5 Polyimides

This chapter covers a series of plastics of which

the imide group is an important part of the molecule.

The imide group is formed by a condensation reac-

tion of an aromatic anhydride group with an aromatic

amine as shown in Figure 5.1.

This group is very much thermally stable.

Aliphatic imides are possible, but the thermal stabil-

ity is reduced, and thermal stability is one of the

main reasons to use an imide type of polymer.

5.1 Polyimide (PI)

PIs are high-temperature engineering polymers

originally developed by the DuPont Company. PIs

exhibit an exceptional combination of thermal sta-

bility (.500°C), mechanical toughness, and chemi-

cal resistance. They have excellent dielectric

properties and an inherently low coefficient of ther-

mal expansion. They are formed from diamines and

dianhydrides such as the two shown in Figure 5.2.

Many other diamines and several other dia-

nhydrides may be chosen to tailor the final proper-

ties of a polymer whose structure is like that shown

in Figure 5.3.

DuPont makes a PI called “thermoplastic poly-

imide.” The structure of this polymer is shown in

Figure 5.4 and might be called a polyetherimide.

The data for polyimides is split into two parts,

one for typical PIs (like Figure 5.3) and the other

for thermoplastic polyimides (like Figure 5.4)

Manufacturers and trade names: DuPont

Kapton®, Vespel®, Ube Industries Upilex®-S, Upitol®.

Applications and uses: aerospace, flexible printedcircuits, automotive, heaters, bar code labels, pressure-

sensitive tape, electrical insulation, and safety.

5.1.1 Standard PIs

Data for standard PI polymers are contained in

Figures 5.5�5.32.

5.1.2 Thermoplastic PIs

Data for thermoplastic PI polymers are contained

in Table 5.1 and Figures 5.33�5.46.

5.2 Polyamide�Imide (PAI)

PAIs are thermoplastic amorphous polymers that

have useful properties:

• Exceptional chemical resistance

• Outstanding mechanical strength

• Excellent thermal stability

• Performs from cryogenic up to 260°C

• Excellent electrical properties

The monomers used to make PAI resin are

shown in Figure 5.47.

When these monomers are reacted, carbon dioxide,

rather than water, is generated. The closer the mono-

mer ratio is to 1:1, the higher the molecular weight of

the polymer shown in Figure 5.48. Other monomer

combinations are shown in Tables 5.2 and 5.3.

Manufacturers and trade names: Solvay

Advanced Polymers Torlon®.

Applications and uses: electrical connectors,

switches and relays, thrust washers, spline liners,

valve seats, bushings, bearings, wear rings, cams,

and other applications requiring strength at high

temperature and resistance to wear.

Data for PAI polymers are contained in

Tables 5.4�5.8 and Figures 5.49�5.57.

Composition details of Solvay Torlon® PAIs

used in Tables 5.4�5.8 and Figures 5.49�5.57:

• Torlon® 4203L: 3% titanium dioxide, 0.5%

fluorocarbon

• Torlon® 4301: 12% graphite powder, 3%

fluorocarbon

199

McKeen: The Effect of Temperature and other Factors on Plastics and Elastomers.

DOI: http://dx.doi.org/10.1016/B978-0-323-31016-1.00005-2

© 2014 Elsevier Inc. All rights reserved.

4,4�-Diaminodiphenyl etheroxydianiline (ODA)

Pyromellitic dianhydride (PMDA)

Figure 5.2 Chemical structures of monomers used to make PIs.

Figure 5.1 Reaction of amine with anhydride to form an imide.

Figure 5.3 Chemical structure of a typical PI.

Figure 5.4 Chemical structure of the thermoplastic PI DuPont Vespel® TP-8000 series [1].

200 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.5 Stress vs. strain at

23°C in compression for DuPont

Vespel® machined PI [2].

Figure 5.6 Stress vs. strain at

300°C in compression for DuPont

Vespel® machined PI [2].

Figure 5.7 Stress vs. strain at

23°C in compression parallel to

forming for DuPont Vespel®

direct-formed PI [2].

2015: POLYIMIDES

Figure 5.8 Stress vs. strain at

260°C in tension parallel to

forming for DuPont Vespel®

direct-formed PI [2].

Figure 5.9 Stress vs. strain at

23°C in tension perpendicular to

forming for DuPont Vespel®

direct-formed PI [2].

