Organofunctional Silanes

Evonik has developed a range of Silanes helping to reach higher performance to adhesives and sealants and brings excellent substrate adhesion, mechanical strength, storage stability, chemical resistance among many other benefits.

Dynasylan® Silanes

Improve product performance

Improve product performance

Adhesives or Sealants formulators traditionally use Silanes to solve specific technical issues where adhesive strength and/or long-term adhesive stability are needed.

By adding only a small amount of Dynasylan® Silane to the formulation (0.1 - 2.5 wt.- %), key benefits can be provided to the final Adhesive or Sealant:


Excellent Substrate Adhesion
Excellent substrate
mechanical Strength
Storage Stability
Polymer modification

Chemical Resistance
Moisture resistance

Excellent substrate adhesion

Dynasylan® Organofunctional silanes act as adhesion promoters or coupling agents between inorganic materials (glass, minerals, and metals) and organic polymers (thermosets, thermoplastics, and elastomers).

Silanes when used as adhesion promoters or as polymer modifier (e.g. PU prepolymer endcapper) can increase the adhesion of any Adhesive or Sealant with the substrate to be bonded.

As an illustration, Dynasylan® GLYMO improves the wet adhesion of an adhesive used to bond glass and aluminum:

Wet adhesion of a Latex Sealant

Figure 1: Wet adhesion of a Latex Sealant on Aluminum and Glass, with and without Dynasylan® silanes.

Dynasylan® AMMO and Dynasylan® 1146 improve the dry adhesion on wooden surfaces:

 Dry adhesion of a SMP-based adhesive

Figure 2: Dry adhesion of a SMP-based adhesive with and without Dynasylan® silanes

In addition, the resulting bonded assembly will exhibit increased durability especially better resistance to the moisture that can appear between the Adhesive/Sealant and the substrate.

Various Dynasylan® products can act as Adhesion promoters:

Adhesion Promoter Technical features
Dynasylan® 1146 Non-sensitizing, low VOC, prevent premature failure in wet environments, low yellowing
Dynasylan® 1124 Polymer modifier (endcapper), effective in PU systems, good adhesive properties on hard-to-bond materials
Dynasylan® SIVO 210 Can be used as a cost-effective aminosilane system instead of AMEO, especially for oxime silicones
Dynasylan® AMMO Fast reacting aminosilane with well-balanced reactivities and good adhesion performance
Dynasylan® TRIAMO Triamino-functional silane with overall good adhesion performance in silicones
Dynasylan® SIVO 202 New aminosilane system for SMP and silicone based adhesives to improve adhesion to PVC
Dynasylan® SIVO 203 New aminosilane system for SMP and silicone based sealants to improve adhesion to plastics
Dynasylan® GLYMO Versatile silane for epoxies, latices, polysulfides and polyurethanes; excellent adhesion on glass
Dynasylan® GLYEO Environmentally friendly, no methanol release equivalent of Dynasylan® GLYMO, higher level of water stability

Mechanical strength / properties

Whether the selected Dynasylan® is an adhesion promoter, a crosslinker or a drying agent, adding silanes in your Adhesive or Sealant formulation will drastically improve the uniformity of cure thereby optimizing the mechanical performance.

In the case of Polyurethane prepolymers, silanes can be used as endcappers to react with the free NCO groups of the isocyanate-terminated PU. Endcapping provides key benefits to these hybrid systems:
  • Higher mechanical performance
  • Lower viscosity silane-modified prepolymer, faciliting any further processing
  • Compliance with REACH regulation in Europe due to the reduction of free NCO groups in the Adhesive/Sealant

The silane adhesion promoter has a b impact on mechanical properties of SMP-systems:

Elongation of a SMP sealant

Figure 1: Elongation of a SMP sealant CaCO3 filled SPU-sealant incl. 1,1 wt.-% silane adhesion promoter

There are several Dynasylan® grades that can help achieving/tailoring mechanical strength:

Mechanical Strength Silanes Technical features
Dynasylan® DAMO-T Standard aminosilane, sensitizing, fast curing
Dynasylan® 1146 Preferred aminosilane for low modulus products, low VOC, low odour, non-sensitizing
Dynasylan® 1189 Best choice for products with high elasticity
Dynasylan® 1124 Recommended for high strength products
Dynasylan® SIVO 202 New aminosilane system for SMP and silicone based adhesives to improve adhesion to PVC

Dynasylan® 1189 is more than an endcapper, it greatly improves elongation:

Endcapper improves elongation

Figure 2: Test in SPUR® - 1,1% Dynasylan® used

Storage stability / water scavenger

Silanes used as drying agents can capture any latent moisture present in the immediate environment.

This moisture absorption capability helps to increase the shelf life of the stored product and to prevent any premature cure by avoiding the reaction between moisture and the active groups in the Adhesive or Sealant.


Shelf Life of a silane terminated polyurethane Sealant

Figure 1: Shelf Life of a silane terminated polyurethane Sealant at 50°C, 
with and without Dynasylan® Silanes. In this specific example, the recommended dosage is 1.4%.

On top of that, the mechanical strength will be improved especially in the case of SMP (hybrid) Sealants.

