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.