Figure 5.10 Stress vs. strain at

23°C in tension perpendicular to

forming for DuPont Vespel®

machined PI [2].

202 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.11 Stress vs. strain at

260°C in tension for DuPont

Vespel® machined PI [2].

Figure 5.12 Flexural modulus

vs. temperature for Mitsui

Chemicals Aurum® PI resins.

Figure 5.13 Flexural modulus

vs. temperature for DuPont

Vespel® direct-formed PI [2].

2035: POLYIMIDES

Figure 5.14 Flexural modulus

vs. temperature for DuPont

Vespel® machined PI [2].

Figure 5.15 Flexural modulus

vs. temperature for Ube

Industries Upitol® SA 101 PI.

Figure 5.16 Flexural strength

vs. temperature for Ube

Industries Upitol® SA 101 PI.

204 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.17 Tensile strength

vs. temperature for DuPont

Vespel® direct-formed PI [2].

Figure 5.18 Tensile strength

vs. temperature for DuPont

Vespel® machined PI [2].

Figure 5.19 Tensile strength

vs. temperature for Ube

Industries Upitol® SA 101 PI.

2055: POLYIMIDES

Figure 5.20 Tensile strength

vs. temperature for DuPont

Vespel® SP-21 and ST-2010 PI

resins [3].

Figure 5.21 Compressive

strength vs. temperature for

DuPont Vespel® SP-21 and ST-

2010 PI resins [3].

Figure 5.22 Elongation

vs. temperature for DuPont

Vespel® SP-21 and ST-2010 PI

resins [3].

206 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.23 Dimension change

vs. relative humidity at 23°C for

DuPont Vespel® direct-formed

PI [2].

Figure 5.24 Dimension change

vs. relative humidity at 23°C for

DuPont Vespel® machined PI [2].

Figure 5.25 Dimension change

vs. temperature perpendicular to

forming for DuPont Vespel®

direct-formed PI [2].

2075: POLYIMIDES

Figure 5.26 Dimension change

vs. temperature for DuPont

Vespel® machined PI [2].

Figure 5.27 Dielectric constant

vs. temperature for DuPont

Vespel® SP1 PI [2].

Figure 5.28 Dielectric strength

vs. temperature for DuPont

Vespel® SP1 PI [2].

208 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.29 Dielectric strength

vs. thickness for DuPont Vespel®

SP1 PI [2].

Figure 5.30 Dissipation factor

vs. temperature and frequency

for DuPont Vespel® SP1 PI [2].

Figure 5.31 Surface resistivity

vs. temperature for DuPont

Vespel® SP1 PI [2].

2095: POLYIMIDES

• Torlon® 5030: 30% glass fiber, 1% fluorocarbon

• Torlon® 7130: 30% carbon fiber

• Torlon® 4275: PTFE and graphite

• Torlon® 4630: PTFE and graphite

• Torlon® 4435: PTFE and graphite

• Torlon® 4645: PTFE and carbon fiber

5.3 Polyetherimide (PEI)

PEI is an amorphous engineering thermoplastic.

Thermoplastic PEIs provide the strength, heat resis-

tance, and flame retardancy of traditional PIs with the

ease of simple melt processing seen in standard

injection-molding resins like polycarbonate and ABS.

The key performance features of PEI resins

include:

• Excellent dimensional stability at high tem-

peratures under load

• Smooth as-molded surfaces

• Transparency, though slightly yellow

• Good optical properties

• Very high strength and modulus

• High continuous-use temperature

• Inherent ignition resistance without the use of

additives

• Good electrical properties with low ion

content

There are several different polymers that are

offered in various PEI plastics. Their structures are

shown in Figures 5.58�5.62 with references to one

of the product lines that utilize that molecule.

The acid dianhydride used to make most of the

PEIs is 4,40-bisphenol A dianhydride (BPADA), the

structure of which is shown in Figure 5.63.

Some of the other monomers used in these PEIs

are shown in Figure 5.64.

Manufacturers and trade names: SABIC

Innovative Plastics Ultem®, DuPont Aurum®.

Applications and uses: surgical probes, pharma-

ceutical process equipment manifolds, high-frequency

insulators used in microwave communications

equipment, clamps used to connect printed circuit

boards to video display units used in airplanes, tanks,

and ships.

