 Linda Dada & Emily Dreyer  Santa Rosa Junior College  SRJC, Engr 45, Fall 2010

 Stephanie Kwolek and her colleagues at DuPont began searching for a new lightweight strong fiber for light, strong tires  discovery of new method of producing polymer chains  high strength Kevlar® (poly-paraphenylene terephthalamide) introduced by DuPont

 The molecular structure includes a Benzene ring which allowed formation of structures on the ring  Alignment of the chains allows Kevlar to be integrated into composite materials  The molecules layer themselves in such a way that in order to break through Kevlar, the molecular bonds have to be broken

Steel Kevlar fibers

Ruptured fibers “string-cheese” failure

 High modulus  High tensile strength at low weight  Low electrical conductivity  High chemical resistance  Low thermal shrinkage  High toughness  High cut resistance  Flame resistant/self extinguishing  Immune to electron radiation

 Causes discoloration and degradation of the Kevlar in the presence of oxygen  Not influenced by moisture or atmospheric contaminants  Damaging if the wave is absorbed by the polymer  SOLUTION: It’s coated with something UV resistant (absorbant)

 Vehicle Armor › Spall Liners › Also protects aircraft and helicopter crews  Military Helmets › Absorb 20% more kinetic energy for Ground Troops › Improve mobility and fatigue of GIs because of low weight  Body Armor › Improved Outer Tactical Vest, ballistic inserts, throat and groin protectors, anti-mine boots and chaps

Ropes and cables Auto hoses and belts Composite materials Tires Fiber optic cables Sporting goods Umbilical hoses on offshore oil and gas refineries Insulation

 Aircraft  Maritime vessels

 In the Mars Pathfinder to reinforce the inflatable landing cushions and securing ropes > survived 40 million mile journey  Space shuttle and communications satellites to protect against impacts from orbital debris › Hubble Telescope!

 Used in modules of the International Space Station (ISS) to protect from micrometeorites and orbital debris  Helps protect crew from radiation  Basic layout of module wall: 1. metal, 2. Kevlar, 3. main structure (pressure shell), 4. thermal insulation

 Lightweight  Low thermal expansion  Resilient  Woven fibers are strong and flexible › Flexibility absorbs shock from impacts

 Fire Resistant Mattresses  Personal Electronics  Sports › Boarding/Skiing › Baseball › Hiking

KEVLAR UNDERWEAR!! Used in the military Reinforced in places that cover big arteries Image:

Questions? Your classmates, Linda & Em

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