Synthetic & Natural Polymers • Addition & Condensation Polymerisation • Important points included
Polymers are large molecules (macromolecules) formed by the repetitive linking of small units called monomers. Major types: natural (e.g., proteins, cellulose, rubber) and synthetic (e.g., polyethylene, nylon, polyester). Polymerisation occurs mainly by addition (chain-growth) or condensation (step-growth) mechanisms. Important concepts: monomer structure, degree of polymerisation, tacticity, copolymers, molecular weight (Mn, Mw), glass transition temperature (Tg), melting point (Tm), cross-linking, biodegradable vs non-biodegradable polymers, polymer processing and applications.
Tips: Remember examples and monomers (e.g., polyethylene from ethene, Nylon-6,6 from hexamethylenediamine + adipic acid). Distinguish addition vs condensation and know typical tests and properties.
1. Polymers are made up of repeating units called:
A) Monosaccharides
B) Monomers ✅
C) Amino acids
D) Nucleotides
2. Polyethylene is prepared by which type of polymerisation?
A) Condensation polymerisation
B) Addition (chain-growth) polymerisation ✅
C) Step-growth polymerisation
D) Emulsion polymerisation
3. Nylon-6,6 is an example of:
A) Addition polymer
B) Condensation polymer (polyamide) ✅
C) Natural polymer
D) Elastomer
4. The polymer formed by joining of phenol and formaldehyde is:
A) Polyethylene
B) Bakelite (phenol-formaldehyde resin) ✅
C) Teflon
D) Polystyrene
5. Which polymerisation involves elimination of a small molecule (like water) during chain formation?
A) Condensation polymerisation ✅
B) Addition polymerisation
C) Radical polymerisation
D) Ionic polymerisation
6. Polystyrene is produced from monomer:
A) Ethene
B) Propene
C) Styrene ✅
D) Vinyl chloride
7. Which of these is a biodegradable polymer?
A) Polylactic acid (PLA) ✅
B) Polyethylene
C) Polystyrene
D) PVC
8. Cross-linking in polymers generally leads to:
A) Lower mechanical strength
B) Increased rigidity and higher melting point ✅
C) Improved solubility
D) Reduced glass transition temperature
9. Which polymer is used for making bullet-proof vests?
A) Polyethylene (low density)
