Correct answer. On the basis of molecular forces, polymers UFR and bakelite are the examples of thermosetting polymers.

Correct answer. Vectran is an aromatic polyester and used as reinforcing (matrix) fibres for ropes, cables, sailcloth and advanced composite materials, professional bike tires and in electronic applications. It is not used in the formation of waterproof seat covers.

Correct answer. PA6 (nylon 6) is an amorphous polymer, which is made from the polymerisation of caprolactam, not from hexamethylenediamine and anthranilic acid. A model from Solvay industries and Trogamid from Evonik Industries are semi-aromatic polyamides and are made from the polymerisation of hexamethylenediamine and terephthalic acid. Hence, both Q and R are false.

Correct answer. Both Kevlar and Twaron are the registered trademark for para-aramid synthetic fibres, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, Kevlar was first commercially used in the early 1970s as a replacement for steel in racing tires. Kevlar is used in modern times to make modern drumheads that withstand high impact, tyre making and underwater applications, etc. Nomex is the registered trademark for meta-aramid synthetic fibre.

Correct answer. Neoprene is a synthetic rubber and is prepared by the polymerisation of chloroprene as monomer unit.

Correct answer. Terylene (polyester) is a synthetic fibre, which is made from the condensation of ethylene glycol and dimethyl terephthalate.

Correct answer. A large number of polymer applications in different fields depend on their unique mechanical properties like tensile strength, elasticity, toughness, etc. These mechanical properties are governed by intermolecular forces such as van der Waals forces and hydrogen bonds present in the polymer. These forces also bind the polymer chains. Under this category, the polymers are classified into the following four subgroups on the basis of magnitude of intermolecular forces present in them - elastomer, fibre, thermoplastic and thermosetting. Elastomers are rubber–like solids with elastic properties. In these elastomeric polymers, the polymer chains are held together by the weakest intermolecular forces. These weak binding forces permit the polymer to be stretched. A few ‘crosslinks’ are introduced in between the chains, which help the polymer to retract to its original position after the force is released as in vulcanised rubber. Examples are buna S, buna N, neoprene, bromobutyl, Viton (a brand of synthetic rubber and fluoropolymer elastomer commonly used in O-rings and other molded or extruded goods), etc.

Correct answer. Cellulose derivatives such as cellulose acetate (rayon) and cellulose nitrate, etc. are the usual examples of this subcategory.

Correct answer. Cellulose is a homopolymer of glucose as a monomer unit. Insulin is a homopolymer of fructose as a monomer unit and Glyptal is a copolymer of ethylene glycol and phthalic acid. Bakelite is a condensation polymer (copolymer) of phenol and formaldehyde. Hence, statements P and S are incorrect.

Correct answer. Polyetherimide (PEI) is an amorphous, amber-to-transparent thermoplastic, which is made from the polymerisation of etherimide.

Correct answer. Poly methyl methacrylate (PMMA) is produced by the homopolymerisation of methyl methacrylate.

Correct answer. Synthetic polymers are human-made polymers. From the utility point of view, they can be classified into four main categories: thermoplastics, thermosets, elastomers and synthetic fibres. An elastomer is a polymer with viscoelasticity (having both viscosity and elasticity) and very weak intermolecular forces. For example, polychloroprene, neoprene, baypren, elastolefin, etc.

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The best known brand name of PTFE is Syncolon. Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a highly non-reactive and pure thermoplastic fluoropolymer produced by the polymerisation of vinylidene difluoride. PVDF is sold under a variety of brand names including Hylar (Solvay), Kynar (Arkema) and Solef (Solvay). Polyethylene oxide (PEO) is formed from the polymerisation of ethylene oxide. The preparation of PEO is sold under the brand names GoLYTELY, GaviLyte C, NuLytely, GlycoLax, Softlax, Fortrans, etc. Hostaphan is the brand name of polyethylene terephthalate (PET).

Hence, the representation of codes A - 2, B - 1, C - 4, D - 3 is correct.

Polyvinyl butyral (PVB) is a resin, which is usually used for applications that require strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility. It is prepared from polyvinyl alcohol by reaction with butyraldehyde. The major application is in the making of laminated safety glass for automobile windshields. Orlon is an addition polymer of acrylonitrile, which is used for making clothes and fabrics like sweaters, hats, yarns, rugs, etc. Bakelite is the condensation polymer (copolymer) of phenol and formaldehyde. Bakelite is high electric-, heat- and chemical-resistant polymer and is used in the insulation of manufacturing wires, manufacturing sockets, electrical devices, brake pads, etc. Twaron is the brandname of Teijin Aramid for a para-aramid. It is a heat-resistant and strong synthetic fibre developed in the early 1970s by the Dutch company AKZO. Twaron is a p-phenylene terephthalamide (PpPTA), the simplest form of the AABB para-polyaramide. It is used in the making of bulletproof body armour, helmets, brake pads, ropes, etc.

Hence, the correct answer using the codes is P - 2 - i, Q - 3 - iv, R - 4 - iii, S - 1 - ii.

Terylene (polyester) is the condensation polymer of ethylene glycol and dimethyl terephthalate. Nylon 66 is the condensation polymer of hexamethylenediamine and adipic acid. Perspex (polymethyl methacrylate) is prepared by the polymerisation of methyl methacrylate. Polyvinyl chloride (PVC) is formed by the polymerisation of vinyl chloride.

Hence, the correct answer using the codes is P - 3, Q - 4, R - 1, S - 2.