Fire resistant optical cables with special plastic coated fibers

It is important to prevent transmission loss increase of optical fiber cables during a fire and fire fighting. One of the main reasons for the loss increase in a fire is the expansion and shrinkage of polymers used in optical fiber cables. The authors have developed a fire resistant optical fiber cable by studying the behavior of coating materials and coated fibers at high temperature. Polymer types investigated are thermoplastics, engineering plastics, and UV cured plastics. The fire resistant optical fibers are coated with a polymer which rapidly produces a carbonized layer by exposure to heat. The rapid carbonizing has the effect of reducing expansion and shrinkage. Besides the coating, the coated fiber is surrounded by carbon yarn to prevent breakage of the fiber. The fire resistant optical fiber cable passed the fire test at 840°C for 30 minutes and VTFT specified IEEE 383, without any breakage of the fibers. The optical loss of the fibers scarcely changed during the tests and after the tests. This paper presents the studies of coating materials and coated fibers at high temperature, the structure and properties of the coated fiber and characteristics of the fire resistant optical fiber cable.     

Coated metals compatible with PVC jackets for bonded sheath cable applications

Mechanical strength in the cable sheath is particularly valuable for both fiber optical and copper pair cable. By bonding a PVC jacket to a coated metal tape, a mechanically strong sheath construction is obtained. Changes in PVC jacket technologies have created the need for PVC compatible coated metals with greater tolerance for variations in PVC jacketing materials. This need has been met by the development of a variety of coated metals having thermoplastic coatings which adhere to PVC. As a consequence of this development, new cable sheath designs for use in a variety of applications, such as riser cable and direct buried cable destined for local area networks, are possible. These cables may utilize both copper conductors and/or optical fibers for signal transmission. Data will be provided in the paper to show the effects of extrusion process conditions on adhesion for a variety of PVC resins. The properties of a variety of coated metals—aluminum, copper, and steel—will be discussed. Data on environmental tests of adhesion will be presented. Relationships between adhesion, metal characteristics, jacket properties, and mechanical performance of the sheath will be discussed. Cable applications for the PVC compatible metals will be discussed. Data on the performance of the bonded sheath in riser cable and buried local area network cable will be presented. New cable applications where coated metals in the sheath can provide lightweight armoring will also be discussed.     

Materials Development of Optical Fiber

Traditionally, new materials are developed in response to the requirements of an emerging device technology. In the optical fiber case, development of glass as a transmission medium came as the culmination of a century-long quest for improved broadband telecommunications, a search that established the superiority of light signals transmitted through glass over electronic signals transmitted by wire.     

炭纤维复合材料在智能建筑结构中的应用

介绍了炭纤维及其树脂复合材料在建筑结构材料智能化技术上的应用。由于炭纤维的高强度、良好的耐火性以及好的导电性,炭纤维不仅被用作高强度结构补强材料,还同时被用作大型结构的安全诊断和寿命预测。炭纤维与玻璃纤维的复合、炭纤维与碳颗粒及陶瓷颗粒的复合、炭纤维布与电热线的复合及其应用,将成为未来大弄构件的智能化发展的重要方向。     

