Silicone resins – structure and
properties
Structure
Silicone resins are heavily crosslinked, three-dimensional networks of
highly branched siloxane polymers that generally require curing at elevated
temperatures. Unlike elastomers, silicone resins do not usually contain silica
fillers.
Silicone resins are very complex structures with complex properties.
They almost always possess silicone reactivity in the form of silanol
(≡SiOH) and may be designed to possess organic reactivity as well.
Properties
In high-performance coatings, silicone resins enhance gloss and color
retention, and resistance to corrosion, moisture, weather, and heat. In
specialty chemical formulations, silicone resins enhance weatherability, water
repellency, physical strength, and release properties.
Silicone resins with high methyl content offer:
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Flexibility
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Water repellency
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Low-temperature flexibility
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Fast cure
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Arc resistance
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Gloss retention
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Heat/shock resistance
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UV stability
Silicone resins with high phenyl content offer:
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Superior thermal stability
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Oxidation resistance
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Greater thermoplasticity
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Toughness
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Compatibility with organic polymers and pigments
A wide range of performance options
Silicone resins can be tailored to suit many applications by varying the
ratio of branched and linear siloxanes in their composition and by attaching
different functional groups to the silicon.
Because silicone resins can combine with many different organic polymers, it
is very easy to optimize cure characteristics, flexibility, adhesion, weather
resistance, and other properties.
| | Did you know ... silicone resins resist heat and
weather better than carbon-based resins because a Si-O-Si bond is much stronger
and harder to break than a C-C bond! | |
|