Functional Monomer

Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA)

CAS31098-21-2

Methacrylic acid 3-sulfopropyl ester potassium salt (SPMA, CAS 31098-21-2) is a water-soluble anionic methacrylate monomer carrying a sulfonate group. It introduces permanent negative charge and hydrophilicity into polymer chains, and is used in hydrogels, aqueous dispersions, polyelectrolyte brushes and ion-conducting materials. KingPharm supplies SPMA for research and production with a batch-specific certificate of analysis.

Chemical structure of Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt
C7H11KO5S · 246.32 g/mol
CAS No.
31098-21-2
Formula
C7H11KO5S
Mol. weight
246.32 g/mol
Appearance
White to Off-white Powder

Product Description

SPMA is the potassium salt of 3-sulfopropyl methacrylate, a white crystalline monomer that combines a polymerizable methacrylate group with a propyl sulfonate side chain. It dissolves readily in water and is supplied in salt form, so it can be used directly in aqueous polymerization without prior neutralization.

The methacrylate double bond copolymerizes by free-radical and controlled radical methods, including surface-initiated ATRP. Each incorporated unit carries a sulfonate group, a strong acid anion that stays ionized over a wide pH range, giving the polymer fixed negative charge, high hydrophilicity and counter-ion mobility.

Compared with carboxylic monomers such as methacrylic acid, SPMA provides charge that does not depend on pH. Compared with acrylamide-based sulfonates such as AMPS, its methacrylate backbone fits naturally into methacrylic resin and coating formulations. The propyl spacer places the sulfonate away from the backbone, which favors swelling and ion exchange.

Buyers usually check assay, appearance, water content and the absence of premature polymer. Because it is a reactive monomer, keep the container closed and store it away from heat, light and radical initiators. A specification and COA are provided with each batch.

Chemical Specifications

Identifiers

CAS number 31098-21-2
Product name Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt
Chinese name 3-磺酸丙基甲基丙烯酸钾盐
IUPAC name potassium 3-(2-methylprop-2-enoyloxy)propane-1-sulfonate
Synonyms SPM; Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt; 3-SULFOPROPYL METHACRYLATE, POTASSIUM SALT
Chinese synonyms 甲基丙烯酸3-磺酸丙酯钾盐; 3-磺酸丙基甲基丙烯酸钾盐; 甲基丙烯酸(3-磺酸丙基)酯钾盐; 3-磺酸丙基甲基丙烯酸钾; 3-磺基丙基异丁烯酸酯钾盐
Molecular formula C7H11KO5S
Molecular weight 246.32 g/mol
EC number 250-466-6
MDL number MFCD00010139
PubChem CID 23682747
InChIKey PNOXUQIZPBURMT-UHFFFAOYSA-M
SMILES CC(=C)C(=O)OCCCS(=O)(=O)[O-].[K+]

Physical and chemical properties

Appearance White to Off-white Powder
Melting Point 238.0-244.0 ( ℃ )

Applications

SPMA is used wherever a polymer needs built-in anionic charge and water affinity.

Hydrogels and biomaterials

Copolymerized into hydrogels to raise water uptake and introduce fixed anionic charge.

Polymer brushes and antifouling surfaces

Grafted by surface-initiated ATRP to form charged hydrophilic brushes, for example on reverse osmosis membranes.

Waterborne dispersions and adhesives

Adds polar sites that improve shear stability of aqueous methacrylic dispersions, adhesives and thickeners.

Ion-exchange and conductive materials

Provides sulfonate groups for ion-exchange membranes, polyelectrolytes and antistatic coatings.

Quality Documentation

The following documents can be provided for Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA) to support technical evaluation and purchasing. Documents are issued for the specific grade and batch supplied.

  • Certificate of Analysis (COA) Batch-specific test results against the specification.
  • Product specification The release specification with test items, limits and methods.
Request documents

Packaging, Storage & Transport

Available pack sizes 25 kg, 10 kg, 1 kg, 500 g, 100 g, 25 g

Read the current safety data sheet before handling. Packaging can be adapted to the order quantity and destination.

Frequently Asked Questions

How does SPMA differ from AMPS or sodium styrenesulfonate?

All three introduce sulfonate charge; SPMA is a methacrylate ester, so it copolymerizes readily with other methacrylates, while AMPS is an acrylamide and styrenesulfonate is a styrenic monomer, which suit different backbones.

Does SPMA need neutralization before use?

No. It is supplied as the potassium salt and dissolves directly in water; if the polymer needs a different counter-ion, it can be exchanged after polymerization.

How should SPMA be stored?

Keep the container tightly closed in a dry place at room temperature, away from heat, light and radical initiators to avoid premature polymerization.

What is the CAS number of Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA)?

The CAS Registry Number of Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA) is 31098-21-2. Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA) is also known as SPM; Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt; 3-SULFOPROPYL METHACRYLATE, POTASSIUM SALT.

What is the molecular formula and molecular weight of Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA)?

The molecular formula of Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA) is C7H11KO5S, and its molecular weight is 246.32 g/mol.

Which quality documents are available for Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA)?

The following documents are available for Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA): Certificate of Analysis (COA); Product specification. Contact KingPharm to request the documents for a specific batch.

How can I request a quotation for Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA)?

Send an inquiry for Methacrylic Acid 3-Sulfopropyl Ester Potassium Salt (SPMA) (CAS 31098-21-2) with the required quantity, target specification, destination country and any documentation requirements. KingPharm will confirm availability, packaging, lead time and price.

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Page last reviewed on by Leo Xiao.