Microfibrillated Cellulose Foams via Salt Templating
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Solution Overview
Problem
The production of cellulose aerogels is typically costly and time-consuming, often requiring freeze drying and hazardous solvent mixtures, with limited control over porosity and pore size.
Innovation Solution
Microfibrillated cellulose-based porous materials are created by mixing microfibrillated cellulose with water-soluble salt particles, followed by oven drying and leaching the salt, allowing for control of pore size and porosity without freeze drying or hazardous solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If freeze drying is used to produce cellulose aerogels, then porous materials with controlled structure can be obtained, but the production becomes costly and time-consuming
Solution Approach 1:
The invention changes the drying parameter from freeze drying to conventional drying at elevated temperatures (e.g., 60-200°C). This parameter change maintains the ability to control porosity through salt particle templating while dramatically reducing production time and cost, eliminating the need for expensive freeze drying equipment and processes
Solution Approach 2:
Water-soluble salt particles serve as an intermediary templating agent that directs pore formation during drying. The salt particles are temporarily incorporated into the cellulose matrix, guide the formation of desired pore structures, and are subsequently removed by dissolution in water, leaving behind controlled porosity without requiring freeze drying
2Productivity
If conventional drying methods are used, then production cost and time are reduced, but control over porosity and pore size is limited
Solution Approach 1:
Water-soluble salt particles act as a templating intermediary that enables precise porosity control during conventional drying. The salt particles are dispersed in the cellulose slurry before drying, creating a template structure that dictates pore size and distribution. After drying, the salts are dissolved in water, leaving behind a cellulose foam with controlled porosity that matches the salt particle arrangement
Solution Approach 2:
The invention uses water-soluble salt particles as sacrificial templates to create controlled porous structures in cellulose foams. The salt particles form a temporary framework that defines pore size and distribution; when dissolved, they leave behind a porous cellulose structure with predetermined characteristics, enabling precise porosity control without freeze drying
3Manufacturing precision
If hazardous solvent mixtures are used for aerogel production, then porous structures can be formed, but safety and environmental concerns arise
Solution Approach 1:
The invention converts the typically harmful role of solvents into a beneficial process by using water-soluble salt particles as templates. Instead of requiring hazardous solvent mixtures for pore formation, the method uses inert, water-soluble salts that can be easily removed by dissolution in water, transforming a potentially harmful chemical process into a safe, environmentally friendly aqueous system
Solution Approach 2:
The invention changes the chemical parameter of the drying medium from hazardous solvent mixtures to water or water-based solutions. This parameter change eliminates safety and environmental concerns associated with volatile organic solvents while maintaining the ability to form controlled porous structures through salt particle templating and subsequent water dissolution
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 method produces lightweight, customizable cellulose foams that are stable and cost-effective, with controlled density and porosity, suitable for various applications replacing polyurethane foams.
Implementation Method 1
immersing the dried material of step (ii) in a solvent, preferably in water, thus leaching out at least 95%, preferably at least 99.5% of the salt added in step (i)
Implementation Method 2
bringing the mixture of (i) into the desired shape and drying this mixture in an oven until dry
Data Source
AI summary
The present invention relates to porous foam materials comprising or essentially consisting of microfibrillated cellulose (“MFC”). These porous foam materials are light weight and can be tailored to specific uses. The present invention also relates to a process for making porous foam materials according to the present invention.