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![]() Teflon Rod |
![]() Nylon Rod |
![]() Teflon & Nylon Sheets |
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About
Teflon/Nylon:
Teflon

Teflon® is polytetrafluoroethylene (PTFE),
a polymer of fluorinated ethylene.

3D model of a section of PTFE
Polytetrafluoroethylene (PTFE) is a fluoropolymer discovered by Roy J. Plunkett
(1910–1994) of DuPont in 1938. It was introduced as a commercial product in 1946
and is generally known to the public by DuPont's brand name Teflon®.
PTFE has the lowest coefficient of friction (against polished steel) of any
known solid material. It is used as a non-stick coating for pans and other
cookware. PTFE is very non-reactive, and so is often used in containers and
pipework for reactive chemicals. According to DuPont its melting point is 327
°C,[2] but its properties degrade above 260 °C.
Other polymers with similar composition are known with the Teflon® name:
fluorinated ethylene-propylene (FEP) and perfluoroalkoxy polymer resin (PFA).
They retain the useful properties of PTFE of low friction and non-reactivity,
but are more easily formable. FEP is softer than PTFE and melts at 260 °C;[3] it
is highly transparent and resistant to sunlight.
Properties and applications
Amongst many other industrial applications, PTFE is used to coat certain
types of hardened, armour-piercing bullets, so as to reduce the amount of wear
on the firearm's rifling. These are often mistakenly referred to as "cop-killer"
bullets by virtue of PTFE's supposed ability to ease a bullet's passage through
body armour. Any armour-piercing effect is, however, purely a function of the
bullet's velocity and rigidity rather than a property of PTFE.
PTFE has excellent dielectric properties. This is especially true at high radio
frequencies, making it eminently suitable for use as an insulator in cables and
connector assemblies and as a material for printed circuit boards used at
microwave frequencies. Combined with its high melting temperature, this makes it
the material of choice as a high performance substitute for the weaker and more
meltable polyethylene that is commonly used in low-cost applications. Its
extremely high bulk resistivity makes it an ideal material for fabricating long
life electrets, useful devices that are the electrostatic analogues of magnets.
Due to its low friction, it is used for applications where sliding action of
parts is needed: bearings, bushings, gears, slide plates, etc. In these
applications it performs significantly better than nylon and acetal; it is
comparable with ultra high molecular weight polyethylene (UHMWPE), although
UHMWPE is more resistant to wear than Teflon®. For these applications, versions
of teflon with mineral oil or molybdenum disulfide embedded as additional
lubricants in its matrix are being manufactured.
Because of its chemical inertness, PTFE cannot be cross-linked like an elastomer.
Therefore it has no "memory", and is subject to creep (also known as cold flow
and compression set). This can be both good and bad. A little bit of creep
allows PTFE seals to conform to mating surfaces better than most other plastic
seals. Too much creep, however, and the seal is compromised. Compounding fillers
are used to control unwanted creep, as well as to improve wear, friction, and
other properties.
Gore-Tex is a material incorporating Teflon® membrane with micropores. The roof
of the Hubert H. Humphrey Metrodome in Minneapolis is the largest application of
Teflon® on Earth, using 20 acres of the material in a double-layered white dome,
made with PTFE-coated fiberglass, that gives the stadium its distinctive
appearance.
Powdered PTFE is used in pyrotechnic compositions as oxidizer together with
powdered metals such as aluminum and magnesium (see Magnesium/Teflon/Viton).
Upon ignition these mixtures form carbonaceous soot and the corresponding metal
fluoride and release large amounts of heat. Hence they are use as infrared decoy
flares and igniters for solid fuel rocket propellants.
Nylon

