Specific Principles and Characteristics

1. Principle of molecular motion: When temperature rises, the thermal motion of dimethyl silicone oil’s molecular chains intensifies. Intermolecular friction and entanglement weaken, leading to enhanced overall fluidity and a macroscopic decrease in viscosity.
2. Temperature sensitivity: Dimethyl silicone oil’s viscosity is quite sensitive to temperature changes, following the rule of "higher temperature = lower viscosity." For example:
   • A dimethyl silicone oil with a viscosity of 1000 cst at 20℃ may drop to approximately 100 cst at 100℃.
   • Low-viscosity silicone oil (e.g., 20 cst) is less temperature-sensitive than high-viscosity silicone oil (e.g., 100,000 cst).
3. Newtonian fluid characteristics: Dimethyl silicone oil is close to a Newtonian fluid. Its viscosity does not change with shear rate at a constant temperature, but temperature changes directly alter its base viscosity value.

Impact on Practical Applications

• In industrial use, if stable viscosity is required, ambient temperature must be controlled (25℃ is typically the standard test temperature).
• For high-temperature working conditions (e.g., mold release, lubricating oil applications), select higher-viscosity silicone oil to ensure lubrication/release effectiveness. This avoids failure due to excessively low viscosity caused by temperature rise.

Summary

1. Dimethyl silicone oil’s viscosity will obviously decrease (thin out) when heated — temperature is a key factor affecting its viscosity.
2. High-viscosity silicone oil’s viscosity is more significantly affected by temperature changes.
3. In practical applications, choose a silicone oil with suitable viscosity based on the working condition temperature.
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