NMR study of molecular dynamics in selected hydrophilic polymers.
The temperature dependencies of the 1H spin-lattice relaxation times T1 and of the proton NMR second moment M2 in the temperature range from about 90 to 420 K were measured for methyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose. The proton spin-lattice relaxation measurements reveal two minima due to the C3 reorientation of the methyl groups of the methoxy, methylenemethoxy or propylene oxide groups and the restricted motion of the segment of the polymer chain. The activation energy barriers for these motions were calculated.
Rachocki
Adam
A
Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland. radam@ifmpan.poznan.pl
Tritt-Goc
Jadwiga
J
Piślewski
Narcyz
N
D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry*; D004735:Energy Transfer; D065347:Hypromellose Derivatives; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000737:chemistry*; D008968:Molecular Conformation; D009038:Motion; D011108:Polymers / Q000737:chemistry; D011522:Protons; D013696:Temperature; D014867:Water / Q000737:chemistry*
D011108:Polymers; D011522:Protons; D014867:Water; D065347:Hypromellose Derivatives; D002482:Cellulose; D008747:Methylcellulose; C008079:hydroxypropylcellulose