P84 polyimide derived from aromatic dianhydrides and aromatic diisocyanates exhibits outstanding thermal stability. The polymer is non melting, has a glass transition temperature of 315 °C. The fibres start to carbonize at temperatures beyond 370 °C. Due to the aromatic structure the polymer and fibres are inherent non flammable. A limiting oxygen index of 38 % can be measured. P84 can be used to temperatures up to 260 °C depending on the environment.
Chemical Resistance
P84 polyimide is stable against most common organic solvents like alcohols, ethers, halogenated hydrocarbons or ethers. Strong polar, aprotic solvents like dimethyl formamide (DMF), dimethyl acetamide (DMAC) , N-methyl pyrrolidon (NMP) or concentrated sulphuric acid dissolve P84.
P84 is sensitive to strong oxidizers like nitrogen dioxide at elevated temperatures.
Strong concentrated aqueous acids such as hydrochloric acid , sulphuric acid or concentrated aqueous Lewis Acids like zinc chloride affect P84.
Fibre Properties
Features of the P84 polyimide fibres are the irregularly lobed cross-section being responsible for the high bulk of the fibres. The stress strain curve shown in the diagram and the typical mechanical fibre data describe that P84 is rather a textile fibre with good knot and loop strength properties. Because of the low modulus and the high elongation P84 polyimide fibres are not destined for typical “reinforcing” applications as p-aramid or carbon fibres.
| P84 Staple Fibre (2,2dtex) Typical Textile Data |
|
Property
|
Test Method
|
Typical Value
|
|
Tenacity
|
|
38 cN/tex
|
|
Elongation at break
|
|
30%
|
|
Shrinkage at 240 °C, 10 minutes
|
|
<3%
|
|
Limiting Oxygen Index (LOI)
|
|
38%
|
|
Glass Transition Temperature (Tg)
|
DSC
|
315 °C
|
|
Density
|
|
1,41 g/cm3
|
Filtration Efficiency
- Good filtration efficiency
- Excellent cake release properties
- Low differential pressure in filter bag house
- Highest surface area compared to other fibres
