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Polydimethylsiloxane (PDMS) - Surfactant, reduces sticking to the bowl and aeration during mixing. Allows for mixing at higher speeds. Improves particle wetting.
Binding Agents
Binding agents form a bond between the surface of Ammonium Perchlorate particles and the polymer matrix, embedding the particles strongly in the propellant web. This slightly slows burn rate and increases hardness.
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Melamine - Used when using HTPB as a liner material
Zinc Borate - improves char layer formation