Here are some Dynasylan® grades particularly suitable to improve storage stability:

Storage Stabilizing Silanes Technical features
Dynasylan® VTMO Product of choice, ideal reactivity to scavenge moisture
Dynasylan® VTMOEO High boiling point, suitable for e.g. polysulfide sealants
Dynasylan® 6490 Low VOC, low odor silane oligomer, acts as a chemical lid for freshly bottled adhesives

Polymer modification (endcapper)

Silanes can modify polymers either when used as a co-monomer during the polymer synthesis or when reacting with an already existing pre-polymer.

NCO-free and bubble-free systems


In addition to providing more formulation options and allowing NCO-free and bubble-free systems, Silane modification improves the overall performance of the polymer by helping to achieve:

  • Improved mechanical performance (tensile strength, elongation at break, hardness)
  • Good adhesion
  • Scratch resistance
  • Scrub resistance
  • Thermal stability
  • Weathering stability
  • Good electrical properties


Several Dynasylan® grades can be used as Polymer modifiers:

Polymer modifying Dynasylan Technical features
Dynasylan® 1189 Ideal PU Endcapper, less polar, improves UV stability
Dynasylan® 1122 Fast reaction with NCO groups (also without catalyst), increased cohesion through double silicon function, methanol free
Dynasylan® 1124 Fast reaction with NCO groups (also without catalyst), increased cohesion through double silicon function
Dynasylan® MEMO Methacrylate-functional silane, suitable for e.g. acrylics
Dynasylan® VTMO Vinyl-functional silane, suitable for grafting or copolymerization within polyolefins
Dynasylan® VTEO Vinyl-functional silane, methanol free, suitable for water-based products


Dynasylan® products have long been used to crosslink polymers such as silicones, polyethers, epoxies, polyethylenes, polyacrylates, polyurethanes, and others. Crosslinking occurs in the presence of moisture.


Crosslinking occurs in the presence of moisture


This cost-efficient technology is used in many application fields.

As an example, Dynasylan® Organofunctional silanes are used to crosslink tailormade RTV-1 alcoxy silicones to seal shower stalls, structural glazing for all-glass constructions, etc.


Crosslinking Dynasylan® Technical features
Dynasylan® A Tetrafunctional, methanol free
Dynasylan® 40 Multifunctional, ethoxysilane oligomer, VOC reduced
Dynasylan® P Tetrafunctional, slower reactivity
Dynasylan® VTMO Trifunctional, less crosslinking sites
Dynasylan® PTMO Trifunctional, lower reactivity

Chemical resistance

Silanes added in the formulation as adhesion promoters, endcappers and/or crosslinkers increase the crosslinking density of the Adhesive or Sealant and improve the performance of the assembly against chemicals even in harsh conditions.

Dynasylan® AMMO and Dynasylan® 1189, when used in SPU Sealants, improve the shear resistance even when joints are immersed 22 days in Isopropanol.

Lap shear strength of an SPU Sealant

Figure 1: Lap shear strength of an SPU Sealant after 22 days ageing in Isopropanol
(Test performed on Aluminum)


The following Dynasylan® grades are recommended when Adhesives and Sealants formulators are looking for improving the chemical resistance:


Chemical Resistance Silanes Technical features
Dynasylan® AMMO Adhesion promoter; non-sensitizing, fast curing
Dynasylan® 1189 Endcapper, fast-reacting with free NCO groups, no side reaction, UV stable, higher hydrophobicity compared to AMMO

Moisture resistance

As adhesion promoters and PU endcappers, Silanes increase the durability of adhesion between the Adhesive or Sealant and the substrate. They provide better resistance to moisture and prevent premature adhesion failure.

Dynasylan® 1189 and low VOC Dynasylan® 1146 oligomer are the right Silane solutions to prevent adhesion failure when Adhesives or Sealants are in a humid environment.They help to improve the shear resistance of an SPU sealant even when a joint is immersed 6 days in water.
Lap shear strength of an SPU Sealant after 6 days

Figure 1: Lap shear strength of an SPU Sealant after 6 days ageing in water at room temperature
(Test performed on Aluminum at 23°C)


In addition, Dynasylan® 1146 can minimize water uptake in MS Polymer sealants:


Water uptake - Dynasylan in MS Polymer Sealants

Figure 2: Water uptake - Dynasylan® 1146 in MS Polymer Sealants For this test, 

the hybrid sealant specimen was stored in H2O at 23°C

Dynasylan® 1189 and Dynasylan® 1146 can help Adhesive and Sealant formulators to increase the moisture resistance of the final product:


Moisture Resistance Silanes Technical features
Dynasylan® 1146 Non-sensitizing adhesion promoter, low VOC, imparts hydrophobicity
Dynasylan® 1189 Ideal PU Endcapper, less polar, improves UV stability

End use applications

Polymer systems

Dynasylan®: a multi-purpose technology

Infographic: Technology overview

Oligomers selection guide

Structural Adhesives selection guide

The right silane for your application

Primer selection guide

Epoxy Functional Silanes

Silanes for Reactive PU Hotmelts

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