Fibers & Textiles

Fibers & Textiles Fiber - the smallest indivisible unit of a textile. Textile - flexible, flat material made by interlacing yarns or threads.

Fabric Production Fabrics are composed of individual threads or yarns that have been woven or knitted together. The degree of stretch, absorbency, water repellence, softness and durability are all individual qualities of the different fabrics.

Weave Terminology Yarn - a continuous strand of fibers or filaments that have been spun together Warp - lengthwise yarn Weft - crosswise yarn Blend - a fabric made up of two or more different types of fiber.

Weave Patterns The simplest and most common weave pattern Plain Weave The simplest and most common weave pattern The warp and weft yarns pass under each other alternately Design resembles a checkerboard

Weave Patterns Alternating pattern of two warp & two weft threads Basket weave Alternating pattern of two warp & two weft threads Open & porous weave Not very durable

Weave Patterns Twill Weave The warp yarn is passed over one to three weft yarns before going under one Makes a diagonal weave pattern Denim is one of the most common examples

Weave Patterns The yarn interlacing is not uniform Creates long floats Satin Weave The yarn interlacing is not uniform Creates long floats Interlacing weave passes over four or more yarns

Fibers Natural or Synthetic?

Fiber Classification Natural Fibers – come from animals, plants & minerals that are mined from the ground.

Natural Fibers Animal Fibers – provide fibers from 3 sources: hair, fur & webbing. All animal fibers are made of proteins. Silk is made from the cocoon part of the silk moth.

Natural Fibers Plant Fibers – grouped according to the part of the plant they come from. All plant fibers are made of cellulose. Include: seed fibers, fruit fibers, stem fibers & leaf fibers. Flax is the fiber used to make linen.

Plant Fibers Seed Fibers – come from the seed of a plant Cotton - from seed hairs, looks like a flattened, twisted ribbon. A cotton fiber

Plant Fibers Stem Fibers – come from the stem of a plant. Grow as bundles. Common examples include: jute, flax & hemp (seen at right).

Natural Fibers Mineral Fibers – neither proteins nor cellulose. Fiberglass – a fiber form of glass. Asbestos – naturally occurring mineral. Asbestos as seen with a scanning electron microscope.

Fiber Classification Synthetic Fibers (man-made) regenerated fibers or polymer fibers A scanning electron micrograph of fibers of a dacron polyester material used in sleeping bags. The core of each fiber has up to seven air cavities that increase its insulating ability.

Synthetic Fibers Produced by joining many monomers together to form polymers Polymer – substance composed of long chains of repeating units Monomers – small molecule that may bond to other monomers to form a polymer

Synthetic Fibers Regenerated fibers (or modified natural fibers) derived from cellulose, mostly plant in origin Imitate natural fibers, generally smooth & silky in appearance Rayon – most common example

Synthetic Fibers Polymer fibers – originate with petroleum products & are non-cellulose based fibers Shape determined by manufacturing process

Filament Cross-Sections Synthetic fibers are forced out of a nozzle when they are hot, and then they are woven. The holes of the nozzle are not necessarily round; therefore, the fiber filament may have a unique shape in cross-section.

Polymer Fibers Polyester - made of ester monomers, added to many natural fibers to provide additional strength Nylon - first introduced as artificial silk Acrylic Spandex

Testing for Identification Microscopic observation Burning - observation of how a fiber burns, the odor, color of flame, smoke and the appearance of the residue Thermal decomposition - gently heating to break down the fiber to the basic monomers Chemical tests - solubility and decomposition