SYNTECH

Basic Identification

• Common Name: SMAS, Sodium Methallyl Sulfonate
• IUPAC: Sodium 2-methylprop-2-ene-1-sulfonate
• CAS No.: 1561-92-8
• EINECS: 216-341-5
• Molecular Formula: C₄​H₇​NaO_3​S
• Molecular Weight: 158.15 g/mol
• SMILES: CC(=C)CS(=O)(=O)[O-].[Na+]
• Core dual functional groups: Methyl-substituted vinyl double bond + hydrophilic sulfonate anion −SO3​Na

SMAS white crystal powder

1. Physical Properties

Test Item	Standard Specification
Appearance	White flaky crystalline powder, odorless
Melting Point	>300 ℃ (decomposes at high heat)
Density (20℃)	1.59 g/cm³
Water Solubility	523 g/L at 20 ℃, fully miscible with water; slightly soluble in methanol, insoluble in hydrocarbons
pH (1% aqueous solution)	7.0–9.0 (mild neutral-alkaline)
LogP	-3.74 (strong hydrophilicity)
Vapor Pressure	Near 0 Pa at room temperature
Bulk Form	Free-flow crystal, low dust

2. Chemical Properties

1. Copolymerizable reactive double bondThe branched methallyl vinyl group undergoes free-radical copolymerization with acrylic acid, acrylamide, acrylonitrile, maleic anhydride; acts as reactive surfmer covalently bound into polymer backbone.
2. Highly hydrophilic sulfonate groupPermanently introduces negative charge to polymers, boosting dispersity, anti-scaling, dye absorption and antistatic performance.
3. Thermal & pH stabilityDry solid stable under normal storage; resistant to weak acid/alkali; concentrated strong alkali or high temperature over 280 ℃ triggers decomposition and sulfur oxide release.
4. Low polymerization self-crosslink riskMethyl branch creates steric hindrance, slower self-polymerization than Sodium Allyl Sulfonate (SAS), better long-term storage stability.
5. Low impurity industrial grade specs (99.5% powder)

• SMAS purity ≥99.5%
• Moisture ≤0.5%
• NaCl ≤0.035%, Na₂SO₃ ≤0.02%, Fe ≤0.4 ppm

3. Two Commercial Grades

1. 99.5% Anhydrous Powder (Main Grade)High purity for polycarboxylate superplasticizer, acrylic fiber, water treatment copolymers; low logistics cost for bulk export. Packed in 25kg lined woven bags.
2. 35% Aqueous Liquid SMASPre-dissolved, no dust, direct dosing for emulsion polymerization, textile auxiliaries; avoid freezing storage. Packed in 25L HDPE drums / IBC tanks.

4. Core Industrial Applications

1. Polycarboxylate superplasticizer co-monomer for concrete, improves water reduction & slump retention
2. Third monomer for acrylic fiber, enhances dye uptake and anti-static property
3. Water treatment scale inhibitor & dispersant for industrial circulating water
4. Reactive emulsifier for latex emulsion polymerization
5. Oilfield chemical, paper & textile antistatic auxiliaries

5. Storage & Handling

• Seal tightly in cool, dry, shaded warehouse; isolate from strong oxidants and concentrated acids
• Shelf life: 24 months for sealed powder; 18 months for liquid
• Wear goggles & dust mask during powder feeding; flush skin/eyes with plenty of water upon contact