Modulation of proton NMR free induction decay by spin diffusion

Journal Article · Mon Feb 01 04:00:00 EST 1982 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.443142· OSTI ID:5770959

Cheung, T T.P.

The effects of spin diffusion on the free induction decay (FID) of protons associated with the noncrystalline domains of two polymers, polyethylene and blended Nylon 66 (ZYTEL-408), have been examined using Goldman--Shen NMR pulse sequence ((1/2)..pi..x-t/sub 0/-(1/2)..pi..x-bar-tau-(1/2)..pi..x-t). At tau< or approx. =100 ..mu..s, the FID is drastically distorted from the exponential form while at longer tau(tau> or approx. =500 ..mu..s) an exponential FID is observed; but its transverse spin relaxation rate is smaller than that of the FID obtained after a single (1/2)..pi..x pulse and approaches this value at the limit of large tau. These findings are interpreted in terms of the theory of rapid spin diffusion. The spatial variation in the spin relaxation rate within the noncrystalline domain is inferred.

• Research Organization: Ames Laboratory-DOE, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
• OSTI ID: 5770959
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 76:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360404* -- Materials-- Polymers &amp; Plastics-- Physical Properties-- (-1987)
DIFFUSION
DOMAIN STRUCTURE
MATERIALS
NMR SPECTRA
NYLON
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYAMIDES
POLYETHYLENES
POLYMERS
POLYOLEFINS
RELAXATION
SPECTRA
SPIN FLIP
SYNTHETIC MATERIALS