Poly(epoxy)ether Membranes via Interfacial Initiation for Harsh Solvent Stability
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Solution Overview
Problem
Existing thin film composite membranes are not stable in harsh conditions such as extreme pH, oxidizing environments, and demanding aprotic solvents, limiting their applicability in industrial processes like chemical and pharmaceutical synthesis, and water treatment.
Innovation Solution
A method involving interfacial initiation of polymerization using ring-opening polymerization of epoxide monomers to create poly(epoxy)ether membranes, which are stable in extreme conditions and maintain salt rejection, by alternatingly re-applying an initiator and monomer phase to densify the thin top-layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional interfacial polymerization is used to create thin film composite membranes, then high solvent permeability and flux are achieved, but the membranes lack stability in harsh conditions such as extreme pH, oxidizing environments, and aprotic solvents
Solution Approach 1:
The patent creates a composite membrane structure combining a poly(epoxy)ether top layer synthesized through interfacial initiation of polymerization with a porous support membrane. This composite structure integrates the chemical stability of the poly(epoxy)ether layer with the mechanical support and permeability of the porous substrate, achieving both reliability in harsh conditions and high solvent permeability
Solution Approach 2:
The patent employs interfacial initiation of polymerization with ring-opening polymerization of epoxide monomers to create a densely cross-linked poly(epoxy)ether top layer. By controlling the polymerization parameters and using specific initiators, the membrane achieves enhanced chemical stability while maintaining high flux and permeability characteristics
2Productivity
If the top layer is made thinner to increase flux, then solvent permeability improves, but salt rejection and selectivity may be compromised
Solution Approach 1:
The patent creates a non-symmetric membrane structure with a thin, densely cross-linked poly(epoxy)ether top layer (providing selectivity and salt rejection) combined with a porous support layer (providing mechanical strength and high flux). This local differentiation of properties allows the thin top layer to maintain both high flux and effective solute separation
Solution Approach 2:
The patent uses a porous support membrane as the base structure, which provides high solvent permeability and mechanical support. The porous structure allows high flux while the thin poly(epoxy)ether top layer deposited on it provides the selective barrier function, achieving both high productivity and manufacturing precision
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 exhibit improved stability and salt rejection in a broad range of pH and chemicals, enabling effective filtration in aggressive aqueous and organic solvents, and maintaining high permeability.
Implementation Method 1
The invention relates to a method for the preparation of thin-film composite (TFC) membranes by interfacial initiation of polymerization (IFIP) and the TFC membranes produced by this method. More particularly, the present invention provides an IFIP method using a ring-opening polymerization reaction of epoxide monomers for making a thin film polymer coating on a porous support membrane.
Implementation Method 2
The invention relates to a method for the preparation of thin-film composite (TFC) membranes by interfacial initiation of polymerization (IFIP) and the TFC membranes produced by this method. More particularly, the present invention provides an IFIP method using a ring-opening polymerization reaction of epoxide monomers for making a thin film polymer coating on a porous support membrane.
Implementation Method 3
Then, the porous support membrane, loaded with the first monomer, is immersed in a water-immiscible (organic) solvent solution containing a second reactive monomer (e.g. a tri- or diacid chloride). The two monomers react at the interface of the two immiscible solvents, until a thin film presents a diffusion barrier and the reaction is completed to form a highly cross-linked thin film layer that remains attached to the support membrane.
Implementation Method 4
Then, the porous support membrane, loaded with the first monomer, is immersed in a water-immiscible (organic) solvent solution containing a second reactive monomer (e.g. a tri- or diacid chloride). The two monomers react at the interface of the two immiscible solvents, until a thin film presents a diffusion barrier
Data Source
AI summary
The invention relates to methods for the synthesis of a thin-film composite membrane, comprising the following steps: a) providing an ultrafiltration porous support membrane, coated at the outer surface with a thin film, synthesized through interfacial polymerisation or interfacial initiation of polymerisation, b) contacting the membrane with a first solution comprising a first monomer, and allowing the solution to impregnate inside the thin film of the membrane, c) discarding the first solution comprising the first monomer, d) contacting the membrane with a second solution comprising a second monomer, and allowing the solution to impregnate inside the thin film of membrane, whereby the second monomer reacts with the first monomer and optionally with reactive groups of the thin film, e) discarding the second solution comprising the second monomer.