47Polymers and Polymerization

📚
MACROMOLECULES
▢ Polymers:
❖ Definition: High molecular mass compounds formed by repeated linking of small units called monomers.
❖ Classification:
◉ On the Basis of Nature:
◈ Organic Polymers / Biopolymers:
  1. Carbohydrates
  2. Proteins
◈ Inorganic Polymers:
  1. Silicates
  2. Silicones
◉ On the Basis of Source:
◈ Natural Polymers:
  1. Obtained from nature
  2. Examples: starch, cellulose, proteins, natural rubber
◈ Synthetic Polymers:
  1. Prepared artificially
  2. Examples: PVC, nylon, polythene, Bakelite, Teflon
◉ On the Basis of Type of Monomers:
◈ Homopolymers:
  1. Only one type of monomer
  2. Example: polyethene from ethene
◈ Heteropolymers / Copolymers:
  1. Two or more types of monomers
  2. Example: Buna-S from butadiene + styrene
◉ On the Basis of Shape:
◈ Linear Polymer:
  1. Monomers joined in straight long chain
  2. Generally thermoplastic
◈ Branched Chain Polymer:
  1. Main chain + side branches
  2. Less close packing
◈ Cross-linked / 3-D Network Polymer:
  1. Chains connected by cross-links
  2. Generally hard, rigid, thermosetting
◉ On the Basis of Intermolecular Force:
◈ Elastomers:
  1. Weak intermolecular force
  2. Elastic
  3. Example: rubber
◈ Fibres:
  1. Strong intermolecular force
  2. High tensile strength
  3. Example: nylon, terylene
◈ Thermoplastics:
  1. Soften on heating
  2. Can be remoulded
  3. Usually linear or slightly branched
◈ Thermosetting Plastics:
  1. Do not soften on heating
  2. Permanent hardening
  3. Cross-linked structure
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THERMOPLASTIC VS THERMOSETTING PLASTIC

