Functional Polymer Membrane with Mercapto Chain Transfer Agent
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Solution Overview
Problem
Conventional ion-exchange membranes face challenges in balancing water permeability and electrical resistance, leading to increased energy requirements for electrodialysis, and have long polymerization-curing times, which hinder large-scale production efficiency.
Innovation Solution
A functional polymer membrane is developed using a styrene-based monomer, crosslinking agent, and a chain transfer agent with a mercapto group, specifically formulated to reduce the product of water permeability and electrical resistance, and optimized for faster polymerization-curing under specific conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chain transfer agents (2,4-diphenyl-4-methyl-1-pentene or saturated hydrocarbons) are used for polymerization-curing, then membrane forming properties are enhanced, but polymerization-curing time becomes excessively long, hindering large-scale production
Solution Approach 1:
The patent changes the chemical structure parameters of the chain transfer agent by introducing a mercapto group (—SH) at the terminal position of the hydrocarbon chain. This structural modification fundamentally alters the polymerization kinetics, enabling rapid curing while maintaining excellent membrane forming properties. The mercapto group acts as an efficient chain transfer site that accelerates the polymerization reaction without compromising membrane quality.
2Reliability
If the coefficient of water permeability is lowered to improve ion-exchange performance, then electrical resistance increases, and vice versa, making it difficult to optimize both parameters simultaneously
Solution Approach 1:
The patent creates a composite membrane structure by incorporating a specifically designed chain transfer agent with mercapto group into the polymer matrix. This composite approach allows simultaneous optimization of multiple properties: the mercapto-containing chain transfer agent forms a crosslinked network structure that provides both appropriate water permeability for ion transport and low electrical resistance for efficient current conduction, resolving the trade-off between these two critical performance parameters.
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 membrane achieves a lower product of water permeability and electrical resistance, reducing energy demands for electrodialysis and enabling efficient large-scale production with shorter curing times.
Implementation Method 1
a chain transfer agent which has a mercapto group as a functional group... conducting a polymerization-curing reaction of a composition containing (A) a styrene-based monomer, (B) a crosslinking agent, and (C) a chain transfer agent
Data Source
AI summary
Provided is a functional polymer membrane having a structure represented by the following Formula (1) and a structure represented by the following Formula (2), in which an ion exchange capacity is 2.0 meq/g to 7.0 meq/g; and a method for producing the same,—S-LL1-LL-LL2-S— Formula (1)in Formula (1), LL represents a single bond or an alkylene group which may have a substituent, —O—, —S—, —NRZ— or a linking group obtained by combining these, LL1 and LL2 represent —(CR1R2)I— or —(CR1R2)I—C(═O)O— (in which the atom bonded to LL is an oxygen atom), R1 and R2 represent a hydrogen atom or an alkyl group, I represents 1 or 2, RZ represents a hydrogen atom or a substituent, however, in a case where terminal atoms of a substituent in LL and a substituent of RZ are a sulfur atom, LL is the sulfur atom having a bond to be incorporated into the polymer chain, andin Formula (2), L1 represents an alkylene group or an alkenylene group, Ra, Rb, Rc, and Rd each independently represent an alkyl group or an aryl group, Ra and Rb, or/and Rc and Rd may be bonded to each other to form a ring, n1 represents an integer of 1 to 10, and X1− and X2− each independently represent an organic or inorganic anion.