Zwitterionic Polymer Thickening in Saline Media
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Solution Overview
Problem
Current polymers used for thickening aqueous solutions are sensitive to high ionic strength and shear conditions, leading to a loss of viscosifying power and stability, particularly in saline media and extreme temperatures.
Innovation Solution
A zwitterionic polymer with a betaine group is synthesized through inverse emulsion polymerization, exhibiting high intrinsic viscosity and stability across a wide range of salinity and temperature, effectively modifying the rheological properties of aqueous media and suspensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymers (acrylamide or methacrylamide polymers) are used for thickening aqueous solutions, then they can provide viscosity modification in deionized water, but they lose viscosifying power and precipitate in media of high ionic strength due to the presence of carboxylate or sulphonate groups
Solution Approach 1:
The patent changes the chemical parameters of the polymer by using zwitterionic monomers with betaine groups instead of conventional carboxylate or sulphonate groups. This fundamental parameter change allows the polymer to maintain its viscosifying power in high ionic strength media by eliminating the electrostatic repulsion and salt sensitivity that plagues conventional polymers.
Solution Approach 2:
The patent creates a composite polymer structure containing both hydrophilic units (for water solubility) and hydrophobic units (for enhanced stability in saline media). This composite approach, achieved through copolymerization with surfactants, gives the polymer dual functionality: it maintains solubility in water while gaining resistance to precipitation in high ionic strength environments.
2Temperature
If polymers are used to thicken aqueous suspensions under severe conditions (high temperature and pressure), then they can provide rheological modification, but they experience decreased viscosifying power due to shear gradient and high temperature
Solution Approach 1:
The patent changes the thermal and mechanical stability parameters of the polymer by introducing zwitterionic betaine groups and hydrophobic units. These structural modifications increase the polymer's resistance to denaturation under severe conditions, allowing it to maintain its viscosifying power at high temperatures and under shear stress where conventional polymers fail.
3Reliability
If zwitterionic polymers are used to improve stability in saline media, then they exhibit greater solubility and viscosity in saline medium, but they may exhibit inadequate resistance to the salinity and shear/temperature conditions of use
Solution Approach 1:
The patent creates a composite polymer structure that combines zwitterionic betaine groups (providing solubility and viscosity in saline media) with hydrophobic units (providing resistance to extreme salinity and environmental conditions). This composite structure, achieved through copolymerization, allows the polymer to simultaneously exhibit both desired properties: high solubility/viscosity in saline media and adequate resistance to extreme conditions.
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 polymer maintains its thickening power and stability in high ionic strength environments and at elevated temperatures, providing enhanced viscosity and surface modification capabilities for various industrial applications.
Implementation Method 1
Method for modifying the properties of an aqueous suspension... use of a polymer for thickening a suspension of solid or liquid particles in an aqueous medium
Implementation Method 2
The polymer is a water-soluble zwitterionic polymer... it is generally important for the polymers to be stable in the fluid or of controllable stability, that is to say for them not to separate from the other constituents
Implementation Method 3
Polyampholytes carrying both positive charges and negative charges, part of which is formed by water-soluble zwitterionic polymers, can be adapted for applications in saline medium. They are generally more soluble and exhibit greater viscosities in saline medium than in deionized water. The reference is then to antipolyelectrolyte behaviour for this type of polymer
Data Source
AI summary
A method for modifying the properties of a suspension of solid or liquid particles in an aqueous medium, includes the step of adding to the suspension or to the aqueous medium a polymer prepared by inverse emulsion polymerization of monomers Ab, comprising a betaine group, and of nonionic monomers Ba included in an aqueous phase dispersed in the form of droplets in a hydrophobic external phase, wherein the molar ratio of the monomers Ab to the monomers Ba is from about 4/96 to about 40/60, the polymer exhibits an intrinsic viscosity of greater than 600 mL/g, the reduced specific viscosity being measured by dissolving the polymer in a 20% by weight aqueous NaCI solution.