PolyDADMAC, a water-soluble cationic polymer with an extensive list of merits including high positive charge density, excellent solubility, tunable molecular weight, high efficiency, non-toxicity, and economic feasibility, has found a multitude of applications within the papermaking sector. Its unique properties have made it a cornerstone in enhancing various stages of the paper manufacturing process.
1. Standard Titrant Utilization
As a medium molecular weight and charge density polymer, PolyDADMAC has become the benchmark cationic polymer for routine titration processes. However, its use as a standard titrant is most effective in solutions with low ionic strength and when dealing with polyelectrolytes that maintain a certain minimum charge density. In scenarios where metal ion concentrations surpass certain levels, the employment of a chromophore-labeled cationic polymer may be more suitable for precise titration purposes.
2. Anionic Containment Agent
The complex environment in paper mills, characterized by closed-loop whitewater systems and the use of highly charged bleached wheat straw pulp, can introduce elevated levels of dissolved and suspended interfering substances into the paper stock. To counteract this, PolyDADMAC serves as a critical chemical auxiliary – acting as an anionic capture agent – by effectively neutralizing these interferences before the addition of other additives, thereby preserving the effectiveness of the paper treatment process.
3. Efficient Flocculant
Within the context of wastewater management in paper manufacturing, PolyDADMAC demonstrates its prowess as a high-performance, non-toxic cationic flocculant. It excels at promoting flocculation through bridging adsorption between itself and suspended colloidal particles in the effluent, thus significantly contributing to efficient and sustainable wastewater treatment.
4. Conductive Paper Enhancement
PolyDADMAC plays a pivotal role in the production of conductive paper, which typically requires a surface resistance of around 1060 Ω·cm for optimal functionality. When exceeding or falling short of this range, issues such as ghosting, image overlap, and inferior copy quality can arise. Here, PolyDADMAC acts as a key conductive material. During polymer synthesis, the diallyl monomer undergoes cyclization to form pyrrole rings, imparting conductivity to the polymer. This conductive PolyDADMAC solution can then be applied onto the paper web via coating techniques such as dip coating, brush application, or wet-end addition, ensuring the paper attains the desired level of conductivity while maintaining excellent print quality.
In summary, PolyDADMAC's multifaceted applications are integral to modern papermaking, addressing challenges from chemical analysis to wastewater treatment and advanced functional paper development.
