Condensation Polymers
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Condensation Polymers

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Questions and Answers

What type of polymerization is characterized by the absence of chain termination due to proton loss or combination?

  • Radical polymerization
  • Cationic polymerization
  • Anionic polymerization (correct)
  • Ring-opening polymerization
  • What is required for anionic polymerization to occur?

  • A moderate nucleophile
  • A very weak nucleophile
  • A very good nucleophile (correct)
  • A very poor nucleophile
  • Why do alkenes require electron-withdrawing substituents for anionic polymerization?

  • To decrease the electron density of the double bond (correct)
  • To increase the electron density of the double bond
  • To make the alkene more electron-poor
  • To make the alkene more electron-rich
  • What is the initiator in anionic polymerization?

    <p>A nucleophile</p> Signup and view all the answers

    What is the result of chain combination or disproportionation in radical polymerization?

    <p>Chain termination</p> Signup and view all the answers

    What is the monomer in Super Glue?

    <p>Methyl α-cyanoacrylate</p> Signup and view all the answers

    What initiates the polymerization reaction in Super Glue?

    <p>Surface-absorbed water</p> Signup and view all the answers

    What is the result of anionic polymerization in Super Glue?

    <p>Two fingers become firmly glued together</p> Signup and view all the answers

    What is the mechanism of polymerization of epoxides when the initiator is a nucleophile?

    <p>Anionic mechanism</p> Signup and view all the answers

    What is the process of hardening rubber by introducing cross-links between polymer chains?

    <p>Vulcanization</p> Signup and view all the answers

    What type of polymerization is used to produce synthetic rubbers from dienes other than isoprene?

    <p>Radical polymerization</p> Signup and view all the answers

    What is the term for polymers formed from a single type of monomer?

    <p>Homopolymer</p> Signup and view all the answers

    What is the result of the reaction between the nucleophile and the epoxide in anionic polymerization?

    <p>Formation of an anionic species</p> Signup and view all the answers

    What type of copolymer has a random distribution of monomers?

    <p>Random copolymer</p> Signup and view all the answers

    What is the type of polymerization that involves the opening of epoxide rings?

    <p>Ring-opening polymerization</p> Signup and view all the answers

    What is the term for the process of creating a polymer from two or more different monomers?

    <p>Copolymerization</p> Signup and view all the answers

    What is the characteristic of condensation polymers?

    <p>They are formed by the reaction of a single compound with two different functional groups</p> Signup and view all the answers

    Which of the following is NOT a class of step-growth polymers?

    <p>Polyethylene</p> Signup and view all the answers

    What is the characteristic of nylon 6?

    <p>It is formed from the polymerization of a single monomer with two different functional groups</p> Signup and view all the answers

    What is the starting material for the synthesis of nylon 6?

    <p>ε-caprolactam</p> Signup and view all the answers

    What is the characteristic of nylon 66?

    <p>It is formed by the reaction of two different bifunctional monomers</p> Signup and view all the answers

    What is the characteristic of Dacron?

    <p>It is a polyester</p> Signup and view all the answers

    What is the characteristic of Kodel polyester?

    <p>It is formed by the transesterification of dimethyl terephthalate with 1,4-di(hydroxymethyl)cyclohexane</p> Signup and view all the answers

    What is the characteristic of epoxy resins?

    <p>They are extensively cross-linked systems</p> Signup and view all the answers

    Study Notes

    Ring-Opening Polymerizations

    • Epoxides undergo chain-growth polymerization, which can occur through an anionic mechanism if the initiator is a nucleophile, or through a cationic mechanism if the initiator is a Lewis acid.
    • In an anionic mechanism, the nucleophile attacks the less sterically hindered carbon of the epoxide.

    Polymerization of Dienes

    • Natural rubber is a polymer of 2-methyl-1,3-butadiene (isoprene).
    • Synthetic rubbers can be made by radical polymerization of dienes other than isoprene.
    • A problem with natural and synthetic rubbers is that they are soft and sticky, but they can be hardened by vulcanization (heating with sulfur), which causes cross-linking of the separate polymer chains through disulfide bonds.

    Copolymers

    • Copolymers are formed from two or more different monomers.
    • Both chain-growth polymers and step-growth polymers can be copolymers.
    • There are four types of copolymers: alternating, block, random, and graft copolymers.

    Condensation Polymers (Step-Growth Polymers)

    • Condensation polymers are formed by the intermolecular reaction of molecules with a functional group at each end.
    • A small molecule, such as H2O, alcohol, or HCl, is often lost during the reaction.
    • Condensation polymers can be formed from a single compound with two different functional groups or from two different compounds.

    Classes of Step-Growth Polymers

    • Polyamides
    • Polyesters
    • Epoxy Resins
    • Polyurethanes

    Polyamides

    • Nylon 6 is a step-growth polymer formed from a monomer with two different functional groups.
    • The carboxylic acid group of one monomer reacts with the amino group of another monomer to form an amide.
    • Nylon 6 is formed from the polymerization of 6-aminohexanoic acid, which contains six carbons.
    • Nylon 66 is formed from the reaction of adipoyl chloride and 1,6-hexanediamine.

    Polyesters

    • Polymers containing many ester groups.
    • Dacron is a common polyester formed by the transesterification of dimethyl terephthalate with ethylene glycol.
    • Kodel polyester is formed by the transesterification of dimethyl terephthalate with 1,4-di(hydroxymethyl)cyclohexane.

    Epoxy Resins

    • They are the strongest adhesives known, with extensive cross-linking.
    • They adhere to almost any surface and are resistant to solvents and high temperatures.

    Anionic Polymerization (Living Polymers)

    • The initiator is a nucleophile that reacts with the monomer to form an anion propagating site.
    • Nucleophilic attack on an alkene requires a very good nucleophile and an alkene with an electron-withdrawing substituent.
    • Living polymers are common in anionic polymerization because the chains cannot be terminated by proton loss or chain combination or disproportionation.
    • Examples of alkenes that undergo anionic polymerization include methyl α-cyanoacrylate (Super Glue).

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    Description

    Learn about condensation polymers, also known as step-growth polymers, and how they are formed through intermolecular reactions with functional groups.

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