Fiber Uniformity

As a result of the adaption of the International System of Units, referred to asSI. the appropriate length unit for breaking tenacity becomes kilometer (km) of breaking length or Newtons per tex (N/tex) and will be equivalent in value to g/tex. 

The strength of a fiber, yarn, or fabric can be expressed in terms of force per unit area, and when expressed in this way the term is tensile strength. The most common unit used in the past for tensile strength has been pounds force per square inch or grams force per square centimeter. In 51 units, the pounds force per square inch x 6.895 will become kilopascals (kPa) and grams force per square centimeter x 9.807 will become megapascals (MPa).  

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The foam prior to collapse normally sits on the surface of the fabric however, once the foam collapses there is a precipitous drop in viscosity and the resultant liquid rapidly flows along the fibers uniformly sheathing them with the dye or finish liquor. This is illustrated in Figures 3 and 4. 

Sommer, R., Schulze, J. and Wolfrum, G. (1974). Exhaust dyeing of (semi) synthetic fibers— uniform yellow shades with a modified diazo dye from organic solvents. Bayer AG Patent DE 2 313 356. [260t]... 

Primary concerns in fiber extrusion are the fiber uniformity and avoidance of breaks. Both of these can be traced to an uneven feeding of the polymer through the die. Textured and hoUow fibers can also be produced. 

Fig. 5.67 SEM of a polished carbon fiber composite specimen reveals details relating to fiber uniformity and packing. Wetting of the fibers with resin is seen clearly. The overview (A) shows several voids (arrows) in the specimen which are seen to be regions where the fibers are poorly wetted with resin (B).

Step 3. Heating the Samples The samples were placed in the oven for approximately 10 minutes to preheat the fluid. They were removed from the oven and re-agitated with the stand mixer to ensure fiber uniformity. The fluid samples were then immediately transferred to 250-mL graduated cylinders, and placed in the oven for one hour. 

There are several primary properties necessary for a polymeric material to make an adequate fiber (1) fiber length to width ratio, (2) fiber uniformity, (3) fiber strength and flexibility, (4) fiber extensibility and elasticity, and (5) fiber cohesiveness. 

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