6 11 Manufactured Fibers What is a manufactured fiber Manufactured fibers fibers created by melting or dissolving polymeric materials and re forming them as fibers o Can be regenerated synthetic or inorganic What is the difference between a regenerated cellulosic fiber and a synthetic fiber Regenerated cellulosic fibers fibers produced from natural materials cotton that cannot be used for textiles in their original form but that can through chemical treatment and processing be made into textile fibers o Cellulose or protein only one o Produced from natural substances containing cellulose or protein in an unusable form as a fiber o Treated with chemicals to produce a solution that can be regenerated or reformed Synthetic fibers made from materials that are created synthetically or unnaturally in a chemical process o Produced from interaction of chemicals in a solution o New polymers not existing in nature in most cases ALWAYS have carbon hydrogen and oxygen What was the first synthetic fiber Nylon manufactured by DuPont in 1938 How does the production of manufactured synthetic fibers differ from regenerated fibers Synthetic fibers use melt spinning o Chemicals combined to create base substance usually as a flake or bead o Synthesized flakes or beads are melted o Extruded into cold air o Fiber solidifies o Shape of spinneret hole determine shape of fibers Lobular Dog bone Hollow Mainly the cross section is circular Regenerated fibers use dry spinning o Natural materials dissolved in chemical Dope solution o Extruded into warm air Some regenerated rayon lyocell acrylics use wet spinning o Natural materials dissolve in chemical o Extruded into a chemical bath What are the steps to produce a manufactured fiber Develop the solution dope Extrude through a spinneret Coagulate or solidify the fiber Draw the fiber What is the most widely used manufactured fiber Polyester What are some end uses of polyester other than clothing Home furnishing pillow and toy stuffing outdoor textiles furnishing and awnings and industrial textiles fire hoses belting How do the three ways of creating manufactured fibers differ from each other dry spinning wet spinning and melt spinning Which one uses the fewest chemicals Dry spinning the formation of manufactured textile fibers in which the polymer is dissolved in a solvent that is evaporated leaving the filament to harden by drying in air Wet spinning the formation of manufactured textile fibers in which the fibers harden by extruding the fibers in a chemical bath Melt spinning the formation of manufactured textile fibers in which the polymer is melted for extrusion and hardened by cooling o Simpler and cheaper o Fewest chemicals Know the unique properties and possible end uses for o Rayon first manufactured cellulose regenerated Artificial silk o Acetate can change color in the environment Popcorn cross section o Lyocell Manufactured by Acordis purchased from Courtaids and Lenzing European manufacturers Trade name is Tencel Wood pulp possibly bamboo Manufacturing process more environmentally friendly Non toxic solvent Recycled chemicals Stronger than viscose rayon can be laundered More crystalline structure fibers do fibrillate separate after several laundering o Nylon first synthetic fiber Lightweight and strong Stretches easily good recovery Parachutes o Aramid Kevlar and Nomex Stiff and high strength Resistant to high temperature Used for racecar drivers and firefighters o Polyester Very oleophilic absorbs oil and hydrophobic Easy care and inexpensive o Acrylics similar to wool Lightweight natural crimp Excellent sunlight resistance o Olefin lightest weight of manufactured fibers Carpets and furniture Low melting point non absorbent and good wicking properties o Spandex can stretch 5 times its length and recover Lightweight Amorphous when in its relaxed state What are elastomeric fibers Elastomeric fibers a fiber made of a natural or synthetic polymer which at room temperature can be stretched repeatedly to at least twice its original length and which after removal of the tensile load will immediately and forcibly return to approximately its original length o Most common spandex and rubber What is special about the structure of spandex that allows it to stretch easily and be very strong When stretched the molecules align and form head spots hydrogen bonds that prevent the fiber from breaking What are some of the end uses of spandex and other elastomeric fibers Used with other fibers Stretchy yarns covered and corespun Shapewear 12 High performance Specialty fibers What are some of the special properties of high performance textiles Engineered for or used in specialty products Include super strong heat resistant fibers Some perform special functions such as biodegradability or microbial resistance Bullet proof non combustible to conduct electricity stores body heat color changing Chapter 13 What is the difference between staple spun yarns and filament yarns Staple yarns are made from staple length fibers o Must be held together by some means to form yarn usually twisting Filament yarns are made from long continuous strands of fiber o May or may not have twists What is the difference between monofilament and multifilament yarns Monofilament yarns a single filament also a single filament that can function as a yarn in commercial textile operations that is it must be strong and flexible enough to be knitted woven or braided Multifilament yarns yarn made from two or more usually more filament fibers Know what an S and a Z twist are Twist the number of turns about the axis of a length of a yarn Turns per inch tip o Need to know which direction it is twisted Fibers are twisted to the left or to the right This twisting is called S twist clockwise or Z twist counterclockwise o No difference in durability o The higher the twist the stronger it is o More Z twists What is a plied yarn If the original single yarns are spun Z what direction does the ply twist need to be Ply yarns a yarn formed by twisting together two or more single yarns The ply twist would be an S twist 2 Ply 3 Ply If you take two or more plied yarns and ply them together again what is the new yarn structure called What would the final plying direction be Cord yarns are made by twisting together two or more ply yarns o Cord yarns will always be twisted the same way as the single yarns but opposite from the ply o Cord yarns are used in making ropes sewing thread and cordage Know the difference