Surface Morphology Analysis of PET Films Treated with Helium and HeliumOxygen Atmospheric Plasma

1
Surface Morphology Analysis of PET Films Treated
with Helium and Helium/Oxygen Atmospheric Plasma

• Textile Chemistry and Nuclear Engineering of
  North Carolina State University
• Class presentation by Joseph Wu

2
Summary

• To observe the effects of plasma on the
  morphology of the PET film over time
• Plasma etches amorphous region not crystalline
  region
• Observed increased percent crystallinity
• Advantages of atmospheric plasma
• Nonthermal
• Continuous

3
Backgroud Information

• PET
• Atmospheric plasma generator
• Differential Scanning Calorimetry (DSC)

4
PET

• Polyethylene terephthalate
• Tm 245 258 C (ref Cleartuf PET Packaging
  Resins, Shell Chemical, 1996, (technical
  datasheet)
• Tg 75 C (ref http//www.thermal-instruments.com
  /Applications/PETech-40.PDF)
• Applications food and beverage containers

5

• Ref Roth, J. Reece at al International Nonwovens
  Journal V10 No 3 Fall 2001 p34-48

6
Ref Roth, J. Reece at al International Nonwovens
Journal V10 No 3 Fall 2001 p34-48
7
Ref Illinois Institute of Technology presentation
8
Applications of DSC

• DSC determines
• transition temperatures
• heat of fusion of a crystal phase
• the degree of crystallization
• crystal kinetic
• heat capacity
• heat of formation
• sample purity

9
DSC

• Principles
• Endothermic reactions absorb heat
• Exothermic reactions release heat
• Crystallinity DHm DHc / DHm100
• Where DHm is the heats of melting (J/g),
• DHc is the cold crystallization (J/g),
• DHm is the heat of melting for 100 crystalline,
  theoretical value 140.1 J/g

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DSC Scan
Endothermic
Exothermic
Ref http//www.thermal-instruments.com/Applicatio
ns/PETech-40.PDF backDSC
Results
11
Experimental Results

• DSC analysis
• Solubility test
• Effects of exposure time

12
DSC Results

• increase (Aave Ainitial)/Ainitial100
• DSC Scan

13
Solubility Test Results
1.5
14
Exposure Time Effects
15
Conclusion

• Plasma treatment increases the percent
  crystallinity up to 13.56
• Plasma treated PET shows less swelling at longer
  plasma exposure time
• PET surface was etched first then redeposited if
  the plasma treatment lasted for more than 2
  minutes
• PET/oxygen treatment increases crystallinity more
  than He/air and He treatment