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Polyester

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Presentation on Polyester By Kushagr , Manish , Neha , Nishu and Nitin , Bachelors in Fashion Technology , NIFT Delhi , India.

Publié dans : Commerce de détail
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Polyester

  1. 1. Polysters By- Kushagr Tantia Nitin Minj Nishu Jalotia Manish Neha Patel
  2. 2. Introduction • Polyester is a term often defined as “long-chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and a terephthalic acid”. In other words, it means the linking of several esters within the fibers. Reaction of alcohol with carboxylic acid results in the formation of esters. • Polyester also refers to the various polymers in which the backbones are formed by the “esterification condensation of polyfunctional alcohols and acids”.
  3. 3. Classification Saturated • Less Reactive • molecular weight liquids used as plasticizers and as reactants in forming urethane polymers, and linear, high molecular weight thermoplastics such as polyethylene terephthalate • Usual reactants for the saturated polyesters are a glycol and an acid or anhydride Unsaturated • More Reactive • consists of alkyl thermosetting resins characterized by vinyl unsaturation • Mostly Used in reinforced plastics • Economical family of resins
  4. 4. Manufacturing Polyesters are an artificial man-made fibre , generally manufactured from petroleum from which the constituent acids and alcohols are derived.There are three steps in the synthesizing of polyester • Condensation Polymerization: When acid and alcohol are reacted in a vacuum at high temperatures it results in condensation polymerization. Once the polymerization has occurred the material is extruded onto a casting trough in the form of a ribbon. Once cool, the ribbon hardens and is cut into chips. • Melt-spun Fibre: The chips are dried completely. Hopper reservoirs are then used to melt the chips. A unique feature of polyester is that it is melt-spun fibre. The chips are heated, extruded through spinnerets and cools upon hitting the air. It is then loosely wound around cylinders. • Drawing: The fibres consequently formed are hot stretched to about five times their original length. This helps to reduce the fibre width. This fibre is now ready and would into cones as filaments. It can also be crimped and cut into staple lengths as per requirements.
  5. 5. Manufacturing - Diagram
  6. 6. Structure The name "polyester" refers to the linkage of The name "polyester" refers to the linkage of several monomers. several monomers. ► There are many possible variation of polyester ► Polyester is a smooth fiber with an even diameter. ► The fiber diameter usually ranges from 12-25 micrometers. ► The fibers are approximately 35% crystalline and 65% amorphous
  7. 7. Structure of Polyester
  8. 8. Close Up of Polyster Fibre
  9. 9. Properties Morphology Fineness - Polyesters are avaiable in many lengths and deniers. Very fine denier or microdenier,some approach 0.5 denier.Microdenier fibers probably will become increasingly important in the apparel sector. Color and Luster The fiber is partially transparent and white or off white
  10. 10. Physical Properties of Polyester • Tenacity ►Polyester filaments and staple fiber are strong because of their extremely crystalline polymer system. ►This allow the very effective van der Waal’s forces. ►This also allows the very weak Hydrogen bonding
  11. 11. Elastic - Plastic Nature • ► The stiffness and hard handle of polyester The stiffness and hard handle of polyester • filaments are due to their extremely crystalline filaments are due to their extremely crystalline • polymer system. polymer system. • ► It prevents the polyester polymer from yielding It prevents the polyester polymer from yielding • readily when the filaments of staple fiber is bent readily when the filaments of staple fiber is bent • or flexed. or flexed. • ► Yielding is actually a lack of stiffness and giving Yielding is actually a lack of stiffness and giving • way the pressure. way the pressure. • ► Polyester filaments are about as plastic as they are Polyester filaments are about as plastic as they are • elastic. elastic.
  12. 12. Hygroscopic Nature ►Polyester filaments are also hydrophobic. Polyester filaments are also hydrophobic. ►The hydrophobic nature of the polyester The hydrophobic nature of the polyester polymer system attracts fats, greases, oils polymer system attracts fats, greases, oils and any other greasy soils. and any other greasy soils. ►In other words we can also say that In other words we can also say that polyester polymer system is oleophilic. polyester polymer system is oleophilic.
  13. 13. Chemical Properties of Polyester Fibre • Effects of Acid ►The ester groups of the polyester polymers are resistant to acids hydrolysis. ►This resistance is further enhanced by the extreme crystallinity of the polymer system
  14. 14. Effect of Alkalis ►Alkaline conditions are economy during laundering. ►It may hydrolyses the polyester polymer at their ester groups. ►The surface polymers of polyester filaments are hydrolysed.
  15. 15. Brief Information on Chemical Properties • Acids : Good resistance to acids in cold condition. But polyester degrades by sulphuric acid at high temperature. • Basic : Good resistance to basic in cold condition but strong NaOH dissolves polyester in boiling. • Effect of bleaching : Polyester does not get affected by bleaching process. • Organic solvent : Organic solvent does not affect polyester. • Protection Ability against mildew : Good • Protection ability against insects : Good • Dyes : Polyester could be dye with disperse , azoic color and some pigments • Solvents : Following are the solvents of polyester -Chlorinated hydrocarbon -F3COOH -Phenol (in hot condition)
  16. 16. Characteristics ►Strong. ►Resistant to stretching and shrinking. ►Quick drying. ►Wrinkle resistant. ►Easily washed. ►Retains heat.
  17. 17. Uses • PET bottles • Ropes • Garments • Insulating Materials • Thread • Hoses • Power Belting • Sails • Floppy Disk Liners • Thermoformed Trays • Glass and various Fibers
  18. 18. Biodegradable Polyesters • Synthetic biodegradable polyesters are made in modified PET polymerization facilities from petrochemical feedstock. Unlike other petrochemical-based polymers that take centuries to degrade after disposal, these polyesters break down rapidly to CO2 and water in appropriate conditions where they are exposed to the combined attack of water and microbes. These products meet U.S., European, and Japanese composting standards, typically breaking down in 12 weeks under aerobic conditions. • Synthetic biodegradable polyesters fall into two broad categories. One is highly amorphous, imparting flexibility and clarity comparable to a conventional LDPE copolymer. A second group of semi crystalline polyesters is more rigid, with properties similar to PET, PP, or PS.
  19. 19. Bibliography • Man made fibers – Moncrieff R.W • Textile Science – Hudson P.B ETC

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