Nylon fiber | Properties, Types | Applications of Nylon fiber

 

Nylon fiber

Nylon fiber is a synthetic polymer that is composed of polyamides. It is a thermoplastic silky material that can be melted-processed into fibers, films, or shapes. It can be mixed with a variety of additives to achieve a wide variety of properties. Nylon polymers have significant commercial applications in fabrics and fibers, sizes, and films.

DuPont began testing for the development of cellulose-based fibers and eventually produced synthetic fiber rayon. Dupont's experience with rayon was an important precursor in the development and marketing of nylon. DuPont's invention of nylon spanned a period of eleven years, ranging from initial research activities on polymers in 1927 to shortly before the opening of the New York World's fair in 1939. Julian W. Hill used a cold drawing method in 1930 to produce polyester.

Later in 1935 Carothers used this cool drawing method to fully develop nylon. The first example of nylon 6, 6 was produced on 28 February 1935 in DuPont's research file at the DuPont Experimental Station. Dupont received a polymer patent in September 1938 and quickly acquired a monopoly on fiber. Carothers died 16 months before the nylon announcement, so he never saw his success.

Properties of Nylon fiber

i. Normal cross-section of Nylon fiber is tribular/circular type

ii. The density of nylon fiber is 1.14 g/cc.

iii. It is 65-85% crystalline

iv. Nylon fibers moisture regain is 4%

v. The high crystallinity of the polymer system makes nylon more crease-resistant.

vi. Nylon fiber has the ability to be very lustrous, semi-lustrous, or dull.

vii. The durability of nylon fiber is very high.

viii. Nylon fiber has an excellent abrasion resistance

ix. Nylon fiber has a high resistance to insects, fungi, and animals, as well as molds, mildew, rot, and many chemicals.

x. Nylon fibers have more chemically sensitive than cotton

xi. They are wrinkle-proof and highly resistant to abrasion and chemicals such as acids and alkalis.

xii. It Melts instead of burning.

Xiii. Substantially inert to alkalis.

Types of Nylon fiber

Nylon 66

Nylon 66 is a type of polyamide or nylon that is most common for the textile and plastic industries. It is made of two monomers that all are containing 6 carbon atoms, hexamethylenediamine, and adipic acid, which is given its name. This reaction creates a nylon salt mixture. After removing water these salts react with adipic acid and amine function, creating an amide bond that means polymer. These polymers are directly spun into fibers by extrusion through a spinneret and cooling for filaments.

n(HOOC-(CH2)4-COOH) + n(H2N-(CH2)6-NH2) = [-OC-(CH2)4-CO-NH-(CH2)6-NH-]n + (2n-1) H2O

Nylon 6

Nylon 6 is another type of polymer that can be modified using comonomers or stabilizers during polymerization to introduce new chain ends or functional groups, which changes the reactivity and chemical properties. It is synthesized by ring-opening polymerization of caprolactam. Caprolactam has 6 carbons, so it is called Nylon 6. When caprolactam is heated at about 533 K the ring breaks and undergoes polymerization. Then the molten polymer is passed through spinnerets to form fibers of nylon 6.

Nylon 510

Nylon 510 is synthesized from pentamethylene diamine and sebacic acid but is more expensive to make. Linear polymers are usually the most effective, but it is possible to introduce nylon branches by concentrations of dicarboxylic acids with polyamines that have three or more amino groups.

Nylon 1,6

Nylon 1,6 is a type of polyamide that is not a condensation polymer but instead is formed by an acid-catalyzed synthesis from adiponitrile, formaldehyde, and water. The material was produced and studied by researchers at DuPont in the 1950s at room temperature in open beakers.

CH2O + NC-(CH2)4-CN + H2O → [-NH-CH2-NH-OC-(CH2)4-CO-] n

Applications of Nylon fiber

i. Nylon fiber is used for making plastic machine parts as it is low-cost and long-lasting.

ii. It is often commonly used in the electronics industry for its non-conductivity and heat resistance.

iii. It is used for screws, bolts, washers, and nuts as well as circuit board hardware.

iv. It is used to make bearings for the appliance industry because of its excellent abrasion resistance

v. It is used in cookware including spatulas, slotted spoons, turners, forks, tongs, and brushes since it has a relatively high continuous service temperature.

vi. It is used in making book bags, backpacks, and flak jackets.

vii. Its fibers are used in textiles, fishing lines, and carpets.

viii. Its films are used for food packaging.

ix. Nylon 6 is used in large applications in sports, such as ski bindings and in-line skates.

x. Nylon 66 is used when needs high mechanical strength, rigidity, good stability under heat, and chemical resistance. It is used in fibers for textiles and carpet making. Its special application is in the electrical and electronics industry.