Carbon nanotube wires and cables: near-term applications and future perspectives

Wires and cables are essential to modern society, and opportunities exist to develop new materials with reduced resistance, mass, and/or susceptibility to fatigue. This article describes how carbon nanotubes (CNTs) offer opportunities for integration into wires and cables for both power and data transmission due to their unique physical and electronic properties. Macroscopic CNT wires and ribbons are presently shown as viable replacements for metallic conductors in lab-scale demonstrations of coaxial, USB, and Ethernet cables. In certain applications, such as the outer conductor of a coaxial cable, CNT materials may be positioned to displace metals to achieve substantial benefits (e.g. reduction in cable mass per unit length (mass/length) up to 50% in some cases). Bulk CNT materials possess several unique properties which may offer advantages over metallic conductors, such as flexure tolerance and environmental stability. Specifically, CNT wires were observed to withstand greater than 200,000 bending cycles without increasing resistivity. Additionally, CNT wires exhibit no increase in resistivity after 80 days in a corrosive environment (1 M HCl), and little change in resistivity with temperature (<1% from 170-330 K). This performance is superior to conventional metal wires and truly novel for a wiring material. However, for CNTs to serve as a full replacement for metals, the electrical conductivity of CNT materials must be improved. Recently, the conductivity of a CNT wire prepared through simultaneous densification and doping has exceeded 1.3 × 10(6) S/m. This level of conductivity brings CNTs closer to copper (5.8 × 10(7) S/m) and competitive with some metals (e.g. gold) on a mass-normalized basis. Developments in manipulation of CNT materials (e.g. type enrichment, doping, alignment, and densification) have shown progress towards this goal. In parallel with efforts to improve bulk conductivity, integration of CNT materials into cabling architectures will require development in electrical contacting. Several methods for contacting bulk CNT materials to metals are demonstrated, including mechanical crimping and ultrasonic bonding, along with a method for reducing contact resistance by tailoring the CNT-metal interface via electroless plating. Collectively, these results summarize recent progress in CNT wiring technologies and illustrate that nanoscale conductors may become a disruptive technology in cabling designs.     

浅析美国标准环境下电缆选型设计

介绍了美国电气设计标准中的AWG导线规格、电缆材料和截面积的选择以及UL电线电缆标志,结合常规电缆选型设计,整理分析了美国标准与中国标准电缆选型设计的异同,供同行业电气工程师在执行美标工程中参考。     

Theoretical analysis of the thermally induced delamination of polymeric coatings in double-coated optical fibers

To maintain its mechanical strength, the glass fiber of optical fibers is coated by polymeric materials during the fabrication process, However, when the thermally induced shear stress at the interface of the glass fiber and primary coating is larger that its adhesive stress, the adhesive bond between the glass fiber and primary coating will be broken. When the polymeric coatings are delaminated from the glass fiber, the optical fiber will lose its mechanical strength. In this article, the thermally induced delamination of polymeric coatings in double-coated optical fibers is investigated. To minimize the coating's delamination, the thermally induced shear stress at the interface of the glass fiber and primary coating should be reduced. The method to minimize such a shear stress is to select suitable polymeric coatings as follows: The thickness and Poissòn's ratio of the primary coating should be increased, but the Young's modulus of the primary coating and the thickness, Young's modulus, and thermal expansion coefficient of the secondary coating should be decreased. Finally, the optimal design of commercialized double-coated optical fibers to minimize the thermally induced coating's delamination is also discussed.     

玻璃光纤制品医用消毒试验分析

通过对玻璃光纤制品进行常规的4种医用消毒试验，发现干热法和湿热法医用消毒对玻璃光纤制品基本无影响，但药物法和辐射法消毒则对玻璃光纤制品产生出不同程度损伤。试验发现，可以通过改变光学玻璃材料或增加表面增强技术等方法适应不同医用消毒方法，并提出了制造适合医用消毒的化学稳定性强的环保型光学玻璃、耐辐射光学玻璃、可拓宽玻璃光纤光传输波段光学玻璃以及研究玻璃光纤束表面增强技术的必要性和时代性。     

Dynamic friction property and mechanism of line‐type thermoplastic polymer materials for new optical wiring technology

We have been developing a new optical wiring technology for installing indoor optical fiber cables directly into apartment houses for fiber to the home. The technology must minimize the friction of optical fiber cable. We reviewed many studies on friction behavior, and studied the friction properties of a wide variety of polymer sheets and optical fiber cables, and considered the friction mechanism. Relatively, soft polymer materials exhibited stick‐slip behavior and the hard polymers exhibited constant slip behavior. Lubricants are effective in reducing friction and play a dominant role as regards the friction property. Silicon and fluorocarbon agents play some role in converting the stick‐slip characteristic into constant slip behavior. A certain roughness is effective in reducing friction. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers.     

