Silicone Oils Are Very Permeable to Gases
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Rhodorsil® Oils 47 Technical information Contents c Introduction - Nomenclature 3 c Applications of Rhodorsil® Oils 47 4 c Chemical Structure of Rhodorsil® Oils 47 5 c General properties of Rhodorsil® Oils 47 7 c Characteristics of Rhodorsil® Oils 47 8 c Physical properties of Rhodorsil® Oils 47 10 v Volatiles content v Heat stability v Flammability v Low temperature behavior v Viscosity – Rheology v Compressibility v Specific gravity v Refractive index v Surface tension v Specific heat v Thermal conductivity v Volume expansion v Sound transmission v Light transmission v Radiation withstand v Vapor pressure c Dielectric properties 20 c Chemical properties – Effects on materials 22 2 Introduction Rhodorsil® Oils 47 are polydimethylsiloxane oils and are a major category of silicones sold by Bluestar Silicones. They are constituted of linear molecular chains of varying lengths whose groups comprise alternating silicon and oxygen atoms (the Si-O-Si siloxane bond). The silicon atoms are saturated by methyl groups – CH3. Whilst the carbon chains of organic substances generally have low resistance to external influences, the stability of the Si-O bonds is basically comparable to that of inert mineral silicates. Nomenclature The Rhodorsil® Oils 47 nomenclatures are constituted: the number 47 a number References of the letter V Bluestar Silicones indicating the viscosity Examples: to indicate viscosity polydimethylsiloxane level in mm2/s at 25 °C - Oil 47 V 100 is an oils oil with a viscosity of 100 mm2/s. - Oil 47 V 1,000,000 is an oil of viscosity 1,000,000 mm2/s The Rhodorsil® Oils 47 range covers a viscosity range of 1 to 1,000,000 mm2/s. 47 V 100 3 Applications of Rhodorsil® Oils 47 There are many different applications of these products. For information, we can mention a few of them such as: c Plasticizers for silicone elastomers (sealants, RTV, etc.) c Foam control agents c Additives for Styrene-Butadiene foams c Release and demolding agents c Lubricants c Textiles softeners c Sewing thread lubricant c Emulsions for off-set printing c Components for household products and polishes for wood, leather, metals, floors, cars c Usage in cosmetics, shampoos, creams c Lubrication of medical equipment c Medical uses, excipient, active ingredient c Treatment and water repellency of fillers c Dielectric fluids c Hydraulic, damping and gearbox fluids c Heating fluids (up to temperatures of around 200 °C) c Cooling fluids 4 Chemical structure of Rhodorsil® Oils 47 They have the following general formula The viscosity of these oils increases with their polymerization degree, which corresponds to value of the “n” index as shown in graph N°1 CH3 CH3 CH3 (viscosity of Rhodorsil® Oils 47 according to degree of polymerization). CH3 – Si – O – Si – O – Si – CH3 ® CH CH CH Rhodorsil Oils 47 are still liquid at ambiant 3 3 n 3 temperatures for a value of the “n” index of around 2,000. For greater values these oils gradually tend to gums. All of these oils are mixtures of polysiloxane chains that are quite regularly distributed around the average molecular mass. For example, graph N°2 shows a distribution of molecular masses in a Rhodorsil® Oil 47 of viscosity 10 mm2/s, obtained by gel permeation chromatography. The average molecular mass increases as a function of the degree of polycondensation “n”, therefore is a function of their viscosity as shown in table N°1 (molecular mass of Rhodorsil® Oils 47 as a function of viscosity). Table 1 Molecular mass of Rhodorsil® Oils 47 Oils Molecular mass (g.mol-1) 47 V 5 900 to 1 100 47 V 10 1 500 to 1 800 47 V 20 2 800 to 3 200 47 V 50 7 000 to 8 000 47 V 100 10 000 to 12 000 47 V 300 18 000 to 20 000 47 V 500 28 000 to 30 000 47 V 1 000 38 000 to 40 000 47 V 12 500 about 80 000 47 V 60 000 about 125 000 47 V 100 000 about 145 000 5 Graph 1 Viscosity of polydimethylsiloxane oils as a function of degree of polymerization “n” Viscosity at 25 °C (mm2/s) Comment: the straight part of the graph 100 000 corresponds to the A.J. BARRY relation for molecular masses > 2500: 0,5 log n cSt = 1,00 + 0,0123 M 10 000 1 000 100 10 1 0 5 10 20 30 40 162 2 000 5 000 10 000 50 000 100 000 Molecular mass (calculated) Graph 2 Molecular mass by EDC* of a polydimethylsiloxane oil of viscosity 10 mm2/s Distribution of molecular masses Average molecular mass In weight Mp ≈ 1560 g/mol In number Mn ≈ 1210 