Preparation of nylon 6,6 by condensation polymerization

 University of Salahaddin college of science

Date: 21/1/2014

Introduction Condensation PolymerizationPolymerization reactions may be broadly classified as step-growth and chain-growthreactions. nylon 6,6 is an aliphatic polyamide that is synthesized using A-A/B-B step-growth condensation-polymerization. The two monomers involved in this polymerization are hexamethylenediamine and adipic acid .each of which is bifuctional (i.e., two ends of each are reactive), and each end contains the same functionality (i.e., A or B functional groups).

IUPAC namePoly[imino(1,6-dioxohexamethylene) imnohexamethylene.

Other namesPoly(hexamethylene adipamide),Poly(N,N′-hexamethyleneadipinediamide), Maranyl, Ultramid, Zytel, Akromid, Durethan, Frianyl, Vydyne

Properties

Molecular formula (C12H22N2O2)n

Density 1.14 g/mL (Zytel)

Melting point 542 K

Except where noted otherwise, data are given for materials in

their standard state (at 25 °C (77 °F), 100 kPa)

Types of nylonNylon 4-

6Nylon 6Nylon 6-

6Nylon 6-

10Nylon 6-

11Nylon 6-

12

synthesis• 

Hexamethlenediamine (1,6-hexanedi-amine)

Adipic acid, Sodium Hydroxide .Solvent: tap water and cyclohexane.

H O O ║ ║

H2N-CH2-CH2-CH2-CH2-CH2-CH2-NH + HOC-CH2-CH2-CH2-CH2-COH

H O O │ ║ ║ H2N-CH2-CH2-CH2-CH2-CH2-CH2-N-C-CH2-CH2-CH2-CH2-C-OH + H2O (Nylon 6,6)

Mechanism of preparation nylon is made by a reaction which is a 

step-growth polymerization, and a condensation polymerization. Nylons are made from diacids and diamines. If you want to see what adipic acid and hexamethylene diamine

propertiesNylon is a family of plastics. Nylon properties include; moisture has significant effect on properties, fair to easy processing, very good physical properties, very good heat resistance, excellent chemical resistance, and excellent wear resistance, moderate to high price.

Physical PropertiesYou may ask yourself, "Why does nylon act as it does?" You may ask yourself, "Why does nylon make such good fibers?" The answer to both is pretty simple: intermolecular forces. the different kinds of intermolecular forces. When we're talking about nylons, the most important intermolecular force is hydrogen bonding. The nitrogen-bonded hydrogens of one nylon chain will hydrogen bond very strongly with the carbonyl oxygens of another nylon chain. These hydrogen bonds make crystals of nylon very strong, because they hold the nylon chains together very tightly. Of course, these strong crystals make strong fibers.

Application of nylon Nylon 6-6 is frequently used when high

mechanical strength, great rigidity, and good stability under heat is required . It is used for ball bearing cages, electro-insulating elements, pipes, profiles and various machine parts. Other popular applications are: carpet fibres, airbags, tyres, ropes.

Nylon fabric Nylon plastic

Nylon roll

AdvantagesVariation of luster: nylon has the ability to be

very lustrous, semilustrous or dull. Durability: its high tenacity fibers are used for

seatbelts, ballistic cloth and other uses. High elongation Excellent abrasion resistance Highly resilient. High resistance to: insects, fungi and animals molds, mildew, rot many chemicals Used in carpets and nylon stockings Melts instead of burning Used in many military applications

Disadvantages

High moisture pick-up with related dimensional instability

- Requires UV stabilization - High shrinkage in molded sections - High moisture absorptivity degrades

electrical and mechanical properties - Attacked by oxidizing agents - Attacked by strong acids and bases - High notch sensitivity

Environment effectIn 1975 a team of Japanese scientists studying ponds containing waste water from a nylon factory, discovered a strain of Flavobacterium that digested certain byproducts of nylon 6manufacture, such as the linear dimer of 6-aminohexanoate