AROMATIC POLYIMIDES

By:

FAKHIR JIBRANE13-325

5th Semester

Metallurgy and Materials Engineering

Introduction of Polyimides Aromatic Polyimide Formation Properties Applications Recent Research on this Material Conclusion References

Contents:

Polymers of Imide-Monomer Excellent heat resistant properties Commercially prepared by

reaction between pyromellitic dianhydride and Di-amines

Have further three types

Introduction of Polyimides

Aliphatic

Semi Aromatic

Aromatic

Do You Know?KAPTON is one ofOldest polyimide Manufactured by man

AROMATIC POLYIMIDES Benzene rings are attached

with chains Most significant type of

polyimide Heat resistant Thermoplastic Aromatic

Polyimides are more commercially available in the form of uncured resins than thermosets

Formation:Reactions between Pyromellitic Di-anhydride and Di-aminesPolymer in stage 1 is soluble which is converted into stable polyimide in stage 2

Formation:One of the oldest and most adopted method is:“Two Step Method Via Poly(Amic acid)s”By Synthesizing the soluble polymer precursor namelyPoly-amic acid and then converting it into polyimide

Heat resistant due to high Thermoxidative Stability

High Modulus of elasticity Superior Chemical resistance Good electrical properties High mechanical strength due to

flexibility BUT

Expensive

Properties:

*Kapton is a common example of Polyimides being used as insulator in electronic circuits.

Applications: *Kapton is a poly-Imide film whichcan remain stablefrom -269 to 400`C

Used in aerospace industry for making insulations, polyimide boost

Due to their flexibility they are used in making space suits

Applications:

Article 1: Partial carbonization of aromatic polyimide films

Recent research on this Material:

•They are partially carburized between temperature of 700 to 100 degrees Celsius•Kapton films were sandwiched between graphite•Kept in hydrogen atmosphere in high temperature•Temperature was kept constant for 30 min. after carburizing temperature reached•The electrical conductivity can be expressed as: α = α* exp (2E / kT ) where k is the Boltzman’s constant; T is the absolute temperature, α and E were found to be a function of the carbonized temperature•It is concluded that impurity level’ lies about 0.4 eV below the conduction band for a specimen carbonized at 700ºC. The band gap depends on thecarbonized temperature. When the carbonized temperature is higher, the band gap is smaller.

they can provide mechanical strength and heat resistance at the same time

Expensive but reliable Its importance will increase in future Due to chemical inertness it can be used for

insulations in severe atmospheres.

Conclusion:

“Carraher’s Polymer Chemistry 8th Edition” by “Charles E Carraher, Jr”

“Polyimides Fundamentals and Applications” by “Malay Ghosh”

scholar.lib.vt.edu/theses/available/etd-051799-162256/.../polyimide1.pdf

www.researchgate.net/...Aromatic_polyimides.../004635265c13ade5ec0

journals.tubitak.gov.tr/chem/issues/kim-06.../kim-30-3-3-0506-12.pdf

Images have been taken from various websites

References:

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