Glassy and Polymer Dynamics of Elastomers by ¹H Field-Cycling NMR Relaxometry: Effects of Cross-Linking.

ABSTRACT: ¹H spin lattice relaxation rate (R ₁) dispersions were acquired by field-cycling (FC) NMR relaxometry between 0.01 and 35 MHz over a wide temperature range on polyisoprene (IR), polybutadiene (BR), and poly(styrene-co-butadiene) (SBR) rubbers, obtained by vulcanization under different conditions, and on the corresponding uncured elastomers. By exploiting the frequency-temperature superposition principle, χ″(ωτ_s) master curves were constructed by shifting the total FC NMR susceptibility, χ″(ω) = ωR ₁(ω), curves along the frequency axis by the correlation times for glassy dynamics, τ_s. Longer τ_s values and, correspondingly, higher glass transition temperatures were determined for the sulfur-cured elastomer

SUBMITTER: Martini F 

PROVIDER: S-EPMC7690040 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature