18.1 starting materials for polymers 18.2 free radical polymerization 18.3 condensation...

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  • 18.1 Starting Materials for Polymers 18.2 Free Radical Polymerization

    18.3 Condensation Polymerization

    18.4 Types of Polymers

    18.5 Carbohydrates

    18.6 Nucleic Acids

    18.7 Proteins Chapter 18. MacromoleculesChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.1 Starting Materials for PolymersLearning objective:

    Describe functional groups and linkage groups in polymersChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.1 Starting Materials for Polymers

    What is a polymer? A polymer is a macromolecule constructed by linking together many copies of much smaller molecules called monomers.Monomers are organic molecules characterized by their functional groups.Functional groups specialized groups of atoms that impart a specific chemical function.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Polymerizable Functional Groups

    Functional groups are only a part of an organic molecule.

    R represents the less important part of the molecule, and can be H or an organic fragment containing carbon atomsChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Examples of Alcohols and a ThiolChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Ammonia and AminesChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • The Carbonyl and Carboxyl GroupsChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Important Polymer Linkage GroupsChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.and phosphate linkages

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.2 Free Radical PolymerizationLearning objective:

    Describe polymers made by free radical polymerizationChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.2 Free Radical Polymerization

    e.g. the synthesis of polyethylene is a three-step sequence Initiation a reactive chemical attacks the p bond of a single ethylene molecule.Propagation the product from step 1 reacts readily with the p bond of another ethylene molecule. Several of these steps occur, building a long chain.Termination chain growth comes to an end when two long chains join.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Initiation an initiator molecule is added to ethylene, with heating, a free radical is formed and the first step occurs

    Propagation the first step leaves a carbon atom with a free radical, ready for another addition of ethylene

    Termination the process ends when two radicals collide and react.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.Important Polymers made from Alkenes

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Example 18 1 Drawing the Structure of a PolymerPolyacrylonitrile, known commercially as Orlon, is made by polymerizing acrylonitrile (see Figure 18 3). Orlon is used to make fibers for carpeting and clothing. Draw the Lewis structure of polyacrylonitrile, showing at least three repeat units.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • RubberPolyisoprene the first alkene polymer to be used in society, came from sap of rubber trees.

    Now, several forms of rubber are commercially produced by polymerizing mixtures of two different monomers to give copolymers.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Cross-linkingHow are rubbers made durable and strong if polymers are long chain molecules? Wouldnt they only be held together by weak intermolecular forces?They are chemically treated to create covalent bonds between the long chain molecules.This process is referred to as cross-linking.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.3 Condensation PolymerizationLearning objective:

    Describe polymers made by condensation polymerizationChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.3 Condensation PolymerizationCondensation reaction: the formation of a bond between two molecules eliminating water or some small molecule.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Polyamides

    Amide a condensation of an amine and a carboxylic

    Polyamides polymers that contain amide linkage groupsChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.Polyamides

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.Polyesters

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Example 18 2 The Structure of a PolyamideQiana, a polyamide that feels much like silk, has the following structure:

    Identify the monomers used to make QianaChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • PolyestersComprise largest segment of market of synthetic fibers (40%)Poly(ethylene terephthalate) is the leading polymerChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.4 Types of PolymersLearning objective:

    Recognize and describe some properties of plastics, fibres, and elastomersChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.4 Types of Polymers

    Polymers can be divided into three categories based on their form and resistance to stretching:PlasticsFibersElastomersChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • PlasticsPlastic is a type of polymer that hardens on cooling or evaporation of the solvent.Thermoplastics plastics that melt or deform when heatedHigh Density Polyethylene (HDPE) very rigid and strong, used to make bottle caps, toys, cabinets for electronic devicesLow Density Polyethylene (LDPE) soft, semi-rigid, used to make plastic bags, squeeze bottles

    Thermosetting plastics that retain their structural integrity when heatedFormicaChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • PlasticizersImprove the flexibilities of some plasticsChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • FibresSynthetic fibres are thin threads of polymer made by forcing a fluid thermoplastic material through a set of tiny pores.The polar functional groups produce strong dipolar forces that add significant strength to the material.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • ElastomersA flexible polymer that can be distorted.Most contain alkenes (double bonds)The polymer chains are held together by cross-links.The number of cross-links will determine the degree of flexibility and the strength of the polymer.Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Effects of Cross-Linking on RubberChemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.Recycling Polymers

    Chemistry, 2nd Canadian Edition 2013 John Wiley & Sons Canada, Ltd.

  • 18.5 CarbohydratesLearning objective:

    Recognize and draw structures of monosaccharides and polysaccharidesChemistry, 2nd Canadian Edition 2013 John Wiley &am

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