2. Introduction
Condensation Polymerization
Polymerization reactions may be broadly
classified as step-growth and chaingrowthreactions.
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).
3. IUPAC name
Poly[imino(1,6-dioxohexamethylene) imnohexamethylene.
Other names
Poly(hexamethylene adipamide),Poly(N,Nโฒ-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 ยฐC (77 ยฐF), 100 kPa)
8. 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
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13. properties
Nylon 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.
14. Physical Properties
You 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.
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16. 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.
19. Advantages
๏ Variation of luster: nylon has the ability to be very lustrous,
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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
20. Disadvantages
๏ High moisture pick-up with related
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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
21. Environment effect
In 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