|
Density |
1.15 g/cm³ |
|
Electrical conductivity (σ) |
10-12 S/m |
|
Thermal conductivity |
0.25 W/(m·K) |
|
Melting points |
463 K-624 K |
Nylon
represents a family of synthetic polymers, a thermoplastic material, first
produced on 28 February, 1935 by Gerard J. Berchet of Wallace Carothers'
research group at DuPont. The first product was a nylon-bristled toothbrush
(1938), followed more famously by women's 'nylons' stockings (1940). It is made
of repeating units linked by peptide bonds (another name for amide bonds) and is
frequently referred to as polyamide (PA). Nylon was the first commercially
successful polymer and the first synthetic fiber to be made entirely from coal,
water and air. These are formed into monomers of intermediate molecular weight,
which are then reacted to form long polymer chains. It was intended to be a
synthetic replacement for silk and substituted for it in parachutes after the
United States entered World War II in 1941, making stockings hard to find until
the war's end. Nylon fibers are now used in fabrics and ropes, and solid nylon
is used for mechanical parts and as an engineering material. Engineering grade
Nylon is processed by extrusion, casting & injection molding. Type 6/6 Nylon 101
is the most common commercial grade of Nylon, and Nylon 6 is the most common
commercial grade of cast Nylon.
Bulk properties
Above their melting temperatures, Tm, thermoplastics like nylon are amorphous
solids or viscous fluids in which the chains approximate random coils. Below Tm,
amorphous regions alternate with regions which are lamellar crystals.[1] The
amorphous regions contribute elasticity and the crystalline regions contribute
strength and rigidity. The planar amide (-CO-NH-) groups are very polar, so
nylon forms multiple hydrogen bonds among adjacent strands. Because the nylon
backbone is so regular and symmetrical, especially if all the amide bonds are in
the trans configuration, nylons often have high crystallinity and make excellent
fibers. The amount of crystallinity depends on the details of formation, as well
as on the kind of nylon. Apparently it can never be quenched from a melt as a
completely amorphous solid.
Nylon 6,6 can have multiple parallel strands aligned with their neighboring
peptide bonds at coordinated separations of exactly 6 and 4 carbons for
considerable lengths, so the carbonyl oxygens and amide hydrogens can line up to
form interchain hydrogen bonds repeatedly, without interruption. Nylon 5,10 can
have coordinated runs of 5 and 8 carbons. Thus parallel (but not antiparallel)
strands can participate in extended, unbroken, multi-chain β-pleated sheets, a
strong and tough supermolecular structure similar to that found in natural silk
fibroin and the β-keratins in feathers. (Proteins have only an amino acid
α-carbon separating sequential -CO-NH- groups.) Nylon 6 will form uninterrupted
H-bonded sheets with mixed directionalities, but the β-sheet wrinkling is
somewhat different. The three-dimensional disposition of each alkane hydrocarbon
chain depends on rotations about the 109.47° tetrahedral bonds of singly-bonded
carbon atoms.
When extruded into fibers through pores in an industrial spinneret, the
individual polymer chains tend to align because of viscous flow. If subjected to
cold drawing afterwards, the fibers align further, increasing their
crystallinity, and the material acquires additional tensile strength.[2] In
practice, nylon fibers are most often drawn using heated rolls at high speeds.
Block nylon tends to be less crystalline, except near the surfaces due to
shearing stresses during formation. Nylon is clear and colorless, or milky, but
is easily dyed. Multistranded nylon cord and rope is slippery and tends to
unravel. The ends can be melted and fused with a flame to prevent this.
There are carbon fiber/nylon composities with higher density than pure nylon.
Historical uses
Bill Pittendreigh, Dupont industries, and other individuals and corporations
worked diligently during the first few months of World War II to find a way to
replace Asian silk with nylon in parachutes. It was also used to make tires,
tents, ropes, ponchos, and other military supplies. It was even used in the
production of a high-grade paper for U.S. currency. At the outset of the war,
cotton accounted for more than 80% of all fibers used, and manufactured and wool
fibers accounted for the remaining 20%. By August, 1945, manufactured fibers had
taken a market share of 25% and cotton had dropped.
Some of the terpolymers based upon nylon are used every day in packaging. Nylon
has been used for meat wrappings and sausage sheaths.
Some people, such as Jack Herer, surmise that Cannabis sativa was made illegal
because the fibers from the hemp plant, used for fabrics and ropes, were in
strong competition with nylon (along with paper, fuel, and other industries).
While the production of rope from hemp requires no chemicals or industrial
processes, nylon fiber is more than twice as strong as hemp and weighs 25% less.
An additional problem is that hemp rope rots from the inside out, making it
difficult to determine the condition of a rope at a glance. While hemp was
originally used in climbing rope, this is no longer the case, even in countries
where cannabis is legal.
Uses
• nylon fiber
• clothing
• pantyhose
• toothbrush bristles
• fishing lines
• carpet fiber
• airbag fiber
• auto parts: intake manifolds, gas (petrol) tanks
• slings and rope used in climbing gear
• machine parts, such as gears and bearings
• parachutes
• metallized nylon balloons
• classical and flamenco guitar strings
• paintball marker bolts
• racquetball, squash, and tennis racquet strings
• Chompy Strings
• Guitar Strings