Polyamide -6,-11,-12,-6,6,-6,9,-6,10 or -6,12:

39.08 - Polyamides in primary forms. 3908.90 - Other This heading covers polyamides and copolymers thereof. Linear polyamides are known as nylons. Polyamides are obtained by condensation polymerisation of dibasic organic acids (for example, adipic acid, sebacic acid) with diamines or of certain ammo-acids (e. ., 11-aminoundecanoic acid) or by rearrangement polymerisation of lactarns (e.g., epsilon-capro actam). f Some of the important n lon type polyamides are olyamide-6, olyamide-1 1, pol amide-12, polyamide-6,6, olyami e-6,9, polyamide-6,lO an~golyamide-tf12. Exam les o non-linear polyamides are t e condensation products of dimerise vegetable oil acids wi amines. Yl 6' 5, Polyamides have a high tensile strength and resistance to shock. They also have excellent chemical resistance, especially to aromatic and aliphatic hydrocarbons, ketones and esters. Apart from their use as textiles, polyamides have a wide application as thenno lastics in moulding. They are also used as coatings, adhesives, packaging films.In solvents,ey!t have a specialised use as lacquers. For the classification of olymers (includin copolymers , chemically modified polymers and polymer blends, see the eneral Explanatory ote to this Jhapter. k