B) Polyethylene (UHMWPE) / Kevlar (aramid) ✅
C) PVC
D) Polystyrene
10. The degree of polymerisation is defined as:
A) Number of monomer units in a polymer chain ✅
B) Number of polymer chains
C) Molecular weight of monomer
D) Number of cross-links
11. Teflon is the trade name for which polymer?
A) Polypropylene
B) Polystyrene
C) PTFE (polytetrafluoroethylene) ✅
D) PVC
12. Which polymerisation technique is commonly used for making PVC?
A) Condensation polymerisation
B) Addition polymerisation (free radical/ionic) ✅
C) Ring-opening polymerisation
D) Polycondensation
13. A copolymer contains:
A) A single type of monomer
B) Two or more different monomers ✅
C) Only natural monomers
D) Cross-linked monomers only
14. Natural rubber is primarily a polymer of:
A) Isopropene
B) Isoprene (2-methyl-1,3-butadiene) ✅
C) Ethene
D) Propene
15. Which property distinguishes thermoplastics from thermosets?
A) Thermoplastics do not soften on heating
B) Thermoplastics soften on heating and can be remolded ✅
C) Thermosets are recyclable easily
D) Thermosets are flexible on heating
16. Bakelite is an example of:
A) Thermoplastic
B) Thermosetting polymer ✅
C) Elastomer
D) Fibrous polymer
17. Which polymer contains ester linkages in its backbone?
A) Polyethylene
B) Polyester (e.g., PET) ✅
C) Polypropylene
D) Polyvinyl chloride
18. Which polymer is formed by ring-opening polymerisation of caprolactam?
A) Nylon-6,6
B) Nylon-6 ✅
C) Polyester
D) Polyacrylonitrile
19. Vulcanization of rubber involves addition of:
A) Oxygen
B) Sulfur (cross-linking) ✅
C) Nitrogen
D) Chlorine
20. Which polymerization method yields step-growth polymers?
A) Addition polymerization
B) Condensation (step-growth) polymerization ✅
C) Radical chain-growth
D) Ziegler-Natta catalysis
21. Which of the following is a naturally occurring polymer?
A) Cellulose ✅
B) Polystyrene
C) Polyethylene
D) Nylon
22. Ziegler-Natta catalysts are used for polymerisation of:
A) Styrene
B) Olefins (e.g., ethene, propene) ✅
C) Vinyl chloride
D) Acrylics
23. Polymer with repeating unit —[—CH2—CH2—]— is:
A) Polypropylene
B) Polyethylene ✅
C) Polystyrene
D) Polyvinyl chloride
24. Which analytical technique measures molecular weight distribution of polymers?
A) UV-Vis spectroscopy
B) Gel Permeation Chromatography (GPC) / Size Exclusion Chromatography ✅
C) IR spectroscopy
D) TLC
25. Polymerisation initiated by free radicals commonly uses which initiator?
A) Acid
B) Base
C) Benzoyl peroxide / AIBN ✅
D) Metal catalyst only
26. Which polymer is famous for its use in textiles as 'polyester'?
A) Polyethylene
B) Polyethylene terephthalate (PET) ✅
C) Nylon
D) Polypropylene
27. What is the repeating unit of polystyrene?
A) —CH2—CH(Ph)—
B) —CH2—CH(Ph)— ✅
C) —CH2—CH2—
D) —CH2—CH(Cl)—
28. Which polymer is used for making fibers like 'Terylene'?
A) Nylon-6
B) Polyester (Terylene / PET) ✅
C) Polypropylene
D) Polyvinyl chloride
29. Addition polymers are formed by _____ of double bonds.
A) Hydrolysis
B) Opening/reacting ✅
C) Condensation
D) Oxidation
30. Which polymer has repeating amide (—CONH—) linkages?
A) Polyester
B) Polyamide (Nylon) ✅
C) Polyethylene
D) Polystyrene
31. PVC stands for:
A) Polyvinyl alcohol
B) Polyvinyl chloride ✅
C) Polyvinyl carbonate
D) Polychloroethylene
32. Which polymer is commonly used to make transparent, shatterproof glass substitutes?
A) PVC
B) Polycarbonate ✅
C) Polystyrene
D) Polyethylene
33. Polymer chains aligned in an ordered manner give:
A) Amorphous polymers
B) Crystalline regions (higher density & strength) ✅
C) Lower melting point
D) Poor mechanical properties
34. Which polymer is used for making 'Nylon rope' and 'bristles'?
A) Polyester
B) Nylon (polyamide) ✅
C) Polyethylene
D) Polypropylene
35. Polyacrylonitrile (PAN) is a precursor for:
A) Polyethylene
B) Carbon fibers ✅
C) Nylon
D) PET
36. The process of converting monomers into polymers is called:
A) Polymerisation ✅
B) Hydrolysis
C) Sublimation
D) Crystallisation
37. Which property is mainly responsible for polymer elasticity?
A) High crystallinity
B) Flexible long chains with limited cross-links (entropic elasticity) ✅
C) High degree of cross-linking
D) Ionic interactions only
38. Vulcanised rubber is less sticky and more:
A) Soluble
B) Elastic and durable ✅
C) Reactive to solvents
D) Easily melted
39. Which polymerisation creates polymers by opening of ring monomers (e.g., lactams)?
A) Ring-opening polymerisation ✅
B) Condensation polymerisation
C) Radical addition only
D) Ionic condensation
40. Which polymer is used widely in packaging as lightweight films?
A) Polyethylene (LDPE/HDPE) ✅
B) Nylon
C) PVC
D) Bakelite
41. Which of these polymers has repeating ester linkages (—COO—)?
A) Polyamide
B) Polyester (e.g., PET) ✅
C) Polyethylene
D) Polyvinyl chloride
42. Plasticizers are added to polymers to:
A) Increase brittleness
B) Increase flexibility and reduce Tg ✅
C) Increase crystallinity
D) Remove color
43. Which polymer is infamous for environmental pollution due to its non-biodegradable nature and foam products?
A) Polystyrene (expanded polystyrene / EPS) ✅
B) Polyethylene
C) Polypropylene
D) PET
44. Which polymer is commonly used in medical sutures (biodegradable)?
A) Polyethylene
B) Polyglycolic acid (PGA) / Polylactic acid (PLA) ✅
C) Polystyrene
D) PVC
45. Copolymers formed by polymerising two different monomers randomly are called:
A) Block copolymers
B) Random copolymers ✅
C) Alternating copolymers
D) Graft copolymers
46. Which polymer is known as 'nylon-6,6' made from hexamethylenediamine and adipic acid?
A) Nylon-6,6 ✅
B) Nylon-6
C) Polyester
D) Polyacrylonitrile
47. Which of the following increases with increasing molecular weight of a polymer?
A) Solubility
B) Mechanical strength and viscosity ✅
C) Volatility
D) Melting point always decreases
48. Which polymer contains chlorine atoms in its repeat unit?
A) Polyethylene
B) PVC (polyvinyl chloride) ✅
C) Polystyrene
D) Polypropylene
49. Which polymer is widely used for making fibers in bulletproof vests (Kevlar) and heat-resistant materials?
A) Aramid fibers (Kevlar) ✅
B) Polyethylene
C) Polypropylene
D) PVC
50. Which of the following statements is TRUE?
A) All polymers are biodegradable
B) Some polymers are biodegradable while others are not ✅
C) Condensation polymers never release small molecules
D) Polymer properties are independent of chain structure