Polymers and Plastics

Polymers that occur naturally is cellulose. Cellulose is made up of a large number of glucose units.

 Synthetic fibers are very durable and no attacked by insects or pests.

 Melamine is a special type of synthetic plastic which is fire resistant and is used in the making of uniforms of firemen. Teflon is also a synthetic fibre but it is not fire resistant.

 Nylon is made when the appropriate monomers adipic acid and hexamethylene diamine.

 PVC is a thermoplastic. Also, polyethylene is a type of polymer that is a thermoplastic and PET is a thermosetting plastic.

 Electric plugs and switches are made of thermosetting plastics because they are bad conductors of heat and electricity. So, bakelite and melamine both are used to manufacture plugs and switches.

Aerogel is a manufactured material with the lowest bulk density of any known porous solid. It is derived from a gel in which the liquid component of the gel has been replaced with a gas. The result is an extremely low-density solid, with a notable effectiveness as a thermal insulator.

 Cyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is used as a non-polar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which are intermediates used in the production of nylon. On an industrial scale, cyclohexane is produced by reacting benzene with hydrogen.

This option is correct because Polythene, PVC and DDT are third generation petrochemicals derived from ethylene, vinyl chloride and chlorobenzene respectively.

Rayon is a manufactured regenerated cellulose fiber. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fiber nor a natural fiber; it is a semi-synthetic or artificial fiber. Rayon is known by the names viscose rayon and art silk in the textile industry. It usually has a high luster quality giving it a bright sheen.

Acrylic fibers are synthetic fibers made from a polymer (polyacrylonitrile) with an average molecular weight of ~100,000, about 1900 monomer units. It s lightweight, soft, and warm, with a wool-like feel. Acrylic is coloured before it is turned into a fiber as it does not dye very well but has excellent colour fastness. 

In friction welding, the two parts to be assembled are rubbed together at a lower frequency (typically 100-300 Hz) and higher amplitude than ultrasonic welding. The friction caused by the motion combined with the clamping pressure between the two parts creates the heat which begins to melt the contact areas between the two parts. At this point, the plasticized materials begin to form layers that intertwine with one another, which therefore results in a strong weld.

Methylaluminoxane, is pyrophoric, and is violently reactive with any chemical bearing an acidic proton. However, it is generally used as a solution in an (aromatic) hydrocarbon due to its relatively high solubility in such hydrocarbons.It is most well known for being a co-catalyst for olefin polymerizations of the Ziegler-Natta type.

Nylon is a synthetic plastic polymer, specifically a polyamide. It was the first completely synthetic fiber and is known for its strength and durability.

This option is correct,  because gutta percha is all trans-polyisoprene while natural rubber is all cis-polyisoprene.