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Research on the preparation process of gradient plastic optical fiber rod

technical report research on the preparation process of gradient plastic optical fiber rod Chu Jiurong, Wen Xuming, Xu Chuanxiang, Wang Shoutai 21 School of electrical engineering, Xi'an Jiaotong University, Xi'an 7100, Shaanxi 2 School of chemical engineering, Shanghai Jiaotong University. Shanghai is a high refractive index doped monomer. It is found that in the early stage of the polymerization reaction, the mixture polymerizes in the environment of vacuum 7, 1, while the later reaction is carried out in a high-pressure atmosphere, and gradient plastic optical fiber rods without any vacuum bubbles and bubbles can be prepared

for example, in recent years, the gradient type 1 plastic optical fiber has been used in small photocopiers in optical fiber welcome and optical integrated circuits based on household materials; The bandwidth of gradient plastic optical fiber has reached the order of hundreds of megahertz, which is very important for fast data transmission, short-distance optical fiber communication and local area. The refractive index in the gradient 01 plastic optical fiber rod is parabolic distribution, and the refractive index is * high at the central axis of the plastic rod, and decreases along the radius direction according to the radius square. Glass and polymer at a certain radius are two kinds of materials we are familiar with, which are used in the field of optics. The former has good light transmittance and low light loss, but its shortcomings are fragility and high processing cost; Although the latter has high optical loss, it has excellent mechanical properties. Date of receipt: 2000 fund project State Key Laboratory of regional optical fiber communication and new optical communication system, Shanghai Jiaotong University. The fund project has many advantages, such as good flexibility, easy processing and low cost. There are many ways to prepare gradient plastic optical fiber rods. Compared with other methods, interfacial gel polymerization has the advantages of integral molding and simplicity. So we use the gel polymerization method 371, 3 pan et al. 31 found that defects can be reduced by increasing the content of initiator from 5 to 1 and chain transfer agent from to 101 inches, because the shrinkage of polymer is reduced by reducing the molecular weight of polymer, but increasing initiator and chain transfer agent will lead to impurities and light loss in plastic optical fiber rod, plus

pressure 1 et al. 21 found that the vacuum high temperature friction and wear experimental bubbles and bubbles formed by the interfacial gel polymerization method are the fruit of the gel effect in the polymerization reaction., In order to avoid the shortcomings of this gel effect, they adopt! 1. Gripping and cutting method to make Gu 01 plastic optical fiber press. Swelling gel polymerizing technology., In this technique, monomer solution is poured into the tube. The gel of the lower temperature clothing continuously changes from, 1 The inner wall of the pipe is facing the bamboo. You must pay attention to the central diffusion. Form gel 1 and then slowly react to polymerize. Thus forming; 1 observation optical fiber sample. After complete polymerization, there are no vacuum bubbles and bubbles in the 01 plastic optical fiber rod

in this paper, we mainly studied the effect of reaction conditions on the formation of vacuum bubbles or bubbles in 01 plastic optical fiber rod. For example, temperature and air melon we, in its mouth. 1 and Xian are two monomers. 30 and 4,1 were used as initiator and chain transfer agent respectively

201 the materials used in the preparation of plastic optical fiber rod mainly include methyl methacrylate PA elbow 99, Xudong chemical plant, bromobenzene 8899.5, Qingpu synthetic reagent plant, which mainly takes into account the benzoyl training 98 of the structure under the action of external force, Hubei University chemical plant, decamercaptan 0 elbow. Feipu synthetic reagent factory. The above drugs need to be improved and purified., Tube length 10.0; The inner and outer diameters are 5.0 and 8.0 respectively. In anshuguang plexiglass factory, the ends of each tube of 01 anode fiber rod are blocked with rubber plugs by the interface gel beam method. The monomer mixture includes 51 elbow people 1880.5180 and 0.0 mixture, which are polymerized at constant temperature for 24 hours, and then post cured under vacuum for 0 and 3 hours

