High Molecular Weight Amphoteric Polyacrylamide
PAM-AMPH-01 is an ultra-high molecular weight amphoteric polyacrylamide engineered for complex solid-liquid separation. By co-polymerizing both cationic (quaternary ammonium) and anionic (carboxylate) functional groups onto a single >18 million Dalton polymer backbone, it bridges mixed-charge colloids across wide pH ranges (pH 3 to 11) and high-salinity matrices where single-charge polymers fail. It acts simultaneously as a charge-neutralizing coagulant and a high-efficiency bridging flocculant.
Technical Specifications
|
Parameter |
Specification Value |
Test Method / Standard |
|
Appearance |
White to off-white granular powder |
Visual Inspection |
|
Molecular Weight |
16 - 22 × 10⁴ g/mol (16 - 22 Million Daltons) |
Ubbelohde Viscometry |
|
Ionic Character |
Amphoteric (Adjustable Cationic/Anionic Ratio) |
Colloidal Titration |
|
Solid Content |
≥ 88% |
Gravimetric (105°C, 2h) |
|
Dissolution Time |
≤ 60 minutes (at 0.1% concentration in clean water) |
Stirred Paddle at 400 RPM |
|
Residual Monomer |
< 0.05% |
HPLC |
|
Bulk Density |
0.65 - 0.85 g/cm³ |
ASTM D1895 |
Molecular Structure & Mechanism
Copolymer Backbone: Integrated dual-site activity prevents the mutual precipitation and ionic cross-linking seen in physical blends of separate cationic and anionic polymers.
Shear Resistance: Extended molecular loops and tails withstand high-shear progressive cavity pumps and mechanical dewatering units (centrifuges, screw presses) without rapid chain rupture.
Electrostatic Neutralization: Overcomes strong surface repulsion in complex industrial effluents, generating dense macro-flocs that accelerate settling velocities in clarifiers and thickeners.
Selection Guide: Grade & Parameters
Low-Ionic / High-MW
Optimized for large-particle bridging in gravity settling tanks, low-shear thickeners, and primary clarification.
High-Ionic / Medium-MW
Optimized for high-charge colloidal suspensions, oily emulsions, and high-shear mechanical dewatering presses.
Customization
Molar ratios can be tailored for dedicated industrial installations via trial validation.
Performance in Process Streams
Municipal Sludge
Increases filter cake dryness to 28% - 42% and reduces capillary suction time (CST) to lower hauling costs.
Industrial Effluents
Captures sub-micron colloids in chemical, textile, and pharmaceutical wastewater, driving overflow turbidity to < 5 NTU.
Mining & Papermaking
Stabilizes fine coal slurry, metal ore tailings underflows, and high-conductivity papermaking wet-end loop retention.
Polymer Preparation & Dosing
Use clean, iron-free process water at 10°C - 35°C to prevent oxidative chain degradation.
Prepare at 0.1% - 0.5% concentration; agitate at 300 - 400 RPM for 45 - 60 minutes.
Dilute stock down to 0.05% immediately before the feed point for uniform dispersion.
20 g - 120 g per metric ton of dry suspended solids (DDS), established via jar testing.
Quality Control & Manufacturing
Monomer Purity: Acrylamide and functional monomers undergo gas chromatography assay verification (>99.5% purity) prior to batch charging.
Polymerization Control: Free-radical reaction temperatures and initiator feed rates are governed via Distributed Control Systems (DCS) to ensure a narrow molecular weight distribution.
Lot Release: Every batch is tested for intrinsic viscosity, dissolution rate, residual monomer, and pH. Retention samples are archived for 24 months.
Packaging, Storage & Logistics
Packaging
- 25 kg multi-wall paper-plastic laminated bags with inner polyethylene liners.
- 750 kg / 1000 kg polypropylene FIBC (jumbo bags) with moisture-resistant spouts.
Storage: Store in original packaging in a dry, ventilated area (5°C - 30°C, relative humidity <70%). Protect from direct sunlight and freezing. Shelf life: 24 months.
Documentation: Shipments include a lot-specific Certificate of Analysis (COA), SDS, commercial invoice, and REACH/GHS-compliant paperwork.
FAQ
Q: How does amphoteric PAM differ from separate cationic and anionic polymer blends?
A: Amphoteric PAM features cationic and anionic groups copolymerized onto the same backbone. Physical blends undergo mutual precipitation and plug dosing lines in aqueous solution. True amphoteric polymers remain fully stable and interact with mixed-charge colloids simultaneously.
Q: What causes "fish-eyes," and how can they be prevented?
A: Fish-eyes occur when dry powder clumps, forming an outer gel barrier that prevents water penetration. Use a mechanical powder dispersion unit (eductor), maintain gentle agitation (300 - 400 RPM), and dust the powder slowly into the vortex rather than dumping it in batches.
Q: Can PAM-AMPH-01 operate in high-salinity or high-TDS wastewater?
A: Yes. Unlike standard anionic polyacrylamides that lose hydrodynamic volume in high ionic-strength brines due to charge shielding, amphoteric polymers maintain effective bridging performance in saline industrial streams (e.g., oilfield produced water, brine blowdown).
Q: How does humidity affect solid powder storage?
A: Polyacrylamide is hygroscopic. Exposure to ambient moisture causes caking, pre-dissolution, and molecular weight degradation. Pallets must be stretch-wrapped, stored off concrete floors, and kept below 30°C.
Q: What is the optimal method to determine plant-scale dosage?
A: Perform a benchtop jar test or capillary suction time (CST) test using fresh representative sludge. Test incremental dosages (30 - 70 ppm) of a 0.1% solution, evaluate floc size, free drainage rate, and filtrate clarity, and verify cake dryness before plant trials.
Q: What safety and handling precautions are necessary?
A: Wear chemical-resistant gloves, safety goggles, and a NIOSH/EN-certified dust respirator to prevent inhalation. Spilled dry powder becomes extremely slippery when wet; sweep up mechanical residue before washing down with water. Residual monomer is <0.05%.
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