Excellent performance and high-end application of phenyl silicone oil
(Complete technical article)
1. Introduction
Phenyl Silicone Oil (PSO) is an organic silicon liquid obtained by partially or completely replacing methyl (- CH3) with phenyl (- C ₆ H ₅) on the main or side chains of polydimethylsiloxane (PDMS). Due to the large π - conjugated structure of the benzene ring, the rigidity, thermal stability, and antioxidant capacity of Si-O chains are significantly improved. The working temperature range of PSO can be extended from -60 ° C to over+300 ° C, making it the "ultimate solution" for extreme lubrication, heat transfer, and insulation conditions.
2、 Structure performance relationship
Phenyl content and properties
Low phenyl group (5-15 mol%): Low viscosity temperature coefficient, excellent low-temperature flowability, used for aerospace hydraulic oil.
• Phenyl group (20-40 mol%): Comprehensive balance, balancing high temperature stability and low temperature pumpability, is the mainstream choice for high-end compressor lubricants.
• High phenyl group (>50 mol%): The glass transition temperature Tg increases by 40-60 ° C, and the dielectric constant rises to 3.3-3.5, making it suitable for high-temperature electrical insulation applications.
Phenyl position effect
• Main chain end phenyl group: antioxidant capacity increased, shear stability slightly decreased.
Side chain phenyl: viscosity coefficient ↑, lubricating film thickness ↑, more suitable for heavy-duty gears.
3、 Core performance data
table
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Comparison of Testing Methods for Typical Index Values (Phenyl PSO) in PDMS
Flash point 310 ° C ASTM D92+70 ° C
Thermal decomposition starting temperature 420 ° C TGA-10 ° C/min+80 ° C
Dielectric strength 45 kV/mm ASTM D877+30%
Volume resistivity 1.5 × 10 ¹⁵Ω· cm ASTM D257 of the same magnitude
Evaporation loss (204 ° C, 6.5 h)<2 wt% ASTM D972-80%
4、 High end application cases
aerospace
Lubrication of turbine engine bearings: After continuous operation at 250 ° C for 2000 hours, the acid value only increased by 0.1 mgKOH/g, while traditional ester oils have already gelatinized.
Satellite attitude control fuel valve: Low phenyl PSO serves as the hydraulic medium, maintaining a viscosity of<1000 cP at -55 ° C to ensure rapid response.
Electronic and Electrical Appliances
High power LED packaging: high phenyl PSO is blended with fluorescent powder, with a refractive index of 1.56, improving light extraction efficiency by 8%.
5G base station RF coaxial connector: as a dielectric filling oil, reduces insertion loss by 0.05 dB@18  GHz。
High end lubricating oil
Vacuum pump oil: maximum total pressure<5 × 10 ⁻⁵ Pa, oil return rate<0.1 mg/(cm ² · h), meeting the requirements of EUV lithography vacuum system.
Precision gyroscope float: specific gravity 1.07, can accurately match the density of beryllium float, temperature drift<0.02 °/h.