Data for PEI polymers are contained in

Figures 5.65�5.83.

Figure 5.32 Volume resistivity vs. temperature for DuPont Vespel® SP1 PI [2].

210 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Table 5.1 Mechanical Properties at Various Temperatures of DuPont Vespel® TP-8000 Series PI Compounds [1]

Properties/Temperature(°C)

TP-8054Unfilled

TP-8395PTFEand

Graphite

TP-821230%Glass

TP-813030%

CarbonFiber

TP-831110%

CarbonFiber

TP-854930%

CarbonFiber

TP-879215%

CarbonFiber,15%PTFE

Tensile Strength (MPa)

240 106 86 158 223 243 257 194

23 85 68 147 203 174 208 181

100 50 48 98 160 144 154 155

150 48 38 96 132 127 138 126

Tensile Elongation (%)

240 13 92 1 1 1 2

23 92 14 2 1 2 1 2

100 102 7 1 1 2 1 2

150 94 8 1 1 2 1 1

Tensile Modulus (MPa)

240 1520 1470 10,200 26,100 28,300 27,000 14,400

23 1120 1210 10,200 22,500 11,200 24,300 16,600

100 742 1040 6500 21,900 10,700 22,800 15,400

150 621 804 6000 21,000 13,300 19,100 14,900

Flexural Strength (MPa)

0 � � � 353 273 380 294

23 137 117 241 336 258 358 278

150 88 � 172 227 191 212 198

Flexural Modulus (MPa)

0 � � � 20,670 9853 21,690 13,504

23 2942 2598 9646 21,042 10,349 21,648 14,104

150 2549 � 8268 19,664 9584 19,113 13,270

Compressive Strength (MPa)

0 � � � 309 229 305 203

23 256 233 331 310 219 306 205

150 154 144 220 220 149 191 145

Compressive Modulus (MPa)

0 � � � 410 348 426 403

23 197 197 391 445 413 417 387

150 166 182 365 434 365 388 389

2115: POLYIMIDES

Figure 5.33 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8054

unfilled thermoplastic PI [1].

Figure 5.34 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8054 unfilled thermoplastic

PI [1].

Figure 5.35 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8130

containing 30% carbon fiber

thermoplastic PI [1].

212 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.36 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8130 containing 30% carbon

fiber thermoplastic PI [1].

Figure 5.37 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8212

with 30% glass thermoplastic

PI [1].

Figure 5.38 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8212 with 30% glass

thermoplastic PI [1].

2135: POLYIMIDES

Figure 5.39 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8311

with 10% carbon fiber

thermoplastic PI [1].

Figure 5.40 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8311 with 10% carbon fiber

thermoplastic PI [1].

Figure 5.41 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8395

with PTFE and graphite

thermoplastic PI [1].

214 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.42 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8395 with PTFE and graphite

thermoplastic PI [1].

Figure 5.43 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8549

with 30% carbon fiber

thermoplastic PI [1].

Figure 5.44 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8549 with 30% carbon fiber

thermoplastic PI [1].

2155: POLYIMIDES

Figure 5.45 Stress vs. strain in

tension at various temperatures

for DuPont Vespel® TP-8792

with 15% carbon fiber and 15%

PTFE thermoplastic PI [1].

Figure 5.46 Stress vs. strain in

compression at various

temperatures for DuPont Vespel®

TP-8792 with 15% carbon fiber

and 15% PTFE thermoplastic

PI [1].

4,4�-Diphenyl methane diisocyanate (MDI) Trimellitic anhydride (TMA)

Figure 5.47 Chemical structures of monomers used to make PAIs.

