聚合反应条件对渐变型塑料光纤预制棒的折射率分布的影响

用甲基丙烯酸甲酯 (MMA)作为基质 ,采用界面 凝胶聚合技术成功地制备了渐变型塑料光纤预制棒 ,并探讨了掺杂剂浓度及其分子体积以及聚合温度对折射率分布的影响 .观察到聚合温度对折射率分布的影响以及掺杂剂分子的分子体积在极端情况下 (如溴苯与MMA分子的分子体积相似 ,联苯分子体积比MMA则要大的多 )对折射率分布的影响 ,清楚地显示出分子体积在界面 凝胶聚合过程中所起的重要作用 .实验结果表明了高温聚合有利于轴心Δn值的升高 ,可得数值孔径NA较大的预制棒 .低温聚合使得折射率分布趋于平缓化 .     

梯度型聚合物光纤中折射率分布的洛仑兹函数模型应用

利用洛仑兹函数对梯度型聚合物光纤(棒)中折射率分布曲线进行模拟,建立折射率分布的洛仑兹函数模型.该模型只需掺杂物的初始浓度、分子体积和聚合温度3个基本参数.利用该模型对各种高折射率的掺杂物掺杂聚甲基丙烯酸甲酯(PMMA)制备的梯度型聚合物光纤中的折射率分布进行了预测,发现掺杂物的折射率比分子体积对折射率梯度的影响更大;惰性掺杂物中二苯硫(DPS)掺杂效率最高;共聚掺杂物中苯甲酸乙烯酯(VB)掺杂效率最高.     

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     

折射率梯度型塑料光纤棒的制备与模拟

采用溴苯作为高折射率掺杂剂，通过界面凝胶聚合法制备了折射率呈梯度型分布的塑料光纤棒，研究发现，在聚合反应前期，混合物在真空与60－70℃的条件下聚合，而后期反应在高压气氛中进行，可以消除光纤棒中的气泡或真空泡，利用Vrentas-Duda自由体积理论，对梯度型折射率分布的形成进行了分析，建立了物理模型，并进行了模拟分析。     

紫外/可见光谱在有机光纤研制中的应用

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/包层界面处折射率无突变,光线在这种光纤的传播路径近似正弦波.沿正弦波处的折射率均小于轴心区的折射率.由于光速是反比于折射率的,因此当光沿着正弦途径传输时,其速度大于光沿着轴心传输的速度.于是,较长的光路被较大的光速所补偿,结果是光在正弦波处的传输时间与在轴心处的传输时间上没有大的区别,而脉冲加宽是正比于传输时间的差值,因此有望在GI型有机光纤中得到较小的脉冲加宽.GI型有机光纤的制备一般可在GI型有机预制棒的基础上通过熔融热拉技术拉制而成.因此,制备GI型有机预制棒及其折射率分布的检测成为关键步骤.折射率分布的测量方法有很多,如近场扫描法、折射近场法、切片干涉法等.本文首次介绍了将紫外/可见吸收光谱应用于预制棒折射率分布的定性测试上,得到了在预制棒芯区沿径向掺杂剂分子溴苯的吸收强度呈抛物线型分布.因测试折射率分布的其他方法较为繁杂以及受仪器的限制,所以利用紫外/可见吸收光谱这一非常普通的仪器来估计折射率分布的情况不失为一种简单易行的方法.     

Fe-Al-8-羟基喹啉催化体系催化甲基丙烯酸甲酯、乙酯聚合

研究了Fe(acac) 3 Al(i Bu) 3 8 羟基喹啉 (ACAC =乙酰丙酮 )催化体系催化甲基丙烯酸甲酯 (MMA)、甲基丙烯酸乙酯 (EMA)聚合 ,用核磁共振、红外光谱研究了聚合物的结构 .结构以全同和间同为主 ,全同和间同含量达 6 7%、82 % .用凝胶渗透色谱研究了聚合物分子量和分子量分布 ,分子量分布较窄 .动力学研究表明聚合反应对单体浓度呈一级关系 ,表观活化能为 36 3kJ mol、4 6 4kJ mol.     

