Method for preparing gradient plastic fibers by continuous reaction coextrusion thermal diffusion method

Abstract

The invention relates to a method for preparing gradient plastic fibers through a continuous reaction coextrusion thermal diffusion method, which comprises the following steps: adding an inert dopant of which the refractive index is higher than that of a main monomer into the main monomer as a sandwich layer material; and polymerizing a fiber sandwich layer fusant of which the light transmittanceis more than 93 percent in a polymerization device, sending the fusant into a sandwich layer area in a double-layer coextrusion die, and simultaneously, using a polymer polymerized from a material having same components with the main monomer as a cladding material which is extruded into the double-layer coextrusion die, wherein the fiber sandwich layer fusant and the cladding material are fused and compounded into double-layer fibers with round cross-sections, the fibers are extruded out of the double-layer coextrusion die, then pass through a temperature control diffusion forming area and stay in the forming area for 10 to 20 minutes to form the gradient plastic fibers, and the main monomer material is a polymer of which the light transmittance is over 90 percent. The method has the advantages of continuous and stable mass production, high production efficiency, simple and convenient production, low production cost and excellent product performance, and can be particularly applied tolarge-scale production of the gradient plastic fibers of which the loss is less than 0.2 dB per meter and the bandwidth is over 1 GHz.100 m.

Description

Technical field: [0001] The invention belongs to the field of optical information transmission and new materials, and relates to a method for preparing plastic optical fibers with gradient refractive index distribution through a continuous bulk polymerization co-extrusion diffusion method. Background technique: [0002] According to the distribution of refractive index, plastic optical fiber can be divided into three types: step type (SI type), multi-step type (MI type) and gradient type (GI type, gradient type), such as figure 1 shown. [0003] The bandwidth of step-type plastic optical fiber is usually 10-100MHz·100m, and it is used in sensor jumpers and decorative lighting fields that do not require high bandwidth. The bandwidth of gradient plastic optical fiber is usually ≥1GHz·100m, which is used in information fields such as fiber-to-the-home LAN with high bandwidth requirements and industrial control LAN with large data transmission volume. The bandwidth of multi-or...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: 1) it is difficult to fundamentally eliminate air bubbles; 2) it is difficult to prepare large-diameter, long qualified gradient polymer optical fiber rods; 3) the polymerization reaction time is long, the production efficiency is low, and there is no practical industrial application value

The disadvantage of this method is that 1) the industrialized production cost of adopting the fluorination process is higher; 2) the fluorination time is long and the production efficiency is low

The disadvantages of this method are: 1) It belongs to the multi-level plastic optical fiber, the refractive index distribution is stepped, and the bandwidth is not as high as the gradient plastic optical fiber; 2) The fewer the layers, the lower the bandwidth; 3) Because the thickness of each layer is usually Only 5-30μm, so the more layers, the more difficult the control, the lower the yield, and it is difficult to stably produce qualified high-bandwidth plastic optical fibers in batches

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