Abstract
Self-diffusion coefficients of linear and cyclic alkanes in melt, in blends with equivalent linear alkanes, and dissolved in linear polyethylene, were measured by pulsed-gradient spin-echo nuclear magnetic resonance at various temperatures. The results indicate the following: (i) at the same carbon number, cyclic alkanes diffuse more slowly than linear alkanes in their respective melts, but linears and cyclics share a similar rapid rate of decrease with increasing carbon number; (ii) in blends of linear and cyclic alkanes at the same carbon number the single average diffusion coefficient observed varies monotonically as a function of composition; and (iii) two distinct diffusion coefficients are observed in the cycloalkane/linear polyethylene blends, with the extrapolated trace cycloalkane diffusion consistent with Rouse behavior. The results are compared with recent numerical simulations and with experiments in other polymer systems, forming a consistent picture of the effects of diffusant mass, molecular shape and flexibility, and the dynamic attributes of the host material.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.