POLYESTER

History Forms Manufacturing Process Future

BYIMRAN IQBALASAD MOTEN

Definition

Polyester (aka Terylene) is a category of polymers which contain the ester functional group in their main chain.

Polyester is currently defined as:

“Long chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and terephthalic acid”. The name “polyester” refers to the linkage of several monomers (esters) within the fiber.

History

In 1926, United States-based E.I. du Pont de Nemours and Co. began research into very large molecules and synthetic fibers

W.H. Carothers, centered on what became nylon, the first synthetic fiber.

1939-41, British research chemists took interest in the du Pont studies and conducted their own research in the laboratories of Calico Printers Association, Ltd. This work resulted in the creation of the polyester fiber known in England as Terylene.

In 1946, du Pont purchased the right to produce this polyester fiber in the United States.

The company conducted some further developmental work, and in 1951, began to market the fiber under the

name Dacron

Raw Materials

Coal Air Water Petroleum

Forms Of Polyester

1. Filament

2. Staple

3. Tow

4. Fiberfill

Uses Of Different Form In Different Places

1. In the filament form, each individual strand of polyester fiber is continuous in length, producing smooth-surfaced fabrics

2. In staple form, filaments are cut to short, predetermined lengths. In this form polyester is easier to blend with other fibers

3. Tow is a form in which continuous filaments are drawn loosely together

4. Fiberfill is the voluminous form used in the manufacture

of quilts, pillows, and outerwear

Microscopic View

Different Structures Of Polyester

STRUCTURE AND APPERANCE

COLOURLESS AND TRANSPARENT SMOOTH AND LUSTURUOS SHAPE AS WE REQIURE SHINY GLASSROD LIKE

Polyester Fiber Characteristics

Strong Resistant to stretching and shrinking Resistant to most chemicals Quick drying Crisp and resilient when wet or dry Wrinkle resistant Mildew resistant Abrasion resistant Retains heat-set pleats and crease Easily washed

Polyester Blends

Polyester and Cotton1. Resist wrinkles2. Resist stains3. Retain shape

Polyester Blends

Polyester and Wool1. Wrinkle resistance2. Shape retention3. Increase durability

Polyester Blends

Polyester and Rayon1. More durable2. Shape retention3. More resilience

Manufacturing Filament Yarn

Polymerization Drying Melt spinning Drawing the fiber Winding

Polymerization To form polyester, dimethyl terephthalate is first reacted with

ethylene glycol in the presence of a catalyst at a temperature of 302-410°F (150-210°C).

The resulting chemical, a monomer (single, non-repeating molecule) alcohol, is combined with terephthalic acid and raised to a temperature of 472°F (280°C). Newly-formed polyester, which is clear and molten, is extruded through a slot to form long ribbons.

Drying After the polyester emerges from polymerization, the long

molten ribbons are allowed to cool until they become brittle. The material is cut into tiny chips and completely dried to prevent irregularities in consistency.

Melt spinning

Polymer chips are melted at 500-518°F (260-270°C) to form a syrup-like solution. The solution is put in a metal container called a spinneret and forced through its tiny holes, which are usually round, but may be pentagonal or any other shape to produce special fibers. The number of holes in the spinneret determines the size of the yarn, as the emerging fibers are brought together to form a single strand.

At the spinning stage, other chemicals may be added to the solution to make the resulting material flame retardant, antistatic, or easier to dye.

Drawing the fiber When polyester emerges from the spinneret, it is soft and

easily elongated up to five times its original length. This increases the strength, tenacity, and resilience of the fiber. This time, when the filaments dry, the fibers become solid and strong instead of brittle.

Drawn fibers may vary greatly in diameter and length, Also, as the fibers are drawn, they may be textured or twisted to

create softer or duller fabrics.

Winding After the polyester yarn is drawn, it is wound on large

bobbins or flat-wound packages, ready to be woven into material.

Properties

Specific weight 1.22-1.38 gm/cm Tenacity up to 85 cN/tex Moisture regain 0.2-0.5 % Heat Resist 150-200 C Sunlight better resistance Insects no effect

Demand For Polyester

RECYCLING

FUTURE

Biodegradable and biocompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a copolymer of microbial polyester, was fabricated as a Nano fibrous mat by electro spinning

The researchers have developed a process in which polyester is dramatically strengthened with a material known as a liquid crystalline polymer. The liquid crystalline polymer used in the research is called Vectra , a plastic material similar to Kevlar that is five times stronger than steel. Polyester is used because its chemical structure is ideal for making bonds with the liquid crystalline polymer

Some Major Polyester Fiber Uses

Apparel: Every form of clothing Home Furnishings: Carpets, curtains,

draperies, sheets and pillow cases, wall coverings, and upholstery

Other Uses: hoses, power belting, ropes and nets, thread, tire cord, auto upholstery, sails, floppy disk liners, and fiberfill for various products including pillows and furniture