中红外碲酸盐玻璃及光纤研究进展

近/中红外激光和超连续光源在红外光电对抗、生物医疗、遥测感知和激光探测及测距(LIDAR)等领域具有十分重要的应用价值。近年来,基于软玻璃光纤来产生和传输高亮度近/中红外(特别是2～5μm)激光方面的研究取得了显著进展。在中红外软玻璃基质中,具有相对较低声子能的碲酸盐玻璃对于设计近红外和中红外激光器和放大器、高功率中红外激光传输和传感应用无源光纤具有特别的吸引力。本文重点总结了低损耗碲酸盐玻璃的关键制备技术,并综述了碲酸盐玻璃及光纤在稀土掺杂中红外发光方面的研究进展,最后对碲酸盐玻璃及光纤应用存在的问题和发展趋势进行了总结和展望。     

电线电缆阻燃化研究现状

分析了电线电缆火灾的成因和危害;简要介绍了低烟低卤阻燃聚氯乙烯电线电缆料的发展现状和方向;重点介绍了低烟无卤阻燃聚烯烃电线电缆料的阻燃机理和研究现状;提出了阻燃剂的无卤化、抑烟和低毒是当前和今后电线电缆阻燃研究领域的前沿课题,但在阻燃电缆的应用上还需进一步深入研究。     

PBO用于绝缘微型光缆增强材料的研究

特殊环境对微型光缆加强材料的要求越来越高。通过对高强微型光缆的结构及非金属加强材料的使用强度要求的研究,采用立式圆形编织机,按照一定的工艺进行编织来研制PBO高强度微型套管。测试结果表明:PBO纤维的拉伸强度、安全使用温度高于目前普遍使用的Kevlar-49纤维和S玻纤等非金属加强材料,3种纤维的理论最大抗拉力分别为1 989 N、960 N、892 N。为此,在抗拉强度要求极高的特殊环境里,PBO纤维是目前微型光缆最佳的非金属绝缘加强材料。     

Rethinking Optical Fiber: New Demands,Old Glasses

From a materials perspective optical fibers are victims of their own success. The advent of the laser, 50 yr ago, coupled with an insatiable demand for information enabled by light‐based communications, ushered in a golden age of glass science and engineering. It is somewhat ironic that the staggering ubiquity of information today, which is carried globally and almost instantaneously via optical fibers, is enabled largely by one material—silica—into which only a few components are added. The richness of the Periodic Table has largely been forgotten. The purpose of this study was to rethink the materials that can be used to make commercially relevant optical fibers and describe the extraordinary properties, with stimulated Brillouin scattering being the primary exemplar, of fibers made from otherwise ordinary materials. In particular, this study focuses on the use of the molten core approach to optical fiber fabrication and the novel yet practical fibers that can be produced. This study is purposely provocative and aims to reassert the centrality (and simplicity and beauty) of glass science as the best approach to meet future challenges for high‐performance optical fibers.     

Novel processing,testing and characterization of copper/carbon nanotube (Cu/CNT) yarn composite conductor

Sustainable electrified aircraft propulsion (EAP) is likely to lead to an increase in the electrical wiring contained within a single aircraft. Since the electrical resistance and mass of copper (Cu) conductors are associated with power losses, it is desirable to design high-conductivity lightweight conductor materials, thus reducing the mass of components like motor windings, low-voltage signal cables, and transmission cables for data and power to improve the overall energy efficiency. This paper describes a unique framework for manufacturing metalized carbon nanotube (CNT) composite conductors, measuring their electrical conductivity and strength, and modeling the overall conductivity and current sharing within such composites. Tensile testing was conducted on the processed composite conductor cables with the use of acoustic emission and electrical resistivity to determine stress-dependent-failure mechanisms while monitoring the electrical conductivity. The average of measured electrical conductivities of annealed Cu/CNT samples from batch 5 was greater than theoretical predictions by 9.8 percent and was also greater than the conductivity of pure annealed Cu by 4.8 percent and had comparable ultimate tensile strengths. Additionally, those Cu/CNT samples provide a 13.5% weight saving over current state of the art copper wires. Theories explaining improved intrinsic conductivity are discussed.     

