CTD 215 Lecture Notes - Lecture 11: Spandex, Polymerization, Dry Cleaning
Document Summary
Spandex: spandexes are elastometric fibers, characterized by high elongation (400 or. 500-600%) and low modulus: low modulus means that they have low resistance to extension. When you first begin to stretch the fibers, the molecules readily give way; there is little resistance to the stretching. As you stretch more, the molecules become aligned and the fiber begins to resist extension. Spandex also called elastane: first produced in 1930 by dupont. Lycra is becoming a commonly used name in a manner similar to kleenex, xerox, and jell-o. Polymerization: starting materials are polymers manufactured from chemicals derived from petroleum; the polymers are not found in nature, spandex polymers are 85% segmented polyurethane block copolymers. Hard blocs hold the structure while soft blocks extend easily. Spinning: polymers are dissolved in suitable solvent systems and can be wet (radicispandex) or dry spun (lycra), fibers are mainly used in continuous filament form.