Polyimide P84®NT

Technical brochurePolyimide P84®NTIntroducing an outstanding highperformance polymer:
Excellent performance at high temperatures

Polyimide P84®NT is used in applications where ordinary plastics wouldsooner melt or decompose.

High heat deflection temperature

Polyimide P84®NT guarantees very good creep resistance even at elevatedtemperatures.

High strength and excellent shape stability

Parts and components made of Polyimide P84®NT provide a rigid structure and can bear high mechanical stress and elongation.

Very good impact resistance

The high impact strength of Polyimide P84®NT ensures easy machinability
with standard tools and good quality of edges and surfaces.

Processing by state-of-the art sinter technologies

Polyimide P84®NT is processable cost-efficiently by common sinter technologies such as hot compression moulding or direct forming.

Powder or granules are commercially available

Commercially available polyimide raw material enables plastics processors
to develop proprietary polyimide parts and compounds.

Small particle size

Homogenous blending with functional fillers or other polymers can beachieved by employing powder grades with particle size less than 10µm.

Low wear and friction behaviour

Tribological compounds with solid lubricants provide dry-lubricated solutions for demanding applications.

2Why choosing Polyimide P84®NT?

Demanding applications

Restrictions of conventional polyimides

High temperatures or frictional wear at high speeds andloads often circumscribes the use of ordinary engineering plastics; hence, advanced high-performance polymers have taken their place in demanding applications.
Plastics processors can use polyimides — which exhibit
remarkable heat stability and creep resistance, even atelevated temperatures of 250°C or higher — where ordinary plastics would sooner melt or decompose.

Processing semi-finished parts made of polyimide is often a difficult undertaking, and the raw material is sometimes not available commercially, prompting some polyimide polymer producers to sell the machined parts athigh prices, affordable in many cases only in niches.
In addition, some polyimides are known to be highly
brittle and thus can not be used in applications that callfor high quality of edges and surfaces and good impact
strength.

Storage modulus in a three point bendig experiment at 1 Hz

Storage modulus E’ [Pa]

1010

109

10850P84®NT1100150

P84®NT2200250
Temperature [C°]Competing PIPAI300

350400350400

PEEK

Temperature ranges

Chart 1-2
High Stiffness of Polyimide P84®NT even above
300°C, relatively simple and economical processing by sinter technologies above 350°C.
P84®NT2 is the high temperature type of thismaterial with glass transition temperature of364°C

Storage modulus E’ [Pa]

1010

109

108

150

200

P84®NT1P84®NT2

250

300
Temperature [C°]range of application

processing temperature3Developing a new polyimide material

Advantages of Polyimide P84®NTTo overcome the above-mentioned limitations,
Evonik Fibres GmbH is now offering Polyimide
P84®NT in powder or granulate form, which is processable by employing common sinter technologies
such as hot compression moulding or direct forming. The high mechanical stability and the impact
resistance of P84®NT parts ensure good machinability with standard tools.

Parts made of Polyimide P84®NT are excellent performers in thermally and mechanically stressed applications. This novel material features a high glasstransition temperature of 337–364°C and a rigidstructure (3705 MPa flexural modulus, 188 MPa
strength in a three-point-bending experiment),
combined with a high elongation at break of over 11percent.

3-point-bending

Stress in MPa

2001501005000510Strain in %P84®NT115Chart 3
Comparison of stress-strain-curves in
3-point-bending experiment (ISO178).
Polyimide P84®NT shows a wide area ofelastic behaviour and high mechanicalstability.

Competing PI

Selected properties

Property

Test method

UnitP84®NT1P84®NT115G*Tensile strengthISO 527

MPa140103

Tensile elongation at breakISO 527%106Tensile modulus

ISO 527

MPa

3581

3998

Compressive strength

ISO 604

MPa

470

269

Compressive modulus

ISO 604%1960

1878

Compression at breakISO 604

MPa

5841

ISO 179-1/1eA notchedkJ.m-2

6

ISO 179-1/1eU unnotchedkJ.m-240

1,8 MPa Method Af°C

319

335

Heat deflection temperature

0,45MPa Method B°C

343

345

Glass transition temperature Tg

DSC°C

337

Electric strength AC

ISO 60243-1

kV.mm-1

22

Impact strength (Charpy)*P84®NT1 15G = Compound of P84 NT1 with 15% graphite

4Simple processing of Polyimide P84®NTHot compression moulding

Big semi-finshed parts like plates, rods and tubes are produced by “Hot compression moulding” (HCM), applying
high pressure and temperature above the glass transition point (Tg) for some hours. The manufacturing of precise
components with high mechanical stability is done by machining these semi-finished parts. Processing parameters are
400kg/cm² pressure and 350-380°C temperature.

