polymers in textile industries

summaries of polymerization.

1. Polymers in textile industries Maharshi A Vyas ME-1 Textile Chemical Processing

2. Polymer Polymer - any of a class of natural or synthetic substances composed of very large molecules, called macromolecules, that are multiples of simpler chemical units called monomers . Monomer - a  single molecule that has the ability to combine with identical or similar molecules, a process also known as polymerization. Polymerization - is the process in which monomer units are linked by chemical reaction to form long chains. These long chains set polymers apart from other chemical species and give them their unique characteristic properties. The polymer chains can be linear, branched, or cross-linked.

3. Everyday Examples Polyethylene - Soft drink cups, Sandwich bags Poly vinyl chloride- Pipes Shower,curtains , Tygon tubing Poly vinyl acetate - Chewing gum.

4. Polymerization The two major types of polymerization are “Addition P olymerization” also called Chain Reaction and “Condensation P olymerization” also called Step Reaction. Step reactions require bifunctional or polyfunctional monomers, while chain reactions require the presence of an initiator.

5. Step & Chain Polymerization Step polymerization requires that there is at least a reactive functional group on each end of the monomer that will react with functional groups with other monomers. For example,

6. Cont …. Chains (i.e., addition) polymerization requires an initiator (I) and proceeds by adding one repeating unit at a time. Example

7. Types of polymers There are two types of polymers: synthetic and natural. Synthetic polymers are derived from petroleum oil, and made by scientists and engineers . Examples of synthetic polymers include  nylon , polyethylene ,  polyester ,  Teflon , and  epoxy . Natural polymers occur in nature and can be extracted i.e. Starch , cellulose, proteins , natural rubber.

8. Natural Polymers

9. Natural Polymers Natural polymers  occur in nature and can be extracted. They are often water-based. Examples of  naturally occurring   polymers  are silk, wool, DNA, cellulose and proteins . There are four basic kinds of biological macromolecules. They are  carbohydrates , lipids ,  proteins  and  nucleic acids . These polymers are composed of different monomers  and serve different functions.  Carbohydrates  - molecules composed of sugar  monomers .

10. Brief on Natural Polymers Proteins and Polypeptides-  Proteins  are the basic type of natural polymers which constitutes in almost all the living organisms. Proteins are said to be most versatile in nature. They can also be as catalysts. Some of the proteins are called as enzymes. These enzymes are responsible for various chemical reactions occurring in our body and it happens about million times faster even without these enzymes. One type of protein in our blood called as hemoglobin carries the oxygen from lungs to the cells of a human body. A protein is usually a naturally occurring type of polyamide. This polymer consists of an amide group present in the backbone chain of human body. Collagen – Collagen is one of the natural polymers and is a protein. It makes up the connective tissue present in the skin of human beings. This Collagen-polymer is also a fiber that creates an elastic layer below the skin and thus helps in keeping it supple and smooth. Latex-  Latex is known to be a kind of rubber, and rubber is a natural polymer. This latex occurs in both the forms either synthetic or natural. The natural form of latex is mainly collected from the rubber trees and it is also found in variety of plants which includes the milkweed. It can also be prepared artificially by the process of building up long chains of molecules of styrene .

11. Cont.. Cellulose – Cellulose is one of the most abundant organic compounds found on the Earth and moreover the purest form of natural cellulose is the cotton. The paper manufactured from the woods of trees and also the supporting materials in leaves and plants mainly comprise of cellulose. Like the amylose, it is also a polymer which is made from the monomers of glucose . Starch – Starch is the derivative of condensation polymerization and consists of glucose monomers, which further split into water molecules when combined chemically. Starch is also a member of basic food groups called the  carbohydrates  and it is found in the grains, cereal and potatoes. Starch is a polymer of monosaccharide glucose. The molecules of starch consists of 2 kinds of glucose polymers namely amylopectin and amylose which are the main component of starch in most of the plants.

12. Synthetic Polymers Synthetic polymers are those which are human-made polymers . The eight most common types of  synthetic-organic  polymers, which are commonly found in households are: Low-density polyethylene (LDPE) High-density polyethylene (HDPE) Polypropylene (PP) Polyvinyl chloride (PVC) Polystyrene (PS) Nylon, nylon 6, nylon 6,6. Teflon (Polytetrafluoroethylene) Thermoplastic polyurethanes (TPU)

13. Synthetic Polymers

14. Polymer Abbreviation Properties Uses Low-density polyethylene LDPE Chemically inert , flexible,  insulator Squeeze bottles , toys, flexible pipes, insulation cover (electric wires),  six pack rings , etc. High-density polyethylene HDPE Inert,  thermally stable , tough and high  tensile strength Bottles, pipes, inner insulation (dielectric) of  coax cable  (see also PTFE), plastic bags, etc. Polypropylene PP Resistant to  acids  and  alkalis , High tensile strength Auto parts, industrial fibers, food containers, liner in bags, dishware and as a wrapping material for textiles and food Polystyrene (thermocole ) PS Thermal insulator. Properties depends on the form, expanded form is tough and rigid Petri dishes ,  CD case ,  plastic cutlery Polytetrafluoroethylene PTFE Very low  coefficient of friction , excellent  dielectric properties , chemically inert Low friction  bearings ,  non-stick pans , inner insulation (dielectric) of  coax cable  (see also HDPE), coating against chemical attack etc. Polyvinylchloride PVC Insulator, flame retardant, chemically inert Pipe ( mainly draining),  fencing , lawn chairs, hand-bags,  curtain  clothes, non-food bottles,  raincoats , toys, vinyl  flooring , electrical installation insulations, etc. Polychlorotrifluoroethylene PCTFE Stable to heat and thermal attacks, high tensile strength and non  wetting valves , seals,  gaskets  etc.

15. P olymers Used in Textile Both synthetic and natural polymers used in textile field, like nylon, polyester, gums such as xanthan and guar gums and carrageenan . Widely used polymers are synthetic polymers in textile industries. Mainly nylon ,polyester, acrylic.

16. N ylon The synthetic polyamides are the urea-formaldehyde resins, which are thermosetting. They are used to produce molded objects and as adhesives and coatings for textiles and paper . Also important are the polyamide resins known as nylons. They are strong, resistant to heat and abrasion, noncombustible, and nontoxic, and they can be colored. Their best-known use is as textile fibers, but they have many other applications . It is a condensation polymerization process.

17. Nylon R epeating Units and Formulation

18. Polyester Polyester  is a category of polymers that contain the ester functional group in their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET ). Synthesis of polyesters is generally achieved by a polycondensation reaction. See "condensation reactions in polymer chemistry". The general equation for the reaction of a diol with a diacid is : ( n+1) R(OH) 2  + n R´(COOH) 2  → HO[ROOCR´COO] n ROH + 2n H 2 O

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