1. Thermosetting Resins

(1) Glass fiber reinforced epoxy resins
In order to meet the electrical properties and heat resistance requirements of epoxy resin laminated plates used with molten solder alloys, silane coupling agents are recommended as a resin modifier for the thermosetting composites. In this case, silane coupling agents are generally used to treat glass fibers that have been pre-treated with a water solution and then dipped in a resin vanish.

(2) Encapsulating semiconductors
The most common use for coupling agents in epoxy molding compounds is as a semiconductor sealing agent that improves the moisture resistance and electrical characteristics of the resultant composite materials. The coupling agents form an interfacial bond between the resins and the filler that is stronger and more hydrolytically stable, yielding a better moisture resistant interface. In this case, volume resistivity and bending strength are also greatly improved.

(3) Coated sand
The casting parts are comprised of fire resistant aggregates (sand) and adhesives. The quality of the resultant casting is reflects the strength of the adhesives coated on the surface of the sand particles. The coupling agents play an important role by improving the strength of the cast as well as preventing moisture. In most cases, the coupling agents are pre-added directly to the resins.

 
2. Thermoplastics

The results obtained from using coupling agents in thermoplastic resins are generally lower than when compared with that of thermosetting resins. However, in a limited number of systems such as nylon and plastic magnets, good results are achieved due to the high polarity of the thermoplastic resins that are used.

 
3. Resin modification

The uses of silane coupling agents are not limited to the interfaces of composite materials. Resin modification can create high performance resins with unique and superior characteristics. Typically, resins modified with silanes display improved adhesion to inorganic materials and moisture curable properties at low temperature, as well as superior resistance to weathering, acid, heat, and solvents. Product development continues, including the applications of polyolefins for electrical wires and acrylic resins for modified sealants.

For resin modifications with the silicon-based compounds, the following reactions are possible:

(1) Grafting

Grafting is widely used to produce polyolefin based materials for sealing electrical wires. Polyolefins that incorporate an unsaturated silane couplant (e.g., vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc.) have a silyltrimethoxy group grafted to the polyolefin backbone that enables moisture crosslinkable resins. Moisture crosslinkable polyolefins are highly preferred for electrical wire applications because of their reasonable cost and excellent electrical insulation, as well as their dielectric and mechanical stability. In these applications, common silanol condensation catalysts such as dibutyltindilaurate, dibutyltindioleate, dibutyltindiacetate, tetrabutyltitanate, and stannous octanoic acid are used in conjunction with the a peroxide for the grafting reaction.

(2) Chemical Reactions

Given the variety of silane coupling agents that are available bearing different organic functional groups as well as the many different types of organic resins produced, a large number of chemical reactions can be developed between using these compounds as reactants. Examples of applications for this type of silane modified resins include modified sealants, where polyoxyalkylene resins bearing a terminal aryl group react with a hydrosilane in the presence of platinum catalyst, and moisture curable urethane resins, where thermoplastic urethane resins have been modified by an amino functional alkoxysilane. These types of methods for resin modification are expected to continue to produce new resins in the future.

(3) Copolymerization

Copolymerization of an unsaturated silane monomer along with one or more organic monomers is widely used to modify acrylic resins for paints. This method often uses a silane couplant with a methacrylic functional group with compatible co-monomers.