Aromatic Polysulfone Membrane Toughness via Molecular Weight Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional aromatic polysulfone resin-based porous membranes are prone to clogging and damage during cleaning due to insufficient toughness, leading to reduced filtration efficiency.

Innovation Solution

Developing aromatic polysulfone resin with a reduced viscosity of 0.55-0.65 dL/g, a number average molecular weight of 22000 or more, and a weight average molecular weight to number average molecular weight ratio of 2.54 or less, along with a specific repeating unit structure, to enhance toughness and suitability for film materials, particularly in porous membranes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional aromatic polysulfone resin is used in porous membranes, then heat resistance and chemical resistance are achieved, but toughness is insufficient leading to damage during cleaning

Engineering Contradiction:
ImprovetoughnessVSAvoidresistance to damage during cleaning
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the reduced viscosity (0.55-0.65 dL/g), number average molecular weight (22000 or more), and molecular weight distribution ratio (Mw/Mn of 2.54 or less) of the aromatic polysulfone resin. These parameter optimizations enhance the toughness and durability of the membrane, preventing damage during cleaning while maintaining heat and chemical resistance.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If porous membranes are cleaned by backflow under excessive pressure, then clogging is removed, but membrane damage such as tears or ruptures occurs due to insufficient toughness

Engineering Contradiction:
Improvefiltration efficiency restorationVSAvoidmembrane integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent implements beforehand cushioning by optimizing the molecular weight and viscosity parameters of the aromatic polysulfone resin before membrane fabrication. This pre-optimization creates a membrane with enhanced toughness that can withstand the mechanical stress of high-pressure backflow cleaning, cushioning against potential damage while enabling effective clogging removal.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If aromatic polysulfone resin with optimized molecular weight and viscosity is used, then toughness and durability are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvemembrane durabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent resolves the contradiction between durability and manufacturing complexity by establishing specific parameter ranges for the aromatic polysulfone resin (reduced viscosity: 0.55-0.65 dL/g, Mn: 22000 or more, Mw/Mn: 2.54 or less). These well-defined parameters simplify the manufacturing process by providing clear targets for resin selection and preparation, reducing variability while ensuring high membrane durability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9587112B2Aromatic polysulfone resin and membranes thereof
Publication Date: 2017.03.07 SUMITOMO CHEM CO LTD

AI summary

According to the present invention, an aromatic polysulfone resin is offered which is suitable as film material, especially in porous membranes. The aromatic polysulfone resin of the present invention has a reduced viscosity of 0.55-0.65 dL/g, and preferably 0.58-0.62 dL/g, number average molecular weight (Mn) of 22000 or more, and preferably 23500 or more, and a value of the ratio of weight average molecular weight (Mw) relative to number average molecular weight (Mn) of 2.54 or less, and preferably 2.50 or less.