锂离子电池PMMA-VAc聚合物电解质的制备与性质研究

以甲基丙烯酸甲酯(MMA)和醋酸乙烯酯(VAc)为单体, 用乳液聚合法合成聚甲基丙烯酸甲酯-醋酸乙烯酯聚合物(PMMA-VAc), 并以此聚合物制备了新型聚烯烃膜支撑的聚合物膜及聚合物电解质. 用红外光谱(FTIR)、凝胶色谱(GPC)、差热和热重分析(DSC/TG)、扫描电镜(SEM)及电池充放电实验等方法研究了聚合物、聚合物膜和聚合物电解质的性质. 红外光谱结果表明, MMA与VAc通过各自的C＝C双键打开聚合成PMMA-VAc. PMMA-VAc易于分散在混合碳酸酯溶剂中并形成凝胶, 凝胶粘度随PMMA-VAc浓度的增加而增加, 当浓度为4%时成膜效果最佳. PMMA-VAc膜具有大量的微孔结构, 具有极强的吸液性能. PMMA-VAc膜具有良好的热稳定性: 在380 ℃范围内保持稳定. 聚烯烃膜支撑的PMMA-VAc膜室温下的离子电导率为1.85×10^－3 S•cm^－1, 用作为锂离子电池的聚合物电解质时, 电池具有良好的循环稳定性和倍率性能.     

氧化-还原低温引发甲基丙烯酸甲酯/丙烯酸丁酯超浓乳液聚合研究

以乳化剂十二烷基硫酸钠 (SDS)和共乳化剂十六烷醇 (HD)作为复合乳化体系 ,过氧化二苯甲酰(BPO)和N ,N 二甲基苯胺 (DMA)作为氧化还原引发体系 ,甲基丙烯酸甲酯 丙烯酸丁酯 (MMA BA)作为混合单体 ,制备了分散相占 83 %以上的稳定的超浓乳液 ,然后在低温下引发聚合 .探讨了引发剂浓度、氧化剂与还原剂的摩尔比、乳化剂的浓度、液膜增强剂的种类、聚合温度等因素对聚合稳定性和聚合速率的影响 ,测定并计算得到了聚合速率的公式 ;用激光散射粒度分布仪测定了聚合物乳胶粒子的大小及粒径分布 ,用透射电子显微镜观察了聚合物乳胶粒的形态 ,讨论了乳化剂浓度、聚合温度等对乳胶粒形态、大小的影响     

邻苯二甲酸二烯丙酯和甲基丙烯酸甲酯共聚物梯度折射率棒制备过程的研究

<正> 梯度折射率棒是折射率沿径向或轴向连续变化的透明圆棒,具有光自聚焦性能。可用于制作自聚焦型光纤维和自焦聚透镜。用玻璃制得的梯度棒直径和折射率差都很小。近年来,开始研究高分子梯度棒,据估计其直径可望达到100mm,折射率差也可达0.1。本文采用二元掖体扩散共聚法,制得梯度棒,其径向折射率分布接近于抛物线型。     

N-异丙基马来酰亚胺在渐变型耐温塑料光纤中的应用

研究了以N－异丙基马来酰亚胺（IPMI）与甲基丙烯酸甲酯共聚物为基材,制备渐变形耐温塑料光纤的可行性。实验确定了链转移剂和N－烷基马来酰亚胺对体系玻璃化温度的影响。通过Lorentz-Lorenz公式,估算出IPMI在共聚物中的折光率值。用元素分析法证明IPMI在塑料光纤预制棒中呈渐变分布,测定了以此材料制备的塑料光纤预制棒的折光率分别布线,说明IPMI在提高塑料光纤耐温性的同时,可作为参杂剂使用。结果表明：IPM／MMA共聚物是制备渐变型耐温塑料光纤的良好材料。     

Preparation of a graded‐index polymeric preform by swollen bulk polymerization

A swollen bulk polymerization approach for the preparation of a preform for manufacturing graded‐index plastic optical fibers was examined. The preform prepared by the proposed approach was transparent and bubble‐free and had a parabolic profile of the refractive index, with the highest refractive index at the center of the rod. The influences of the polymerization temperature and the type of dopant on the properties of the prepared preform were discussed. A higher temperature resulted in a steeper parabolic profile of the refractive index for the formed preform, and a lower temperature resulted in a higher refractive index near the core‐cladding region of the preform. The refractive‐index profiles of the preform were affected by the addition of the different types of dopants used. The concentration distribution of the dopant in the preform correlated to the refractive‐index distribution. In a comparison of bromobenzene (BB) and 1,2,4‐trichlorobenzene (TB) as dopants, it was observed that BB distributions along the profile were more uniform than TB distributions, and a dopant with a larger molecular volume was more concentrated in the core center. It was concluded that the refractive‐index distribution of the graded‐index preform could be controlled by the both temperature and the addition of different types of dopants during the swollen bulk polymerization process. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1813–1818, 2003     

Correction of Refractive-Index Distribution Model in Graded-Index Polymer Optical Fiber Rod

The theoretical and experimental validation was made to Lorenz function model of refractive index distribution in graded index polymer optical fiber (GI POF) by experimental data. It was found that simulating error is great when molecule bulk ratio is larger than one. According to calculating results, exponent parameter of the molecule bulk ratio in the model was corrected to 1.1, so the simulating error was remarkably reduced from ≤65% to <20%. It showed that influence of the molecule bulk ratio on refractive index distribution in GI POF is great.     

