ISSN:
0887-6266
Keywords:
molecular-scale heterogeneity
;
dynamic viscoelastic behavior
;
CP/MAS 13C nuclear magnetic resonance relaxation
;
proton spin-lattice relaxation time in the rotating frame, T1ρ
;
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Dynamic mechanical and solid-state 13C nuclear magnetic resonance (NMR) analyses have been used to assess a molecular-scale heterogeneity in a raw elastomer (butadiene-acrylonitrile copolymer elastomer, NBR), a microcrystalline polymer (poly(vinyl chloride), PVC), and their 50/50 blend. The presence of the microcrystalline heterogeneity in PVC and in the blend was characterized by the temperature dependence of the frequency-swept dynamic mechanical behavior. The NMR T1ρ relaxation experiments with cross-polarization (CP) and magic-angle spinning (MAS) revealed that (1) NBR contained a substantial fraction (ca. 27%) of a molecular-scale heterogeneity identified as butadiene blocks, (2) the fraction of microcrystallites in PVC was ca. 14%, (3) pure phases of both component polymers were present in the blend, dispersed in the mixed matrix, (4) the upper limit of the heterogeneous domains was estimated to be ca. 2.4 nm, and (5) fractions of heterogeneity tend to increase upon blending, indicating that the solubility of the butadiene block and syndiotactic PVC block decreases in the blend. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 709-716, 1997
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
