PERFORMANCE CHARACTERISTICS OF MATERIALS Flashcards
Fibre production: cotton
Cotton is grown in tropical parts of the world. when the seed pods of the plant (bolls) ripen, the seeds inside bolls become covered with fine cotton fibres. When the seed pod eventually bursts, it becomes a fluffy ball.
As the sun dries the fibres, they collapse and become flatter like a ribbon, then twisted
How short are fibres in the cottons Boll
short, about 2-5cm in length
Fibre production: linen
Come from the stem of the flax plant. The stalk is made up of bundles of fibres surrounding a centre pith. The fibres are separated from the parts of the plant that are not wanted.
Linen fibre characteristics in production
smooth round hollow centered tubes with cross markings down their length, they are about 3-4cm long.
Fibre production: wool
wool mostly comes from sheep. the sheep are sheared and the fleeces are sent to the mills for processing.
other luxury wools come from other animals - cashmere from goats, mohair from angora goats, angora wool from angora rabbit.
how long are wool fibres
between 4 and 39 cm long, staple fibres
fibre production: silk
comes from the cocoon of the silk caterpillar. It spins the cocoon with two triangular shaped filaments, held together with natural gum (sericin) one from each side of its mouth. It can only be made into silk if its boiled before the caterpillar breaks free as a moth, because this can ruin the filaments.
(regenerated fibre production) how is spinning solution made
using wood pulp - its cleaned and the cellulose is pressed into sheets. The sheets are dissolved in a solvent to make a thick, sticky liquid (spinning solution)
how is spinning solution made into viscose fibres using a spinneret (wet spinning)
the spinning solution is filtered to remove any undissolved particles, then pumped through a spinneret. The spinnneret is immersed in a bath of chemicals, which solidify the visocse filaments as they emerge from small holes in the spinneret. The fibres solidify from the outside inwards at an irregular rate.
The filaments are stretched before being wound on to a spool as filament yarns, or cut into short staple lengths.
The shape of the holes in the spinneret can be changed to make fibres of different characteristics
(production) Melt spinning of synthetic fibres
synthetic fibres are made from chemicals that come from oil. the chemicals are made into a polymer which is cut into small pieces. These are melted to make a spinning solution that is then pumped though spinnerets.
As long filaments leave the spinneret, they are passed through a stream of cold air that solidifies them, before they are stretched out three or four times their og length
what happens to the long filament fibres often?
they are cut to shorter staple lengths so that they can be mixed with other staple fibres like cotton.
Technical and modern materials
a new material that has been developed from its original form. It has special qualities suited to specific uses, but its not a smart material
some examples of technical and modern materials
Gore-Tex, Kevlar, nomex, phosphorescent textiles, reflective (glass beads), coolmax, micro-encapsulated fibres, purista/chitopoly (protects against bacteria, fabrics with electronics, geotextiles, materials using nano-tech, microfibres
Phosphorescent materials
materials that glow in the dark by transforming invisible energy forms into light
how can phosphorescent materials be used in textiles?
phosphorescent dyes can be incorporated into synthetic fibres and yarns, used for printing pastes or applied as surface coating
what is phosphorescent materials most purpose
for high visibility safety clothing
micro-encapsulated fibres and fabrics
health and cosmetic chemicals can be incorporated into the hollow centres of microfibres. The chemicals are released slowly or absorbed the skin of the wearer.
example of micro-encapsulated fibres
those that release scents
ceramic and carbon fibres are used in the production of nano fibres, why?
they are extremely lightweight and very strong
how are nano-fibres made?
using an electro-spinning process and are collected in the form of sheets as big as a football pitch
what are the nano-fibre sheets used for
breathable membranes. They allow perspiration to pass out of sportswear garments, and at the same time, prevent large water droplets and other potentially harmful particles passing through
Where can carbon fibres also be used
in the production of electro-conductive fibres which are used to make intelligent fabrics or wearable computers
where can ceramic fibres also be used
when incorporated with synthetic firbes through encapsulating the fibre or coating, it can give a fabric UV protection or make fabrics that regulate body temperature
example of UV protective fabrics
Esmo, sunfit