Compounding — Process Challenge

Silane Coupling Agents for Filled Polymers

Mineral-filled thermoplastics/thermosets suffer poor filler-polymer bonding, low mechanical strength, and moisture-driven debonding; silane coupling agents bridge the inorganic filler and organic matrix
Updated Jun 2026
Solution Approach

RawSource supplies the base chemicals that go into these programs. We can help with product selection, grade matching, and sourcing from multiple origins for supply security.

Typical Formulation Workflow
1
Polymer & Process Definition
Identify the resin and process (extrusion, molding, film) and the targets — thermal stability, clarity, flame retardance, slip, or color.
2
Additive Selection
Match stabilizers, antioxidants, plasticizers, lubricants, flame retardants, or masterbatch carriers to the polymer and processing temperatures.
3
Compounding Trial
Confirm loading and dispersion on a compounding or molding trial, checking processability, mechanicals, and aesthetics against the control.
4
Validation & Scale-Up
Verify long-term performance (heat aging, migration, weathering) and lock the formulation, packaging, and lot specs for production.
Recommended Chemistries (5)
3-aminopropyltriethoxysilane (APTES)
CAS 919-30-2
Silanes & Organosilanes
Primary amino silane
Triethoxy end hydrolyzes to silanols that condense onto mineral-filler hydroxyls while the pendant primary amine reacts with the polymer, forming a covalent filler-to-matrix bridge
Melting Point: -70 °C   Boiling Point: 217 °C   Density: 0.94 at 25 °C
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3-aminopropyltrimethoxysilane (APTMS)
CAS 13822-56-5
Silanes & Organosilanes
Methoxy amino silane
Methoxy version hydrolyzes faster than ethoxy for quicker filler surface anchoring; the amine couples to acidic/anhydride-functional polymers
Physical Description: Clear to straw-colored liquid with an ammoniaca…
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3-(2-Aminoethylamino)propyltrimethoxysilane (diamine silane)
CAS 1760-24-3
Silanes & Organosilanes
Enhanced adhesion
Two amine groups give higher reactive-site density at the interface, raising bond durability under moisture for filled compounds
Physical Description: Light yellow liquid   Vapor Pressure: 0.03
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(3-Aminopropyl)silanetriol
CAS 58160-99-9
Silanes & Organosilanes
Pre-hydrolyzed
Pre-hydrolyzed water-borne aminosilane needs no in-situ hydrolysis, useful for aqueous filler-slurry treatment
Physical Description: 0.1-5.0% aqueous solution: Colorless odorless l…
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Hydrophobic Modified Fumed Silica
CAS 68909-20-6
Silanes & Organosilanes
Treated silica for non-polar systems
A filler already silane-surface-treated, demonstrating the hydrophobized-interface effect that improves wet-out and dispersion in non-polar matrices
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