Polyimides

Polyimides

Normally infusible, coloured (often amber) high performance polymers with predominantly aromatic molecules of high thermal stability. Semi-fabricated shapes are usually supplied by the polymer manufacturer and made by powder sintering or working with more tractable pre-cursors and completing polymerization in final form, though some melt-process able grades of resin are manufactured.
They have excellent high temperature properties and radiation resistance, inherently low flammability and smoke emission, low creep and high wear resistance and are very expensive. They have moderately high water absorption and are prone to hydrolysis and attack by alkalis and concentrated acids.

General Properties:

Chemical Resistance

Acids – concentrated Poor
Acids – dilute Fair
Alcohols Poor
Alkalis Poor
Aromatic hydrocarbons Good
Greases and Oils Good
Halogenated Hydrocarbons Good
Halogens Fair
Ketones Good

Electrical Properties

Dielectric constant @1MHz 3.4
Dielectric strength ( kV mm-1 ) 22
Dissipation factor @ 1kHz 0.0018
Surface resistivity ( Ohm/sq ) 1016
Volume resistivity ( Ohmcm ) 1018

Mechanical Properties

Coefficient of friction 0.42
Elongation at break ( % ) 08 to 70
Hardness – Rockwell E52 to 99
Izod impact strength ( J m-1 ) 80
Tensile modulus ( GPa ) 2.0 to 3.0
Tensile strength ( MPa ) 70 to 150

Physical Properties

Density ( g cm-3 ) 1.42
Flammability V0
Limiting oxygen index ( % ) 53
Radiation resistance Good
Refractive index 1.66
Resistance to Ultra-violet Poor
Water absorption – over 24 hours ( % ) 0.2 to 2.9

Thermal Properties

Coefficient of thermal expansion ( x10-6 K-1 ) 30 to 60
Heat-deflection temperature – 1.8MPa ( C ) 360
Lower working temperature ( °C ) -270
Specific heat ( J K-1 kg-1 ) 1090
Thermal conductivity @23C ( W m-1 K-1 ) 0.10 to 0.35
Upper working temperature ( C ) 250 to 320

Member Testimonials

ONGC – Oil and Natural Gas Corporation Limited

"ONGC - Oil and Natural Gas Corporation Limited" - Our complex drilling application where Shaft was eccentric and application was robust & muddy. Replacement was never easy. Mech Spares designed Oil seals resolved difficulty. This gave a complete joy to my maintenance team.
2014-06-08T07:48:57+00:00
“ONGC – Oil and Natural Gas Corporation Limited” – Our complex drilling application where Shaft was eccentric and application was robust & muddy. Replacement was never easy. Mech Spares designed Oil seals resolved difficulty. This gave a complete joy to my maintenance team.

Kuwait National Petroleum Company

"Mr Mohammed Al Duaigy" of (Kuwait National Petroleum Company) : We tried several diaphragms from renown worldwide Rubber manufacturing companies. We found Mech Spares technical know how and product to be of great durability and lasted 3 times more then anticipated. They have accurate understanding of there products.
2014-06-08T07:49:23+00:00
“Mr Mohammed Al Duaigy” of (Kuwait National Petroleum Company) : We tried several diaphragms from renown worldwide Rubber manufacturing companies. We found Mech Spares technical know how and product to be of great durability and lasted 3 times more then anticipated. They have accurate understanding of there products.

McCafferty BM Design Ltd, KENT United Kingdom

"McCafferty BM Design Ltd, KENT United Kingdom" - Most of the O rings manufacturing company suggested to use larger diameter and expensive elastomers. We learnt with Mech Spares that elastomer being weaker compare to metal and alloys and needs appropriate back up for high pressure or high vacuum applications. Further not necessary the most expensive elastomer is the best for all applications. We trust Mr Nilesh chodhari completely for all our O rings designing applications.
2014-06-08T07:50:26+00:00
“McCafferty BM Design Ltd, KENT United Kingdom” – Most of the O rings manufacturing company suggested to use larger diameter and expensive elastomers. We learnt with Mech Spares that elastomer being weaker compare to metal and alloys and needs appropriate back up for high pressure or high vacuum applications. Further not necessary the most expensive View Full →

Bhabha Atomic Research Centre ( BARC )

"Dr. A. Singh" of BARC: The electric Insulation mat manufactured by MECH SPARES as per IS 15624 tested at ERTL and found to withstand 40 Kv and still didn't tear. We have been using since 5 years and still didn't generate any fatigue. They arranged bulk delivery in short period.
2014-06-08T07:16:20+00:00
“Dr. A. Singh” of BARC: The electric Insulation mat manufactured by MECH SPARES as per IS 15624 tested at ERTL and found to withstand 40 Kv and still didn’t tear. We have been using since 5 years and still didn’t generate any fatigue. They arranged bulk delivery in short period.

Tata Steel

"Tata Steel" - One of our old machines started making loud noise and disturbed the entire village. We were compelled to stop the machines which lead to huge production loss. With the help of Mech Spares designed bellows in two part we could retain the lubrication and eliminate the noise.
2014-06-08T07:17:16+00:00
“Tata Steel” – One of our old machines started making loud noise and disturbed the entire village. We were compelled to stop the machines which lead to huge production loss. With the help of Mech Spares designed bellows in two part we could retain the lubrication and eliminate the noise.
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