first, the mixture monomer swells the inner wall of the tube and forms a gel phase on the inner wall of the tube. 13. At this time, due to the gel effect, the polymerization reaction speed in the gel phase is much faster than that in the liquid phase. Therefore, the polymerization reaction starts from the gel phase on the inner wall

with the thickening of gel phase, the concentration of monomer 88 gradually increased in the central area of the tube. Since the concentration at the beginning is ten times higher than that of 8, and the diffusion coefficient of 88 monomer 1 is ten times smaller, it is easier to diffuse into the gel phase than that of Xun Fen Shi at the beginning. As the reaction proceeds, the concentration of 81 in the central 1 domain reaction mixture increases, and the phase transition of gel increases. No

as the sentence goes, when the reaction of 1 beam 1 reaches the position just like the central axis, 1 Cape Qiao Dou optical fiber is formed

4 Conclusion 3 discuss the influence of 3.1 reaction temperature. First, put the samples in 556007, 8 and atmospheric oven to react 24 to prepare series, 1 plastic optical fiber rods. We found that with the increase of reaction temperature, the polymerization rate accelerated, and the gel phase soon appeared in the tube. With the reaction, the interval is prolonged. 551 sample, the tube is deformed and cracked. This is due to the slow reaction speed and the long-term swelling and softening of monomers. The strength of brother 1 tube is reduced; Other samples are not deformed, but there are more bubbles. 0 with the increase of reaction temperature, bubbles increase

we believe that there are two reasons for the generation of vacuum bubbles and or bubbles. First, during the heating process, the air dissolved in the reaction mixture and the gas generated by the decomposition of the initiator continue to overflow, but when the polymerization reaction reaches a certain degree, due to the large average molecular weight and the viscosity of the reactant. So that the gas can not overflow smoothly from the reactant. Thus in; 1. Bubbles are formed in the optical fiber rod; When the molecular weight of the polymer increases to a certain degree, the viscosity of the system increases, the reactants quickly polymerize, and the volume shrinks, while the liquid level of the system is difficult to drop and fill, resulting in the formation of vacuum bubbles

the experimental results are as follows: 1. Reduce the reaction temperature to make the polymerizing reaction proceed slowly and evenly. At the beginning, detect the air leakage completely, and at the later stage, make the gel phase fully shrink and backfill the gap generated by the volume shrinkage of monomer polymerization. In this way, 1 plastic optical fiber rod has fewer bubbles. The temperature should be kept at 607,1

3.2 effect of reaction pressure according to the theoretical analysis in Section 3.1, we believe that changing the reaction pressure can also reduce the bubble of one fiber rod. First, keep the sample in a fixed vacuum for a fixed time, then pressurize the sample and keep it until the polymerization is complete. In the early stage of the reaction, when the reaction mixture is polymerized under 70 ℃, the constant vacuum degree promotes the gas in the mixture to overflow completely; In the late stage of the reaction, the mixture polymerizes under high gas and is compressed. The detection system is easier to overcome the resistance caused by the viscosity of Yamagata, which makes the system backfill the voids generated by the volume shrinkage of monomer polymerization, making it difficult for the system to form vacuum bubbles. Using this process, we prepared a gradient bar with good performance. The gradient bar has no vacuum bubbles and deformation under light

the laser transmits the gradient rod. We observed that the forward path of the sine wave of light in the rod can be determined by the prepared rate gradient distribution formula, whose required emissivity distribution is 2 small

overflow reduces bubbles, but too low reaction temperature will cause deformation of plastic optical fiber rod. In the early stage of the reaction, put the reaction mixture under vacuum to promote the complete overflow of the gas in it; In the late stage of the reaction, keep the reaction temperature constant and pressurize the sample, so that the reaction mixture is compressed and it is difficult to form vacuum bubbles. Adopting this new technology is conducive to making bubble free and deformation free; 1 plastic optical fiber rod