Improving Accessibility and Reactivity of Celluloses of Annual Plants for the Synthesis of Methylcellulose

Abstract

Pretreatments (water-soaking, pre-mercerization, mercerization under a pressure of 15 bars and steam explosion) were used to improve the accessibilities and reactivities of celluloses of bleached flax, hemp, sisal, abaca and jute pulps for the synthesis of methylcellulose. Degrees of crystallinity were determined by X-ray Diffraction (XRD) spectra. The iodine adsorption accessibilities of pulps were low and accessible fractions ranged from 1.3 to 5.2%. Accessible fractions in amorphous cellulose were calculated in the 5-18% range. The accessibilities of these pulps were hemp pulp > flax pulp > sisal pulp > jute pulp > abaca pulp. Fourier Transform Infrared (FTIR) spectra showed that mean hydrogen bond strengths were weakened and relative crystallinity indexes were decreased by pretreatments. The accessibility and reactivity of the abaca pulp were improved by water soaking, mercerization under 15 bars pressure, steam explosion and preliminary mercerization, of which steam explosion and pre-mercerization were the best treatments. Species was the main factor for the accessibility and reactivity.

Methylcellulose, a Cellulose Derivative with Original Physical Properties and Extended Applications

“…Then, purification and removal of by-products is applied by washing in hot water, followed by drying and pulverization of the prepared MC. Sometimes acetone, toluene, or isopropanol are also added, after the etherifying agent, in order to reach different substitution degrees [37][38][39]. Therefore, the heterogeneous route from cellulose semi-crystalline solid state produces a heterogeneous polymer, composed of hydrophobic highly substituted regions corresponding to the swollen amorphous zones in cellulose and more hydrophilic regions with lower average DS.…”

Application of ultrasonic waves in activation of microcrystalline cellulose

“…However, the aldehyde content of DAC is usually low because of its insolubility, highly ordered structure, and crystallinity. Therefore, it is generally recognized that some types of activating treatments are needed to improve the accessibility and trends of heterogeneous reactions of cellulose 4, 5. Traditionally cellulose is activated by milling, alkali swelling, and steam explosion 6.…”

Dissolution and hydrolysis of fibre sludge using hydroxyalkylimidazolium hydrogensulphate ionic liquids

“…industry, pulp is soaked and cooked in solution of sodium hydroxide (NaOH) for softening and the 211 resulting pulp goes to the further process. Fibre sludge, the residual from pulp mill, consists of 212 hydroxyl groups and it was rapidly dissolved in the hydroxyalkylimidazolium hydrogensulphate 213 ionic liquids, methylcellulose can be the by product in the substitution reaction by replacing 214 hydrophilic hydroxyl groups (-OH) with hydrophobic methoxide groups (-OCH 3 ) [14] [15] [16]. 215…”