R a d i a t i o n

C h e m i c a l

Y i e l d s :

G

V a l u e s

M . C. Senake Perera Magnetic Resonance Facility, School of Science, Griffith University, Nathan, QId 4111, Australia D a v i d J. T. H i l l Department of Chemistry, University of Queensland, St Lucia, QId 4072, Australia

A. Introduction B. Tables of G values Table 1. Homopolymers 1.1. Polydienes 1.2. Polyolefins 1.3. Polyacrylates 1.4. Poly(methacrylates) 1.5. Poly(styrenes) 1.6. Poly(vinyls) 1.6.1. Acrylamides and Nitriles 1.6.2. Vinyl Monomers 1.7. Miscellaneous Polymers 1.7.1. Cellulose and Derivatives 1.7.2. Poly(siloxanes) 1.7.3. Poly(amino acids) 1.7.4. Polyesters 1.7.5. Polysulfones 1.7.6. Polyketones 1.7.7. Fluoropolymers 1.7.8. Others Table 2. Copolymers 2.1. Copolymers with Ethylene 2.2. Copolymers with Methyl Methacrylate 2.3. Copolymers with Styrene 2.4. Copolymers with Sulfur Dioxide 2.5. Other copolymers Table 3. Polymers Blends Table 4. Composites C. References

11-481 11-481 M-482 M-482 II-482 II-483 II-484 II-485 II-486 II-486 M-486 II-487 II-487 II-487 II-487 II-488 II-488 II-488 II-488 II-489 II-490 II-490 II-490 11-491 11-491 II-492 II-493 II-493 II-493

A.

INTRODUCTION

The G values quoted in the following tables are defined as the radiation chemical yields of individual atomic or molecular events for 100 eV of energy absorbed by the system. G(R) represents the yield of free radicals, G(X) the yield of crosslinks, G(S) the yield of main chain scission, and G(products) the yield of product molecules per 10OeV of absorbed radiation. This table has been compiled from the polymer literature that has been published since the third edition of the "Polymer Handbook" (i.e. 1986-1997). In many cases, the tabulated data are only representative of the total data in the paper, and the original publication should be consulted. B. TABLES OF G VALUES Notes to the Tables General: Unless otherwise stated, the conditions applying are y-rays, vacuum, room temperature (ambient). Symbols/Abbreviations + — vac RT e

cation radical anion radical vacuum room temperature electron beam

d.b. t-v Y X n

double bond trans-vinylene crosslinks crosslinks neutron

TABLE 1. HOMOPOLYMERS Polymer 1.1.

G(R)

G(X)

G(S)

G(products)

Radiation conditions

38.7 (d.b.)

e, 263 K

Refs.

POLYDIENES

Polybutadiene 610 (1,2) 0.0054

2.1 Various

Polyisoprene

0.009 0.5-0.8 Various

NR latex Polychloroprene

77 K 9.3 105 3.36/9.4 5.3

112 (Vinyl) Various 0.34/0.19 90

Various

Various

41 7.2

Poly(2-phenyl butadiene)

1.2.

Comments

3.0

1.6-2.1 Various Various 3.9

e 77K/RT Air, 295 K

Excitation scavenger 1, 2-PBD Radical pairs, isotactic Syndiotactic cis 1,4

64 138 74 97 84 98 104

Effect of pressure Various Review 186 G(Cy) > G(X) 261 G(X) depend on MW G (initiation), 262 G(X) increases G(Cy), G(db) decreases with Crosslinker Vac, 303 K 180 Vac/303 K, ethyl178 ene dichloride 77 K Radical pairs 74 Var cis content 15

94-168 (d.b.), CH 4 , H 2 Various

Various

2.8 (-Cl)

Vac/77, 303 K

186 248 179

RT, vac

235 226

Review +acrylate

POLYOLEFINS

Squalene Poly(butene-l)

1.0

Poly(ethylene)

1.09-1.39 0.63

3.2

4 4.1

4 1.4 15-30 0.25 1.50-2.40

3.0 (H 2 ) 13.9 (-isotactic pentad) 7 (COOH) 9.1 (O 2 ) - 2 (MO

e, air Vac/O2 300K

0.48 8-15

Carries

Air, 300/450K

Pressure effects

1.08-1.69

Various

303-373 K He, 77K O 2 , CCl 4

e pre-irradiated

2.8, 5.8 (C 2 D 4 ) 2.4

Fibers,

89 101 107 172 116 169 30 63 52 147 151

G(S)ZG(X) = 1

1.1-2.8

0.05-2.7 Various gases

1.1 1.5

0.55 0.07-0.19

137 1.4-2.4

0.38-2.2

Various

69

Air

72

3.8 0.05-0.7

17

77 K

Also TFEM

140

0.4-4.4

72

1.9

77 K

2.8-3.4*

65 *G(S)-G(X)

17

1.6

137

1.35-8.5

1.6 1.51-5.5

77 K

0.077 0.04-0.59

Various 0.055 0.0-0.09

Vac

4.3/33

2.8/17

Air

0.3-3.0 Various

Various

313 K 77 K

0.04-0.38

2.18-2.47

Various compositions 246

6.5

65 246

COPOLYMERS WITH STYRENE

Poly(styrene-coacrylates) Poly(styrene-c