渐变型聚合物光纤共挤扩散过程工艺参数的正交优化研究

基于相关数学模型，对共挤扩散过程的芯皮层体积流量比、总体积流量、扩散温度等工艺参数进行了正交优化试验，利用计算流体动力学软件FLUENT求解出模拟试验结果。为了合理方便地评价试验结果的优劣，提出了一个评判标准，较好地评价了模拟试验所得光纤折射率分布曲线与抛物线型折射率分布曲线的吻合程度。本研究中，该值约在10^-4～10^-2之间，其值越小说明两者吻合程度越好。正交优化分析表明，芯皮层体积流量比、总体积流量是影响光纤折射率分布的主要工艺参数，当两者分别在1：1、6．9cm^3／min附近时，对应的模拟试验所得光纤折射率分布最接近抛物线型分布。     

渐变型折射率钇铝硅酸盐玻璃光纤的制备

使用钇铝石榴石(YAG)单晶芯棒和光学级石英管构成预制棒,基于管中熔体共拉法制备了钇铝硅酸盐(YAS)玻璃光纤,研究了拉丝过程中由于元素迁移形成的光纤纤芯附近的元素分布和折射率分布。结果表明,使用管中熔体共拉法制备的光纤为折射率渐变型光纤,芯包层折射率差Δn从预制棒的0.380变为光纤中的0.057。所获得的YAS光纤理论最大数值孔径为0.41,具有较高的耦合效率。这种光纤有潜力应用于自聚焦效应相关的领域。     

光学玻璃纤维折射率截面的测量

在研究光学玻璃纤维材料的制备、改进和发展以及设计新型的光学玻璃纤维材料时,测量它的折射率截面(分布)有重要的意义。本文着重介绍应用两种光学干涉测量方法进行光纤折射率截面的测试,即双光束干涉法和干涉-剪像法。在叙述了所用的设备、原理和测量步骤之后,给出了若干拉丝棒和个别光纤样品折射率截面曲线的测试结果,并略加讨论。     

耐热性有机高分子的性能研究及其在塑料光纤中的应用

本文以N－环乙基马来酰亚胺（CHMI）和甲基丙烯酸甲酯（MMA）共聚得耐热性透明材料，讨论了共聚产物的透明性和玻璃化温度与CHMI含量的关系。以上述材料为基础，应用界面凝胶法制备光纤预制棒，在探讨了CHMI和PCHMI的折射率的基础上，分析并测试了光纤预制棒的折射率分布，最后拉制成塑料光纤（GI－POF）并测试了光纤的光透射窗口。     

光导纤维的制备工艺

根据光线从光密介质（高折射率）射入光疏介质（低折射率）时在界面处向光密介质内反射的原理,光线通过光纤时经反复反射向前输送。由于制造方法的不同。全反射型光导纤维又分为多模光纤和单模光纤。塑料光纤制备的工艺流程：单体精制→聚合→纺丝→包层和拉伸→光缆加工。     

N-异丙基马来酰亚胺在渐变型耐温塑料光纤中的应用

以N-异丙基马来酰亚胺(IPMI)与甲基丙烯酸甲酯(MMA)的共聚物为实验基本原料,探究了IPMI含量对其聚合物的透明度和力学性能的影响,同时初步探讨了制备渐变型耐温塑料光纤的方法。通过元素分析证明N-异丙基马来酰亚胺在光纤预制棒的折射率分布规律,进一步测定以IPMI为基本材料制成的塑料光纤预制棒的折光率分布规律曲线,通过此次实验可以确定IPMI能很好地提高塑料光纤的耐温性。因此IPMI/MMA共聚物是制备渐变型耐温塑料光纤的良好原材料。     

界面-凝胶法制备渐变型塑料光纤预制棒配方的研究

通过研究POF损耗、引发剂用量对预制棒气泡的影响、以及对预制棒玻璃化转变温度Tg的测量、掺杂剂对折射率分布的影响等方面,得出制备预制棒的最佳原材料配比是引发科AIBN质量分数为0．15％,链转移剂硫醇摩尔浓度为0．010 mol／L。     

