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Nonionic Polyacrylamide (NPAM)
CAS No.:
9003-05-8
Molecular Formula:
(C3H5NO)n
Structural Formula:
Property:
Nonionic polyacrylamide exhibits charge neutrality in papermaking. Its molecular chain contains only —CONH2 groups, ensuring electrical stability at pH 4~9. It remains stable across water hardness levels of 0~1000 mg/L (as CaCO3) and varying salt concentrations, with a ζ-potential variation of less than 3 mV.
Typical relative molecular weight ranges from 8~18*106. The radius of gyration Rg is approximately 200~260 nm. A single chain can bridge 10~30 fibers or filler particles, thus primarily forming flocs through bridging. The fractal dimension Df of the flocs is about 2.3, approximately 0.2 higher than that of anionic types at the same concentration. Shear resistance increases by about 25~35%, exhibiting greater stability under high-speed and shear disturbances.
Low surface activity prevents charge neutralization with dyes, alum, or sizing agents. This avoids color spots and deposits, making it suitable for paper grades demanding high brightness and surface quality, such as cultural paper and thermal paper. Overall, it enhances retention rate, dewatering efficiency, and process stability.
Specification:
| Products | Product Name | Degree of Hydrolysis | Molecular Weight | Application |
|---|---|---|---|---|
| Nonionic PAM Powder | IROFLOC100 | Low | Medium | Lead, zinc, nikel ore, etc |
| Nonionic PAM Powder | IROFLOC101 | Low | High | |
| Nonionic PAM Powder | IROFLOC134 | Low | High | Phosphate ore, copper ore,etc. |
| Nonionic PAM Powder | IROFLOC135 | Medium | High |
Application:
1. Wet-End Retention and Drainage Enhancement
During production on high-speed paper machines (800~1800 m/min), the extensive use of CaCO₃ fillers (≤30%) often causes the initial retention rate to drop below 65%. To address this issue, implementing wet-end retention and drainage enhancement technology becomes particularly crucial.
A dual-addition approach combining nonionic polyacrylamide (0.3~0.8 kg/t paper) and PAC (3~5 kg/t paper) in the wet section, spaced 3~5 seconds apart, was implemented. This composite addition method elevated retention rates to 78~82%. Concurrently, wire drainage rates increased by 10~15%, significantly reducing steam consumption to 0.15 t steam/t paper. This demonstrates that optimizing retention and drainage formulations effectively enhances paper machine productivity.
2. Dry Strength Agents
Blending NPAM with aluminum sulfate (Al2O3 0.8% pulp concentration) at a dosage of 0.5~1.0 kg/t paper significantly improved the finished paper's ring crush index by 12~18% and burst index by 10%. Particularly in processing OCC and mixed waste paper, nonionic polyacrylamide outperforms anionic additives without causing a decrease in sizing degree, thereby maintaining overall paper quality.
3. White Water Recovery and Fresh Water Recycling
In closed white water systems with suspended solids (SS) concentrations of 800~1500 mg/L, adding NPAM (0.5~1 mg/L, combined with PAC at 10 mg/L) reduces SS in flotation effluent below 30 mg/L and turbidity below 10 NTU. This technology elevates clean water reuse rates to over 90%, reducing fresh water consumption per ton of paper to below 5 m³. This approach conserves water resources while lowering production costs.
Usage:
1. Drug Dissolution Procedure
Drug dissolution is fundamental to ensuring nonionic polyacrylamide (NPAM) efficacy and requires strict control of the following key parameters.
Concentration Control: Maintain a fixed range of 0.05%~0.1%. Excessively high concentrations may cause clumping and incomplete dissolution; excessively low concentrations reduce efficiency and increase delivery costs.
Environmental Requirements: Water temperature must be maintained between 15°C~35°C. Below 15°C, dissolution slows; above 35°C, polymer degradation may occur.
Agitation and Time: Maintain an agitation line speed of 1~1.5 m/s to prevent molecular chain shearing from excessive speed. Dissolution time must be ≥45 minutes to ensure complete molecular unfolding.
Water Treatment: When water hardness exceeds 300 mg/L, softening is mandatory. Calcium ions in hard water react with amide groups of NPAM to form calcium carboxylate gel, directly causing NPAM failure.
2. Addition Point Selection
The choice of addition point directly impacts the effectiveness of NPAM interaction with the pulp.
Core Position: Set after the pressure screen and before the headbox. The pressure screen removes impurities to prevent clogging of downstream equipment; adding before the headbox ensures thorough mixing of nonionic polyacrylamide with the pulp.
Residence Time: Ensure an 8~12 second residence time between addition and entry into the headbox to allow nonionic polyacrylamide to fully adsorb onto fibers and fillers.
Avoid interference: Maintain a minimum 3-meter separation from addition points of cationic additives like cationic starch or cationic polyacrylamide (CPAM). Proximity between additives with opposing charges causes charge neutralization, disrupting flocculation and nullifying retention effects.
3. Dosage Optimization
Optimal dosage must be achieved through a combination of laboratory testing and on-site fine-tuning to maximize effectiveness while minimizing costs.
Laboratory Pre-screening (DDJ Method). First, fix the polyaluminum chloride (PAC) dosage at 5 kg/ton of paper. Then add NPAM in a gradient of 0.2, 0.5, 0.8, and 1.0 kg/ton of paper. Select the lowest NPAM dosage that achieves the highest first-pass retention rate and white water turbidity < 20 NTU as the baseline reference value.
Field Fine-Tuning: Start dosing at 90% of the laboratory-determined optimal dose (i.e., optimal value minus 10%). Continuously monitor white water turbidity using an online turbidity meter. If turbidity exceeds 20 NTU, moderately increase the dosage. If retention rate shows no significant improvement, reduce the dosage to prevent waste.
Package and Storage:
25Kg/bag(Powder), 25Kg/bag(Colloid), inner bag is PVC film, outer weaved plastic bags. Keep dry.
Synonyms:
China nonionic polyacrylamide; nonionic polyacrylamide flocculant; chemicals nonionic polyacrylamide pam; polyacrylamide nonionic water-soluble polymer