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Questions and Answers
What type of mechanism occurs when an epoxide is polymerized with a Lewis acid initiator?
What type of mechanism occurs when an epoxide is polymerized with a Lewis acid initiator?
- Cationic mechanism (correct)
- Anionic mechanism
- Free radical mechanism
- Coordination mechanism
What is the purpose of vulcanization in rubber synthesis?
What is the purpose of vulcanization in rubber synthesis?
- To create hard and flexible polymers (correct)
- To create weak and brittle polymers
- To create soft and sticky polymers
- To create strong and brittle polymers
What type of polymerization occurs when dienes are polymerized with a radical initiator?
What type of polymerization occurs when dienes are polymerized with a radical initiator?
- Radical polymerization (correct)
- Ring-opening polymerization
- Step-growth polymerization
- Chain-growth polymerization
What is the name of the polymer synthesized from 2-methyl-1,3-butadiene?
What is the name of the polymer synthesized from 2-methyl-1,3-butadiene?
What type of copolymer consists of blocks of each kind of monomer?
What type of copolymer consists of blocks of each kind of monomer?
What is the purpose of an anionic initiator in epoxide polymerization?
What is the purpose of an anionic initiator in epoxide polymerization?
What type of bond is formed during vulcanization of rubber?
What type of bond is formed during vulcanization of rubber?
What type of polymerization occurs when epoxides are polymerized with a nucleophile initiator?
What type of polymerization occurs when epoxides are polymerized with a nucleophile initiator?
What is the characteristic of condensation polymers?
What is the characteristic of condensation polymers?
Which of the following is an example of a polyamide?
Which of the following is an example of a polyamide?
What is the starting material for the synthesis of nylon 6?
What is the starting material for the synthesis of nylon 6?
What is the characteristic of epoxy resins?
What is the characteristic of epoxy resins?
What is the process of forming Dacron polyester?
What is the process of forming Dacron polyester?
What is the characteristic of nylon 66?
What is the characteristic of nylon 66?
What is the common name of the polyester polymer formed by the transesterification of dimethyl terephthalate with 1,4-di(hydroxymethyl)cyclohexane?
What is the common name of the polyester polymer formed by the transesterification of dimethyl terephthalate with 1,4-di(hydroxymethyl)cyclohexane?
What is the characteristic of step-growth polymers?
What is the characteristic of step-growth polymers?
What is the main reason why nucleophilic attack on an alkene does not occur readily?
What is the main reason why nucleophilic attack on an alkene does not occur readily?
What type of polymerization is more prone to termination by proton loss from the polymer?
What type of polymerization is more prone to termination by proton loss from the polymer?
What is the role of surface-absorbed water in the polymerization of methyl α-cyanoacrylate?
What is the role of surface-absorbed water in the polymerization of methyl α-cyanoacrylate?
Why do living polymers are most common in anionic polymerization?
Why do living polymers are most common in anionic polymerization?
What is the characteristic of the initiator required for anionic polymerization?
What is the characteristic of the initiator required for anionic polymerization?
What is the purpose of electron-withdrawing substituents in anionic polymerization?
What is the purpose of electron-withdrawing substituents in anionic polymerization?
What is the result of the polymerization reaction of methyl α-cyanoacrylate when it comes into contact with skin?
What is the result of the polymerization reaction of methyl α-cyanoacrylate when it comes into contact with skin?
What type of polymerization is Super Glue an example of?
What type of polymerization is Super Glue an example of?
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Study Notes
Condensation Polymers (Step-Growth Polymers)
- Formed by intermolecular reaction of molecules with a functional group at each end, resulting in the loss of a small molecule such as H2O, alcohol, or HCl.
- Can be formed by the reaction of a single compound with two different functional groups, A and B, or by the reaction of two different compounds, one with two A functional groups and the other with two B functional groups.
Classes of Step-Growth Polymers
- Polyamides
- Polyesters
- Epoxy Resins
- Polyurethanes
Polyamides
- Nylon 6 is an example of a step-growth polymer formed from a monomer with two different functional groups, resulting in the formation of an amide.
- Nylon 6 is formed from the polymerization of 6-aminohexanoic acid, which contains six carbons.
- The starting material for the synthesis of nylon 6 is ε-caprolactam.
- Nylon 66 is an example of a step-growth polymer formed by two different bifunctional monomers, adipoyl chloride and 1,6-hexanediamine.
Polyesters
- Polymers containing many ester groups.
- Dacron is the most common polyester polymer, made 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, being extensively cross-linked systems.
- They can adhere to almost any surface and are resistant to solvents and high temperature.
Addition Polymers
Ring-Opening Polymerizations
- Some compounds can polymerize well, rather than ethylene and substituted ethylenes, in chain-growth polymerizations.
- Epoxides undergo chain-growth polymerization, which can occur by an anionic or cationic mechanism.
Polymerization of Dienes
- The manufacture of rubber involves the polymerization of 2-methyl-1,3-butadiene (isoprene).
- Synthetic rubbers can be made by radical polymerization of dienes other than isoprene.
- Natural and synthetic rubbers can be hardened by vulcanization, which involves heating rubber with sulfur, resulting in cross-linking of the separate polymer chains through disulfide bonds.
Copolymers
- Formed by the polymerization of two or more different monomers.
- Can be classified into four types: alternating, block, random, and graft copolymers.
Anionic Polymerization or Living Polymers
- The initiator is a nucleophile that reacts with the monomer to form an anion propagating site.
- The mechanism involves an initiating step and propagation steps.
- Living polymers are most common in anionic polymerization because the chains cannot be terminated by proton loss or by chain combination or disproportionation.
- Examples of alkenes that undergo anionic polymerization include methyl α-cyanoacrylate, which is used to make Super Glue.
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