注塑成型光学制品折射率分层模拟与实验研究

与玻璃制造光学制品相比,高分子注塑光学制品具有质量轻、易加工、抗冲击性好等优点,在航空航天、精密透镜等高端领域得到广泛应用。然而受注塑过程复杂压力场、温度场的耦合作用,注塑透明制品折射率通常呈非均匀的分布,存在角偏差、光畸变等光学缺陷。因此,开展注塑工艺对其折射行为影响的模拟与实验研究,对实现折射率可控光学制品的成型具有重要意义。基于Hele Shaw注塑理论和Lorentz Lorenz物理光学理论,构建了注塑光学制品厚度方向折射行为分层预测模型,开发了相关模拟程序,基于自主研发的注塑模软件ZMold实现了注塑过程与折射率分布的一体化模拟。以聚碳酸酯注塑平板件为例,利用Brewster法对折射率模拟结果进行了验证。该方法成功应用到神舟系列航天舱外服面窗的研制。     

注塑成型光学制品折射率分层模拟与实验研究

与玻璃制造光学制品相比,高分子注塑光学制品具有质量轻、易加工、抗冲击性好等优点,在航空航天、精密透镜等高端领域得到广泛应用。然而受注塑过程复杂压力场、温度场的耦合作用,注塑透明制品折射率通常呈非均匀的分布,存在角偏差、光畸变等光学缺陷。因此,开展注塑工艺对其折射行为影响的模拟与实验研究,对实现折射率可控光学制品的成型具有重要意义。基于Hele Shaw注塑理论和Lorentz Lorenz物理光学理论,构建了注塑光学制品厚度方向折射行为分层预测模型,开发了相关模拟程序,基于自主研发的注塑模软件Z-Mold实现了注塑过程与折射率分布的一体化模拟。以聚碳酸酯注塑平板件为例,利用Brewster法对折射率模拟结果进行了验证。该方法成功应用到神舟系列航天舱外服面窗的研制。     

一种制备梯度型聚合物光纤预制棒的新方法及其折射率分布的调控

针对现有制备方法对梯度型聚合物光纤（GI—POF）折射率分布（RID，直接影响带宽）的调控能力有限的特点，提出了一种制备GI-POF预制棒的新方法，可以实现对RID的自如调控。通过理论计算阐述了这种方法制备预制棒时RID的调控方法。结果表明，制备预制棒时所用物料的层数越多，预制棒的RID越接近理想分布，最终实际所得预制棒的RID与理论计算十分一致。     

Stability of high‐bandwidth graded‐index polymer optical fiber

The properties of poly(methyl methacrylate) (PMMA)‐based graded‐index polymer optical fiber (GI POF), including the thermal stability, thermal humidity, and mechanical properties, were studied for polymer optical fiber research and applications. The glass‐transition temperature of the fiber core was 103°C in the presence of the dopant, which was close to that of the PMMA matrix without the dopant. A special refractive‐index profile derived from the distribution of the dopant was stable at 60°C. Moreover, GI POF exhibited good mechanical properties. The excellent performance indicated that GI POF could be applied not only for indoor use but also for outdoor use. However, PMMA‐based GI POF exhibited poor hot‐water/humidity resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2330–2334, 2004     

Preparation of heat‐resistant gradient‐index polymer optical fiber rods based on poly(N‐isopropylmaleimide‐co‐methyl methacrylate)

Using the interfacial gel polymerization method, a heat‐resistant gradient‐index polymer optical fiber (GI POF) was developed based on the copolymer of methyl methacrylate (MMA) and N‐isopropylmaleimide (IPMI) as the matrix material and bromobenzene (BB) as dopant. The gradient distribution of IPMI in the GI POF rod was determined by element analysis. IPMI had great advantage in improving glass transition temperature (T_g) and forming a gradient‐index profile. There was a significant enhancement in the heat‐resistant property in comparison with a conventional GI POF rod. The combination of high thermal stability and easy fabrication makes the novel BB–IPMI–MMA system very suitable for heat‐resistant GI POF. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 280–283, 2003     

Graded‐index plastic optical fiber with high mechanical properties enabling easy network installations. II

