Chemical properties
Nylon 6, 6 fibres is more resistant to acids or alkalis in comparison with nylon 6 fibre because of light intermolecular forces present in the structure. The fibre is unaffected by most mineral acids, except hot mineral acids. The fibre dissolves with partial decomposition in concentrated solutions of hydrochloric acid, sulphuric acid and nitric acid. The fibre is soluble in formic acid. In a similar way, the fibre is attacked by strong alkalies under extreme conditions otherwise it is inert to alkalis. The fibre can be bleached by most of the bleaching agents. The fibre is mostly insoluble in all organic solvents except some phenolic compounds.
The fibre has excellent resistance to biological attacks. Prolonged exposure to sunlight causes fibre degradation and loss in strength.
The fibre can be dyed by almost all type of dyestuffs like direct, acid, metal-complex, chrome, reactive, disperse and pigments. However only acid and metal complex dyes are preferred because of higher fastness properties.
Applications
Nylon polymers has been used in many different aspects of our life. Nylons are mostly used as fibers. It is also used in tiers, ropes, ponchos, parachutes and other military goods. Nylon resins are widely used in the automobile industry especially in the engine compartment. Molded nylons are used in mechanical parts such as machine screws, gears and other low- to medium-stress components. Nylon is available in glass-filled variants which increase structural and impact strength and rigidity, and molybdenum disulfide-filled variants which increase lubricity. Nylon was used to make the stock of the Remington Nylon 66 rifle. The frame of the modern Glock pistol is made of a nylon composite. Nylon polymers are also used in brushes, 3d printers and guitars.
Conclusion
After all the research works and information we conclude that Nylon 6,6 is a semi-crystalline, off-white engineering thermoplastic that is the strongest and most abrasion resistant reinforced aliphatic nylon with better low temperature toughness than Nylon 6 or acetal. Its very low melt viscosity can give industrial processing difficulties and weathering can cause embrittlement and color change unless it is stabilized or protected. Available with a wide range of fillers notably glass fibre, which gives a marked increase in stiffness, and solid and liquid (oil) lubricants. Super-tough grades are also available whose impact properties and low notch sensitivity are amongst the best of all engineering thermoplastics.
Applications include mainly engineering components eg gears, bearings, nuts, bolts, rivets and wheels and power tool casings and rocker box covers. Widely used as monofilament for brushes etc and fibre - notable for its resilience and high abrasion resistance - for apparel, carpet and industrial end-uses.
References