Table 1: Thermoplastic and thermosetting plastic

Thermoplastic
Thermosetting Plastic
Soften on heating
Do not soften on heating
Formed by addition as well as condensation polymerization
Generally formed by condensation polymerization
Temporary formation
Permanent formation
Generally linear structure
Cross-linked structure
Can be remoulded again and again
Cannot be remoulded after setting
Examples: Nylon-6, Nylon-6,6, PVC, polystyrene, Teflon
Examples: Bakelite, urea-formaldehyde resin
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ON THE BASIS OF MODE OF POLYMERIZATION
▢ Condensation Polymers:
❖ Meaning:
  1. Formed by condensation polymerization
  2. Monomers join with elimination of small molecules such as H₂O, HCl, NH₃, alcohol etc.
  3. Usually step-growth polymerization
❖ Polyesters:
◉ Glyptal / Alkyd Resin:
◈ Monomers:
  1. Phthalic acid
  2. Ethylene glycol
◈ Reaction: n phthalic acid + n ethylene glycol → glyptal + small molecules
◈ Linkage: Ester linkage: –COO–
◉ Terylene / Dacron:
◈ Monomers:
  1. Terephthalic acid
  2. Ethylene glycol
◈ Reaction: n terephthalic acid + n ethylene glycol → terylene / dacron + small molecules
◈ Linkage: Ester linkage: –COO–
❖ Polyamides:
◉ Nylon-6 / Perlon:
◈ Monomer: Caprolactam
◈ Polymer: Nylon-6
◈ Linkage: Amide linkage: –CONH–
◉ Nylon-6,6:
◈ Monomers:
  1. Adipic acid: HOOC–(CH₂)₄–COOH
  2. Hexamethylene diamine: H₂N–(CH₂)₆–NH₂
◈ Reaction: n adipic acid + n hexamethylene diamine → nylon-6,6 + H₂O
◈ Linkage: Amide linkage: –CONH–
◉ Nylon-6,10:
◈ Monomers:
  1. Sebacic acid: HOOC–(CH₂)₈–COOH
  2. Hexamethylene diamine: H₂N–(CH₂)₆–NH₂
◈ Reaction: n sebacic acid + n hexamethylene diamine → nylon-6,10 + H₂O
◈ Linkage: Amide linkage: –CONH–
❖ Phenol-Formaldehyde Polymer:
◉ Common Name: Bakelite
◉ Monomers:
  1. Phenol
  2. Formaldehyde / HCHO
◉ Structure Type: Cross-linked thermosetting polymer
◉ Use: Electrical switches, handles, insulating materials
❖ Urea-Formaldehyde Resin:
◉ Monomers:
  1. Urea
  2. Formaldehyde
◉ Polymer Type: Thermosetting resin
❖ Melamine-Formaldehyde Polymer:
◉ Monomers:
  1. Melamine
  2. Formaldehyde
◉ Polymer Type: Thermosetting resin
❖ Natural Condensation Polymers:
◉ Starch:
◈ Monomer: α-D-glucose
◈ Components:
  1. Amylose
  2. Amylopectin
◉ Glycogen:
◈ Monomer: α-D-glucose
◈ Nature: Animal starch
◉ Cellulose:
◈ Monomer: β-D-glucose
◈ Nature: Structural polysaccharide
▢ Addition Polymers:
❖ Meaning:
  1. Formed by addition polymerization
  2. Unsaturated monomers add repeatedly
  3. No small molecule eliminated
  4. Chain-growth polymerization
❖ Polyethene / Polyethylene:
◉ Monomer: Ethene / CH₂=CH₂
◉ General Reaction: nCH₂=CH₂ → [–CH₂–CH₂–]ₙ
◉ Low Density Polythene / LDPE:
◈ Condition: 1500 atm, 200°C
◈ Polymer: [–CH₂–CH₂–]ₙ
◉ High Density Polythene / HDPE:
◈ Condition: Ziegler-Natta catalyst
◈ Polymer: [–CH₂–CH₂–]ₙ
❖ Polypropene / Polypropylene:
◉ Monomer: Propene / CH₂=CH–CH₃
◉ Condition: Ziegler-Natta catalyst
◉ Polymer: [–CH₂–CH(CH₃)–]ₙ
❖ Polyvinyl Chloride / PVC:
◉ Monomer: Vinyl chloride / CH₂=CHCl
◉ Condition: Peroxide
◉ Polymer: [–CH₂–CH(Cl)–]ₙ
❖ Polyacrylonitrile / PAN / Orlon / Acrilan:
◉ Monomer: Acrylonitrile / vinyl cyanide / CH₂=CH–CN
◉ Condition: Peroxide
◉ Polymer: [–CH₂–CH(CN)–]ₙ
❖ Polystyrene:
◉ Monomer: Styrene / CH₂=CH–C₆H₅
◉ Condition: Organic peroxide
◉ Polymer: [–CH₂–CH(C₆H₅)–]ₙ
❖ Polymethyl Methacrylate / PMMA:
◉ Monomer: Methyl methacrylate
◉ Polymer: PMMA
◉ Common Name: Plexiglass / acrylic glass
◉ Type: Addition polymer
❖ Synthetic Rubbers:
◉ Neoprene / Polychloroprene:
◈ Monomer: Chloroprene / CH₂=C(Cl)–CH=CH₂
◈ Polymer: Polychloroprene
◈ Repeating Unit: [–CH₂–C(Cl)=CH–CH₂–]ₙ
◉ Butyl Rubber:
◈ Monomers:
  1. Isobutylene
  2. Butadiene
◈ Other Name: Isobutylene-butadiene rubber
◈ Type: Copolymer
◉ Buna-N / Nitrile Rubber:
◈ Monomers:
  1. Acrylonitrile / vinyl cyanide
  2. Butadiene
◈ Other Name: Acrylonitrile-butadiene rubber
◈ Type: Copolymer
◉ Buna-S / SBR:
◈ Monomers:
  1. Styrene
  2. Butadiene
◈ Other Name: Styrene-butadiene rubber
◈ Type: Copolymer
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HIGH-YIELD POLYMER LINKS

