36 Questions
What is the primary mechanism governing the increase in chain length in addition polymerisation?
Free radical mechanism
What type of compounds are used as monomers in addition polymerisation?
Unsaturated compounds
Which type of polymerisation involves the formation of a distinct functionalised species in each step?
Step-growth polymerisation
What is the outcome of each step in step-growth polymerisation?
A bifunctional species
Which type of polymerisation results in a significant increase in chain length?
Addition polymerisation
What is an example of a reaction that involves the addition of molecules of the same monomer?
Polymerisation of ethene to polythene
What is the characteristic of Cross-linked or Network Polymers?
They are formed from bifunctional and trifunctional monomers.
What type of polymerisation is involved in the formation of polythene from ethene?
Addition Polymerisation
What is the characteristic of Addition Polymers?
No part from the monomer units are lost during polymerisation.
What is the type of polymer formed by the polymerisation of two different monomers?
Copolymer
What is the catalyst used in the formation of Buna-S?
Na
What is the type of polymerisation involved in the formation of Bakelite?
Condensation Polymerisation
What is the primary characteristic of Melamine-Formaldehyde polymer that makes it suitable for producing unbreakable crockery?
Its ability to undergo cross-linking
Which type of polymerisation reaction is characterized by the formation of a distinct functionalized species in each step?
Step-growth polymerisation
What is the primary difference between cis-polyisoprene and trans-polyisoprene?
The spatial arrangement of the polymer chain
Which type of polymerisation reaction involves the reaction of two or more different monomeric species?
Copolymerisation
What is the primary reason for the elasticity of natural rubber?
The coiled structure of the polymer chain
Which type of polymerisation reaction is used to produce phenol-formaldehyde polymers?
Condensation polymerisation
What is the primary mechanism governing the formation of polymers in addition polymerisation?
Chain initiation and propagation
What is the characteristic of Low Density Polythene (LDP)?
Chemical inertness and high flexibility
What is the primary outcome of each step in addition polymerisation?
Increase in chain length
Which of the following is an example of an addition polymer?
Low Density Polythene
What is the role of benzoyl peroxide in addition polymerisation?
Initiator of the chain reaction
Which type of polymerisation is characterised by the formation of a free radical?
Addition polymerisation
What is the primary difference between addition and condensation polymerisation?
Type of species formed in each step
What is the primary difference between High Density Polythene (HDP) and Low Density Polythene (LDP)?
Conditions of polymerisation
Which type of polymerisation is used to produce polymers with high molecular weights?
Addition polymerisation
What is the outcome of chain termination in addition polymerisation?
Formation of a polymeric product
What is the primary mechanism governing the increase in chain length in condensation polymerisation?
Formation of bifunctional species
Which type of polymerisation is characterised by the formation of a polymer with a high molecular weight in a single step?
Addition polymerisation
What is the primary characteristic of polymers formed through addition polymerisation?
No part of the monomer units are lost during polymerisation.
What is the primary difference between homopolymers and copolymers?
The number of monomeric species used in their formation.
What is the primary characteristic of Cross-linked or Network Polymers?
They contain strong covalent bonds between various linear chains.
What is the primary mechanism of chain growth in addition polymerisation?
The repeated addition of monomers possessing double or triple bonds.
Which type of polymerisation is involved in the formation of polythene from ethene?
Addition polymerisation
What is the primary characteristic of polymers formed through condensation polymerisation?
They are formed by the condensation of bifunctional and trifunctional monomers.
Study Notes
Types of Polymerisation Reactions
- Polymerisation reactions can be classified into three types: Addition, Condensation, and Copolymerisation
- Addition polymerisation involves the addition of monomers to form a polymer, resulting in an increase in chain length
- Condensation polymerisation involves the formation of a polymer through the condensation of monomers, resulting in the loss of a small molecule such as water or methanol
- Copolymerisation involves the polymerisation of two or more different monomers to form a copolymer
Addition Polymerisation
- Addition polymerisation involves the addition of monomers to form a polymer, resulting in an increase in chain length
- The mechanism of addition polymerisation involves three steps: initiation, propagation, and termination
- Initiation involves the formation of a free radical, which then reacts with a monomer to form a larger radical
- Propagation involves the repeated addition of monomers to the growing radical chain
- Termination involves the combination of two radicals to form the final polymer product
Homopolymers and Copolymers
- Homopolymers are formed by the polymerisation of a single monomer species
- Examples of homopolymers include polythene, polypropylene, and polyacrylonitrile
- Copolymers are formed by the polymerisation of two or more different monomers
- Examples of copolymers include Buna-S and Buna-N
Chain Growth and Step Growth
- Chain growth polymerisation involves the addition of monomers to form a polymer, resulting in an increase in chain length
- Step growth polymerisation involves the formation of a polymer through the condensation of monomers, resulting in the loss of a small molecule such as water or methanol
- Chain growth polymerisation can take place through the formation of either free radicals or ionic species
- Step growth polymerisation is also known as condensation polymerisation
Characteristics of Polymers
- Polymers can be classified based on their molecular structure, such as branched-chain, linear, and cross-linked polymers
- Branched-chain polymers are formed from monomers with multiple functional groups
- Linear polymers are formed from monomers with a single functional group
- Cross-linked polymers are formed from bifunctional and trifunctional monomers
- Cross-linked polymers contain strong covalent bonds between various linear chains
Examples of Polymers
- Low density polythene (LDP) is a branched-chain polymer formed from the polymerisation of ethene under high pressure and temperature
- High density polythene (HDP) is a linear polymer formed from the polymerisation of ethene in a hydrocarbon solvent
- Polyacrylonitrile (PAN) is a polymer formed from the polymerisation of acrylonitrile
- Polytetrafluoroethene (PTFE) is a polymer formed from the polymerisation of tetrafluoroethene
- Bakelite and Melamine are examples of cross-linked polymers
Test your knowledge of different types of polymers, including branched-chain, cross-linked, and addition polymers. Learn about their characteristics, formation, and examples. Identify the differences between various classes of polymers.
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