How we can interpret the T1 dispersion of MC, HPMC and HPC polymers above glass temperature?

• Published in: Solid state nuclear magnetic resonance Vol. 30; no. 3-4; pp. 192 - 197
• Main Authors: Rachocki, Adam, Kowalczuk, Joanna, Tritt-Goc, Jadwiga
• Format: Journal Article
• Language: English
• Published: Netherlands 01.10.2006
• Subjects: Cellulose - analogs & derivatives; Cellulose - chemistry; Hypromellose Derivatives; Magnetic Resonance Spectroscopy - methods; Methylcellulose - analogs & derivatives; Methylcellulose - chemistry; Temperature
• ISSN: 0926-2040
• DOI: 10.1016/j.ssnmr.2006.10.001

The chain dynamics in methyl cellulose (MC), hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) were studied with the aid of field-cycling NMR relaxometry technique in the temperature range from 300 to 480 K that is above the glass transition, but below thermal degradation. The frequency dependence of proton spin-lattice relaxation time was determined between 24 kHz and 40 MHz for selected temperatures. The experimental spin-lattice relaxation dispersion data were fitted with the power law relations of T(1) proportional variant omega(gamma) predicted by the tube/reptation model. The exponent's values found from the fitting procedure for MC, HPMC and HPC almost exactly match the ones predicted in tube/reptation model for limit II (gamma=0.75) and in MC also for limit III (gamma=0.50). Remarkably, this finding concerns the polymers in networks formed of the same polymer species.