Properties of fibers Fibers can be either staple fibers or monofilaments. Staple fibers are bundles of parallel short fibers, such as cotton or wool. Monofilaments are extruded long lengths of synthetic fibers. Monofilaments can be used as single large diameter fibers (such as fishing line) or can be bundled or twisted and used in applications similar to staple fibers. Continuous filaments can be made of almost infinite length. Synthetic staple fibers can be prepared by cutting continuous filament to short uniform length, between 3.5 and 15cm. Tensile properties of fibers are not usually expressed in terms of tensile strength (lb./inch2, Kg/cm2). The strength of fiber is more often denoted by tenacity. Tenacity (or bearing tenacity) is the breaking strength of a fiber or yarn in force per unit denier (lb./denier or g/denier). A denier is the weight in grams of 9,000m of fiber at 900F and 65% relative humidity) The curl or waviness is placed in synthetic fiber by chemical or mechanical action, is called crimp. Cotton and wool possess natural crimp. Another unit is the tex , which is the weight of 1000m

  Important fibers 1.Natural

2. Cellulosic

Rayon Accetate

Properties Strongest and hardest wearing of all polymers

Preparation of caprolactam

Preparation of nylon 6

(ii) Preparation of hexamethylenediamine

Preparation of nylon 6,6

Polyolefin

Preparation of nylon 6,6