Polymer

n_D

Dielectric 
constant

Stability

Acetals

1420

65

8

1.46

0.23

1.48

10¹⁵

—

Attacked by some acids and alkalies, good resistance to organic solvents.

Cellulose (cotton, wood
    pulp) and regenerated

1480–1530

80–240

—

1.3–1.5

0.23

1.53–1.56

10⁷–10¹⁴

6.7–7.5

Decomposed by oxid. agents and strong acids or by heating to 270 °C. Absorbs water.

Cellulose acetate:
    Moulded

1220–1340

12–58

8–18

1.26–1.8

0.17–0.33

1.46–1.50

10¹⁰–10¹⁴

3.5–7.5

Softens at ~ 130 °C, decomposed by strong acids and alkalies, soluble in ketones and esters, softened or dissolved by chlorinated or aromatic hydrocarbons.

    Sheet

1280–1320

30–52

10–15

1.26–2.1

0.17–0.33

1.49–1.50

10¹¹–10¹⁵

3.5–7.5

Cellulose nitrate
(Celluloid)

1350–1400

50

8–12

1.3–1.7

0.12–0.21

1.49–1.51

10¹⁰

7.0–7.5

Softens at ~ 60 °C and ignites ~ 160 °C. Decomposed by strong acids and alkalies. Soluble in alcohol, ethers and esters.

Chlorinated polyether

1400

39

8

—

0.13

—

10¹⁵

3.1

Unattacked by acids or alkalies except by oxid. acids. Resists most solvents.

Epoxy cast resins

1110–1400

26–85

4.5–6.5

1.0

0.17–0.21

1.55–1.61

10¹²–10¹⁷

3.5–5.0

Unattacked by weak acids and alkalies, some attack by strong acids and alkalies. Generally resistant to organic solvents.

Nylon-6
    (Poly-ε-caprolactam)

1120–1170

45–90

28

1.6

0.25

—

10¹²–10¹⁵

3.7–5.5

Stable at 100 °C. Softens at ~ 230 °C. Attacked by strong acids but resistant to alkalies. Resistant to common organic solvents but dissolves in phenol and formic acid.

Nylon-66
    (Polyhexamethylene-
    adipamide)

1130–1150

60–80

8

1.7

0.25

1.53

10¹⁴–10¹⁵

4.0–4.6

Stable at 100 °C. Softens at ~ 230 °C. Attacked by strong acids but resistant to alkalies. Resistant to common organic solvents but dissolves in phenol and formic acid.

Phenolic cast resins

1240–1320

33–59

6–8

1.25–1.67

0.15

1.58–1.66

10¹²–10¹³

6.5–17.5

Not affected by acids, attacked by strong alkalies, little affected by organic solvents.

Phenol-formaldehyde
    moulding compounds

1250–1300

45–52

2.5–6.0

1.59–1.76

0.13–0.25

1.5–1.7

10¹¹–10¹²

5.0–6.5

Slightly attacked by acids and alkalies. Depending on composition soluble or insoluble in organic solvents.

Polyacrylonitrile

1160–1180

200
(fibres)

7

—

—

1.52

10¹⁴

6.5

Fair resistance to weak alkalies but soluble in strong nitric and sulphuric acids.

Polycarbonates

1200

52–62

6.6

1.17–1.25

0.19

1.59

10¹⁶

2.97–3.17

Unattacked by weak acids, some attack by strong acids and alkalies. Resistant to paraffinic solvents but soluble in aromatic and chlorinated hydrocarbons.

Poly-2-chloro-1,3-buta-
    diene (Neoprene)

1230–1250

—

20

2.18

0.19

1.56

10¹⁰–10¹³

—

Soluble in many organic solvents but resistance to heat and oil greater than that of natural rubber.

Polychlorotrifluoro-
    ethylene

2100–2200

29–39

4.5–7.0

0.9

0.20–0.22

1.43

10¹⁸

2.24–2.8

Not affected by acids or alkalies but halogenated organic solvents cause slight swelling.

Polyethylene
    Low density

910–925

4–15

10–20

—

0.33

1.51

10¹⁵–10¹⁸

2.25–2.35

All grades melt ~ 133 °C, insoluble in common solvents below 60 °C, resistant to acids and alkalies but attacked by oxid. acids.

    Medium density

926–940

8–22

10–20

—

0.33–0.42

1.52

10¹⁵–10¹⁸

2.25–2.35

    High density

940–965

20–36

10–20

—

0.45–0.52

1.54

10¹⁵–10¹⁸

2.30–2.35

Polyethylene
   terephthalate

1370–1380

66

6

1.25

0.29

1.54

10¹⁶

3.25

Softens ~ 250 °C. Resistant to dilute acids and alkalies but attacked by oxid. acids. Insoluble in many common solvents but soluble in hot aromatic and chlorinated hydrocarbons.

Polyimide aromatics

1430

68

4–5

1.12

—

opaque

>10¹⁶

3.4

Thermally very stable and does not burn. Resistant to acids but attacked by alkalies. Insoluble in organic solvents.

Polyisoprene
   Natural rubber

 
906–913

 
—

 
22

 
1.88

 
0.13

 
1.52

 
10⁶

 
—

 
Swells in many organic solvents. More resistive to attack by chemicals than natural rubber.

   Hard rubber

1130–1180

39

 6

1.38

0.16

1.6  

10¹⁶

—

Polymethylmethacrylate

1170–1200

45–72

5–9

1.5

0.17–0.25

1.48–1.50

>10¹⁴

3.3–4.5

Softens at ~ 180 °C. Attacked by high concentrations of oxid acids. Soluble in ketones, esters, aromatic and chlorinated hydrocarbons.

Polypropylene

902–906

28–36

6–10

1.92

0.12

1.49

>10¹⁶ 

2.2–2.6

Softens at ~ 160 °C. Resistant to acids and alkalies but attacked by oxid. acids. Insoluble in common organic solvents below 80 °C.

Polystyrene

1040–1090

30–100

3.4–21

1.3–1.5

0.04–0.14

1.59–1.60

>10¹⁶

2.45–2.65

Softens at ~ 98 °C and burns. Unaffected by acids or alkalies, attacked by strong oxid. acids. Soluble in aromatic and chlorinated hydrocarbons.

Polytetrafluoroethylene
moulding compound

2140–2200

13–33

10

1.0

0.25

1.35

>10¹⁸

—

Not affected by acids, alkalies or organic solvents.

Polyurethane
    Cast liquid

1100–1500

1–65

10–20

1.8

0.21

1.50–1.60

10¹¹–10¹⁵

4.0–7.5

Slightly attacked by weak acids and alkalies. Strongly attacked by strong acids and alkalies. Only slightly affected by organic solvents.

Polyurethane
    Elastomer

1110–1250

29–55

10–20

1.8

0.07–0.31

—

10¹¹–10¹³

5.4–7.6

Attacked by acids and alkalies and may dissolve. Resistant to most organic solvents.

Polyvinylchloride
    (PVC)

1300–1400

~ 50

7–8

0.84–1.17

0.12–0.17

1.53–1.55

10¹⁶

3.2–3.6

Softens at 80 °C. Soluble in organic solvents.

Polyvinylidene chloride
    moulding compounds

1650–1720

20–33

19

1.34

0.13

1.60–1.63

10¹⁴–10¹⁶

4.5–6.0

Resistant to acids and alkalies, little or only slightly affected by organic solvents.

Silicone cast resin

1300

—

8–30

—

0.15–0.32

1.43

10¹⁴–10¹⁵

2.7–4.2

Excellent stability to heat and oxidation, water repellent, insoluble in many organic solvents.