Direct forming

If a large quantity of small parts is to be produced cost efficiently and rapidly, Polyimide P84®NT powder can be processed by means of direct forming. This technology includes the production of “green parts” at extremely high pressure and ambient temperatures, with subsequent sintering in an external furnace. Processing is done at 3000kg/cm²pressure and 350-380°C temperature. The sintered parts can be manufactured with a high degree of precision and require little or no machining before they are used. High stroke rates of up to 40 parts per minute are possible.

5Fillers adding function

Compounding

By blending it with functional fillers, plastics processors can adjust the properties of Polyimide
P84®NT to meet specific requirements. Solid lubricants such as graphite, molybdenum disulfide, orPTFE make components self-lubricating. Moreover,fillers affect the electrical and thermal conductivityof polyimide compounds and have an impact onthermal expansion.

Carbon fibres increase the stiffness of polyimide
parts. Polyimide is also used as matrix for abrasive
material. Since Polyimide P84®NT is available as fine
powder of 1-10 µm particle size, it can be used asfunctional filler itself, improving creep resistance atelevated temperatures or decreasing frictional wear.

Pin-on-disk experiment @ 20N load and 0.5m/s velocity on steel cronidur
Friction coefficient []00,10

10,20,30,40,50,64

56Competing PI 40G @ 300°CP84®NT1 40G @ 300°C
Competing PI 15G 10P @ 250°CP84®NT1 15G 10P @ 250°C

Friction coefficient µ []Relative wear [10-6.mm3/Nm]

23
Relative wear [10-6.mm3/Nm]

Chart 4Comparable tribological behaviour of Polyimide P84 NT and other conventional
polyimides. Tested compounds have been 40G (polyimide with 40% graphite)and 15G 10P (polyimide with 15% graphite and 10% PTFE).

7µm
Scanning electron micrograph (SEM) at 4000× magnification. Spherical particles of Polyimide P84®NT with smooth surface.

6Benefitting from Polyimide P84®NTApplications

Given the variability of its properties, the simple processing of the raw material, and the good machinabilityof parts with standard tools, Polyimide P84®NT is theright choice for applications where plastics are used forcommercial or technical reasons and demands on temperature stability are high.
For example, bushings made of a polyimide-graphite
compound are used as bearings for windscreen wipers —for a lifetime of oil- and grease-free lubrication. Spacer
discs in gear boxes can be made by direct forming, including all the necessary notches, thus minimizing postprocessing and ensuring high-temperature stability andlow wear. This new promising material is used in bushings, seals, bearings components, guides, gear wheels,and valve parts in the automotive and aerospace industries and in industrial equipment.

Product portfolio

Polyimide P84®NT is available as neat polymer as well as
blended with functional fillers. Standard compounds
contain 15% or 40% graphite, 15% MoS2 or 15%
graphite combined with 10% PTFE. Moreover, developing custom-tailored solutions with proprietary formulations are possible.

Legal References
This information and all further technical advice isbased on our present knowledge and experience.
However, it implies no liability or other legal responsibility on our part, including with regard to existing third party intellectual property rights, especially patent rights. In particular, no warranty,
whether express or implied, or guarantee of productproperties in the legal sense is intended or implied.
We reserve the right to make any changes according
to technological progress or further developments.
The customer is not released from the obligation toconduct careful inspection and testing of incoming
goods. Performance of the product described hereinshould be verified by testing, which should be carried out only by qualified experts in the sole responsibility of a customer. Reference to trade names
used by other companies is neither a recommendation, nor does it imply that similar products could
not be used.

Evonik Fibres GmbH
Gewerbepark 44861 Schörfling am Attersee
Austria
phone +43 7672 701-2867
fax +43 7672 92046
www.­p84nt.com