CAS NO. 53459-43-1 Phosphonic acid, [(4-ethenylphenyl)methyl]-

Frequently Asked Questions：

What is (4-vinylbenzyl)phosphonic acid (CAS 53459-43-1)?

It is a dual-function phosphonic monomer with the structure p-CH₂=CH–C₆H₄–CH₂–P(=O)(OH)₂ (molecular formula C₉H₁₁O₃P, MW 198.16). It combines a polymerizable styrenic vinyl group with a benzyl phosphonic-acid group, and is supplied as a white to off-white solid at 95% min purity.

How does it differ from vinylphosphonic acid (VPA)?

VPA has the phosphonic acid directly attached to the polymerizing vinyl unit (CH₂=CH–PO₃H₂), while VBPA places the phosphonic acid on a benzyl group of a styrenic monomer. Published particle studies show VBPA copolymerization yields a higher surface density of phosphonate groups than VPA, and the aromatic styrenic backbone offers different solubility and packing behavior.

How does it polymerize?

The para-vinyl group is a standard styrenic double bond: it undergoes free-radical homopolymerization or copolymerization with styrene, (meth)acrylates, acrylamide and other vinyl monomers, using thermal initiators such as AIBN/BPO or photoinitiation. The phosphonic-acid group remains intact as a pendant acidic/anchoring group on the resulting polymer.

Why are phosphonic-acid groups used instead of sulfonic acid?

The C–P bond in phosphonic acid is more chemically and hydrolytically stable than the C–S bond in sulfonic acid. Phosphonic-acid polymers retain proton conduction at high temperature and low humidity, where sulfonic-acid membranes depend strongly on water, and phosphonates also bind strongly to metal-oxide surfaces.

Which surfaces does it bind to?

Phosphonate groups show excellent adhesion to metal oxides — especially titanium dioxide (TiO₂), silica and alumina — as well as metals and calcium-containing mineral surfaces such as hydroxyapatite. This makes VBPA-derived polymers useful as anchor groups for coatings on titanium implants and oxide substrates.

What is its role in battery electrolytes?

The vinyl group can form crosslinked polymer networks that give solid/gel electrolytes mechanical strength and shape stability, reducing swelling and thermal-degradation risk, while phosphonic-acid oxygens coordinate lithium/metal ions and support ionic migration and conduction. It is investigated in solid-state lithium-battery polymer-electrolyte development.

What purity and grades do you supply?

Standard grade is 95% min, suitable for R&D, coating and polymer development, with COA for every batch. Higher-assay batches (97%+) and controlled water/impurity profiles can be quoted as custom batches against your target specification.

How should it be stored?

Store sealed, dry and frozen, recommended at below −20 °C. Protect from moisture and heat and keep away from radical initiators/oxidizers, because the vinyl group can polymerize unintentionally. Allow the sealed container to equilibrate to room temperature before opening to avoid water uptake.

What are the safety considerations?

Classified with GHS07 (signal word Warning): harmful if swallowed and may cause skin, eye and respiratory irritation (H302–H315–H319–H335). Wear gloves and eye protection, avoid dust inhalation and use standard ventilation. Full guidance and handling details are in the SDS.

Can I get a sample and full documents?

Yes — evaluation samples (gram scale), COA and SDS are provided, with scale-up to 1 kg and 25 kg production packs. Send your target application, purity and pack size to James Zhang at james.zhang@dakenchem.com; we reply with specification, price and lead time, usually within one working day.

Application Cases：

Case 1 — Phosphonated Polystyrene Particles for Titanium Implant Coatings

Copolymerized with styrene in a miniemulsion process to produce nanoparticles carrying a high density of surface phosphonate groups; the particles strongly adhere to titanium/TiO₂ surfaces and nucleate hydroxyapatite, supporting bioimplant coatings with improved bone interaction.

Case 2 — Crosslinked Polymer Electrolyte for Solid-State Batteries

Used as a crosslinking acidic monomer in polymer electrolytes: the styrenic network provides mechanical strength and suppresses swelling, while phosphonic-acid groups coordinate lithium ions and maintain ionic conduction for improved battery stability and safety.

Case 3 — High-Temperature Proton-Exchange Membrane

Polymerized/copolymerized into phosphonic-acid membranes that conduct protons under high-temperature, low-humidity conditions, exploiting the superior chemical stability of the C–P bond over sulfonic-acid C–S membranes in fuel-cell research.

Case 4 — Adsorbable Antimicrobial Block Copolymers

Incorporated as a phosphonic anchor block in amphiphilic block copolymers that graft onto titanium via “grafting to” adsorption, combined with cationic antimicrobial blocks to create biocompatible, bacteria-resistant surface brushes.

Case 5 — Metal Chelation, Adhesion Promotion & Custom Polymer R&D

Supplied from gram-scale samples to bulk for water-treatment/scale-inhibiting polymers, metal-surface adhesion promoters and specialty copolymer development, with consistent specification and batch documentation.