1. Fundamentals of Polymer Science and technology
University of Shanghai for Science and Technology
Hua Zou

2. Table of Contents Topic Classes Introduction to Polymer Science 3
Polymer Synthesis 18
Solid-State Properties 9
Viscoelasticity
Polymer Degradation and Environment
Polymer Solutions
Miscellaneous 6
In Total 45

3. References

4. Lecture 1: Introduction to Polymer Science
1.1 What is a ‘Polymer’?
1.2 Classification of Polymers
1.3 Polymer Structure
1.4 Molecular Weight
1.5 Thermal Transition

5. 1.1 What is a ‘Polymer’
Definition: Many units of monomers (or repeating units) covalently bonded together to form a long chain (or macromolecule).
‘poly’ meaning ‘many’
‘meres’ meaning ‘parts’
e.g.
n H2C = CH2
CH2 n O
H2C
CH2 n
H2N
NH2 R1 +
HOOC
COOH R2 NH CO n
H2O

6. Is Polymer Science Important?
Polymer production is 200 M tons p.a. (>> all other synthetic chemicals combined);
More than 50 % of industrial chemists work on polymer-related projects;
Many diverse applications for polymer-based materials;
It is believed that polymers will play important roles in future biomedical advances and in soft nanotechnology.

7. Natural Polymer Materials

8. Synthetic Polymer Materials

9. Polymers are Everywhere!

10. Nomenclature Vinyl polymers name is just prefixed by ‘poly’.
e.g. Polyethylene, Polystyrene, Polypropylene, Poly(ethylene oxide)
Non-vinyl polymers usually named according to the initial monomer or the functional group of the repeating unit
e.g. poly(hexamethylene adipamide)聚(己二酰己二胺)
IUPAC nomenclature: unambiguous but not widely used
Abbreviations
PS = polystyrene, PVC = poly(vinyl chloride), PMMA = poly(methyl methacrylate)

11. Resin Identification Code

12. A Brief History of Polymer Science/Technology
Vulcanisation of natural rubber (Goodyear)
Celluloid – made by nitration of cellulose
Bakelite – first truly synthetic polymer invented by Baekeland
1920’s Staudinger – first to recognise the long-chain nature of polymers
1929 Carothers – invented condensation (or step) polymerisation
1937 Synthesis of polystyrene
1939 Commercial production of polyethylene by ICI
Herman Staudinger
A pioneer of
polymer science
Wallace Carothers
Inventor of Nylon
1953 Nobel Prize

13. A Brief History of Polymer Science/Technology
1947 Nylon is a major commercial success for Du Pont & Nemours in USA
P. J. Flory developed thermodynamic theory of polymer solutions
K. Ziegler and G. Natta: co-ordination polymerisation
M. Szwarc invented living (anionic) polymerisation
1960’s Development of gel permeation chromatography (GPC)
1960’s-present Many speciality (high value) applications developed for polymers
P. J. Flory
K. Ziegler
G. Natta
M. Szwarc
1963 Nobel Prize
1974 Nobel Prize

14. A Brief History of Polymer Science/Technology
2000 Nobel Prize in chemistry, for the discovery and development of conductive polymers
Alan J. Heeger
Alan G. MacDiarmid
Hideki Shirakawa

15. Many Diverse Applications for Polymers
Poly(ethylene oxide)
(PEO)
Various cosmetics and drug formulations
(since water-soluble, biocompatible, non-fouling)
Hard
contact
lenses
Acrylic
baths
Poly(methyl methacrylate)
(PMMA)
Electrical cable
insulation
Double glazing
Poly(vinyl chloride)
(PVC)

16. Many Diverse Applications for Polymers
Poly(vinyl acetate)
(PVAc)
Latex paints
PVA glue
Polypropylene (PP)
Plastic chairs
Food packaging
Disposable coffee cups
Fast food containers
Polystyrene (PS)

17. Many Diverse Applications for Polymers
Polyethylene (PE)
Artificial hip joints
Disposable carrier bags
Polyacrylamide (PAAm)
Clarification of beer, wine
Polyacrylonitrile (PAN)
Carbon fibre precursor
Polytetrafluoroethylene (PTFE)
Non-stick frying pans
High vacuum taps

18. Many Diverse Applications for Polymers
Poly(vinyl alcohol) (PVA)
Postage stamp
adhesive
Also: water-soluble
films and fibres
Used as a blood
plasma substitute
in World War II
Poly(N-vinyl pyrrolidone) (PVP)
Poly(ethylene
terephthalate)
(PET)
Poly(amides)
some ‘high strength’
applications: Kevlar
bullet-proof vests
textiles, tapes,
beer bottles

19. 1.2 Classification of Polymers
1.2.1 Based on Processing Behaviour
1.2.2 Based on Polymerisation Mechanism
1.2.3 Based on Polymer Structure
1.2.4 Based on Application and Properties

20. 1.2.1 Based on Processing Behaviour
Thermoplastic polymers:
Hard
Soft
heat
cool
This is a physical + reversible change
Thermoplastic polymers are melt-processable and hence potentially recyclable
e.g. polystyrene, polyethylene, polypropylene, poly(vinyl chloride) etc.
heat
Thermoset polymers:
Soft
Hard
Thermoset polymers become hard and rigid on heating due to inter-chain cross-linking reactions (known as ‘curing a resin’).
This is a chemical, irreversible change
e.g. epoxy resins, phenol-formaldehyde resins (Bakelite), etc.

