gives Є- amino carproic acid which polymerises to give nylon – n n n 533K H O H N (CH ) COOH -H O NH (CH ) Nylon - It is used in the manufacture of tyrecards fabrics etc…. II. Preparation of terylene (Dacron) The monomers are ethylene glycol and terepathalic acid (or) dimethylterephthalate. When these monomers are mixed and heated at 500K in the presence of zinc acetate and antimony trioxide catalyst, terylene is formed.
XII U15 Chemistry in XII U15 Chemistry in - - - - HO HO n ethan- , -diol benzene- , -dicarboxylic acid K Zn(OOCCH ) + Sb O OCH Terylene (an polyester) n n It is used in blending with cotton or wool fibres and as glass reinforcing materials in safety helmets. Preparation of Bakelite The monomers are phenol and formaldehyde. The polymer is obtained by the condensation polymerization of these monomers in presence of either an acid or a base catalyst. Phenol reacts with methanal to form ortho or para hydroxyl methylphenols which on further reaction with phenol gives linear polymer called novolac.
Novalac on further heating with formaldehyde undergo cross linkages to form bakelite. H + / OH CH -OH CH - OH CH OH n - n H O No n volac n H OH CH OH CH OH CH (Bakelite) Uses: Navolac is used in paints. Soft bakelites are used for making glue for binding laminated wooden planks and in varinishes, Hard bakelites are used to prepare combs, pens etc.. XII U15 Chemistry in XII U15 Chemistry in - - - - Melamine (Formaldehyde melamine): The monomers are melamine and formaldehyde.
These monomers undergo condensation polymerisation to form melamine formaldehyde resin. NH H N NH Melamine Methanal NH H H N H condensation Polymerisation HN NH H * n Melamine-formaldehyde polymer Uses: It is used for making unbreakable crockery Urea formaldehyde polymer: It is formed by