Polymer and polymer nano-composites
It has been established in recent years that polymer-based composites reinforced with a small percentage of strong fillers can significantly improve the mechanical, thermal and barrier properties of the pure polymer matrix. Moreover, these improvements are achieved through conventional processing techniques without any detrimental effects on processability, appearance, density and aging performance of the matrix. Now-a-day's hybrid polymers (such as Organoallcoxy silanes), which are the hybrid structure of inorganic-organic nano-composite materials are being used to impart the combination of scatch resistance with dirt-repellent effect, high transparency, special barrier properties or antimicrobial function to the material.
Clay nano-particles: Clay basically consists of hydrous aluminosilicate and is low in density. Nanosize clay particles or flaks can impart excellent flame retardant functionality to the textile due to the heat resistant behaviour of the nanoclay (14). UV blocking power and outstanding barrier functionality are due to the internees of nanoclay to corrosive chemicals and its neatly layers configuration inside fibre. In terms of mechanical attributes, nylon6 clay composite with a clay mask fraction of 5% shows 40% higher tensile strength, 68% greater tensile modulus, 60% higher flexural strength, and 126% greater flexural modulus.
Such a significant improvements in composite strength even leads to application of nano clay filler as a protective insert in infantry helmets. Nano clay fillers modified with quaternary ammonium salt have been introduced into polypropylene fibre, the resultant fibre can be coloured by acid and disperse dyes to 1-4% colour shades for incorporation of less than 5% nano-dry fillers. The modified nano clay introduces dye attaching sites to the polypropylene fibre generates void space inside the fibre to entrap dyes without degrading the beneficial properties of polypropylene.
Carbon nano particles: Carbon nano black particles are extremely effective reinforcing material for composite fibres . With their high aspect ratio, carbon black nano particles can improve abrasion resistance and hence increase the durability of composite fibres. Carbon black nano particles can also result in high chemical resistance and electric conductivity after they are mixed with fibre polymer matrix. Polyester, nylon and polypropylene have been used as polymer matrix with weight percentage of nano size filler range from 5% to 20%.
Dapeng Li and Gang Sun have reported that carbon black nano-particles can directly be used in traditional dyeing processes to dye polyester and acrylic fabrics. Polyester and acrylic fabric were dyed with nano carbon black particles using a dip-pad, dry and cure technique. Effective colouration of these fabrics has been reported with 8 nm particles, using cationic dispersing agent, at 1800C treatment temperature.
