Polymer fiber technology

The first model is based on the carbon fiber experience. Once the high-performance aerospace business had been established, other markets, such as racing cars, sporting goods, and industrial products, were developed. All of these applications have grown in volume as prices have come down. The second model is based on the Kevlar fiber experience, in which DuPont was skilled in polymer fiber technology prior to the development of Kevlar. 

Pegoretti pointed out that a possible route for introducing nanofillers into polymers, while retaining a certain control of orientation and improving filler dispersion, can be found in polymer fiber technology... 

Polymer fiber technology is a field of research branching out into many diverse applications. Fashion, healthcare, smart materials, electronics and load bearing elements both on then-own and in composite materials are just a selection of some of the areas where they can be found. Regardless of their application, the smallest practical size of any pol5rmer fiber can be specified as approximately 50 nm. This can be inferred from the fact that the typical size of a polymer crystallite (lamella) has dimensions in the order of 5 to 50 nm [4]. Below this value (the case of a polymer crystallite) the structure has become so small that it takes on the form of an ordered array of atoms rather than that of a fiber. However, in most melt crystallized polymers it is these lamellae that aggregate and grow linearly to form fibrils [4]. 

Mueller, Dieter, H., Biodegradable nonwovens - natural and polymer fibers, technology, properties , INTC 2003 Proceedings, Baltimore, Maryland, September... 

The number of reports about hemicelluloses that have been covered by this review indicates the significantly increased importance of all types of hemicelluloses as plant constituents and isolated polymers during the last decade. Attention has been paid not only to known hemicelluloses but also to the primary structure, physicochemical, physical, and various functional properties of hemicelluloses isolated from hitherto uninvestigated plants. The efforts to exploit a variety of plant as potential sources of hemicelluloses were pointed out particularly for agricultural crops, wood wastes, as well as for by-products of pulp and rayon fiber technologies. Many studies were devoted to characterize seed-storage hemicelluloses from plants that have been traditionally applied in food and medicine of many underdeveloped countries to find substitutes for imported commercial food giuns. 

Light wave technologies provide a number of special challenges for polymeric materials. Polymer fibers offer the best potential for optical communications in local area network (LAN) applications, because their large core size makes it relatively cheap to attach connectors to them. There is a need for polymer fibers that have low losses and that can transmit the bandwidths needed for LAN applications the aciylate and methacrylate polymers now under study have poor loss and bandwidth performance. Research on monomer purification, polymerization to precise molecular-size distributions, and weU-controlled drawing processes is relevant here. There is also a need for precision plastic molding processes for mass prodnction of optical fiber connectors and splice hardware. A tenfold reduction in the cost of fiber and related devices is necessaiy to make the utilization of optical fiber and related devices economical for local area networks and tlie telecommunications loop. 

Standardization of the world fiber business on PET guarantees that future fiber technology efforts will remain focused on this polymer. Costs and efficiencies will get better, and other fiber types will be even less competitive. Domination of the PET commodity fiber business by Asian countries will encourage more efforts by Western and Japanese producers to further expand into niche markets with special fiber types, and to further displace natural and other synthetic fibers from their markets. 

Kokta, B.V., Maldas D., Daneault C., and Beland P. Composites of poly(vinyl chloride)-wood fibers. I. Effect of isocyanate as a bonding agent. Polymer-Plastics Technology and Engineering 29(1 - 2) 87-118 (1990). 

In dialysis, size exclusion is the main separation mechanism, while osmotic pressure and concentration difference drive the transport across two typically aqueous phases. While dialysis is used in some analytical separations, dialysis for the removal of toxins from blood (hemodialysis) is the most prominent application for hollow fiber technology in the biomedical field. The hemodialyzers are used to treat over one million people a year and have become a mass produced, disposable medical commodity. While the first hemodialyzers were developed from cellulosic material (Cuprophane, RC, etc.), synthetic polymers such as polyacrylonitrile, poly(ether) sulfone, and polyvinyl pyrrolidone are increasingly used to improve blood compatibility and flux. Hemodialyzer modules consist of thousands of extremely fine hollow fibers... 

G. S. Bhat, V. Narayanan, L. C. Wadsworth, and M. Dever, Conversion of Recycled Polymers/Fibers into Meltblown Nonwovens, Journal of Polymer-Plastics Technology and Engineering, 38 (3) 499-511 (1999). 

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