| 초록 |
Poly(vinyl butyral)(PVB) has hydrophobic butyl groups and hydrophilic hydroxyl groups. Dynamics of water in PVB samples with initial water contents of 20 and 30 w/w% as a function of temperature was studied with 1H magic angle spinning(MAS) and static spectra. Our 1H magic angle spinning spectra acquired at room temperature show peaks at 4.9, 4.4, and 1 ppm assigned as free water, bound water exchanging protons with hydroxyl groups in the PVB, and alkyl groups in the PVB, respectively. The peak at 4.9 ppm disappears as the temperature increases while the one at 1 ppm does not change much. The linewidth of the peak at 4.4 ppm becomes narrower at higher temperature. The 1H MAS and static spectra manifest some free water not freezed even below 0℃, suggesting the free water is trapped in nano size cavity. Our results indicate that the PVB sample loses water faster and has faster proton exchanging and molecular dynamics at higher temperature. |
