POSS® (Polyhedral Oligomeric Silsesquioxane) Molecules
POSS is an abbreviation for polyhedral oligomeric silsesquioxanes.
Silsesquioxane Cage Structure- like hybrid molecules of silicon and oxygen with similarities to both silica and silicone. When mixed with virtually any ordinary polymer, they bond to the organic molecules and to one another, forming large chains that weave through the polymer. The result is a nanostructured organic- inorganic hybrid polymer. The POSS chains act like nanoscale reinforcing fibers, producing extraordinary gains in heat resistance.
Chemical Name: Polyhedral oligomeric silsesquioxane
POSS Technology is derived from a continually evolving class of compounds closely related to silicones through both composition and a shared system of nomenclature. POSS chemical technology has two unique features:
(1) The chemical composition is a hybrid, intermediate (RSiO1.5) between that of silica (SiO2) and silicone (R2SiO).
2) POSS molecules are physically large with respect to polymer dimensions and nearly equivalent in size to most polymer segments and coils.
POSS Polymer Systems:
1) POSS molecules can be thought of as the smallest particles of silica possible. However unlike silica or modified clays, each POSS molecule contains covalently bonded reactive functionalities suitable for polymerization or grafting
POSS monomers to polymer chains. Each POSS molecule contains nonreactive organic functionalities for solubility and compatibility of the POSS segments with the various polymer systems.
2) The chemical diversity of POSS technology is very broad and a large number of POSS monomers and polymers are currently available or undergoing development.
3) POSS chemical technology is easy to use with monomers available in both liquid and solid form and they are soluble in most common solvents. Hence, POSS technology can be used in the same manner as common organics, in either monomer or polymeric (resin) form. POSS chemical feedstocks can be added to nearly all polymer types (glassy, elastomeric, rubbery, semicrystalline and crystalline) and compositions.
4) Enhancements in the physical properties of polymers incorporating POSS segments result from POSS’s ability to control the motions of the chains while still maintaining the processability and mechanical properties of the base resin.
This is a direct result of POSS’s nanoscopic size and its relationship to polymer dimensions.
Property Enhancements Via POSS:
1) Benefits Through POSS Incorporation- Use of POSS segments in plastics results in enhancement of the physical properties of the compositions.
2) Enhanced Fire Retardation- Compared to common fire retarded plastics, polymers containing POSS show delayed combustion and major reductions in heat evolution.
3) Higher Use Temperature- POSS’s ability to control chain motion results in usage temperature enhancement of nearly all types of thermoplastics and thermoset polymers. In many cases the glass transition can be increased by 100-200°C or even up to the decomposition temperature of the polymer.
4) Lightweight- Use of POSS additives often eliminates the need to use common (dense) fillers such as silica. Depending on loading level, bulk density reductions of up to 10% have been observed with viscosity reductions of up to 24% relative to silica.
5) Improved Mechanical Properties- POSS incorporation increases modulus and hardness while maintaining the stress and strain characteristics of the base resin. Additionally since POSS is a chemical nanotechnology, processing and moldability is maintained.
6) Diversity- Because of its chemical nature POSS technology can be tailored to meet resin and consumer compatability needs.
7) Beat Your Competitors Patents- Since POSS is a new chemical feedstock technology it can be used to upgrade the properties of existing patented compositions while enabling the patentability of the new material composition.
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Heat/abrasion resistant paints and coatings
Mechanical property modifiers
Space resistant resins
Resins and elastomers
Ablative materials (nozzles, insulations etc.)
Precursors to glassy or ceramic matrices
1) Jars, pails, and drums.
2) For further information on packaging options contact READE. Packaging may vary according to HAZMAT and TSCA (SARA Title III) status.
POSS Typical Characteristics:
1) Heat resistance
2) Extends resin temperature ranges
3) Makes resins stronger; lighter, and more durable.
4) Boosts oxidation resistance while lowering thermal conductivitry, flammability, and heat evolution.
POSS TSCA (SARA Title III) Status: Unknown. For further information please call the E.P.A. at +1.202.554.1404. A Report from NIOSH- Visit This External CDC Link
POSS® Trademark Acknowledgement: POSS® is a registered trademark of Hybrid Plastics, Inc. READE is an informal distributor of the POSS chemicals