1. Presented by: PARISA KHOSHNOUD Materials Science and Engineering
PVC Foam-Fly Ash Composites A profitable solution to boost Fly Ash utilization in the polymer industry
Research Advisor:
Nidal Abu-Zahra
Presented by:
PARISA KHOSHNOUD
Materials Science and Engineering
9/21/2018

2. Outline Introduction to Polymer Foams Introduction to Fly Ash
Objective
Evaluating the Effect of Chemical Composition of Fly Ash on PVC Foam Composites Properties
Summary and Conclusion
9/21/2018

3. Introduction to Polymer Foams
Materials containing gaseous voids surrounded by a denser matrix.
Global market size in 2012: $82.6 bln estimated to reach $131 bln by 2018.
Polymer foam types: PU, PS, PE, PP, PVC, PC, etc.
Extrusion Foaming Process
The 2 manufacturing techniques which are widely used in traditional polymeric foams are soluble foaming and reactive foaming
Soluble foaming employs a blowing agent dissolved into the polymer solution at high pressure.
A reduction in pressure causes the vaporization leading to the nucleation and bubble growth.
Reactive foaming leads to gas generation due to a chemical reaction in the polymeric mixture, more widely used technique.
3 steps - Gas discharge, Expansion and Stabilization of the foam
Figure: Extrusion: most commonly used technology in the foam industry.
single- and twin-screw extruders can be used for plastic foaming.
Picture: CO2 Foaming gas is first injected into the barrel and mixed with the polymer
the homogenous polymer/gas mixture passes through a die
Rapid pressure drop induces phase separation and cell nucleation.
Extra shaping die is used to control the product shape and foam expansion.
9/21/2018
Sriram Kiran Annapragada, PhD. Thesis, Georgia Institute of Technology, 2007

4. Introduction to PVC Foam
Third most widely produced polymer in the world.
Commercial PVC is generally produced by addition polymerization.
PVC cell type: Closed
General Features:
High thermal and acoustic insulation properties
Fire resistant, water proof
Cost effective - acid, heat, light, vibration and noise resistant
PVC foam is third most widely produced in the world.
Image: structure of PVC. + Closed cell
Commercial PVC is generally produced by addition polymerization.
Features: Cost effective, Fire resistant, water proof, High thermal insulation,
Uses of PVC : Wide like: in houses, cars and sport equipment
Filler increase cost effectiveness of polymers while, can extend resin, increase stiffness and strength, improve impact performance.
Replacement of traditional fillers with new materials to improve mechanical and thermal properties has been a sight of interest
In past few years, use of FA has been extensively reported in different applications
Applications:
Interior and exterior decoration
Automotive
Sport equipment
9/21/2018