Elektroisolierstoffe mit hoher Wärmebeständigkeit

Electrical Insulating Materials with High Thermal Stability Polymers to be classified into the group of highly thermostable materials must possess certain properties even at elevated temperatures. Thermostable substances suitable for electrical insulation possess good insulating properties at high temperatures. Materials with high thermal stability have found their way in the field of electrical insulation, especially in wire coatings. Such materials are polyesters of terephthalic acid, polyimides, polyamidimides and esterimides. The processes for the preparation and properties of these polymers are described. Furthermore a few polymers are mentioned, whose chemical structure deserve special attention.     

我国电缆料行业的发展趋势和市场需求

分析了我国电线电缆行业的发展趋势,介绍了我国电缆料产品的构成,预测了未来几年我国主要电缆料的市场需求,指出了我国电缆料行业的发展方向。     

玻纤在绝缘行业中的应用和展望

介绍了玻璃纤维及制品在浸渍纤维制品、层压制品、塑料制品、云母制品等绝缘材料行业中的应用,分析了十二·五绝缘行业规划中涉及玻璃纤维的新型发电设备、输变电设备、用电设备配套的绝缘材料产品的发展,展望了高性能超薄型玻纤布、玻纤毡、特性化玻纤等特殊要求的绝缘材料的发展前景。     

Study of the electrical properties of flame retardant poly(vinylchloride) using positron annihilation lifetime spectroscopy

Since the large fire at the Brown Ferry cable plant which occurred at noon on March 22, 1975 in Alabama, attention has been given to the use of flame retardant cable in buildings to meet fire safety requirements. Flame retardants are used in wire and cable applications to prevent the conversion of an electric spark into fire and subsequently to prevent the spread of fire throughout a structure along the wiring. There are many substances used as flame retardants in wires and cables. In Egypt, Multi‐Purpose Reactor insulation and jacket cables have been constructed from a flame retardant substance, poly(vinylchloride) (PVC). In the present work, elemental and X‐ray fluorescence analyses have been performed to determine the composition of PVC in the jacket cable samples. In addition, the conductivity (σ), permittivity (?′), and dielectric loss (?″) as well as positron annihilation lifetime (PAL) are measured in the temperature range 30 to 140 °C. It is found that the amount of chlorine in the flame‐retardant PVC (FRPVC) jacket cable is significantly higher (5%) than the conventional PVC jacket cable. Inverse relationships between σ and free volume size and fractions (V, f) through the temperature range are obtained. However, a distinct positive relationship between σ and I₂ above 100°C is found. The results of PAL and electrical measurements indicate that FRPVC has good electrical insulation properties below 100°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 638–644, 2005     

Influence of As2O3 on the Optical Properties of Ultrapure Multicomponent Silicate Glasses and Optical Fibers

To obtain low transmission loss optical fibers from ultrapure multicomponent silicate glasses, it is necessary to add small quantities of As₂O₃ (or Sb₂O₃). In optical fibers prepared from glasses without these agents, a significant increase in loss is observed. To investigate this effect, the influence of As₂O₃ (added to the batch and present in the glass as As₂O₅) on the optical properties of ultrapure silicate glasses was studied. These properties are the Rayleigh scattering loss coefficient, transition metal absorption, and position of the uv absorption edge. This study showed that the increase in loss of As₂O₃-free glass cannot be assigned to any of these contributions and was attributed to absorption by electrons, trapped in relatively shallow traps in the glass network. The As⁵⁺ ions serve as deep traps and therefore remove the additional absorption. The same phenomenon, although much more pronounced, was observed in optical fibers prepared from alkali borosilicate glasses.