I. Low-Temperature Flow Properties of Phenyl Silicone Fluid
Phenyl silicone fluid exhibits excellent low-temperature flow properties, primarily due to its unique molecular structure:

Low-Temperature Flow Range:
Low-phenyl silicone fluid maintains fluidity at -70°C
Phenyl-methyl silicone fluid has a freezing point of ≤-40°C
Operating temperature range extends down to -50°C

Viscosity Characteristics:
Viscosity changes minimally at low temperatures, maintaining stable flow properties.
The viscosity-temperature coefficient is low, so temperature has a relatively small effect on viscosity.

II. Key Factors Affecting Low-Temperature Flow
Phenyl Content:
Silicone fluids with lower phenyl content exhibit lower low-temperature torque and better fluidity.
Low-phenyl silicone fluids exhibit superior low-temperature performance compared to high-phenyl silicone fluids.

Environmental Conditions:
Viscosity changes more significantly under pressure.
Performance under vacuum is better than under atmospheric pressure.

III. Comparison of Low-Temperature Performance with Other Silicone Fluids
Performance Indicators: Phenyl silicone fluid Methyl silicone fluid Mineral oil
Minimum Operating Temperature: -70°C -40°C -20°C
Freezing Point: ≤-40°C -50°C Not applicable
Low-temperature viscosity stability: Excellent, Good, Poor
Temperature adaptability: -50°C to 250°C, -50°C to 200°C, -20°C to 150°C
Phenyl silicone fluids offer superior low-temperature performance compared to methyl silicone fluids, maintaining fluidity even at extremely low temperatures (-70°C).

IV. Modification Methods for Improving Low-Temperature Flow
Molecular Structure Optimization:
Control the molecular weight distribution to obtain products with a narrow molecular weight distribution (PDI ≈ 1.05).
Adjust the phenyl content to balance low-temperature flow and high-temperature performance.

Functional Group Modification:
Introducing polyether groups to improve low-temperature flow.
Using amino endcapping to improve low-temperature performance.
Epoxy modification can optimize low-temperature adhesion.

Process Improvement:
Using gradient polymerization technology to control molecular structure.
Precisely control reaction conditions (temperature, time, catalyst).

V. Application Recommendations
Low-Temperature Application Selection:
For extremely low-temperature environments (-70°C), low-phenyl silicone oils are preferred.
Phenylmethyl silicone oils can be selected for temperatures between -40°C and -50°C.

Performance Balance:
For applications requiring both high and low-temperature performance, products with a medium phenyl content can be selected.
For special applications, modified silicone oils (such as polyether modification) may be considered.

Precautions for Use:
Silicone oils with different phenyl content may not be compatible; compatibility must be considered.
Viscosity changes under pressure should be considered.