g/mol Polydispersion index Mp/Mn = 1,29 N.B.: Mn : Average mass by number ∑(niMi) ∑(ci) Mn = = ∑(ni) ci ∑(Mi) Where ni and ci respectively represent the number and concentration by weight of each molecule of mass Mi Mp : average mass by weight ∑(niMi2) ∑(ciMi) Mp = = ∑(niMi) ∑(ci) The sum is carried out from i = 1 9 500 1 230 390 ∑ (monomer) to i = ∞, i representing the degree Molecular mass of polymerization (number of groups) Polydispersion index * Exclusion Diffusion Chromatograph The ratio Mp/Mn is equal to 1 for strictly monodisperse polymers 6 General properties of Rhodorsil® Oils 47 The polysiloxane chains very flexible due to the wide range in value of possible angles in the Si-O-Si group; this flexibility allows lateral groups to occupy the space in an exceptional number of positions. In addition, the rotary freedom of the methyl group around the Si-C bond is maintained even at extremely low temperatures. The macromolecular chains will be arranged in loosely configured spirals with a high amount of internal free space leading to low intermolecular forces and very low interaction between chains. c This macromolecular chain structure gives c These properties open up a very wide Rhodorsil® Oils 47 a very specific set of range of applications: characteristics and features: v demolding or release agents, v low pour point (around -50 °C), v hydraulic, heat transfer and dielectric fluids, v very low glass transition temperature v lubricants, (around -125 °C), v foam control agents, v low viscous pouring activation energy, v active components in maintenance product v low viscosity (compared to carbon-chain formulations, organic products of the same length), v active components in cosmetic, v low variation in viscosity as a function pharmaceutical or food preparations of temperature, (food contact). v low surface tension, v high compressibility, N.B.: in cosmetic, pharmaceuticals and food Rhodorsil® Oils 47 v excellent intensive and prolonged shear contact applications, strength, of controlled are sold under the names of Mirasil v low and high temperature resistance, DM, Silbione DM GMP and Silbione 70047. v resistance to oxidation and hydrolysis, v lack of ageing by atmospheric agents These oils are discribed in separate documentation. (oxygen-ozone-water-light-UV), v chemically inert (no risk of corrosion), v very limited combustibility, v non miscibility with many organic products. 7 Characteristics of Rhodorsil® Oils 47 The table on page 9 gives the characteristics of Rhodorsil® Oils 47. The values given are average values and not specifications. At the start of the table is oil 41 V 0.65 which can be assimilated to hexamethyldisiloxane a Rhodorsil® Oils 47 with the index “n” equal to 0. The formula is as follows: CH3 CH3 (CH3)3 – Si – O – Si – (CH3)3 CH3 CH3 47 V 5000 Oils 41 V 0.65 47 V 3 47 V 5 47 V 20 47 V 50 47 V 100 47 V 350 47 V 500 47 V 1000 to Characteristics V 600000 Viscosity at 25 °C (mm2/s) 0,65 3 5 20 50 100 350 500 1000 5000 to 600000 Specific gravity at 25 °C 0,760 0,890 0,910 0,950 0,959 0,965 0,970 0,970 0,970 0,973 Flashpoint at °C - 4 75 120 240 280 > 300 > 300 > 300 > 300 > 300 (closed cup) Freezing point at °C - 67 - 80 - 65 - 60 - 55 - 55 - 50 - 50 - 50 - 45 Refractive index at 25 °C 1,375 1,395 1,397 1,400 1,402 1,403 1,403 1,403 1,403 1,404 Surface tension (mN/m) 15,9 18,9 19,7 20,6 20,7 20,9 21,1 21,1 21,1 21,1 Vapor pressure at 200 °C NA NA NA 1,33 1,33 1,33 1,33 1,33 1,33 1,33 (Pascal) Expansion coefficient between 1,34.10-3 1,16.10-3 1,15.10-3 1,07.10-3 1,05.10-3 9,45.10-4 9,45.10-4 9,45.10-4 9,45.10-4 9,45.10-4 25 °C and 100 °C (cm3/cm3. °C) Specific heat (Joules/g, °C) 2,9 NA NA 1,63 1,46 1,46 1,46 1,46 1,46 1,50 Thermal conductivity 0,10 0,11 0,12 0,14 0,16 0,16 0,16 0,16 0,16 0,16 (Watt/m. °C) Viscosity/temperature 0,31NA 0,55 0,59 0,59 0,60 0,62 0,62 0,62 0,62 coefficient Dielectric strength 14 14 14 14 15 16 16 16 16 18 (kV/mm) Dielectric constant at 25 °C 2,18 2,50 2,59 2,68 2,80 2,80 2,80 2,80 2,80 2,80 between 0.5 and 100 kHz Loss angle at 25 °C 0,5 kHz NA 2.10-5 4.10-5 2.10-4 2.10-4 2.10-4 2.10-4 2.10-4 2.10-4 100 kHz 1.10-5 1.10-5 1.10-5 1.10-4 1.10-4 1.10-4 1.10-4 1.10-4 1.10-4 Volume resistivity at 25 °C NA 1.1015 1.1015 1.1014 1.1014 1.1015 1.1015 1.1015 1.1015 1.1015 (ohm/cm) (NA: not available) Notes: v Oil 604 V 50 is a version of 47 V 50 oil, v The percentage of silicon in Rhodorsil® Oils 47 manufactured specially for dielectric uses.