Product Identification
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Chemical Name: 2-Acrylamido-2-Methylpropane Sulfonic Acid Sodium Salt
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Common Trade Names/Abbreviations: ATBS.Na, AMPS-Na, NaAMPS, NaATBS
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CAS Number: 5165-97-9
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Molecular Formula: C7H12NNaO4S
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Molecular Weight: 229.23 g/mol
Product Description
ATBS.Na is a highly reactive, strongly hydrophilic, anionic polymerized monomer. It is most commonly manufactured and utilized as a 50% aqueous solution to facilitate immediate blending, co-polymerization, or transport without the hygroscopic clumping issues associated with its dry solid counterpart.
The incorporation of the sulfonic acid group grants polymers synthesized with ATBS.Na high calcium tolerance, superior thermal/hydrolytic stability, and powerful dispersion characteristics across a wide pH range.
Technical Specifications (50% Liquid Solution)
These specifications represent the typical industrial standard for commercial-grade ATBS.Na liquid solutions:
| Technical Parameter | Specification Limit | Test Method / Reference |
| Appearance | Colorless to pale-yellow, transparent liquid | Visual inspection |
| Active Monomer Content | 47.0% – 50.0% | HPLC / Titration |
| Total Solid Content | 50.0% pm 1.0% | Gravimetric oven method |
| pH (as is, 25℃) | 8.0 – 10.0 | pH meter |
| Density (20℃) | 1.18 – 1.23g/cm3 | Hydrometer / Pycnometer |
| Viscosity (25℃) | 10mPa.s | Brookfield Viscometer |
| Color (APHA / Pt-Co) | 100 (typically 50) | Colorimetry |
| Iron Content (Fe) | 5 ppm | ICP-OES / Spectrophotometry |
| Inhibitor (MEHQ) | 60 – 100 ppm | HPLC (prevents self-polymerization) |
| Refractive Index (nD20) | 1.419 – 1.424 | Refractometer |
Core Molecular Properties
The performance of ATBS.Na in polymer synthesis is governed by three distinct structural features:
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The Acrylamide Group: Enables rapid radical polymerization with other vinyl monomers (e.g., acrylic acid, acrylamide, maleic anhydride).
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The Geminal Dimethyl Group: Provides steric hindrance directly behind the nitrogen atom. This shields the amide bond from nucleophilic attack, preventing the polymer from hydrolyzing at high temperatures and high pH levels.
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The Methylpropane Sulfonic Acid Group: Fully dissociated and negatively charged at all operating pH values. It acts as a powerful hydrophilic “anchor,” granting polymers exceptional tolerance to high salinity and divalent cations (such as Ca2+ and Mg2+).
Key Applications
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Water Treatment Formulation: It is a core co-monomer for manufacturing scale inhibitors and dispersants (such as AA/AMPS copolymers) used in high-stress industrial cooling towers, boilers, and reverse osmosis systems.
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Oilfield Chemicals: Highly utilized in drilling fluids, cementing additives, and polymers for polymer flooding/Enhanced Oil Recovery (EOR), where thermal stability and high-salinity tolerance are non-negotiable.
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Textiles & Acrylic Fibers: Functions as an auxiliary to improve dye receptivity, enhance moisture absorbency, and provide antistatic properties to synthetic fibers.
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Emulsion Polymerization: Acts as a polymerizable surfactant/reactive co-emulsifier in styrene-acrylic, vinyl acetate-acrylic, and pure acrylic latex paints to prevent surfactant migration and improve wet-scrub resistance.