Crosslinked Polymer Brush Membranes for Organic Solvent Separation
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Solution Overview
Problem
Industrial separation of organic solvents using polymeric membranes is challenging due to limitations in pore flexibility, structure design, and stability of polymers in organic solvents, leading to the reliance on energy-intensive distillation processes.
Innovation Solution
A membrane system comprising a support membrane made of polyimide or its copolymers, combined with a polymer brush layer grafted from the support membrane surface, utilizing hydroxyethyl methacrylate (HEMA) and aminoethyl methacrylate (AEMA) monomers, and crosslinked with ethylene glycol dimethacrylate (EGDMA) or triethylene glycol dimethacrylate (TEGDMA).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If polymeric membranes are used for organic solvent separation, then energy consumption is reduced compared to distillation, but separation performance is insufficient due to polymer limitations
Solution Approach 1:
The invention uses composite materials by combining polyimide support membrane with grafted polymer brushes (HEMA, AEMA) and crosslinkers (EGDMA, TEGDMA) to create a hybrid structure that leverages the mechanical strength of the support membrane while the grafted layers provide tailored separation functionality and chemical stability in organic solvents
Solution Approach 2:
The invention changes the chemical and physical parameters of the membrane by controlling the composition ratios of monomers and crosslinkers, adjusting grafting density, and optimizing crosslinking degree to achieve desired pore size, flexibility, and stability for specific organic solvent separations
2Ease of manufacture
If conventional polymeric membranes are used, then manufacturing is simpler, but pore flexibility and structural design capability are limited
Solution Approach 1:
The invention applies preliminary action by pre-grafting polymer brushes onto the support membrane surface before final membrane assembly, allowing the porous structure and chemical functionality to be predetermined and optimized for specific separation applications while maintaining a relatively simple overall manufacturing process
Solution Approach 2:
The invention implements local quality by creating functionally distinct regions within the membrane structure - the polyimide support provides mechanical strength and basic porosity, while the grafted HEMA and AEMA brush layers provide localized chemical functionality, hydrophilicity, and size-selective separation properties
3Productivity
If polymeric membranes are used for organic solvent separation, then the separation process becomes more economical, but polymer stability in organic solvents is insufficient
Solution Approach 1:
The invention uses crosslinkers (EGDMA, TEGDMA) as intermediaries that form covalent bonds between polymer chains and between the support membrane and grafted brushes, creating a crosslinked network that enhances chemical stability and structural integrity in organic solvent environments while maintaining separation functionality
Solution Approach 2:
The invention employs readily available, cost-effective monomers (HEMA, AEMA) and crosslinkers (EGDMA, TEGDMA) that can be easily synthesized or purchased, allowing for economical membrane production while achieving the required stability through crosslinking rather than relying on expensive specialized polymers
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 system achieves improved selectivity and permeability for organic solvents, reducing energy requirements and enabling efficient separation of solvents like methanol and toluene, potentially replacing distillation with a more energy-efficient process.
Implementation Method 1
a polymer brush layer including a plurality of polymer brushes grafted from a surface of the support membrane, the polymer brushes including hydroxyethyl methacrylate (HEMA) monomers, aminoethyl methacrylate (AEMA) monomers
Implementation Method 2
the polymer brush layer includes a plurality of crosslinks between the polymer brushes, wherein the crosslinks include one or more crosslinkers composed of ethylene glycol dimethacrylate (EGDMA), triethylene glycol dimethacrylate (TEGDMA)
Implementation Method 3
The membrane system achieves improved selectivity and permeability for organic solvents, reducing energy requirements and enabling efficient separation of solvents like methanol and toluene
Data Source
AI summary
A membrane for separating organic solvents such as methanol and toluene is provided. A plurality methacrylate polymer brushes, e.g., composed of hydroxyethyl methacrylate (HEMA) monomers or aminoethyl methacrylate (AEMA) monomers, are grafted from a crosslinked polyimide support using Single Electron Transfer-Living Radical Polymerization (SET-LRP). The polymer brushes themselves are also crosslinked by ethylene glycol dimethacrylate (EGDMA), triethylene glycol dimethacryalte (TEGDMA) trimesic acid, and/or itaconic acid. These hydrophilic polymeric brush membranes demonstrate pore stiffening and yet also opening, obtaining high selectivity at reasonable permeability and reduced energy requirements for commercially relevant separations, e.g., methanol/toluene. The addition of the crosslinker prevents loss of selectivity as a result of imparting increased rigidity, enabling the membranes to be operated at higher operating pressures for increased throughput. These membranes would be beneficial for use in pharmaceutical, chemical, petroleum, food, and biotechnology industries, e.g., in the manufacture of polymethacrylic acid, the manufacture of paraxylene, etc.