Pushing the Limits: Polyimide vs Acrylate: Why Polyimide is Essential at 300℃

Company Name	Beijing Dacheng Yongsheng Technology Co., Ltd. (DCYS)
Product Brand	OFSCN®
Product Model	300℃SM Polyimide Optical Fiber (Maximum Operating Temperature 350℃)

Introduction: The Coating is the Fiber's "Lifeline"

In fiber optic applications, the coating material is the key factor determining environmental adaptability. When facing extreme temperatures of 300℃or higher, the fiber's "outer layer"—the coating—directly dictates signal stability and the fiber's lifespan. There is a fundamental performance gap between traditional Acrylate coated fibers and specialized Polyimide (PI) fibers.

I. Acrylate: The "Standard Model" That Stops at Low-Mid Temperatures

Acrylate is the most commonly used coating material for standard communication fibers, offering advantages like easy stripping and good flexibility. However, its thermal stability has a fatal flaw:

• Low Thermal Decomposition Threshold: The maximum operating temperature for traditional acrylate coated fibers is generally limited to between +85℃and +125℃.
• High-Temperature Degradation: Once the ambient temperature exceeds its limit, the acrylate coating will rapidly undergo carbonization, cracking, and delamination. This degradation not only reduces the fiber's mechanical strength but, more critically, causes a sharp increase in micro-bending loss due to coating shrinkage and stress, leading to signal attenuation and the complete failure of the communication or sensing link.

Conclusion: For any application requiring continuous and stable operation at 300℃, choosing an acrylate coated fiber is unacceptable, as it cannot provide long-term reliability.

II. Polyimide (PI): The "Performance King" Engineered for Extreme Environments

The OFSCN® 350℃Polyimide Fiber, utilizing a PI coating, completely breaks through temperature limitations. PI is a high-performance polymer hailed as the ideal material for solving high-temperature challenges:

1. Breakthrough Temperature Limit:

The PI coating boasts an extremely high thermal decomposition temperature, allowing the fiber to operate stably at an extreme high temperature of +350℃, an increase of over200℃} compared to the limit of standard fibers. Concurrently, it offers excellent resistance to ultra-low temperatures, capable of withstanding the severe cold of up to -200℃.

2. Exceptional Stability Across Wide Temperature Ranges:

The PI coating features a favorable thermal expansion coefficient match with the fiber's silica material. This means that during severe Temperature Cycling (TCC) from -200℃to +350℃, the fiber will not experience attenuation spikes or coating cracking due to thermal stress differences, ensuring signal integrity and long-term low loss.

3. Superior Chemical and Mechanical Protection:

Compared to acrylate, the PI coating maintains extremely low gas evolution and mass loss at high temperatures and possesses excellent chemical corrosion resistance. Paired with a tensile strength of up to100 kpsi, it reliably guarantees the mechanical fatigue life of the fiber in corrosive environments with high temperatures and high pressures, such as oil and gas downhole operations and chemical pipelines.

III. Value-Added Guarantee: The Importance of the Carbon Seal Option

For industries sensitive to hydrogen and moisture, such as oil and gas and petrochemicals, we strongly recommend the PI + Carbon Coating (Carbon Seal) option for OFSCN® fiber. The carbon seal layer is particularly crucial in a 300℃high-temperature environment:

• Eliminating Hydrogen Darkening: The carbon seal layer forms a dense barrier outside the fiber cladding, effectively preventing the diffusion and penetration of small hydrogen molecules into the core at high temperatures. This fundamentally eliminates hydrogen darkening (i.e., increased fiber attenuation) caused by high temperatures, greatly extending the service life of the fiber in hydrogen-containing environments.

Conclusion: The Only Choice for Harsh Environments

When your application environment exceeds +125℃, especially when demanding extreme conditions above 300℃, the OFSCN® 350℃Polyimide Optical Fiber is the only correct choice for achieving long-term system reliability. Choosing PI means choosing performance, and more importantly, choosing sustained, stable operation in harsh environments.

Company Name	Beijing Dacheng Yongsheng Technology Co., Ltd. (DCYS)
Product Brand	OFSCN®
Product Model	300℃SM Polyimide Optical Fiber (Maximum Operating Temperature 350℃)
Product Details Page	https://www.ofscn.org/optical-fibers/polyimide-coated-sm-300.html

Contact us immediately to secure your investment in extreme environments with PI fiber!

All data in this document are typical values. Specific specifications and test reports are subject to the final supply contract and product data sheet.