Table 1: Important polymer-monomer table

Polymer
Monomer / Monomers
Type
Polyethene
Ethene
Addition, homopolymer
Polypropene
Propene
Addition, homopolymer
PVC
Vinyl chloride
Addition, homopolymer
PAN / Orlon / Acrilan
Acrylonitrile
Addition, homopolymer
Polystyrene
Styrene
Addition, homopolymer
Neoprene
Chloroprene
Addition, homopolymer
Butyl rubber
Isobutylene + butadiene
Addition, copolymer
Buna-N
Acrylonitrile + butadiene
Addition, copolymer
Buna-S
Styrene + butadiene
Addition, copolymer
Glyptal
Phthalic acid + ethylene glycol
Condensation, polyester
Terylene / Dacron
Terephthalic acid + ethylene glycol
Condensation, polyester
Nylon-6
Caprolactam
Polyamide
Nylon-6,6
Adipic acid + hexamethylene diamine
Condensation, polyamide
Nylon-6,10
Sebacic acid + hexamethylene diamine
Condensation, polyamide
Bakelite
Phenol + formaldehyde
Condensation, thermosetting
Urea-formaldehyde resin
Urea + formaldehyde
Condensation, thermosetting
Melamine-formaldehyde resin
Melamine + formaldehyde
Condensation, thermosetting
Starch / glycogen
α-D-glucose
Natural polymer
Cellulose
β-D-glucose
Natural polymer
Q1.
Nylon-6,6 is
📅IOM 2008•Bangladesh 2008•KU 2002
Q2.
PVC is formed by the polymerization of
📅IOM 2011
Q3.
Polymerization of acetaldehyde in presence of concentrated H2SO4 forms pleasant-smelling paraldehyde. Paraldehyde is used
📅IOM 1997
Q4.
Bakelite is obtained by the condensation of
📅BPKIHS 2005
Q5.
PVC is a
📅MOE Curriculum
Q6.
Polymer of tetrafluoroethylene is
📅MOE 2066
Q7.
Nylon-6,6 is the polymer of
📅MOE 2008•MOE 2011
Q8.
Chemically, natural rubber consists of
📅KU 2003
Q9.
Starch is polymer of
📅IE 2003
Q10.
Which of the following is an example of thermosetting polymer?
📅IE
Q11.
Nucleic acid is polymer of
📅IOM 2011
Q12.
Polyethene is an example of
📅MOE 2069
Q13.
Teflon is a polymer of
📅MOE 2011
Q14.
Which of the following is a linear polymer?
Q15.
Which of the following is a branched polymer?
Q16.
Which of the following is a step-growth polymer?
Q17.
Soft drink bottles and baby feeding bottles are generally made up of
Q18.
Which of the following is a fully fluorinated polymer?
Q19.
Which of the following is a chain-growth polymer?
Q20.
The polymer used for making contact lenses for eyes is
Q21.
Chain transfer reagent is
Q22.
The monomer used to produce Orlon is
Q23.
Which of the following are not thermosetting polymers?
Q24.
Which of the following is currently used as a tyre cord?
Q25.
Polymers have
Q26.
Which is not true about polymers?
Q27.
F2C=CF2 is a monomer of
📅MOE
Q28.
Which is a naturally occurring polymer?
Q29.
The product of addition polymerization reaction is
Q30.
Polymerisation in which two or more chemically different monomers take part is called
Q31.
The turbidity of a polymer solution measures
Q32.
Orlon is a polymer of
Q33.
Natural rubber is a polymer of
Q34.
Natural rubber is a polymer of
Q35.
Which one is a natural polymer?
Q36.
Synthetic polymer which resembles natural rubber is
Q37.
Teflon, styron and neoprene are all
Q38.
Terylene is a condensation polymer of ethylene glycol and
Q39.
The fibre obtained by condensation of hexamethylene diamine and adipic acid is
📅MOE
Q40.
Synthetic polymer prepared by using caprolactam is
Q41.
Nylon threads are made of
Q42.
Polymer used in bulletproof glass is
Q43.
Which of the following is called a polyamide?
Q44.
Polymer formation from monomers starts by
Q45.
Cellulose is a condensation polymer of
Q46.
Bakelite is a product of the reaction between
Q47.
Which is an example of thermosetting polymer?
Q48.
Which one of the following can be used as monomer in a polymerisation reaction?
Q49.
Synthetic rubber is
Q50.
Bakelite is made from phenol and formaldehyde. The initial reaction between the two compounds is an example of
Q51.
The catalyst used in the manufacture of polyethylene by Ziegler method is
Q52.
Heating of rubber with sulphur is known as
Q53.
Among the following polymers, the strongest molecular forces are present in
Q54.
Which of the following contains isoprene units?
Q55.
Which of the following is used to make non-stick cookware?
Q56.
The compound used in the manufacture of Terylene is
Q57.
Copolymer is
Q58.
Which of the following is not an example of addition polymer?
Q59.
Glyptal polymer is obtained from glycol by reacting with
Q60.
Which of the following is used in paints?
Q61.
Chloroprene is used in making
Q62.
The common acid used in the manufacture of rayon and plastics is
Q63.
Of the following, which is a step-growth polymer?
Q64.
Which polymer contains nitrogen?
Q65.
Which of the following polymers is prepared by condensation polymerisation?
Q66.
Which of the following polymers has an ester linkage?
Q67.
Which of the following is a biodegradable polymer?
Q68.
Buna-S is a polymer of
Q69.
Which of the following is used as an initiator in chain-growth polymerization?
Q70.
The mass-average molecular mass is obtained by measurement of a property such as
Q71.
For natural polymers, the polydispersity index is
Q72.
Synthetic human hair wigs are made from a copolymer of vinyl chloride and acrylonitrile and is called
Q73.
Among the following polymers, the strongest molecular forces are present in
Q74.
Ziegler-Natta polymerisation is an example of