Polysaccharide Air Filter Membranes Without PFAS Hydrophobization

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Solution Overview

Problem

Current hydrophobic membranes made from polyfluorinated materials like polytetrafluoroethylene (PTFE) pose environmental hazards due to their persistence and toxicity, necessitating a sustainable alternative.

Innovation Solution

A method involving crosslinked polysaccharide polymers, such as cellulose, modified by reacting hydroxyl groups with carboxylic acids or their derivatives to introduce hydrophobic properties, eliminating the need for polyfluorinated substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyfluorinated materials like PTFE are used to create hydrophobic membranes, then hydrophobicity and aeration properties are achieved, but environmental persistence and toxicity increase

Engineering Contradiction:
ImprovehydrophobicityVSAvoidenvironmental persistence
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing polyfluorinated materials with polysaccharide-based materials that have been chemically modified to achieve hydrophobicity through esterification with fatty acids, thereby maintaining the desired hydrophobic properties while eliminating environmental persistence issues

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs biodegradable polysaccharide-based materials that can be decomposed under normal environmental conditions, replacing the 'ever-chemicals' that persist indefinitely, thus allowing the membrane to perform its function and then naturally degrade without long-term environmental harm

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If polyfluorinated materials are used for membrane hydrophobization, then aeration function is maintained, but manufacturing complexity and regulatory restrictions increase

Engineering Contradiction:
Improveaeration functionVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical parameters of polysaccharide polymers through esterification reactions with fatty acids having specific chain lengths (C12-C22), creating hydrophobic surfaces that maintain aeration function while using more accessible manufacturing processes compared to polyfluorinated material processing

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If crosslinked polysaccharide polymers are used as membrane base material, then structural stability is improved, but hydrophobicity requires additional chemical modification steps

Engineering Contradiction:
Improvestructural stabilityVSAvoidprocessing steps
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines two separate processes - crosslinking of polysaccharide polymers and esterification with fatty acids - into an integrated manufacturing approach where the crosslinked structure provides stability and the simultaneous or subsequent esterification imparts hydrophobicity, achieving both goals through a coordinated process

Inventive Principle:
Principle #5Merging (Combining)

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 resulting membranes are sustainable, maintain aeration properties, inhibit microbial growth, and provide effective filtration without altering the membrane structure or function, offering comparable hydrophobicity to PTFE membranes.

Implementation Method 1

reacting hydroxyl groups of the polysaccharide polymer of the membrane with a carboxylic acid having 6 to 30 carbon atoms or a derivative thereof

Methodology Applied
Scientific EffectEsterification: Chemical Bonding

Data Source

PatentEP4703028A1Hydrophobic membranes based on polysaccharides
Publication Date: 2026.03.04 SARTORIUS STEDIM BIOTECH GMBH
  • EP4703028A1 patent drawingFigure 1a~2b
  • EP4703028A1 patent drawingFigure 3~4
  • EP4703028A1 patent drawing

AI summary

The present invention relates to a membrane, in particular an air filter membrane, as well as a method for producing a respective membrane.