Silanes for Composites & Reinforcement
Coupling agents for fiberglass sizing, mineral filler treatment, and adhesion promotion in composite manufacturing — from wind turbine blades to PV encapsulant films.
Request Samples & TDSThe mechanical performance and durability of a fiber-reinforced composite depend on the interface between reinforcement and matrix. A glass fiber surface is hydrophilic and inorganic; the surrounding polymer matrix is hydrophobic and organic. Without chemical bridging at this interface, the composite fails not through fiber breakage or matrix cracking, but through delamination — the fiber simply pulls out of the matrix under load. Silane coupling agents prevent this by forming covalent bonds on both sides of the interface: the alkoxy groups hydrolyze and condense onto the glass or mineral oxide surface, while the organic functional group reacts into the polymer network.
Selecting the right silane depends on the cure chemistry of your resin system. Amine-reactive matrices (epoxy, phenolic, polyurethane, melamine) pair with aminosilane or ureidosilane coupling agents. Free-radical-cure matrices (unsaturated polyester, vinyl ester, acrylic, POE/EVA encapsulant films) pair with methacryloxysilane. Epoxide-reactive systems can use either aminosilane or epoxysilane depending on whether the silane should participate in the crosslinking reaction or function primarily at the interface.
Beyond fiberglass sizing, the same coupling agents treat mineral fillers (silica, alumina, wollastonite, calcium carbonate) to improve dispersion and interfacial adhesion in filled composite systems — from electronic encapsulation compounds to dental restorative materials.
APTES(γ-Aminopropyltriethoxysilane)
CAS 919-30-2China: KH-550
The most widely specified coupling agent in fiberglass composite manufacturing. APTES bonds to glass fiber surfaces through its triethoxysilyl group and reacts with amine-reactive resin matrices — epoxy, phenolic, polyurethane, and melamine — through its primary amine. The triethoxy hydrolysis rate provides working time compatible with continuous fiberglass sizing processes, where the silane must remain active in the size bath but bond rapidly on the hot fiber surface. In mineral filler treatment, APTES modifies silica, alumina, and wollastonite surfaces to improve dispersion and interfacial adhesion in filled composites. As a primer, it activates concrete and cementitious substrates for adhesive or coating adhesion.
Fiberglass sizing for epoxy, phenolic, and polyurethane matrices. Mineral filler surface treatment for reinforced composites. Adhesion promotion in protective coating systems. Concrete and cementitious substrate primers. Key industries: wind energy blade manufacturing, construction FRP, automotive reinforced plastics, protective coatings.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
Request Specifications →APTMS(γ-Aminopropyltrimethoxysilane)
CAS 13822-56-5China: KH-540
Fast-hydrolysis variant of APTES. The trimethoxy functionality provides faster surface activation than the triethoxy equivalent — important in waterborne sizing systems and processes where short dwell times limit the reaction window. Where APTES gives you minutes of open time, APTMS gives you seconds. This makes it the preferred choice for waterborne coating adhesion promotion, rapid primer systems, and nanoparticle surface functionalization where controlled, fast bonding is required.
Waterborne coating adhesion promotion, rapid primer systems, nanoparticle and mesoporous substrate functionalization, perovskite solar cell interface passivation.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
Request Specifications →AEAPTMS(N-(β-Aminoethyl)-γ-aminopropyltrimethoxysilane)
CAS 1760-24-3China: KH-792
Diamine-functional coupling agent delivering approximately twice the amine equivalent weight per molecule compared to mono-aminosilanes. The secondary amine on the ethylene bridge and the primary terminal amine both participate in crosslinking reactions with amine-reactive matrices, producing higher interfacial crosslink density. Specified where standard aminosilane coupling does not provide sufficient bond strength — high-temperature structural composites, demanding adhesive primer applications, and textile fiber surface treatments requiring maximum wash durability.
High-temperature composites, structural adhesive primers, textile fiber treatment, enhanced adhesion in polyurethane and epoxy systems.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
Request Specifications →UPTES(3-Ureidopropyltriethoxysilane)New
CAS 23779-32-0
Ureidosilane providing superior wet strength retention compared to standard aminosilanes. The ureido group (-NH-CO-NH₂) forms hydrogen bonds and covalent linkages with both amine-reactive and hydroxyl-reactive resin systems, while its cyclic tautomer resists the hydrolytic cleavage that degrades standard aminosilane bonds under sustained moisture exposure. This makes UPTES the coupling agent of choice wherever composite structures operate in wet, submerged, or high-humidity environments for years or decades. The practical consequence: a wind turbine blade sized with UPTES retains a measurably higher fraction of its dry flexural strength after moisture conditioning than the same laminate sized with APTES.
Fiberglass sizing for moisture-exposed composites (wind turbine blades, marine laminates, underground piping). Mineral filler treatment where wet mechanical properties are critical. Glass fiber reinforcement for polyester and vinyl ester matrices in exterior or below-grade service. Key industries: wind energy, marine composites, chemical-resistant FRP piping, infrastructure composites.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
Request Specifications →GPTMS(γ-Glycidoxypropyltrimethoxysilane)
CAS 2530-83-8China: KH-560
Epoxysilane for coupling in epoxy-matrix composites and electronic encapsulation compounds. The glycidoxy group participates directly in epoxy ring-opening cure reactions, integrating the coupling agent into the polymer network through covalent bonds rather than relying solely on secondary interactions. This mechanism produces interfaces with high chemical resistance and thermal stability. In electronics packaging, GPTMS is the standard filler treatment for silica and quartz particles in epoxy molding compounds (EMC) and PCB laminate fiberglass sizing. The interfacial bonding quality it provides directly affects moisture resistance, coefficient of thermal expansion, and electrical reliability of the finished package.
Epoxy-matrix composite filler treatment, EMC filler coupling (silica, quartz), PCB laminate fiberglass sizing, sol-gel and optical coatings, dental composite adhesion, structural adhesive formulation. Key industries: electronics packaging, semiconductor, optical coatings, dental materials, structural adhesives.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
Request Specifications →GPTES(γ-Glycidoxypropyltriethoxysilane)
CAS 2602-34-8
Extended pot-life epoxysilane. The triethoxysilane hydrolysis kinetics provide longer working time than GPTMS in formulations where premature coupling causes viscosity build or shelf-life failure. Specified for two-component epoxy adhesive systems, slow-cure composite processes, and any application where the sizing bath, primer pot, or adhesive formulation needs to remain stable for hours rather than minutes.
Two-component epoxy adhesives, slow-cure composite systems, formulations requiring extended storage stability and controlled hydrolysis kinetics.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
Request Specifications →MPTMS(γ-Methacryloxypropyltrimethoxysilane)
CAS 2530-85-0China: KH-570
Methacryloxysilane for free-radical-cure polymer systems. The methacrylate group copolymerizes with acrylic, methacrylic, and vinyl monomers under peroxide, UV, or redox initiation — making MPTMS the standard coupling agent for unsaturated polyester, vinyl ester, acrylic, and UV-cure resin matrices where aminosilanes and epoxysilanes are unreactive. The largest and fastest-growing application is photovoltaic encapsulant film production. MPTMS promotes adhesion between POE or EVA encapsulant films and the glass front sheet of solar modules. As global PV module production scales beyond 500 GW annually, encapsulant film producers consume increasing volumes of methacryloxysilane.
POE/EVA photovoltaic encapsulant film coupling, dental composite adhesion, polyester resin concrete, artificial marble and quartz stone, BMC/SMC filler treatment, UV-cure coating crosslinking. Key industries: solar PV module manufacturing, dental materials, engineered stone, automotive composites.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
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