Polyimides are strong, heat and chemically resistant polymers formed from acid dianhydrides and diamines. They have applications as coatings, insulators, and mechanical parts due to their strength and durability. Polyimides are synthesized through a two-step polyaddition and dehydration reaction of acid anhydrides and diamines. They can replace metals and glass in applications due to their high heat resistance, strength, and transparency to microwaves.

1. POLYIMIDES -K.SAI MALLESWAR

2. INTRODUCTION What are polyimides? what is the basic structural unit? Polyimides are polymers formed by the combination of acid dianhydrides and diamines.

4. Aromatic hetero cyclic polyimides3

5. PHYSICAL AND THERMAL PROPERTIES: 4

7. Very low creep

8. Inherent resistance to flame combustion

9. Un effected by commonly used solvents and oils

11. Not usable in alkaline or highly acidic environment. 5

13. They are highly heat resistant and chemical resistant.

14. They can often replace glass and metals such as steel.

16. 8 WHY POLYIMIDES ARE SO STRONG???

18. 2.Subsequent Dehydration

20. Later, Polyamic acid is processed into final insoluble and infusible polymer product. 9

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23. They are also used as polyimide heaters.

24. Polyimides are used in the cooking cavity of microwave oven. Polyimides are also used in food packaging.

27. As a coating on tubes used in surgeries

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32. Cross linked bonds will break during thermal degradation

34. Incase of aromatic polyimides, delocalization energy of Pi-electrons is released. THERMAL DEGRADATION OF POLYIMDES: 19

35. BIBLIOGRAPHY: www.wikipedia.org Polymer Science and Technology by Joel R.Fried www.google.com 4. Text Book Of Polymer Science by Fred W. Billmeyer 20

36. THANK YOU 21