Transcript Chapter 15 Multistep Syntheses

Chapter 16
Polymeric Materials
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Monomers and Polymers
Linear and Branched Polymers
Types of Polymerization
Addition Polymerization
Condensation Polymers
Extensively Cross-Linked Polymers (SKIP)
Three-Dimensional Structure Polymers (SKIP p. 813-818 top)
Chapter 16
Polymeric Materials
• Polymer Nomenclature - Monomers and Polymers
– Definitions of polymer, monomer, plastic, thermoplastic and
thermoset plastic in “handout”
– repeat units, average degree of polymerization
• Polymer Architecture - Linear and Branched Polymers
– See handout for depiction of linear, branched, star, comb, ladder
and cross-linked networks
• Polymer Morphology
– ordered = crystalline regions
– random = amorphous regions
• Polymer properties and transitions
– Modulus (degree of hardness/softness)
– Glass Transition Temperature (transition from glassy to rubbery)
– Melt Temperature(transition to viscous flow)
Chapter 16
Polymeric Materials
• Types of Polymerization
• Addition (also called chain-growth)
 Radical (three steps – initiation, propagation, termination)
 Cationic
 Anionic (called “ living” polymer, can make block co-polymers)
• Condensation (also called step-growth) loss of
water
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Polyester
Polyamide
Polycarbonate
Polyurethane
Epoxy resins
Polysaccharides (starch)
Polypeptides and proteins
Chapter 16
Polymeric Materials
• Addition Polymerization
– Radical Polymerization
• 3 steps (initiation, propagation, and termination) see handout
– Ionic Polymerization
• cationic
• anionic (living polymers, useful to make “block” co-polymers)
– Cross-Linking in Polymers (can use bi-functional, tri functional,
quadri-functional monomers)
– Heteroatom-Containing Addition Polymers
• Polyols
– can not make polyvinyl alcohol from vinyl alcohol, instead polymerize
vinyl acetate and then hydrolyze to polyvinylalcohol
• Polyethers (e.g., poly(ethylene glycol)
• Polyacetals (e.g., paraformaldehyde from formaldehyde)
Chapter 16
Polymeric Materials
• Condensation Polymers
– Polyesters (from a dicarboxylic acid and diol)
– Polysaccharides (from carbohydrate (or sugar)
condensation)
– Polyamides (from dicarboxylic acid and diamine)
– Polypeptides (from20 common amino acids)
– Polyurethanes (form bis-isocyanate and diol)
Chapter 16
Polymeric Materials
• Three-Dimensional Structure of Polymers
– Polypropylene (SKIP pages 813-818 top)
– Naturally Occurring Polypeptides
• Primary structure - amino acid sequence
• Secondary structure
– -pleated - deviation from planarity due to steric interactions
– -helix - hydrogen bonding from peptide units in the same chain
• Tertiary structure - spatially dispersed -pleated and -helix
• Quaternary structure - several polypeptides form a complex
– Cellulose and Starch
• Starch from -glucose (axial C1-OH group)
• Cellulose from -glucose (equatorial C1-OH group)
Chapter 16
Polymeric Materials
• Review of Reactions
– Be able to draw the basic polymerization mechanism for
• radical, anionic, cationic
• general condensation polymerization for a polyester, polyamide,
polyurethane, polypeptide
• Review Problems
– Especially review problem 16.1
– Know nomenclature of synthetic and natural polymers
– Know how to identify repeat units
Chapter 16
Polymeric Materials
• Summary
– Definitions for polymer, monomer, plastic, thermoplastic,
thermoset, melt temperature, glass transition temp.
– Nomenclature for simple addition and condensation polymers
– Linkages between monomers include
• C-C bonds in vinyl polymers
• C-O bonds in polyesters, polyacetals, polyethers, polysaccharides
• C-N bonds in polyamides, polypeptides
– Role of Hydrogen bonding in nitrogen and oxygen containing
polymers
• intermolecular H-bonding in  pleated peptides
• intramolecular H-bonding in  helix peptide structures
• primary, secondary, tertiary and quaternary structures