Advanced Review Antimicrobial polymers as synthetic mimics ...
Synthetic Polymers
description
Transcript of Synthetic Polymers
![Page 1: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/1.jpg)
© 2014 Pearson Education, Inc.
Synthetic Polymers
Paula Yurkanis BruiceUniversity of California,
Santa Barbara
Chapter 27
![Page 2: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/2.jpg)
© 2014 Pearson Education, Inc.
Polymerization
A polymer is a large molecule made by linking together repeating units of small molecules called monomers.
![Page 3: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/3.jpg)
© 2014 Pearson Education, Inc.
A Chain-Growth Polymer(polystyrene)
Chain-growth polymers (also known as addition polymers), are made by chain reactions.
![Page 4: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/4.jpg)
© 2014 Pearson Education, Inc.
Step-Growth Polymer(Dacron)
Step-growth polymers (also called condensation polymers), are made by combining two molecules while removing a small molecule.
![Page 5: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/5.jpg)
© 2014 Pearson Education, Inc.
![Page 6: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/6.jpg)
© 2014 Pearson Education, Inc.
Chain-Growth Polymers
Chain-growth polymers are formed by one of three mechanisms.
• Radical polymerization
• Cationic polymerization
• Anionic polymerization
![Page 7: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/7.jpg)
© 2014 Pearson Education, Inc.
Radical Polymerization
The initiator is a radical.
![Page 8: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/8.jpg)
© 2014 Pearson Education, Inc.
Propagation Steps
![Page 9: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/9.jpg)
© 2014 Pearson Education, Inc.
Termination Steps
![Page 10: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/10.jpg)
© 2014 Pearson Education, Inc.
Chain Transfer
The molecular weight of the polymer can be controlled by a process known as chain transfer.
![Page 11: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/11.jpg)
© 2014 Pearson Education, Inc.
Head-to-Tail Linkage
Chain-growth polymerization of monosubstituted ethylenes exhibits a marked preference for head-to-tail addition.
![Page 12: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/12.jpg)
© 2014 Pearson Education, Inc.
Poly(vinyl chloride)
Head-to-tail addition forms a polymer with a substituent on every other carbon.
![Page 13: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/13.jpg)
© 2014 Pearson Education, Inc.
Stabilization of the Propagating Site
Head-to-tail addition is favored for steric reasons.
Head-to-tail addition is favored by groups that stabilize radicals.
![Page 14: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/14.jpg)
© 2014 Pearson Education, Inc.
Alkenes Used in Radical Polymerization
![Page 15: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/15.jpg)
© 2014 Pearson Education, Inc.
Radical Initiators
![Page 16: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/16.jpg)
© 2014 Pearson Education, Inc.
Branching of the Polymer Chain
![Page 17: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/17.jpg)
© 2014 Pearson Education, Inc.
Branched Polymers are More Flexible
![Page 18: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/18.jpg)
© 2014 Pearson Education, Inc.
Recycling Symbols
![Page 19: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/19.jpg)
© 2014 Pearson Education, Inc.
Cationic Polymerization
The initiator is an electrophile.
![Page 20: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/20.jpg)
© 2014 Pearson Education, Inc.
Propagating Steps
![Page 21: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/21.jpg)
© 2014 Pearson Education, Inc.
Three Ways to Terminate the Chain
![Page 22: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/22.jpg)
© 2014 Pearson Education, Inc.
A Carbocation Monomer Can Undergo Carbocation Rearrangement
![Page 23: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/23.jpg)
© 2014 Pearson Education, Inc.
Alkenes Used in Cationic Polymerization
Monomers with electron-donating substituents undergo cationic polymerization.
![Page 24: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/24.jpg)
© 2014 Pearson Education, Inc.
Anionic Polymerization
The initiator is a nucleophile.
![Page 25: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/25.jpg)
© 2014 Pearson Education, Inc.
Propagating Steps
Nonterminated chains are called “living polymers” and remain active until they are “killed.”
![Page 26: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/26.jpg)
© 2014 Pearson Education, Inc.
Alkenes Used in Anionic Polymerization
Monomers with electron-withdrawing substituents undergo anionic polymerization.
![Page 27: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/27.jpg)
© 2014 Pearson Education, Inc.
Super Glue(an example of anionic polymerization)
![Page 28: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/28.jpg)
© 2014 Pearson Education, Inc.
What Determines the Mechanism?
Alkenes with substituents that can stabilize radicals undergo radical polymerization.
Alkenes with electron-donating substituents that can stabilize cations undergo cationic polymerization.
Alkenes with electron-withdrawing substituents that can stabilize anions undergo anionic polymerization.
Some alkenes undergo polymerization by more than one mechanism.
![Page 29: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/29.jpg)
© 2014 Pearson Education, Inc.
Ring-Opening Polymerization (anionic)
![Page 30: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/30.jpg)
© 2014 Pearson Education, Inc.
