Cationic Cross-Linked Polymers for Water-in-Water Dispersion Dewatering
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Solution Overview
Problem
Existing water-in-water polymer dispersions used in papermaking lack satisfactory properties for dewatering and retention, particularly under shear conditions, due to the absence of a cationic polymeric dispersant during polymerization, leading to inefficient flocculation and ash retention.
Innovation Solution
A method for manufacturing water-in-water polymer dispersions by subjecting an aqueous reaction mixture containing a cationic polymeric dispersant and a monomer composition to free radical polymerization, ensuring the presence of the cationic polymeric dispersant during polymerization to form an interpenetrating complex with the cross-linked cationic copolymer, which enhances dewatering and retention properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer dispersions are used without cationic polymeric dispersant during polymerization, then the manufacturing process is simpler, but the dewatering and retention performance is insufficient
Solution Approach 1:
The cationic polymeric dispersant is incorporated into the polymerization process from the beginning, before the polymer chains are fully formed. This preliminary action allows the dispersant to become integrated into the polymer structure during synthesis, ensuring optimal distribution and interaction between the dispersant and polymer chains, which directly enhances dewatering and retention performance
Solution Approach 2:
The invention creates a composite system where the cationic polymeric dispersant and the polymer chains form an interpenetrating complex. This composite structure combines the functional properties of both components - the dispersant's ability to interact with cellulosic fibers and the polymer's structural integrity - resulting in superior flocculation and retention characteristics
2Ease of manufacture
If cationic polymeric dispersant is added after polymerization, then the polymerization process is simpler, but gel blocks form that cannot be properly handled
Solution Approach 1:
The cationic polymeric dispersant is incorporated into the polymerization process from the beginning, before the polymer chains are fully formed. This preliminary action allows the dispersant to become integrated into the polymer structure during synthesis, ensuring optimal distribution and interaction between the dispersant and polymer chains, which directly enhances dewatering and retention performance
Solution Approach 2:
The cationic polymeric dispersant acts as an intermediary during the polymerization process, mediating between the monomers and the forming polymer chains. This intermediary role prevents uncontrolled aggregation and gel block formation by ensuring uniform distribution and controlled interaction throughout the polymerization process
3Ease of manufacture
If cationic polymeric dispersant is added as aqueous solution after polymerization, then the polymerization process is simpler, but the water content dilutes the overall composition
Solution Approach 1:
The cationic polymeric dispersant is incorporated into the polymerization process from the beginning, before the polymer chains are fully formed. This preliminary action allows the dispersant to become integrated into the polymer structure during synthesis, ensuring optimal distribution and interaction between the dispersant and polymer chains, which directly enhances dewatering and retention performance
Solution Approach 2:
The invention merges the polymerization process with the dispersant incorporation process. Instead of treating them as separate steps where the dispersant is added afterward, the dispersant is combined with the monomers and polymerized together in a single integrated process, eliminating the need for additional water and concentration adjustments
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 polymer dispersions exhibit improved dewatering and ash retention performance, particularly under shear conditions, by forming an interpenetrating complex with the cationic polymeric dispersant, leading to enhanced flocculation and retention efficiency in papermaking processes.
Implementation Method 1
subjecting an aqueous reaction mixture comprising (i) a cationic polymeric dispersant and (ii) a monomer composition to free radical polymerization
Implementation Method 2
apply water soluble polymers to the cellulosic suspension in order to effect flocculation of the cellulosic solids
Implementation Method 3
cationic cross-linked polymers in water-in-water polymer dispersions... useful as flocculants, dewatering (drainage) aids and retention aids
Data Source
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AI summary
The invention relates to water-in-water polymer dispersions containing cross-linked cationic polymers, methods for their preparation and their use. The water-in-water polymer dispersions are useful inter alia as flocculants, dewatering (drainage) aids and retention aids in papermaking.