Reinforcement filaments

The first continuous filaments were rayon, and these, as well as polyacrylonitrile (PAN) fibers, have been pyrolyzed to produce graphite fibers. High-modulus reinforcing filaments have also been produced by the deposition of boron atoms from boron trichloride vapors onto tungsten or graphite filaments. 

Continuous-fiber reinforcement gives plastic products which are not simply quantitatively, but often qualitatively, superior to most present commercial practice. Most plastic processing is limited to conventional melt flow of short-fiber reinforcements, which sacrifices much of the potential benefits of reinforcement. There are a few processes for incorporating continuous fiber reinforcement—filament-winding, pultru-sion, swirl conformation of fibers in polymer... 

Continuous reinforced filaments should be used to develop an efficient high-strength to low-weight FW structure. Structural properties are derived primarily from the arrangement of continuous reinforcements in a netting analysis system in which the forces, owing to internal pressure, are resisted only by pure tension in the filaments (applicable to internal-pressure systems). 

A summary of the most important reinforcing filaments and their properties is presented in Tables 21-2.1. 

The smallest unit of a fibrous material. The basic units formed during drawing and spinning, which are gathered into strands of fiber for use as reinforcements. Filaments usually are of great length and small diameter, d < 25 pm. 

Reinforcing filaments saturated with thermosetting resin are pulled through an orifice in a heated die. Polymerization of the resin occurs as the wet bundle passes through the die, forming a continuous, rigid profile corresponding to the orifice shape. 

F rovides precisely oriented reinforcing filaments excellent strength-to-weight ratio good uniformity. 

The use and acceptance of buried large-diameter glass fiber, plastic reinforced, filament-wound pipe has increased steadily since the 1950s. Such RP was selected for its superior corrosion-resistance characteristics and installation-cost savings. ASTM standards use the term Reinforced Thermoset Resin Pipe (RTRP). Filament-wound pipe with a double helical angle of continuous-glass reinforcement (discussed later) is but one of several types of RTR pipe constructions. 

Table 2 Typical Properties of Boron fibers and of other Commercially Available Reinforcement Filaments (1)...

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