Ring-Opening Polymerization(cationic)
![Page 31: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/31.jpg)
© 2014 Pearson Education, Inc.
Stereochemistry of Polymerization
Long, unbranched polymers with either isotactic or the syndiotactic configuration can be prepared using an aluminum–titanium initiator (a Ziegler–Natta catalyst).
![Page 32: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/32.jpg)
© 2014 Pearson Education, Inc.
Mechanism for Ziegler–Natta-Catalyzed Polymerization
![Page 33: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/33.jpg)
© 2014 Pearson Education, Inc.
Polymerization of Dienes
These rubbers have cis double bonds.
![Page 34: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/34.jpg)
© 2014 Pearson Education, Inc.
Neoprene(a synthetic rubber)
Neoprene has trans double bonds.
![Page 35: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/35.jpg)
© 2014 Pearson Education, Inc.
Disulfide Bonds in Rubber
The more sulfur used in vulcanization, the more rigid the polymer.
![Page 36: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/36.jpg)
© 2014 Pearson Education, Inc.
Four Types of Copolymers
![Page 37: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/37.jpg)
© 2014 Pearson Education, Inc.
![Page 38: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/38.jpg)
© 2014 Pearson Education, Inc.
Step-Growth Polymers
The monomer can have two different functional groups.
The monomer can be two different bifunctional compounds.
![Page 39: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/39.jpg)
© 2014 Pearson Education, Inc.
Step-Growth Polymerization Requires High Yields for Long Chains
![Page 40: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/40.jpg)
© 2014 Pearson Education, Inc.
Nylon is a Polyamide
Nylon 6 is an example of a step-growth polymer formed by a monomer with two different functional groups.
![Page 41: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/41.jpg)
© 2014 Pearson Education, Inc.
Commercial Synthesis of Nylon 6
![Page 42: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/42.jpg)
© 2014 Pearson Education, Inc.
Nylon is a Polyamide
Nylon 66 is an example of a step-growth polymer formed by two different bifunctional monomers.
![Page 43: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/43.jpg)
© 2014 Pearson Education, Inc.
Aromatic Polyamides are Called Aramides
The incorporation of aromatic rings into polymers improves the physical strength of the polymers.
![Page 44: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/44.jpg)
© 2014 Pearson Education, Inc.
Kevlar
![Page 45: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/45.jpg)
© 2014 Pearson Education, Inc.
Dacron is a Polyester
Polyesters are step-growth polymers in which the monomer units are joined together by ester
groups.
![Page 46: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/46.jpg)
© 2014 Pearson Education, Inc.
Kodel is a Polyester
![Page 47: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/47.jpg)
© 2014 Pearson Education, Inc.
Lexan is a Polycarbonate
Polycarbonates have two ester groups bonded to the same carbon.
![Page 48: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/48.jpg)
© 2014 Pearson Education, Inc.
An Epoxy Resin is a Cross-Linked Polymer(it is the strongest adhesive known)
![Page 49: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/49.jpg)
© 2014 Pearson Education, Inc.
A Urethane
A urethane has an OR and an NHR bonded to the same carbonyl carbon.
![Page 50: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/50.jpg)
© 2014 Pearson Education, Inc.
A Polyurethane
![Page 51: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/51.jpg)
© 2014 Pearson Education, Inc.
Crystallites are Highly Ordered Regions
![Page 52: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/52.jpg)
© 2014 Pearson Education, Inc.
The More Crystalline the Polymer is, the Denser, Harder, and More Resistant it is to Heat
![Page 53: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/53.jpg)
© 2014 Pearson Education, Inc.
A Thermosetting Polymer
Thermosetting polymers are cross-linked.
The greater the degree of cross-linking, the more rigid the polymer.
![Page 54: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/54.jpg)
© 2014 Pearson Education, Inc.
An Oriented Polymer
These polymers are stronger than steel and can conduct electricity.
![Page 55: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/55.jpg)
© 2014 Pearson Education, Inc.
A Plasticizer
A plasticizer is an organic compound that is added to a polymer tomake it more flexible.
![Page 56: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/56.jpg)
© 2014 Pearson Education, Inc.
Recycling a Polymer
This is the reverse of the transesterification reaction that formed the polymer.
![Page 57: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/57.jpg)
© 2014 Pearson Education, Inc.
Biodegradable PolymersPolylactic Acid (PLA)
Biodegradable polymers can be broken into small molecules by microorganisms.
![Page 58: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/58.jpg)
© 2014 Pearson Education, Inc.
PLA Cannot Be Used for Hot Drinks
![Page 59: Synthetic Polymers](https://reader035.fdocuments.us/reader035/viewer/2022062309/56813b6c550346895da47059/html5/thumbnails/59.jpg)
© 2014 Pearson Education, Inc.
Biodegradable Polymers(polyhydroxyalkanoates)
Polyhydroxyalkanoates (PHAs) are condensation polymers of 3-hydroxycarboxylic acids.