Oxidized Cellulose Dissolution via LiCl/DMAc Solvent System
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Solution Overview
Problem
Current cellulose dissolution processes are cumbersome, expensive, and require harsh conditions, leading to degradation and limited solubility in common solvents, which hinders the full exploitation of cellulose potential.
Innovation Solution
A process involving a polar aprotic solvent and a salt, used in a step-wise manner under an inert atmosphere, to dissolve modified cellulose with controlled temperature and minimal shearing, minimizing degradation and maintaining the molecular weight and degree of oxidation of the cellulose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cellulose dissolution processes (cuprammonium and xanthate processes) are used, then cellulose can be dissolved, but the processes are cumbersome, expensive, and require harsh conditions with high ionic strength solvents
Solution Approach 1:
The patent changes the chemical parameters of the dissolution process by using lithium chloride in N,N-dimethylacetamide as a solvent system with controlled ionic strength and pH. This allows cellulose dissolution under milder, more controllable conditions compared to traditional cuprammonium or xanthate processes, reducing process complexity while maintaining solubility.
Solution Approach 2:
The patent introduces lithium chloride as an intermediary substance that facilitates cellulose dissolution in N,N-dimethylacetamide. This mediator enables the dissolution process to proceed under simpler, less harsh conditions compared to direct use of traditional solvents, thereby reducing process complexity while achieving reliable solubility.
2Productivity
If high thermal treatment and excessive physical manipulation are applied to dissolve cellulose, then dissolution can be achieved, but cellulose degradation and removal of oxidized groups occur
Solution Approach 1:
The patent optimizes dissolution parameters by using a controlled temperature range (not excessive thermal treatment) and limited physical manipulation. The lithium chloride/N,N-dimethylacetamide system enables dissolution at moderate conditions, maintaining cellulose integrity and preventing degradation of oxidized groups while achieving acceptable dissolution rates.
Solution Approach 2:
The patent applies preliminary protective measures by conducting dissolution under controlled conditions that prevent degradation before it can occur. The selected solvent system and processing parameters are designed to minimize thermal and mechanical stress on cellulose, thereby preserving its structural integrity and oxidized groups throughout the dissolution process.
3Reliability
If lengthy treatment periods are used for cellulose dissolution, then complete dissolution can be achieved, but cellulose degradation and removal of oxidized groups increase
Solution Approach 1:
The patent changes the temporal parameter by using a solvent system that achieves dissolution more efficiently. The lithium chloride/N,N-dimethylacetamide system facilitates faster dissolution compared to traditional methods, reducing treatment time while maintaining complete dissolution and preventing degradation of oxidized groups through shortened exposure to processing conditions.
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
This process effectively dissolves cellulose with minimal degradation, maintaining a high degree of oxidation and molecular weight, enabling the formation of stable solutions and particles suitable for various applications, including medical devices and bioactive agent encapsulation.
Implementation Method 1
contacting a modified cellulose with a solvent under an inert atmosphere to form a swelled modified cellulose
Implementation Method 2
contacting the swelled modified cellulose with a salt under the inert atmosphere to form a modified cellulose solution
Implementation Method 3
adjusting the mixture to a first temperature from about 115° C. to about 145° C.
Data Source
AI summary
A microsphere and method for forming the same are disclosed. The microsphere includes modified cellulose and at least one of a visualization agent, a magnetic material, or a radioactive material.