Acrylic and Silicone Polymers

I posted this question before and didnt get a answer. Some sealants contain Acrylic polymers, some contain Amino-Fuctional Silicone polymers. What is the difference, and why would one company choose one over the other?
 
I think this question would be best directed to each respective manufacturer.



Call each one and do a bit of research. They *should* know their products well.



For instance, Sal Zaino has a very good grip on his product technology and what it works with, how it works, why it works, etc.
 
AMINO FUNCTIONAL SILICONE POLYMERS



Aminopropyl-terminated siloxanes are used to form a variety of block copolymers including polyamides,polyurethanes and polycarbonates. The generic structure of an aminopropyl terminated silicone fluid is represented below. These silicones are employed to produce silicone modified epoxy resins. They also have improved adhesion to both painted and unpainted metal surfaces allowing use in corrosion resistant coatings and polishes.

Amino functional silicones are reactive additives to both epoxy and urethane formulations.

Aminoalkyl functional T-structure polymers demonstrate the same range of chemical reactivity as the aminopropyl-terminated siloxanes (reactivity with epoxides,isocyanates, carboxylic acids, etc.). The branched polymers are more likely to find application as formulative additive rather than as prepolymers. Typical applications include detergent polishes, leather finishes, and as internal mold releasing agents.

http://www.fluorochemsilanes.co.uk/index.htm



Acrylic Polymers



Overview of Acrylic



Acrylic polymer, derived from the monomer methyl methacrylate (MMA), was first developed more than 60 years ago. Since then, formulations have extended the material's performance range, resulting in varying levels of melt flow, impact resistance, colorability, gamma recovery, and other controlled characteristics. General-purpose acrylic grades contain a comonomer, added during the polymerization process, to facilitate flow during injection molding and extrusion. Specialty grades are formulated to perform in applications requiring high impact strength and heat resistance. UV-light-transmitting formulations are also available, and are specified for certain critical diagnostic equipment in which even slight UV absorption or variation in material flow could be detrimental.

Acrylic offers light transmittance of 92%--theoretically the maximum obtainable--with particular clarity at lower wavelengths of 270 to 350 nm.

Acrylic is resistant to a wide range of chemicals including salts, bases, aliphatic hydrocarbons, fats and oils, most common gases and inorganic chemicals, dilute mineral and organic acids, and dilute and concentrated solutions of most alkalis. It is attacked by strong acids, chlorinated and aromatic hydrocarbons, ketones, alcohols, ethers, and esters.

http://www.devicelink.com/mpb/archive/96/01/001.html
 

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I've read that acryllics are harder and a little more brittle than silicone sealants-that may be one reason that they bead water so well
 
The words acrylic and polymer are synonomous and can be used interchangably. Marketing and advertising folks do so with abandon. Both words are as vague as words like plastic or elastic are.



Only when you get down into specific chemical formulations do you get into real differences. ABS and polyprop are both plastics, but very different. Same with acrylics and polymers.



As to why different companies chose different formulations, it's cost, marketing, effect, etc. All striving for what they think the market will want. There are differences. Some transmit light better than others. Some survive different conditions better than others. Some flow easier or smoother, some cure faster. The list goes on and on.
 
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