High‐thermally stable and high‐bandwidth graded index plastic optical fiber for vehicle networks

Radial refractive index profiles within the graded index plastic optical fiber (GI‐POF) is formed by adding a dopant to a polymer. This addition of the dopant significantly decreased the T_g of the polymer due to the plasticization. This disadvantage made the installation of the GI‐POF difficult, especially in vehicle networks in which high thermal stability is required. We have suggested 9‐bromophenanthrene (BPT) as a novel dopant induced less plasticization for poly(methyl methacrylate) (PMMA) than the conventional dopants. However, although the fabricated GI‐POF using BPT had high enough thermal stability for vehicle networks, the attenuation was 800 dB/km and it could not be used. This high attenuation was caused by contaminant in the fabrication process of fibers. In this study, we succeeded to fabricate a GI‐POF with low‐attenuation and high‐thermal stability using highly pure BPT. Its attenuation was improved to 240 dB/km at 650 nm, which was enough transparency for vehicle networks. The T_g of the GIPOF was improved to 107 °C from 90 °C. The thermal stability of the GI‐POF below 85 °C/dry and 75 °C/85%RH was demonstrated to be as high as that of the commercially available step index POF. The bandwidth of the GI‐POF could be estimated over 4.0 GHz for the 50‐m fiber. These results demonstrated that our GI‐POF should qualify to be used in vehicle network. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1464–1469, 2011     

梯度折射率塑料光纤的研究进展

论述了梯度折射率塑料光纤的研究背景。并对当前梯度折射率塑料光纤的制备方法,梯度折率塑料光纤的折射率梯度的形成机理的研究,及功能梯度折射率塑料光纤的研究状况进行综述。同时展望了梯度折射塑料光纤的发展趋势。     

无乳化剂乳液聚合法合成单分散大粒径高分子微球的研究

无乳化剂乳液聚合法合成单分散大粒径高分子微球的研究朱世雄杜金环金熹高陈柳生（中国科学院化学研究所北京１０００８０）关键词无乳化剂乳液聚合，单分散，均相成核，低聚物胶束微米级大粒径单分散高分子微球在标准计量、情报信息、分析化学等许多领域都有广泛的...     

Theoretical analysis on the preparation of gradient‐index polymeric rods by a centrifugal field

A theoretical analysis was conducted on the preparation of gradient‐index (GI) polymeric rods by a centrifugal field. Two kinds of materials system were used in this study: a polymer/monomer mixture and a polymer/dopant mixture. The predicted refractive index distribution (RID) was in good agreement with the experimental data reported in the literature. The effects of the essential parameters, including the molecular weight of the polymer, the composition and component properties (refractive index and density) of the mixture, the rotating speed, and the diameter of the GI rod on the RID were investigated. The results of a numerical simulation reveal that the essential parameters have significant effects on the RID. A materials property requirement was established theoretically for obtaining a rod RID with the refractive index decreasing from the center to the periphery. That is, the order of the density between the polymer and monomer (or dopant) needs to be the reverse of the refractive index. The enhancement of the polymer molecular weight, rotating speed, and rod radius increases the refractive index difference between the rod center and the periphery (Δn). However, the optimization of these parameters is required to obtain a suitable RID for practical applications. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1764–1772, 2000     

用多官能链转移剂通过普通自由基聚合制备两亲性杂臂星形聚合物

以偶氮二异丁腈为引发剂,四(3-巯基丙酸季戊四醇四酯)(PETMP)为链转移剂进行甲基丙烯酸甲酯(MMA)的自由基聚合,得到了含有残余巯基的聚甲基丙烯酸甲酯大分子链转移剂(HS-PMMA).然后,以HS-PMMA作为大分子链转移剂进行甲基丙烯酸叔丁酯(tBMA)的自由基聚合,合成了杂臂星形聚合物.最后,将所得杂臂星形聚合物的PtBMA链段水解得到了两亲性杂臂星形聚合物.