Purifying Water-Soluble Polymers via pH-Induced Nano-Precipitation
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Solution Overview
Problem
Current methods for purifying water-soluble polymers from hydrophobic contaminants, such as dialysis, reprecipitation, and chromatography, are inefficient and costly, especially for achieving high degrees of purity, and lack effective strategies for removing hydrophobic low molar mass nonpolymeric molecules.
Innovation Solution
A method involving ionization of polymer chains with pH-modifying compounds to release hydrophobic contaminants as stable nano-objects, which can be filtered out using chemically resistant nanoporous filters, followed by deionization and removal of low molar mass salts, utilizing environmentally-friendly solvents and avoiding the need for expensive additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dialysis is used for purification of water-soluble polymers, then hydrophilic contaminants can be removed, but hydrophobic contaminants cannot be effectively removed
Solution Approach 1:
The patent changes the physical-chemical state of hydrophobic contaminants from dissolved to precipitated form by adjusting pH parameters. By ionizing polymer chains through pH modification, the solubility of hydrophobic contaminants changes, causing them to precipitate out of the aqueous solution while the polymer remains soluble, enabling selective removal through filtration.
Solution Approach 2:
The patent utilizes phase transition of hydrophobic contaminants from dissolved state in aqueous solution to precipitated solid phase. Through pH-induced ionization of polymer chains, the contaminants undergo phase separation and precipitation, allowing them to be removed from the solution by filtration while the polymer remains in the soluble phase.
2Manufacturing precision
If reprecipitation is used to remove hydrophobic impurities, then some purification is achieved, but large volumes of expensive solvents are required and liquid polymers cannot be processed
Solution Approach 1:
The patent extracts hydrophobic contaminants from the aqueous polymer solution through pH-induced precipitation and filtration. By selectively removing contaminants in the solid precipitate form, the method achieves purification without requiring large volumes of organic solvents, as only water and pH modifiers are needed.
Solution Approach 2:
The patent uses pH modifiers as intermediary substances to facilitate the removal of hydrophobic contaminants. The pH modifiers induce ionization of polymer chains, which indirectly causes contaminants to precipitate. This intermediary approach avoids the need for direct contact with large volumes of expensive organic solvents.
3Manufacturing precision
If extraction is used for purification, then separation based on solubility is achieved, but the process is slow and requires pure expensive solvents
Solution Approach 1:
The patent changes the solubility parameters of the system by adjusting pH. This induces rapid phase separation and precipitation of hydrophobic contaminants, dramatically increasing purification speed compared to conventional extraction. The pH-induced ionization creates immediate solubility differences that facilitate fast separation without requiring slow diffusion-based extraction processes.
4Manufacturing precision
If preparative chromatography is used, then efficient separation of individual compounds is achieved, but equipment cost and operational complexity are high
Solution Approach 1:
The patent extracts and removes hydrophobic contaminants through simple pH-induced precipitation and filtration, eliminating the need for complex chromatographic equipment. By separating contaminants based on their precipitation behavior rather than requiring sophisticated chromatographic separation, the method achieves high purity with minimal equipment complexity.
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
This method enables the purification of water-soluble polymers to very high purity, reducing hydrophobic contaminant concentrations to less than 1 ppm, is cost-effective, and suitable for large volumes, without requiring highly skilled personnel or sophisticated equipment.
Implementation Method 1
ionization of monomeric units in polymer chains by adding a first pH-modifying compound into the solution, in such an amount that 20% to 100% of monomeric units become ionized, thereby releasing the hydrophobic contaminants from polymer chains
Implementation Method 2
removal of the nano-objects from the solution using chemically resistant nanoporous filter with effective pore size equal or less than 500 nm
Data Source
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AI summary
This invention comprises a method of purification of water-soluble polymers from hydrophobic contaminants to high degrees of purity. This method can be considered as a complementary method to routinely used methods of dialysis and various variants of ultrafiltration capable of the removal of hydrophilic unwanted compounds from water-soluble polymers. The method is based on the separation of hydrophobic contaminants adhered to polymer chains by their ionization in aqueous solution, subsequent nanosegregation of hydrophobic compounds (contaminants) landed in bulk water into nanoparticles/nanodroplets sufficiently stable over time, mechanically strong and stable in shape, with dimensions distinct from polymer chains, and hence removable by filtration using filters with pores capable of retaining nanoparticles/nanodroplets comprising hydrophobic contaminants and permeating polymer chains. The advantage of the given method is the low cost without necessity of expensive equipment, expensive and environmentally unfriendly reactants or highly qualified personnel. The method according to this invention can reduce the content of particular hydrophobic contaminants in polymer to levels between 0.5 and 5 ppm).