5. Introduction to Fly Ash
Fly ash (FA) is one of the residues created during the combustion of coal in coal-fired power plants.
Approximately, 45 million tons of FA is produced annually in the Unites States
Nearly half of the produced FA is currently disposed in landfills.
FA: by-product of coal combustion in coal-fired Power plants
Figure: Product of burning finely ground coal in a boiler to produce electricity. Formed in electrostatic precipitators, or bag houses
70 MT of FA is produced annually in the US
less than half is consumed in different areas
Currently the greatest challenge before the processing and manufacturing industries is the Utilization of the residual waste products.
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6. Introduction to Fly Ash Chemical Composition
Fine, powdery material
Contains:
Quartz , Mullite, Hematite, Magnetite, Lime, and gypsum
Two classes (ASTM C618) :
Class C
Generally contains more than 20% lime (CaO)
Particle size: µm
Coarser than F type
Class F
Min major oxide (SiO2 +Al2O3 +Fe2O3): 70%
Contains less lime
Particle size: µm
very fine, powdery material, composed mostly of silica.
Most particles are spherical in shape.
Consists mostly of silt-sized and clay-sized glassy spheres.
Mainly contains quartz, mullite, hematite magnetite, lime and gypsum
2 Classes:
F contains less than 20% lime. On the other hand,
C fly ash (FA-C) contains more than 20% lime.
The density of 2.4 and 2.5 g/cm3
C particles are found to be coarser than F particles.
The particle size distribution of FA-F particles were found to be in the range of 0.1 to 150µm, while those of FA-C particles were in the range of 1 to 180µm.
Component
Class F
(Wt %)
Class C
(Wt. %)
Silicon
23.95
26.39
Sodium
1.05
1.27
Oxygen
17.28
13.75
Titanium
1.04
0.71
Aluminum
14.25 15
Sulfur
3.11
1.15
Iron
22.65
5.77
Magnesium
1.08
2.10
Calcium
13.22
26.78
Carbon
0.53
0.57
Potassium
1.58
1.77
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7. Evaluating the Effect of Chemical Composition of Fly Ash on PVC Foam Composites Properties
Study the chemical composition effect of FA as a filler on PVC foams to
For this purpose: 4 different FA loaded composites containing two different classes of FA (C and F) were prepared in Triplicates
Raw Materials (phr)
FA-F6
FA-F40
FA-C6
FA-C40
PVC resin
Compound
100
FA-F 6 40
FA-C
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8. Results and Analysis Mechanical Characterization
Objective #2
Results and Analysis Mechanical Characterization
Modulus increases by adding FA
Higher tensile and flexural strength in class-C reinforced foam composites
Maximum strength observed in FA-C6
Tensile modulus increases by adding FA, same trend in flexural modulus
C reinforced foam composites shows higher tensile and flexural strength due to its chemical composition.
Calcium carbonate is the predominant filler used in PVC compounding
higher calcium contents compared to class F may cause better interaction between the filler and the matrix.
Reduced strength due to probability of agglomeration at higher filler loading
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9. Results and Analysis Viscoelastic and Thermal Characterization
Objective #2
Results and Analysis Viscoelastic and Thermal Characterization
TGA:
Higher second decomposition temperature (SDT) in class-C reinforced composites
Better bonding between FA-C and PVC matrix
Storage modulus in DMA:
Below Tg: Stiffness
Increases with adding FA and depends on filler loading
Above Tg: Higher increase rate in class-C reinforced composites
Higher SDT C composites: more energy to break backbone indicating some bonding between the filler and the matrix.
maximum SDT in FA-C6 : due to better bonding between FA-C and PVC matrix. Confirms mechanical properties  
residual weight depends on filler loading not class of FA
Storage modulus in DMA:
Below Tg (stiffness): increases with adding FA, depends on filler loading
Above Tg: increases more in class-C reinforced composites: better interaction btwn class-C FA and polymer
Sample
PDTa (̊C)
SDTb (̊C )
%Residual weight at 800 ̊C
FA0
277.02
428.76
9.31
FA-F6
270.02
444.73
19.48
FA-C6
275.05
446.68
18.76
FA-F40
265.23
438.25
37.13
FA-C40
271.21
438.18
40.72
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10. Results and Analysis Microstructural Characterization
Objective #2
Results and Analysis Microstructural Characterization
Uniform dispersion of FA within the PVC Foam matrix at lower loadings
Aggregation and agglomeration at higher FA loading
Presence of mechanically interlocked FA particles within the PVC matrix in all composites
Higher debonding in the higher loaded composites
Uniform dispersion of FA within the PVC Foam matrix at lower loadings
Aggregation and agglomeration at higher FA loading
Presence of mechanically interlocked FA particles within the PVC matrix in all composites
Higher debonding in the higher loaded composites
SEM micrograph of the PVC foam composites, a) FA-F6, b) FA-C6, c) FA-F40, and d) FA-C40
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11. Summary and Conclusion
Objective #2
Summary and Conclusion
Summary
Better interaction between class-C FA and PVC matrix
Good dispersion, distribution, and interaction in both classes
Enhanced thermal and viscoelastic properties in class-C filled composites
Conclusion
Chemical composition of FA has remarkable effect on final properties of the prepared foam composites
9/21/2018

12. Thank You!