Ultraviolet cross-linked polyphosphazene, preparation method, composite coating low-temperature temperature measurement optical fiber and preparation method

Abstract

The invention discloses ultraviolet cross-linked polyphosphazene, a preparation method, a composite coating low-temperature temperature measurement optical fiber and a preparation method, and belongsto the technical field of optical fiber manufacturing. The preparation method of the composite coating low-temperature temperature measurement optical fiber comprises the following steps: S1, dispersing ultraviolet cross-linked polyphosphazene in a tetrahydrofuran solvent, mixing with an ultraviolet initiator and a polymerization aid, and fully stirring for defoaming to obtain a coating solution;s2, putting the coating liquid into a coating mold, enabling the bare optical fiber to penetrate through the coating mold, carrying the coating liquid, and enabling the bare optical fiber to pass through an ultraviolet curing furnace under the protection of nitrogen; performing drying through a blast drying oven to form a polyphosphazene elastic coating on the surface of the bare optical fiber; and S3, enabling the optical fiber with the polyphosphazene elastic coating to pass through a secondary coating mold containing low-melting-point molten metal, and coating the surface of the polyphosphazene elastic coating with a metal melt to finally obtain the composite coating low-temperature temperature measurement optical fiber. According to the invention, the defects of cracking and poor interface bonding force of the polymer coating in the traditional composite coating optical fiber in the metal melting coating process can be overcome.

Description

technical field [0001] The invention relates to a technology in the field of optical fiber manufacturing, in particular to an ultraviolet light cross-linked polyphosphazene, a preparation method, a composite coated low-temperature temperature-measuring optical fiber, and a preparation method. Background technique [0002] Superconducting equipment has the characteristics of low loss and high current carrying capacity, and has attracted extensive attention from the power industry. However, superconducting devices have always faced the risk of quench failure. Due to the thermal effect of the resistance after quenching, the heat in the local area will accumulate rapidly and the temperature will rise. If it cannot be found in time and dealt with accordingly, the thermal effect accumulation will cause the cooling medium in the confined space to boil, the strip will burn, and even lead to more serious problems. risks of. Therefore, monitoring the temperature changes in various p...

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Problems solved by technology

[0003] At present, the temperature measurement and control of superconducting equipment mainly faces two problems: First, most high-temperature superconducting equipment works at the temperature of liquid nitrogen, and the sensors for temperature monitoring at low temperatures are mostly electrical signal sensors such as thermal resistors and thermocouples. Conductive equipment often operates in high-voltage, high-current, strong magnetic field and other working conditions. The electrical signal sensor is greatly disturbed by the electromagnetic field, and the test accuracy will be seriously affected. It is difficult to meet the temperature measurement requirements of high-temperature superconducting equipment.

[0005] However, one of the challenges that the Rayleigh scattering-based distributed optical fiber sensing technology must overcome is the high temperature sensitivity of the measuring fiber at low temperature.

Early studies have shown that coating polymers with high thermal expansion coefficients (polyimide, polymethyl acrylate) on the surface of bare optical fibers can improve the temperature sensitivity coefficient of optical fibers in low temperature environments to a certain extent, but the improvement effect is not significant

In recent years, metal (such as Sn) coatings have been coated on the surface of optical fibers coated with polymethyl acrylate coatings by melting method, making full use of the synergistic effect of Young's modulus (E) and coefficient of thermal expansion (CTE) of composite coatings. , the sensitivity of the prepared composite coated optical fiber is improved at low temperature, but due to the high temperature process of melting and coating metal, the inner polymethylacrylate coating will be pyrolyzed, resulting in "bare optical fiber and polymethylacrylate coating" The interfacial bonding between the "layers" and "polymethyl acrylate coating and metal coating" is significantly reduced, which eventually leads to the degradation or loss of the low temperature sensitivity of the optical fiber

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