It was shown how high mechanical strength should be provided in the high numerical aperture (NA) graded‐index plastic optical fiber (GI POF). In this newly developed GI POF, a copolymer of methyl methacrylate (MMA) and 2,2,2‐trifluoroethyl methacrylate (3FMA) was used to increase the NA. The GI POF we proposed previously was composed of a PMMA homopolymer cladding and a doped PMMA core. It was previously shown that substituting the copolymer P(MMA–3FMA) for the PMMA as the cladding material made little change in the fiber's light‐transmission characteristics. This study focused on mechanical flexibility, which is one of the most important advantages of the POF. It was found that the P(MMA–3FMA)‐clad GI POF had almost the same or superior mechanical strength in addition to the excellent light‐propagation characteristics. It was also found that such excellent mechanical properties were achieved using a small dopant concentration and optimum heat‐drawing conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 410–416, 2004     

紫外／可见光谱在有机光纤研制中应用

有机光导纤维是近十几年来在新型光功能性高分子材料领域中的一支独秀．相对于玻璃光导纤维，有机光导纤维加工容易、口径大、轻而柔软、抗挠曲、抗冲击、耦合容易，更重要的因素是制作成本低和用途广泛．通常光导纤维是一种带包层的透明圆柱型的细丝．芯子的折射率高于包层并且是不变的，这种纤维称为突变型（ＳＩ）光纤．由于ＳＩ型光纤的带宽小，不能满足高信息量传输的需要，因而渐变型（ＧＩ）有机光纤得以发展．在这种光导纤维中，纤芯的折射率是呈抛物线型分布的，其轴心的折射率最大，折射率由纤维轴心沿径向到包层逐渐变小，在芯／…     

Preparation of graded index plastic rods doped with Sm3+ by interfacial-gel polymerization

A novel graded index (GI) poly(methyl methacrylate) (PMMA) rod was prepared by interfacial-gel polymerization carried out in a PMMA tube with one closed end. Bromobenzene (BB), a higher refractive index molecule, was used to obtain a graded index distribution and samarium octanoate (SOA) was used as a dye with Sm³⁺ concentrations from 60ppm to 700ppm. For a poly-merization system containing methyl methacrylate (MMA) as monomer, azobis-isobutyronitrile (AIBN) as initiator and dodecyl mercaptan as chain transfer agent, the difference of the refractive index from the centre to the periphery of the rod (Δn) with various BB and Sm³⁺ contents was determined. Experimental results showed that a parabolic profile of refractive index formed on the cross-section of the rod and Δn increased with increase of BB content. SOA has little effect on the profile within the given concentrations. The GI distribution may be calculated by free volume theory. The result is identical with the experimental distribution. © 1998 SCI.     

Graded‐index plastic optical fiber with high mechanical properties enabling easy network installations. I

A doped poly(methyl methacrylate) (PMMA)–based graded‐index plastic optical fiber (GI POF) with high mechanical strength is reported for the first time. Although the POF is generally believed to have a good mechanical flexibility even if it has a large‐core diameter, such a high mechanical strength has been provided by making the polymer chains in the POF highly oriented in its axial direction. If such an orientation of polymer chains is eliminated, the POF becomes brittle, which is similar to silica‐based fibers. On the other hand, too high an orientation of the polymer chains induces fiber deformation in a high‐temperature atmosphere resulting from orientation relaxation. This study reports how high mechanical strengths such as the tensile strength and the large elongation are provided to the GI POF. By selecting the optimum heat‐drawing conditions, the GI POF has a mechanical strength comparable to that of the commercially available step index (SI) POF. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 404–409, 2004     

Preparation and characterization of gradient refractive index plastic rods with small calibers

A series of gradient refractive index (GRIN) plastic rods with diameters of 2–4 mm were fabricated using the centrifugal diffusion polymerization (CDP) technique. Methyl methacrylate (MMA) was used as the monomer having a lower refractive index, and poly‐(methyl methacrylate) (PMMA) was used as a prepolymer dopant. The reactive benzyl methacrylate (BzMA), and an unreactive agent chosen from bromonaphthalene (BN) and diphenyl sulfide (DS) with higher refractive index were used as the second component of the feed mixture. Effects of feed composition, centrifugal conditions, and initiator concentration on the optical characteristics of plastic GRIN rods are investigated. Refractive index profiles and image transmission qualities of the GRIN rods prepared in this investigation are estimated.