A blowing agent is a substance which is capable of producing a cellular structure via a foaming process in a variety of materials that undergo hardening or phase transition, such as polymers, plastics and metals. Chemical blowing agents are isocyanate and water (for PUs), azo-, hydrazine and other nitrogen-based materials (for thermoplastic and elastomeric foams), sodium bicarbonate (aka baking soda, used in thermoplastic foams). Titanium hydride is used as a foaming agent in the production of metal foams, as it decomposes to form titanium and hydrogen gas at elevated temperatures.

The glass transition temperature is the reversible transition in amorphous materials or in amorphous regions within semicrystalline materials from a hard and relatively brittle state into a molten or rubber-like state. The glass transition temperature of polymethyl methacrylate is 105 ^oC. The glass transition temperature of polyvinyl alcohol is 85 ^oC. The glass transition temperature of polyvinyl chloride is 80 ^oC. The glass transition temperature of polyethylene terephthalate is 70 ^oC. The glass transition temperature of poly carbonate is 145 ^oC. Hence, poly carbonate has the highest Tg.

Thermosetting polymers: These polymers are cross-linked or heavily branched molecules which, on heating, undergo extensive cross linking in moulds and again become infusible. These cannot be reused. Some common examples are bakelite, urea-formaldelyde resins (UFR), etc. Melamine resin is an example of thermosetting polymers and used in the making of worktop surfaces. Duroplast is a thermosetting polymer that is light in weight. It is used for making car parts.  Hence, melamine resin and duroplast are the examples of thermosetting polymers.   

Polynucleotides such as DNA are composed of a variety of nucleotide subunits as monomer units.

Polyacrylonitrile (PAN) is made from the addition polymerisation of acrylonitrile and is manufactured under the brand name of Orlon.

The examples of non-biodegradable polymers are- PMMA (poly methyl methacrylate), PVC (polyvinyl chloride), PVAc (polyvinyl acetate), PFR (phenol formaldehyde resin), PP (polypropylene) etc.

P. PVC (polyvinyl chloride) has glass transition temperature of 80 ^oC. The glass transition temperature of nylon-6,6 is 70 ^oC. Q. Polyetherimide (PEI) is an amorphous, amber-to-transparent thermoplastic. Ultem is a family of PEI products manufactured by SABIC as a result of acquiring the General Electric Plastics Division in 2007. Ultem resins are used in medical and chemical instrumentation due to their heat, solvent and flame resistance properties. R. Polyethylene terephthalate (PET), or polyethylene terephthalic ester (PETE), is a condensation polymer produced from the monomers ethylene glycol, (a dialcohol) and dimethyl terephthalate (a diester). PET fibers are manufactured under the trade name of Dacron. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The best known brand name of PTFE is Teflon by DuPont Co. Hence, the statement R is false.

P. Polysulfone describes a family of thermoplastic polymers. A typical polysulfone is produced by the reaction of a diphenol and bis(4-chlorophenyl)sulfone, forming a polyether by elimination of sodium chloride. Q. Urea formaldehyde resin (UFR) is prepared from the condensation reaction of urea with formaldehyde. R. Orlon is the brand name of polyacrylonitrile, that is used mainly in the making of clothes and fabrics like sweaters, hats, yarns, rugs. Hence, only statement P is false.

An adhesive is any substance applied to the surfaces of materials that binds them together and resists separation. The examples of polymers used as adhesives are- polyvinyl acetate (PVAc), dextrin from vegetable starch, cyanoacrylates, polyurethane (PU), epoxy resins (ER) etc. Polychlorotrifluoroethylene (PCTFE) is stable to heat and thermal attacks, has high tensile strength and non wetting properties. It is used in the making of valves, seals, gaskets etc.

Polytetrafluoroethylene (PTFE) has the glass transition temperature of 115 ^oC. The glass transition temperature of polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is -35 ^oC. Polysulphone (PSF) has the glass transition temperature of 185 ^oC. The glass transition temperature of nylon-6 is 47 ^oC. Hence, the representation of codes A - 2, B - 1, C - 4, D - 3 is the correct answer.

