MERCAPTOPROPYLTRIMETHOXYSILANE- ▸ Sealants and caulks: Coupling agent in polysulfide and polyurethane systems
- ▸ Adhesion promotion: Surface primer linking organics to mineral and metal substrates
- ▸ Composites: Binder and filler treatment for reinforced polymers
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
Request SDS →(3-Mercaptopropyl)trimethoxysilane (CAS 4420-74-0) is a mercapto-functional organosilane coupling agent. It is used as an adhesion and coupling promoter in polysulfide and polyurethane caulks and sealants and as a binder linking organic polymers to mineral and metal surfaces.
Frequently Asked Questions
What is mercaptopropyltrimethoxysilane (MPTMS) used for?
(3-Mercaptopropyl)trimethoxysilane (CAS 4420-74-0) is a mercapto-functional organosilane coupling agent. It is used as an adhesion and coupling promoter in polysulfide and polyurethane caulks and sealants, as a surface primer linking organic polymers to mineral and metal substrates, and as a binder or filler treatment in reinforced composites.
What is the difference between 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane?
Both are mercapto-functional silane coupling agents; the difference is the alkoxy group. The trimethoxysilane (MPTMS, CAS 4420-74-0, formula C6H16O3SSi) hydrolyzes releasing methanol, while the triethoxy analog releases ethanol and hydrolyzes more slowly. MPTMS is the methoxy version RawSource supplies.
How does the mercapto (-SH) group function in a coupling agent?
The thiol (-SH) end bonds to organic polymers and metals (notably copper, gold, and sulfur-cure rubber systems), while the trimethoxysilyl end hydrolyzes and condenses onto mineral, glass, and metal-oxide surfaces. This dual reactivity is why MPTMS works as an adhesion promoter and filler-to-polymer coupling agent.
What is the molecular weight and identity of MPTMS?
Mercaptopropyltrimethoxysilane is CAS 4420-74-0, formula C6H16O3SSi, with a molecular weight of approximately 196.3 g/mol. It is also called (3-mercaptopropyl)trimethoxysilane or MPTMS. RawSource supplies it in bulk with a CoA and SDS.
What is the cost of bulk mercaptopropyltrimethoxysilane?
Bulk MPTMS pricing depends on volume, purity, packaging, and destination. We quote per order rather than publishing spot pricing — request a bulk quote and RawSource will return current pricing along with the CoA and SDS for the lot.