Approximate general chemical structure(CH3)3 SiO[SiH(CH3)O]x
Si(CH3)3 with x is approx. 45 - 90 and the molecular weight is
Poly (methyl hydrosiloxane) has a shelf life of at least12 months
when stored at 25 °C in the tightly closed original container. The
'Best use before end' date of each batch appears on the product
Storage beyond the date specified on the label does not necessarily
mean that the product is no longer usable. In this case however,
the properties required for the intended use must be checked for
quality assurance Reasons.
On heating for a short time in the absence of
moisture,decomposition only occurs above 300 °C. In the presence of
moisture, decomposition occurs at much lower temperatures together
with the release of hydrogen, a viscosity increase and gelation,
especially with thin films.
In the presence of certain catalysts H-siloxane may depolymerise
with formation of volatile hydrogencontaining cyclic siloxanes.
Solubility, reactivity and hazards
Can be mixed with many organic solvents of low or average polarity.
Can react with water, alcohols and proton active reagents of
similar strength in the presence of suitable catalysts (acids,
amines, metals,metallic salts) with hydrogen being released.
Particularly strong reactions can take place if only traces of
alkalinematerial are present in a homogeneous mixture. Direct
contact of H-siloxane with alkalis must be avoided, as well as the
influence of strong oxidizing agents.
In our experience, the self-ignition temperature of H-siloxane is
above 240 °C in the absence of reactive materials. Contact with
porous or fibrous surfaces, eg, asbestos or asbestos substitutes,
reduces the ignition temperature considerably. Foamy, resinous
reaction products resulting from partial decomposition can also
reduce the ignition temperature.
In the event that H-siloxane splashes onto or is soaked up by the
insulating material, the insulating material must be changed
immediately. Please see our safety data sheet.
|Appearance||colourless, clearliquid; mild odour|
|Volatility (5 g substance, 1 hour at 150 °C, cylindrical crucible,
30 mm diameter, 40 mm high)||less than 1.5% residue remains liquid|
|Density at 25 °C||approx. 1|
|Refractive index at 25 °C||approx. 1.39|
|Viscosity at 25 °C||approx. 15-25[mm²/s]|
|Hydrolysable chlorine (as HCI)||max. 5 [mg/kg]|
|Hydrogen content (released by alkali)||1.55-1.6%|
These figures are intended as a guide and should not be used in
Detailed safety information is contained in each material data
safety sheet, which can be obtained from our sales offices.