21. Synthesis of a Phenol-Formaldehyde Thermoset ResinC O H +
formaldehyde OH
phenol H OH C OH H
- H2O OH
CH2
H2C HO
Bakelite
- H2O OH C H
Multiple cross-links are formed between the polymer chains on curing at elevated temperature

22. 1.2.2 Based on Polymerization Mechanism
Carothers (1929) distinguished between polymers on the basis of chemical composition.
Two main categories: Condensation and Addition polymers.

23. Examples of Some Addition Polymer Derived from Ethylene

24. Examples of a Condensation Polymerization

25. Examples of a Condensation Polymerization
Modern definition: Distinguishes between polymers on the basis of their polymerisation mechanism (either Step or Chain polymerisation)
Usually:
‘Step’ = ‘Condensation’
But occasionally some grey areas!
‘Chain’ = ‘Addition’
For example, step polymerizations do not always involve the elimination
of a small molecule e.g. H2O, HCl, MeOH, NH3 etc. (consider polyurethanes) +
But no condensate
is formed in this case! n

26. Examples of a Condensation Polymerization
Step polymerisations produce heteroatom polymer backbones
Chain polymerisations produce homoatom polymer backbones
However, there are some exceptions (e.g. ring-opening polymerisation!)
Ring-opening polymerisation:
An unusual example of a chain
polymerisation that produces a
heteroatom polymer backbone! n
ethylene oxide

27. Comparison of Step-Growth and Chain-Growth Polymerization

28. 1.2.3 Based on Polymer Structure
Homochain polymers
Heterochain polymers: contain more than one atom type in their backbone

29. 1.2.4 Based on Application and Properties
Plastics
Rubber
Fiber
Coating
Adhesive
Functional polymer

30. 1.3 Polymer Structure 1.3.1 Copolymer 1.3.2 Tacticity
1.3.3 Geometric Isomerism

31. 1.3.1 Copolymer Homopolymer: A A A A A A A A A A
Nomenclature: polyA or poly(A)
(i) Alternating copolymer: A B
Nomenclature: poly(A-alt-B)
(ii) Block copolymer:
Nomenclature: poly(A-b-B) A B
(iii) Statistical copolymer:
Nomenclature: poly(A-stat-B) A B
(iv) Graft copolymers: B B B B B
Nomenclature: poly(A-g-B) B B A A A A A A A A A A B

32. 1.3.2 Tacticity * Three spatial arrangements are possible: *
Consider: * n
CH2 C
CH2 C C*
= chiral carbon R R n
Three spatial arrangements are possible:
Consider Tacticity in Poly(vinyl alcohol)
CH2 C H n * OH
Isotactic
Syndiotactic
Atactic

33. 1.3.2 Tacticity Isotactic: Syndiotactic: Atactic: 全同立构
all R groups pointing in one direction
间同立构
Syndiotactic:
alternating R groups 无规
Atactic:
random distribution of R groups
Isotactic, Syndiotactic polymers have ordered microstructures:
Efficient interchain packing leads to high crystallinity & density
Can often be synthesized using Ziegler-Natta catalysts

34. Why is Tacticity Important?
Tacticity affects the physical properties
In general, tactic polymers (i.e., isotactic or syndiotactic) are partially crystalline,
while atactic polymers are amorphous.
Other polymer properties, such as thermal and mechanical behavior, can be
significantly affected by the tacticity of the polymer.
Polypropylene (PP) is a good example
Atactic PP is a low melting material with no commercial importance.
Isoatactic PP is high melting (176 oC), crystalline, tough material that is industrially
useful.
Syndiotactic PP has similar properties, but is very clear. It is harder to synthesize.

35. 1.3.3 Geometric Isomerism
When there are unsaturated sites along a polymer chain, several different isomeric forms are possible.

36. Number fraction of chains with mass M
1.4 Molecular Weight
Problem:
Polymers have different chain lengths
Unlike small molecules, polymers are ‘polydisperse’ (no unique molecular weight)
Hence need to measure the Molecular Weight Distribution (MWD):
Define N(M) as the number fraction of polymer chains of molecular weight M:
N(M),
Number fraction of chains with mass M
Molecular Weight, M
 Real polymer (narrow MWD)
 Real polymer (broad MWD)
 Ideal polymer (or small molecule)

37. Number fraction of chains with
Molecular Weight
Number-average:
Weight-average:
Z-average: Mn
Number fraction of chains with
mass M
Mn is biased towards low mol. wt. species Mw
Mz is seldom used
Mn < Mw < Mz Mz
for all real polymers

38. 8 mol 5000 molecular weight
4 mol 9000 molecular weight, 4 mol 1000 molecular weight

39. Polydispersity Index, PDI
PDI = Mw/Mn
a crude measure of the width of the MWD curve
PDI = (or Mn = Mw = Mz) for an ideal, perfectly monodisperse polymer
where all chains have exactly the same length (or mass)
If PDI < 1.20, near-monodisperse polymer (by living anionic polymerisation);
If PDI > 1.20, polydisperse polymer (PDI > 2.0 very often)

40. Degree of Polymerisation, Dp
Dp = mean number of monomer units per polymer chain
Dp = 9
Mn of polymer chain
molecular weight of monomer
Dp =
e.g. Calculate the Dp of a polystyrene chain with an Mn of 10,000
Dp =
10,000
104
= = 96
N.B. Dp must be an integer
(cannot get a fractional monomer unit!)
If Dp < 10, get OLIGOMERS, not POLYMERS

41. 1.5 Thermal Transition

42. Thank you for your attention!