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Polymer Chemistry

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... synthesized for selected physical properties. Physical. Properties. Too low ... Physical Property. Structure and Morphology. MANY Classifications of Polymers ... – PowerPoint PPT presentation

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Title: Polymer Chemistry


1
Polymer Chemistry
  • Welcome to the Polymer Age
  • Dr. Martin J. Maresch

2
Structure of the Course
  • Upper level course
  • Weigh your time!
  • Utilize previous chemical knowledge
  • Requires massive reading and comprehension
  • Interactive style (ask any kind of question)
  • Performance evaluation
  • At the end of class periods and homework
  • Examinations with Polymer ACS Final
  • Paper (topic due one month from today)

3
Field Trip to Avery Dennison
  • 1130 am to 100 pm
  • Next Wednesday or Friday

4
Background for Polymers
  • Preview of atoms and the number of bonds that
    they can form
  • Name the symbol
  • Determine the number of bonds that it can form
  • Determine its atomic weight
  • Name Bonds Weight
  • H
  • C
  • N
  • O
  • F
  • Si
  • S
  • Cl

5
Background for Polymers
6
Basics for Polymers
  • Activity for understanding Polymers
  • Stand up and form a double hand hold with another
    individual choosing a 1 and 2
  • When the instructor grabs a 1 hand, his/her
    partner will rapidly grab a 1 hand from the
    nearest paired group.
  • Repeat this process rapidly until no pair is
    close enough to grab.
  • Repeat this process two more times noting the
    number of pairs in the chain.

7
Basics for Polymers
  • Count the number of original repeat units or
    monomers.
  • How many monomers were there in the chain?
  • This is the Degree of Polymerization DP
  • How many monomers did not react?
  • Calculate the percent which reacted.
  • If each monomer had a mass of 150 kg, determine
    the mass of the polymer.
  • On a molecular level, Molecular Weight.

8
Basics for Polymers
  • What else determines the mass of the chain?
  • The mass of the Instructor (initiator) and the
    end group (terminator) are minor for polymers.
  • What is the relationship between Degree of
    Polymerization (DP), the Molecular Weight of the
    monomer and polymer?
  • MWtPolymer DP x MWtMonomer MWtEnds
  • What is the average DP and MWtPolymer?

9
Basic Nomeclature
  • Monomer (One Unit)
  • -any molecule capable of reacting to form
    repeating units
  • Oligomer (Few Units)
  • -few monomers (usually 2-10) reacted with each
    other
  • Polymer (Many Units)
  • A giant molecule made up of many monomers
    (Molecular Wt typically greater than 5,000)

10
Molecular Weight WindowOligomer vs Polymer
  • Polymers are synthesized for selected physical
    properties

Physical Property
Viscosity Too High POLYMER
Desired Range POLYMER
Physical Properties Too low OLIGOMER/ POLYMER
Degree of Polymerization Number of Monomers
11
Structure and Morphology
  • MANY Classifications of Polymers
  • Start with Their SOURCE
  • Natural
  • Made by Nature
  • Synthetic
  • Made by Technology
  • Both
  • Made by Nature and modified by Science

12
Natural Polymers
  • Polysaccharides (Natural Polyethers)
  • MW 150,000 to gt 1,000,000
  • examples cellulose
  • Repeat unit glucose

13
Natural Polymers
  • Natural Rubber
  • MW about 1,000,000
  • examples hevea braziliensis (cis) - rubber
    bands, auto tires.
  • palaquium oblongifolium (trans) - golf ball cover
    (gutta-percha)
  • Repeating unit isoprene(2-methyl-1,3-butadiene)

14
Natural Polymers
  • Proteins (Natural Polyamides)
  • MW 10,000 to gt 1,000,000
  • examples wool, silk, us
  • Repeat unit amino acid

15
Synthetic Polymers
  • Vinyls
  • Polyethylene (PE)
  • Polypropylene (PP)
  • Polyvinyl chloride (PVC)
  • Polystyrene (PS)
  • Polyvinylacetate (PVAc)
  • Polyvinylalcohol (PVA)
  • Polymethylmethacrylate (PMMA)
  • Polyacrylonitrile (PAN)
  • Others
  • Polyesters (PET)
  • Polyethers (PEG)
  • Polyamides (Nylon)
  • Polyurethanes
  • Polycarbonates (Lexan)
  • Silicones
  • Ceramics

16
Structure and Morphology
  • Modified Natural Polymers
  • Convert functional groups on the monomers
  • Cellulose

17
Structure and Morphology
  • Secondly, Classified by their LINKAGE
  • Molecules with the RIGHT STUFF
  • Functionality
  • Review the functional groups that react to form
    NEW COVALENT BONDS
  • Number of Functional Groups per Molecule
  • At least TWO (may have more) to be a monomer
    molecule

