Analysis of the effects of restriction of longitudinal contraction on the conversion from cellulose I to cellulose II using CP/MAS 13C NMR: mercerization of ramie fibers under noncooling and cooling conditions

摘要: Ramie fiber samples were treated with aqueous NaOH at room temperature and −5 °C without contraction restriction along the length. The effects of both temperatures on conversion from cellulose I to II quantitatively estimated based intensity change in deconvoluted resonances C1, C4, C6 spectra obtained using CP/MAS 13C NMR. Contraction length makes changes C1-up, C4-down C6-down that remain constant initial stage during treatment regardless temperature: their are related remaining ratio I, crystallinity degree II, respectively. Furthermore, spectral corresponds longitudinal dimension. These experimental results demonstrate is indispensable II.