Polyacrylamide (PAM) is a highly versatile polymer widely employed in the papermaking industry for its exceptional properties as a retention aid, filter aid, dispersant, and flocculant. However, not all PAMs are created equal. Understanding the different types of polyacrylamide – primarily anionic, cationic, and non-ionic – is crucial for selecting the most effective product for specific papermaking applications and achieving optimal results.

1. Anionic Polyacrylamide (APAM):
Anionic PAM carries a negative charge along its polymer chain. In papermaking, APAM is particularly effective in applications where the pulp system has a positive charge or where strong flocculation of negatively charged particles is required. It is commonly used as:

  • Wastewater Treatment: APAM excels at flocculating inorganic suspended solids, such as those found in industrial wastewater from steel plants or metallurgical processes, and also in papermaking effluent containing fine particles.
  • Filter Aid: In certain papermaking processes, APAM can improve the dewatering of pulp by promoting flocculation.
  • Retention Aid: While cationic PAM is more common for retention, APAM can be used in specific neutral to alkaline papermaking systems to enhance the retention of fillers and fines.

APAM typically performs best in neutral to alkaline pH conditions.

2. Cationic Polyacrylamide (CPAM):
Cationic PAM possesses a positive charge, making it highly effective in systems with negatively charged components, which is prevalent in papermaking. CPAM is widely used as:

  • Retention Aid: This is perhaps CPAM's most critical role in papermaking. It strongly adsorbs onto the negatively charged cellulose fibers and fillers, forming bridges that improve their retention on the forming fabric. This leads to higher paper quality, reduced raw material loss, and cleaner white water.
  • Filter Aid & Drainage Aid: CPAM significantly enhances the dewatering of pulp on the paper machine, allowing for higher machine speeds and reduced energy consumption.
  • Sludge Dewatering: In wastewater treatment, CPAM is exceptionally effective at thickening and dewatering the sludge generated by paper mills.
  • Dispersant: In some contexts, it can also help prevent excessive fiber agglomeration, contributing to better sheet formation.

CPAM is particularly effective in neutral to acidic conditions.

3. Non-ionic Polyacrylamide (NPAM):
Non-ionic PAM has minimal to no charge along its polymer chain. Its effectiveness relies primarily on bridging mechanisms. NPAM is often used for:

  • Flocculation: Effective in flocculating suspended solids in various industrial wastewaters, including some papermaking effluents.
  • Filter Aid: It can aid in the filtration of suspensions.
  • Dispersion: In specific scenarios, it can be used to stabilize dispersions.

While less common as a primary retention aid in papermaking compared to CPAM, NPAM finds its niche applications where charge neutrality is beneficial.

NINGBO INNO PHARMCHEM CO.,LTD. offers a comprehensive portfolio of polyacrylamide products, catering to the diverse needs of the papermaking industry. Our technical team can assist in selecting the most appropriate PAM type and concentration to optimize your specific papermaking processes and achieve your quality and efficiency goals.