18
Structure and Morphology
  • What linking monomers can FORM
  • Linear chain or backbone with pendant groups
  • Pendants can be any functional group
  • Reactive or not
  • Branching chain
  • With more that 2 functional Groups in which short
    chains emerge from the backbone
  • Cross-linked chain
  • Branching but the backbones merge together

19
Structure and Morphology
  • Ladder chains
  • When the adjacent pendant groups react with one
    another

20
Structure and Morphology
  • Review functional groups
  • Hydrocarbons
  • Alkyl
  • Alkenyl
  • Alkynyl
  • Nitrogens
  • amines
  • Amides
  • Nitriles
  • Urea

21
Structure and Morphology
  • More Functionality
  • Oxygens
  • Ethers
  • Ketones/Aldehydes
  • Carboxylic Acids
  • Esters
  • Epoxides
  • Carbonates

22
Structure and Morphology
  • Sulfur
  • Thiols
  • Thiol Ethers
  • Halides

23
Structure and Morphology
  • Solid State Classification
  • When polymers form solids, they can fall out of
    solution in two ways because of their size
  • Crystalline Dictated by the chains ATTRACTION
    for itself
  • Linear chains are folded neatly into stacked
    regions but certain segments cannot contact
  • Amorphous Segments or whole polymers that
    cannot make contact
  • Certain bulky group polymers wont stack

24
Structure and Morphology
  • Forces at workINTERMOLECULAR
  • van der Waals (dispersion) weak
  • Dipole-dipole stronger
  • Hydrogen Bonding special type of Dipole
  • Between Oxygen or Nitrogen and Hydrogen

25
Structure and Morphology
  • Degree of Crystallinity
  • The portion of the total polymer that is stacked
  • If partially crystalline, the solid has a Melting
    Pt
  • If completely amorphous, it does not
  • Only glassy solid with a temperature in which it
    liquifies.
  • Glass Temperature
  • Polyethylene (PE), Polyethylene tert-Phthalate
    (PET), Polyacrylonitrile (PAN), Teflon (PTFE) can
    be up to 90 Crystalline

26
Structure and Morphology
  • Classified Homopolymer or Copolymer
  • Homopolymers are made from one type of repeating
    unit
  • Synthesized from one molecule (propylene)
  • Synthesized from two molecules to make one
    repeating unit (ethanediol with phthallic acid
    make PET)
  • Copolymers are made from two types

27
Structure and Morphology
  • Arrangement of Homopolymers
  • Head to tail
  • Atactic (random allignment of pendant groups)
  • Isotactic (pendant groups all on same side)
  • Syndiotactic (alternating pendant groups)

28
Structure and Morphology
  • Copolymers (with 2 monomers)
  • Random process by mixing two similarly reactive
    monomers
  • Alternating processes yield alternating monomers
  • Block process has segments of each monomer
  • Graft processes add a different polymer onto an
    existing polymer backbone

29
Structure and Morphology
  • Polymers classified by how they FOLD/ ALIGN
    together for STRENGTH
  • Fibers polymers with high interaction when
    folded
  • High modulus (STIFFNESS)
  • High tensile strength
  • Low Elongation

30
Structure and Morphology
  • Elastomers polymers with irregular structures
    leading to poor interaction
  • Usually due to crosslinking
  • Opposite of Fibers
  • Not very stiff or strong
  • Great elongation (1000)

31
Structure and Morphology
  • Plastics polymers with strengths in between
    Fibers and Elastomers
  • Firm yet Flexible

32
Structure and Morphology
  • Polymers are classified by their mechanism of
    synthesis
  • Step reaction (condensation)
  • Two molecules react with each other an form a new
    molecule while liberating a small molecule
    (water, HCl,etc) Repeat step again.
  • Chain reaction (addition)
  • Many molecules rapidly add in a chain until
    terminated with no loss of mass

33
Structure and Morphology
  • Classified by the polymers THERMAL
    characteristics
  • Thermoplastics
  • Can be made to flow when heated to elevated
    temperatures
  • Cycle can be repeated
  • Thermosets
  • Prepolymers (urea and formaldehyde) are mixed
    before permanently setting with heat

34
Structure and Morphology
  • Polymers can be classified by their PREPARTION
    TECHNIQUES
  • Bulk monomer and initiator in a tank
  • Solution -monomer and initiator with a solvent in
    which the product is soluble
  • Suspension same as above but product
    precipitates out
  • Emulsion two phases with surfactant micelles

35
Structure and Morphology
36
Structure and Morphology
37
Structure and Morphology
38
Structure and Morphology
39
Structure and Morphology
40
Structure and Morphology
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