Cellulose Derivative Depolymerization for Water Solubility
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Solution Overview
Problem
Cellulose derivatives used in various applications often have undissolved portions due to incomplete derivatization, leading to defects in ceramic products, pharmaceutical coatings, and other materials, as these undissolved parts can cause clogging, porosity, and uneven drug release.
Innovation Solution
Depolymerizing cellulose derivatives with acids, alkalis, or enzymes to reduce viscosity and enhance water solubility, thereby minimizing undissolved floating portions by breaking hydrogen bonds and facilitating hydration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cellulose is derivatized by ester or ether bond to break hydrogen bonding, then water solubility is improved, but undissolved portions remain due to incomplete reaction at intervals of several tens or hundreds of μm
Solution Approach 1:
The patent applies preliminary action by dispersing cellulose in an alkali solution before derivatization to form alkali cellulose. This preliminary step swells the cellulose structure and makes hydroxyl groups more accessible, enabling more uniform subsequent derivatization reaction and reducing undissolved portions.
Solution Approach 2:
The patent changes physical parameters by controlling the degree of substitution and molecular weight of cellulose derivatives. By adjusting these parameters, the patent achieves optimal balance between solubility and uniformity of dissolution, ensuring complete dissolution without undissolved portions.
2Ease of manufacture
If cellulose in solid form is dispersed in alkali solution for activation, then derivatization reaction can proceed, but reaction reagent does not freely react with all three hydroxyl groups around pyranose rings
Solution Approach 1:
The patent applies preliminary action by first forming alkali cellulose through dispersion in alkali solution. This preliminary treatment activates the cellulose by making hydroxyl groups more reactive and accessible, enabling the subsequent derivatization reagent to react more completely with all three hydroxyl groups around pyranose rings.
Solution Approach 2:
The alkali solution acts as an intermediary that facilitates the derivatization reaction. By forming alkali cellulose intermediate, the patent enables better contact and reaction between the derivatization reagent and hydroxyl groups, improving reaction completeness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method significantly reduces undissolved portions in water, improving the quality of cellulose-based products by ensuring complete dissolution and reducing defects in ceramics and pharmaceutical coatings.
Implementation Method 1
Depolymerizing cellulose derivatives with acids, alkalis, or enzymes to reduce viscosity and enhance water solubility, thereby minimizing undissolved floating portions by breaking hydrogen bonds and facilitating hydration
Implementation Method 2
breaking hydrogen bonds and facilitating hydration
Data Source
AI summary
Provided is a method for preparing a cellulose derivative having solubility improved and therefore having less undissolved floating portions when the derivative is added into water. More specifically, provided is a method for preparing a cellulose derivative, comprising a step of depolymerizing a cellulose derivative to produce a depolymerized cellulose derivative having a viscosity at 20° C. in a 2% by weight aqueous solution of the depolymerized cellulose derivative reduced by at least 10% compared with that of the cellulose derivative before the depolymerization so that the number of undissolved floating portions in the aqueous solution of the depolymerized cellulose derivative is decreased compared with that of the cellulose derivative before the depolymerization. Depolymerization is effected preferably by an acid, alkali or enzyme.