216 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Table 5.2 The Polymer Units of Various Amide�Imide Polymers (Refer to Figure 5.48 for Polymer Structure)

PAI Code R1 from Acid Anhydride R2 from Diisocyanate

PAI(TMI/DPA)

PAI(TMI/HEA)

PAI(TMI/TFA)

PAI(TMI/CDA)

PAI(PMI/CDA)

Table 5.3 The Polymer Units of More Amide�Imide Polymers (Refer to Figure 5.48 for Polymer Structure) [4]

PAI Code R1 from Acid Anhydride R2 from Diisocyanate

PAP

PAO

PAM

PAD

PAT

218 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Table 5.4 Compressive Properties for Solvay Advanced Polymers Torlon® PAI Resins at VariousTemperatures per ASTM D695 [5]

Property/Temperature (°C)

Grade

4203L 4601 4630 4645 5030 7130

Compressive Strength (MPa)

23 172 165 96 124 214 234

100 131 124 83 124 165 186

150 103 103 76 110 138 158

200 83 83 62 90 110 124

Compressive Modulus (MPa)

23 3163 3114 4706 5236 4892 6139

100 2191 2122 2026 3645 3273 3803

150 2136 2067 2115 3149 3087 3790

200 2067 2046 2019 3383 3121 3645

Table 5.5 Tensile Properties for Solvay Advanced Polymers Torlon® PAI Resins at Various Temperatures perASTM D1708 [5]

Property/Temperature (°C)

Grade

4203L 4301 4275 4435 5030 7130

Tensile Strength (MPa)

23 192 164 131 110 205 203

135 117 113 116 90 160 158

232 66 73 56 52 113 108

Tensile Elongation at Break (%)

23 15 7 7 6 7 6

135 21 20 15 4 15 14

232 22 17 17 3 12 11

Tensile Modulus (GPa)

23 4.5 6.8 8.8 14.5 14.6 16.5

Table 5.6 Flexural Modulus (in GPa) at Various Temperatures of Solvay Advanced Polymers Torlon® PAIResins [5]

Temperature (°C)

Torlon® Grade

High Strength Grades Wear Resistant Grades

4203L 5030 7130 4301 4275 4435 4630 4645

2196 7.9 14.1 24.6 9.6

23 5.0 11.7 19.9 6.9 7.3 14.8 6.8 12.4

135 3.9 10.7 15.6 5.5 5.6 11.2

232 3.6 9.9 13.1 4.5 5.1 10.3

Note: ASTM Test Method D790.

2195: POLYIMIDES

Table 5.7 Flexural Strength (in MPa) at Various Temperatures of Solvay Advanced Polymers Torlon® PAIResins [5]

Temperature (°C)

Torlon® Grade

High Strength Grades Wear Resistant Grades

4203L 5030 7130 4301 4275 4435 4630 4645

2196 282 374 310 200

23 244 338 355 219 212 152 131 154

135 174 251 263 165 157 129

232 120 184 177 113 111 91

Note: ASTM Test Method D790.

Table 5.8 Specific Heat at Various Temperatures of Solvay Advanced Polymers Torlon® PAI Resins [5]

Temperature (°C)

Specific Heat (cal/gm°C)

Grade

4203L 4301 5030 7130

25 0.242 0.240 0.229 0.230

100 0.298 0.298 0.276 0.285

200 0.362 0.359 0.327 0.346

250 0.394 0.385 0.353 0.375

Figure 5.48 Chemical structure of a typical PAI.

220 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.49 Stress vs. strain

detail in tension at 23°C tested

on ASTM D638 type 1

specimens for Solvay Advanced

Polymers Torlon® PAI resins [5].

Figure 5.50 Stress vs. strain in

tension at 23°C tested on ASTM

D638 type 1 specimens for

Solvay Advanced Polymers

Torlon® PAI resins [5].

Figure 5.51 Stress vs. strain in

tension for various Solvay

Advanced Polymers Torlon® PAI

resins at 135°C.

2215: POLYIMIDES

Figure 5.52 Stress vs. strain in

tension for various Solvay

Advanced Polymers Torlon®

PAI resins at 200°C [5].

Figure 5.53 Stress vs. strain in

tension for Solvay Advanced

Polymers Torlon® 4203LF PAI at

various temperatures [5].

Figure 5.54 Flexural modulus

vs. temperature for Solvay

Advanced Polymers Torlon®

PAI resins [5].

222 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.55 Flexural strength vs.

temperature for Solvay Advanced

Polymers Torlon® PAI resins [5].

Figure 5.56 Tensile strength vs.

temperature for Solvay Advanced

Polymers Torlon® PAI resins [5].

Figure 5.57 Moisture absorption

vs. relative humidity for Solvay

Advanced Polymers Torlon®

PAI resins [5].

2235: POLYIMIDES

Figure 5.58 Chemical structure of BPADA-PPD PEI (SABIC Innovative Plastics Ultem® 5000 series).

