spider silk
TRANSCRIPT
What is spider silk ?
• Spider silk is protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or sosoons for protection for their offspring . They can also suspend themselves using their silk.
• The silk is secreted from glands inside the spiders spinnerets, located on the back of a spiders abdomen.
Spider silk is renounced for being stronger than steal by mass and is surprisingly elastic and has generated interest for an array of applications.
Properties Each spider and each type of silk has a set of
mechanical properties optimised for their biological function.
They exhibit a unique
combination of high tensile
strength and extensibility. This
enables a silk fiber to absorb
a lot of energy before breaking (toughness, the area under a stress-strain curve).
Silk is stronger than steel , but not as strong as kevlar.
silk is ,however ,tougher than kevlar
Strength • In detail a spider silk’s tensile strength is
comparable to that of high-grade alloy steel (450 - 1970 MPa),and about half as strong as aramid filaments, such Kevlar (3000 MPa).
Toughness
• The combination of strength and ductility gives dragline silks a very high toughness (or work to fracture), which "equals that of commercial polyaramid (aromatic nylon) filaments, which themselves are benchmarks of modern polymer fiber technology".
Density
• Consisting of mainly protein , silks are about a sixth of the density is steel (1.31 g/cm3). As a result , a strand long enough to circle the earth eould weigh less than 500 grams(18 oz).
Silk used by humans Fabrics
textile Bullet proof vests Nets Air bags Seat belts Parachutes Ropes Dressing wounds Bait