked poly(ethylene oxide)s (PEO) in bulk at temperatures well above the T g . The introduction of cyclosiloxane cross-links does not induce a strong modification of the local dynamics of PEO segments, in contrast to results observed in urethane cross-linked PEOs. Moreover, in these networks, the local chain dynamics are satisfactorily described by considering a damped bond orientation diffusion process and a fast libration of limited extent of the internuclear CH vectors about their rest position