Gelation and Gel Structure of Cellulose/aqueous Calcium Thiocyanate Solution System.

Abstract

: The gelation conditions of cellulose/aqueous calcium thiocyanate solution system were determined by temperature jump method and the structure of the gel was analyzed by DSC and X-ray measurements. The time necessary to occurring gelation was shorter for the higher molecular weight sample, the solution with higher concentration, and at lower temperature. For the all solutions, cloud point was observed before occurring gelation, suggesting that the gelation was induced by liquid-liquid two phase separation. The heat to formation of 1 mol of network junctions in the gel and the mean molecular weight of the chain adjoining adjacent crosslinks were estimated from melting point determined by ball drop method and the heat of fusion by DSC. The X-ray diffraction curve indicated that the gel is almost amorphous.

Preparation and characterisation of nanofibrous cellulose plate as a new solid support for microbial culture

“…It was proposed that cooling a hot solution of cellulose in a saturated solution of Ca(SCN) 2 induces a microscopic phase separation into a cellulose-rich phase and a salt-rich phase. 20 Recrystallisation of cellulose is induced in the cellulose-rich phase, which provides cross-linking points and solidifies the whole solution. 20 The gelation is thermoreversible at around 80 uC, but is fixed once the salt is removed.…”

“…20 Recrystallisation of cellulose is induced in the cellulose-rich phase, which provides cross-linking points and solidifies the whole solution. 20 The gelation is thermoreversible at around 80 uC, but is fixed once the salt is removed. 14 The resulting white mass consists of fine fibres of cellulose (Fig.…”