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The Power of Thermodynamics in the Characterization of Materials. Zeki Y. Al-Saigh Department of Chemistry Buffalo State, State University of New York 1300 Elmwood Avenue Buffalo, N.Y., USA. Outline. Background about Materials Techniques used in the Characterization

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the power of thermodynamics in the characterization of materials
The Power of Thermodynamics in the Characterization of Materials

Zeki Y. Al-Saigh

Department of Chemistry

Buffalo State, State University of New York

1300 Elmwood Avenue

Buffalo, N.Y., USA

outline
Outline
  • Background about Materials
  • Techniques used in the Characterization
  • The Physics of Characterization
  • Results Derived from the Speaker’s Research: Polymers, Polymer Blends, Conducting Polymers, Biodegradable Polymers.
characterization of materials
Characterization of Materials
  • Obtaining information on the physical and chemical properties of materials, such as:
  • Mechanical Properties
  • Thermal Properties
  • Interaction Forces Among Molecules
  • Crystallinity
  • Molecular Weight
  • Diffusion of Gases into Layers
materials
Materials:
  • Can be anything which exists in nature:
  • Plastics (polymers), synthetic and natural
  • Rubbers
  • Alloy and Ceramics
  • Oil, Coal and carbon fibers
  • Powders and clay
  • Food
polymer blends
Polymer Blends
  • A new class of materials is always needed to replace heavy metal alloys.
polymer blends6
Polymer Blends
  • Blending of polymers is a fast and inexpensive route to obtaining a new class of materials

FOR MORE INFO on IGC of polymer blends...

Z.Y.Al-Saigh, International J. of Polymer Analysis and Characterization, 3, 249-291 (1997)

polymer blends7
Polymer Blends
  • Solubility of Polymers is the key term in polymer characterization
polymer blends8
Polymer Blends
  • A pair of polymers may be:
  • Compatible (soluble)
  • Incompatible (insoluble)
  • Partially compatible

FOR MORE INFO on IGC of polymer blends...

Z.Y.Al-Saigh, Trends in Polymer Science, 5, 97 (1997)

present techniques available
Present Techniques Available
  • Glass transition temperature
  • Thermal & mechanical
  • NMR
  • Electron spin resonance
  • Solvent vapor sorption
  • heat of mixing
  • Small angle light & X-ray scattering
  • Small angle neutron scattering
  • Inverse gas chromatography
unfortunately
Unfortunately
  • Most of these techniques are beset by a number of technical difficulties
for example
For Example
  • Vapor sorption method takes a long time for the establishment of equilibrium between the vapor and the polymer
  • Neutron scattering uses modified dueterated polymers which are chemically different from the parent polymer
gas chromatography
Gas Chromatography
  • As an alternative method for polymer analysis and characterization

Al-Saigh, Z.Y. and Guillet, J., in “Inverse Gas Chromatography in Analysis of Polymers and Rubbers”, Invited Chapter. Encyclopedia of Analytical Chemistry: Instrumentation and Applications, R. Meyers, Editor, PP. 7759-7792, John Wiley & Sons Ltd, Chichester, (2000).

gas chromatography is
Gas Chromatography is:
  • A technique by which a mixture of components can be separated, analyzed and quantified.
  • It works on the principle of interactions of two phases; stationary and mobile.
  • The stationary phase contains material with active interaction sites, such as sand.
  • The mobile phase is the vapor of the mixture to be analyzed.
inverse gas chromatography
Inverse Gas Chromatography
  • The method is called inverse gas chromatography because the stationary phase (polymers or polymer blends) is of interest, unlike the traditional GC method.
inverse gas chromatography16
Inverse Gas Chromatography

IGC may provide data about:

  • Polymer-solvent interaction
    • Homopolymers
    • Blends
  • Diffusion
  • Glass Transition
current use of igc

Current Use of IGC

1. Interaction parameters of polymer-solvent systems

2. Interaction parameters of polymer-polymer systems

3. Solubility parameters and weight fraction coefficients

4. Molar heat, free energy, and entropy of mixing

5. Molar heat, free energy, and entropy of sorption

slide18
6. Degree of crystallinity of semicrystalline polymers7. Diffusion of gases and liquids into the polymer layer8. Glass transition and melting temperatures9. Surface energy of solids10.Detection of melting point depression of a polymer blend as an indicator of miscibility
blend of semicrystalline diluent
Blend of semicrystalline diluent
  • Are interesting systems for the characterization by inverse gas chromatography

C.T.Chen and Z.Y.Al-Saigh, Macromolecules, 24, 3788 (19910

FOR MORE INFO...

blend of semicrystalline diluent24
Blend of semicrystalline diluent
  • Two blend systems were studied:
  • Poly(vinylidene fluoride)-poly(ethyl methacrylate) [PVF2-PEMA]
  • Poly(vinylidene fluoride)-poly(vinyl methyl ketone) [PVF2-PVMK]
blend of semicrystalline diluent25
Blend of semicrystalline diluent
  • Above PVF2 m.p., both polymers are at melt
  • Below PVF2 m.p., two retention mechanisms are expected:
  • Adsorption of solutes on crystal surfaces
  • Absorption of solutes by the amorphous layer
slide28
Conducting Polymers: The unique properties have lead to an interest in the potential use of PANI as a new class of conductors. This interest was generated due to the relative ease of synthesis, low cost, and the stability of PANI in the air. However, the insulating form a PANI, polyaniline emeraldine base (PANI-EB) suffers from the limited solubility in organic solvents.
table iii interaction parameters of alkanes at a temperature range 140 170 c for 7 pani eb
Table III : Interaction Parameters of Alkanes at a Temperature Range 140-170°C for 7% PANI-EB
table iv interaction parameters of alkanes at a temperature range 80 130 c for 7 pani hebsa
Table IV : Interaction Parameters of Alkanes at a Temperature Range 80-130°C for 7% PANI-HEBSA
surface energies of polymers
Surface Energy (mJ/mA2)

11.04

26.47

200

41.50

40.00

28.90

20.30

33.10

61.00-106.00

Polymer

PEO

PVMK

Hg

PVC

PMMA

Polypropylene

Polyurethane

Polyethylene

doped PPY

Surface Energies of Polymers

Comparative Data on Surface Energy of Several Polymers

inverse gas chromatography of polyaniline
Inverse Gas Chromatography of Polyaniline

REFERENCES:

  • By Ali Al-Ghamdi & Zeki Y. Al-Saigh, Journal of Chromatography, A, 969, (2002) 229.
  • Al-Saigh & Guillet, Encyclopedia of Analytical Chemistry, Volume 9, Page 7759 (2000), Wiley.
slide38
Application of IGC to Biodegradable Polymers
  • ------------------------------------------------------------
  • Fibers acid/base interaction potential
  • Wettability test (determination of water sorption isotherm)
  • Surface adsorption characterization
  • Thermodynamic studies
  • wood-polymer interface studies
current research
Current Research
  • Characterization of Starch-Based Polymers such as Amylopectin
  • Amylopectin is known to be mechanically weak.
  • Blending Amylopectin with another biodegradable polymer may improve the mechanical properties.
latest applications of igc
Latest Applications of IGC
  • Amorphous, co-polymer and blends
  • Semicrystalline polymers and blends
  • Inorganic polymers
  • Amorphous-plasticizer blend
  • Conducting polymers
  • Rubbers
  • Coal and carbon fibers
  • Powders and clay
  • Food