Accession Number : ADA198099

Title :   Variable Temperature Solid State NMR of Side-Chain Crystalline Comb Polymers.

Descriptive Note : Technical rept. no. 12, 15 Jul-3 Aug 88,

Corporate Author : UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER SCIENCE

Personal Author(s) : Mathias, Lon J

PDF Url : ADA198099

Report Date : 03 Aug 1988

Pagination or Media Count : 12

Abstract : Polymers with side-chain groups capable of crystallization independent of the backbone have been of interest for many years. Recent reviews summarize the syntheses and characterization of a large number of different families of comb polymers. The easiest to synthesize and evaluate with respect to property trends in a homologous series are those containing linear alkyl side-chains. Derivatives with greater than 8-12 carbons form side-chain crystals with hexagonal packing of the alkyl moieties. In this type of packing, individual alkyl groups adopt an all-trans conformation but with rotational disorder between side-chains. In the process of characterizing the various DHA polymers synthesized, we became interested in the use of solid state C NMR to evaluate several thermal transitions that we have tentatively ascribed to separate side-chain and backbone molecular relaxation processes. In the course of this project, a closely related paper appeared on the use of variable temperature CP/MAS to study side-chain and backbone molecular relaxation processes. In the course of this project, a closely related paper appeared on the use of variable temperature CP/MAS to study side-chain and backbone motion of poly(eta-n-octadecyl L-glutamate) (POG). We describe here the variable temperature C CP/MAS NMR behavior of the C18 DHA polymer along with several commercially available comb polymers for comparison. Keywords: Molecule molecule interactions, Molecular structure, Nuclear magnetic resonance. (kt)

Descriptors :   *CRYSTALLIZATION, *POLYMERS, ALKYL RADICALS, CRYSTALS, MOLECULAR PROPERTIES, MOLECULAR STRUCTURE, MOLECULE MOLECULE INTERACTIONS, MOTION, NUCLEAR MAGNETIC RESONANCE, ORDER DISORDER TRANSFORMATIONS, PACKAGING, PATTERNS, ROTATION, TEMPERATURE, THERMAL PROPERTIES, TRANSITIONS, VARIABLES

Subject Categories : Polymer Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE