Preform fabrication

To exploit the numerous applications for floating catalyst VGCF in engineered plastics, production rates are projected to be on the order of several pounds per hour from a single tube reactor. Demonstration experiments on a small scale have shown feasibility of accomplishing the desired rate of production. Economic production of such quantities will involve recapture of energy in the heated unreacted gas which exits the reactor, as well as automated collection, debulking, and preform fabrication systems. 

Reinforced RIM (RRIM) elastomers are used. By the addition of reinforcing fillers such as milled glass fiber, glass flake, or mineral fillers in the polyurethane or short to long glass fiber in preforms, fabric, or mat forms placed in the mold cavity, the properties of the material can be altered to meet high performance requirements of the part (Chapter 15). The reinforced elastomers are used to increase flexural modulus, improve thermal properties, and improve dimensional stability.267... 

Another technique suitable for fluoride glass preform fabrication is extrusion. This technique consists in the preparation of preforms with the help of pressure (5 MPa) under moderate temperature (410°C). This is a high-viscosity process with less favorable conditions for crystal growth. Losses of 6 dB km-1 are obtained with multimode fluorozircoaluminate fibers drawn from extruded preforms [159,160]. 

Biswas, P, Li, X.M., and Pratsinis, S.E., Optical wave-guide preform fabrication— silica formation and growth in a high-temperature aerosol reactor, J. Appl. Phys., 65, 2445, 1989. 

Gao Y, Guo N, Gauvreau B, Rajabian M, Skorobogata O, Pone E, Zabeida O, Martinu L, Dubois C, Skorobogatiy M (2006) Consecutive solvent evaporation and co-rolling techniques for polymer multilayer hollow fiber preform fabrication. J Mater Res 21 2246-2254... 

There is a possible reduction in the mechanical properties of the structures due to binders or tackifiers in preforming fabrics. 

Quartz fibers offer superior IR and UV transmittance, but contain water, and therefore exhibit a strong hydroxyl group in their IR transmission spectra. The presence of water blocks IR transmission in a critical region of the spectra, but it can be avoided by selecting a synthetic route that yields water-free quartz for the preform fabrication. Mined quartz may contain traces of uranium or thorium, which emit alpha particles and can disturb delicate electronic circuits or signals. Uranium- and thorium-free quartz fibers afford quiet HT circuit boards and/or electronic packaging. 

T. Izawa and N. Inagaki, Materials and processes for fiber preform fabrication-vapor phase final deposition, Proc. IEEE. 68. [10] 1184-87 (1980). 

Preformed fabrication that provides shapes matching the application and allowing easy reactor loading. 

Bise R., Trevor D.J., Monberg E., Dimarcello F. Impact of preform fabrication and fiber draw on the optical properties of microstructured fibers. In Proceedings International Wide Cable Symposium Proceedings 2002 51 339-343... 

Multidirectional fiber preforms, fabricated from ex-PAN carbon fibers were used. Their main characteristics were given in a previous paper. ... 

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