P. Poly(methyl methacrylate) (PMMA) or perspex by brand name, is a transparent thermoplastic often used as a lightweight or shatter-resistant alternative to glass. Q. Rayon is a semi-synthetic polymer. It is made from purified cellulose, primarily from wood pulp, which is chemically converted into a soluble compound. It is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in synthetic fibers of nearly pure cellulose. R. Celluloids are a class of compounds created from nitrocellulose and camphor, with added dyes and other agents. Generally considered the first thermoplastic, it was first created as Parkesine in 1856 and as xylonite in 1869, before being registered as celluloid in 1870. Celluloid is easily molded and shaped, and it was first widely used as an ivory replacement. The main purpose was movie and photography film industries. Hence, only statement R is the correct answer.

Mylar is the brand name of polyethylene terephthalate (PETP). Poly ethylene 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, Fortrans etc. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The most common brand or trade name of PTFE is Teflon. Poly-p-phenylene-2,6-benzobisoxazole (PBO) has very high tensile strength and thermal stability. It is marketed as zylon and is used in the making of tennis racquets, table tennis blades, body armor etc. Hence, the representation of codes A - 2, B - 1, C - 4, D - 3 is correct.

The usage of printing thickeners depends on the printing technique and fabric and dyestuff used. Typical thickening agents are- starch derivatives, Polyacrylamide (PAA), sodium alginate (SA). Albumen is both a thickening and a fixing agent for insoluble pigments such as chrome yellow. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene having numerous applications such as low friction bearings, non-stick pans, anticorrosive coating materials etc. Hence, P, Q, R are used as thickening agents for textiles and papers.

Plasticizers or dispersants are additives that increase the plasticity or fluidity of a material. The dominant applications are for plastics, especially polyvinyl chloride (PVC). Examples are- Trimethyl trimellitate (TMTM), Dioctyl adipate (DOA), Dibutyl sebacate (DBS), Tricresyl phosphate (TCP) etc. Epoxy resins, also known as polyepoxides,  are a class of reactive prepolymers and polymers which contain epoxide groups. The applications for epoxy-based materials are extensive and include coatings, adhesives and resin matrices for composite materials. Examples are- Bisphenol F epoxy resin (BPFER), Novolac epoxy resin (NER). Hence, 1, 2 and 4 are the examples of plasticizers.

Ticona, brand name of Liquid-crystal polymers (LCPs), is a class of aromatic polyester polymers. They are extremely unreactive and inert, and highly resistant to fire. Because of their various properties, LCPs are useful for electrical and mechanical parts, food containers, and any other applications requiring chemical inertness and high strength. Zenite is a liquid crystal polymer with 45% glass fiber filler, originally developed by DuPont, which is used for injection molded parts with intricate features. Polystyrene (PS) has very good thermal stability and thus used in the making of squeeze bottles. Polyacrylonitrile (PAN) is used for making clothes and fabrics like sweaters, hats, yarns, rugs etc. and as a precursor of carbon fibres. Hence, the correct sequence using the codes is P - 3, Q -4, R - 1, S - 2

Safer plasticizers with better biodegradability and fewer biochemical effects are being developed. Some such plasticizers are- Trimethyl citrate (TMC) that are compatible with PVC, Acetyl tributyl citrate (ATBC), compatible with PVC and vinyl chloride copolymers etc. The examples of non-biodegradable plasticizers are- Butanetriol trinitrate (BTTN), Trimethylolethane trinitrate (TMETN) etc. Hence, P and Q both are examples of biodegradable plasticizers.

Polystyrene (PS) has good thermal insulator properties and is used in the making of moulded materials. Polyvinyl acetate (PVAc) is frequently used in adhesives. Polytetrafluoroethylene (PTFE) has very low coefficient of friction, excellent dielectric properties and chemical inertness. It is used mainly in the making of anticorrosive low friction bearings, non-stick pans, etc. Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerisation of chloroprene. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. It is used in a wide variety of applications such as laptop sleeves, orthopedic braces (wrist, knee, etc), electrical insulation, liquid and sheet applied elastomeric membranes or flashings, and automotive fan belts. Hence, the correct answer using the codes is P - 2, Q - 4, R - 1, S - 3.

The monomeric precursor unit for neoprene (NP) is chloroprene. Vinyl alcohol is the precursor unit of polyvinyl alcohol (PVA). Terylene is prepared by the reaction of ethylene glycol and dimethylterephthalate. The precursor unit of phenol formaldehyde resin (PFR) or bakelite is phenol and formaldehyde. Hence, the presentation of codes P - 3, Q - 1, R - 4, S - 2 is correct.