Figure 5.59 Chemical structure of biphenol diamine PMDA PEI (DuPont Aurum®).

Figure 5.60 Chemical structure of BPADA-DDS PEI sulfone (SABIC Innovative Plastics Ultem® XH6050).

Figure 5.61 Chemical structure of BPADA-MPD PEI (SABIC Innovative Plastics Ultem® 1000 series).

Figure 5.62 Chemical structure of BPADA-PMDA-MPD co-PEI (SABIC Innovative Plastics Ultem® 6000 series).

224 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.63 Chemical structure of BPADA monomer.

Oxydianiline(ODA)

Diamino diphenyl sulfone(DDS)

m-Phenylene diamine(MPD)

Biphenol diamine(BP diamine)

p-Phenylene diamine(PDA)

Methylene dianiline(MDA)

Pyromellitic dianhydride (PMDA)

Figure 5.64 Chemical structures of some other monomers used to make PEIs.

2255: POLYIMIDES

Figure 5.65 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

1000—general purpose

PEI resin.

Figure 5.66 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

2100—10% glass reinforced

PEI resin.

Figure 5.67 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

2200—20% glass reinforced

PEI resin.

226 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.68 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

2300—30% glass reinforced

PEI resin.

Figure 5.69 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

2400—40% glass reinforced

PEI resin.

Figure 5.70 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

3452—45% glass/mineral

reinforced PEI resin.

2275: POLYIMIDES

Figure 5.71 Stress vs. strain at

various temperatures for SABIC

Innovative Plastics Ultem®

4000—wear resistant, 25%

glass, 15% PTFE PEI resin.

Figure 5.72 Stress vs. strain at

23°C for several SABIC

Innovative Plastics Ultem®

PEI resins.

Figure 5.73 Stress vs. strain in

compression for SABIC

Innovative Plastics Ultem®

1000—general purpose

PEI resin.

228 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.74 Flexural modulus

vs. temperature for several

SABIC Innovative Plastics

Ultem® glass reinforced

PEI resins.

Figure 5.75 Shear modulus vs.

temperature for several SABIC

Innovative Plastics Ultem® glass

reinforced PEI resins.

Figure 5.76 Tensile strength vs.

temperature for several SABIC

Innovative Plastics Ultem®

PEI resins [6].

2295: POLYIMIDES

Figure 5.77 Specific strength at

elevated temperatures for

Extem® XH resin vs. cast

aluminum [7].

Figure 5.78 Storage modulus of

unfilled Extem® XH resin vs.

other unfilled polymers as a

function of temperature by

DMA [7].

Figure 5.79 Pressure-specific

volume�temperature (PVT) for

SABIC Innovative Plastics

Ultem® 1000—general purpose

PEI resin.

230 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS

Figure 5.80 Moisture absorption

vs. relative humidity for SABIC

Innovative Plastics Ultem®

1000—general purpose

PEI resin.

Figure 5.81 Dielectric constant

vs. frequency and temperature

for SABIC Innovative Plastics

Ultem® PEI resin [6].

Figure 5.82 Dielectric constant

vs. temperature and frequency

for SABIC Innovative Plastics

Ultem® PEI resin [6].

2315: POLYIMIDES

References

[1] DuPontt Vespel® TP-8000 series design hand-

book. DuPont; 2007.

[2] Properties of DuPont VESPEL® parts. DuPont;

1997.

[3] Introducing the new generation in high-

temperature components—technical informa-

tion. DuPont; 2000.

[4] Cao X, Lu F. Structure/permeability relation-

ships of polyamide�imides. J Appl Polym Sci

1994;54:1965�70.

[5] Torlon® PAI design guide. Solvay Specialty

Polymers; 2013.

[6] SABIC Innovative Plastics engineering thermo-

plastics product guide, Ultem® PEI resin.

SABIC Innovative Plastics; 2008.

[7] Extem® resins products, markets and proces-

sing guide extreme performance made easy.

SABIC Innovative Plastics; 2008.

Figure 5.83 Dissipation factor

vs. temperature and frequency

for SABIC Innovative Plastics

Ultem® PEI resin [6].

232 THE EFFECT OF TEMPERATURE AND OTHER FACTORS ON PLASTICS AND ELASTOMERS