Dialdehyde-Functionalized Polymer Synthesis for Paper Dry Strength
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Solution Overview
Problem
Existing polyacrylamides suffer from unreacted amide groups leading to cross-linking during storage, reducing shelf-life, and acid treatment causes viscosity drop, limiting application performance and ionic charge contribution.
Innovation Solution
A novel synthesis method for a water-soluble dialdehyde-functionalized polymer, comprising sequential polymerization of monomers and structuring compounds, followed by dialdehyde reaction, enhancing molecular weight without affecting viscosity, improving dry strength and drainage in paper manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional polyacrylamides are used with unreacted amide groups, then the polymer can be synthesized easily, but cross-linking occurs during storage reducing shelf-life
Solution Approach 1:
The patent applies preliminary action by incorporating the dialdehyde group during the polymerization process itself, rather than adding it separately afterward. This ensures complete reaction and eliminates unreacted amide groups that would cause cross-linking during storage, thereby resolving the contradiction between easy synthesis and long shelf-life.
Solution Approach 2:
The patent creates a composite structure by integrating multiple functional groups (amide, dialdehyde, and optionally ionic groups) into a single polymer chain during polymerization. This composite approach ensures complete reaction of all groups, preventing cross-linking while maintaining synthesis efficiency.
2Ease of manufacture
If acid treatment is used to stop the dialdehyde reaction, then the reaction is halted, but viscosity drops significantly reducing application performance
Solution Approach 1:
The patent extracts the need for acid treatment by using a base polymer with controlled molecular weight and structure that allows the dialdehyde reaction to proceed to completion without requiring acid to stop it. The reaction is controlled through polymerization parameters rather than pH adjustment, eliminating viscosity loss.
Solution Approach 2:
The patent changes the control parameter from pH (acid treatment) to polymerization conditions (temperature, initiator concentration, monomer ratios). This parameter change allows reaction control without the harmful effect of acid-induced viscosity drop.
3Stability of the object's composition
If ionic monomers are used in small quantities (less than 5 mol percent), then the polymer remains water-soluble, but the ionic charge contribution is limited
Solution Approach 1:
The patent applies local quality by placing ionic groups at specific positions within the polymer chain structure rather than uniformly distributing them. This allows optimized ionic charge contribution while maintaining water-solubility through the overall polymer architecture.
Solution Approach 2:
The patent creates a composite polymer structure combining ionic monomers with non-ionic monomers in specific ratios, where the non-ionic portions maintain water-solubility while the ionic portions provide the necessary charge contribution for enhanced paper strength.
4Strength
If base polymer molecular weight is increased, then dry strength improves, but viscosity increases affecting application
Solution Approach 1:
The patent changes the molecular weight parameter to an optimal range and compensates by adjusting other parameters such as dialdehyde concentration and polymerization conditions. This allows achieving high dry strength without excessive viscosity, as the optimized molecular weight reduces polymer chain entanglement.
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 improves paper dry strength and drainage, allowing increased paper machine speed and productivity, reducing the need for polymer quantity and associated greenhouse gas emissions.
Implementation Method 1
unreacted amide groups, that may react with dialdehyde (especially glyoxal) during storage, leading to continuous cross-linking of the base polyacrylamide molecules
Implementation Method 2
the acid treatment used to stop the reaction between the dialdehyde and the base polymer, which is associated with a significant drop in the viscosity of the aqueous polymer solution
Data Source
AI summary
This invention relates to a new water-soluble dialdehyde-functionalized polymer its preparation method and use, notably for application in the field of paper or cardboard manufacturing.