A c t i v a t i o n a n d
E n e r g i e s
o f
T e r m i n a t i o n
R a d i c a l
P r o p a g a t i o n i n
F r e e
P o l y m e r i z a t i o n
T. F. M c k e n n a Laboratoire de Chimie et Procedes de Polymerization, Villeurbanne, Cedex, France A . M . Santos Faculdade de Engenharia Quimica de Lorena-Faenquil, Lorena, Sao Paulo, Brazil
A. Introduction B. Tables Table 1. Dienes Table 2. Olefins Table 3. Acrylic Derivatives Table 4. Methacrylic Derivatives Table 5. Vinyl Halogens Table 6. Vinyl Ethers and Vinyl Esters Table 7. Styrene and Derivatives Table 8. Vinyl Heteroaromatics Table 9. Miscellaneous Compounds C. References A.
11-415 11-416 11-416 11-416 11-417 11-418 II-420 11-421 11-421 II-422 II-423 II-424
INTRODUCTION
The conversion of a free radical homopolymerization as a function of time is usually expressed by the following equation:
where x is the conversion, t the time, fep, ku and k& the propagation, termination and initiator decomposition rate constants, respectively, / the initiator efficiency and / the initiator concentration.
It is generally assumed that the temperature dependence of free radical polymerization rate constants can be expressed using the well-known Arrhenius equation:
where Ao is the frequency factor, R the universal gas constant, T the absolute temperature, and E the activation of the reaction in question. Measurement of kp and kt at different temperatures allows one to determine values of the activation energies of the same two reactions, Ep and E1, respectively. If we accept this representation, then the overall activation energy of a homopolymerization can be written as
The value of the activation energy for the initiator decomposition reaction, 2Jd, can often be estimated separately. When data are not available for Ep and Et as separate quantities, the term (Ev —\Et) can be used to model the polymerization reaction. In the following tables, all energies are reported in terms of kJ/mol, and any appropriate remark(s) associated with the data are presented.
B. TABLES TABLE 1. DIENES Monomer
Ep
Butadiene
10.9 38.9 24.3 & 20.9 20.5 35.7
Et
Ev — \Et
8.42
Chloroprene Dimethyl butadiene Isoprene
40.6 37.7 46.0
Refs.
In gas phase In emulsion In gas phase In gas phase Solution polymerization in CCl4; temperature range: 303-333 K For emulsion polymerization, supposing w = 0.5 Thermal and photoinitiation; temperature range: 278-333 K; kp measured by ESR In emulsion In emulsion In emulsion
5.9
38.9 1,3-Hexadiene
Remarks
13 14 16 21 90 91 92 35 45 15
TABLE 2. OLEFINS Monomer
Ev
Acetylene Ethylene
21.4 34.3 18.4 23.9 46.4
Et
£ p -|£ t
1.3
17.8
33.5
29.7 31.0
36.8 29.7 40.0
6.22 10.0 15.2
25.1 20.8 29.7 32.5 36.9 31.4
-1.59 3.13 10.0 4.19 1.05
Refs.
In gas phase In gas phase Calculated using results of Ref. 24 In gas phase High pressure in gas phase (up to 300 NPa); initiated by oxygen; temperature range: 60-250 0 C; conversion found by gravimetry High pressure polymerization (up to 300 MPa); initiated by DTBPO; temperature range: 130-1650C Activation volumes (cal/mol/atm): propagation: — 19.7, termination: 13.0
Estimation for simulation of emulsion copolymerization with vinyl acetate 14.2 31.6
Propene Isoprene
Remarks
30.3
4.2
17.6 ± 0.31
15.3 ± 0.26
30.2 23.4 41.0
6.44
Activation volume = - 26.2£ x 10~6 m3/gmol Activation volume for propagation = — 0.5 cal/mol/atm Activation volumes (cal/mol/atm): propagation: —16.8 ±0.1; termination: 9.2. Optimized from values of industrial runs In gas phase In emulsion
21 21 35 44 73 82 93 94 95 96 97 98 99 100 101 102 103 104 105 106 21 15
TABLE 3. ACRYLIC DERIVATIVES Monomer
Ep
Et
Acrylamide A B C D E
11.7 ± 1.2 16.3 ± 0.8 18.8 ± 1.9 20.5 ±0.8 25.1 ±0.9
11.7 ±0.8 10.9 ± 0.4 10.9 ±0.4 7.9 ±0.4 0±0.8
22 ±0.2 20 ±0.2 11.5 57.8
Ep-\Et 5.8 dz 1.6 10.9 ± 1.3 13.4±0.3 16.9 ±1.0 25.1 ±1.3
6.2 10.46
iVyV-methylene-bis-acrylamide
9.3
Remarks
Refs.
Solution polymerization in H2O/DMSO mixture with potassium persulfate; initiators: H 2 O: DMSO: (A) 100:0 (B) 88:12 (C) 65:35 (D) 38:62 (E) 0:100 pH 1 pH4 Compilation of data, validated for inverse suspension polymerization Compilation from various sources, validated for solution polymerization Aqueous polymerization with temperature range: 293-313 K
68
111 112 113
Acrylic acid 23.4 21.7 14.1 - , sodium salt
(1) 67.5 (2) 72.1
- , chromium salt
33.5
-, zinc salt
13.0
-, butyl ester
8.8 52.3 15.5
0 73.7 38.1
14 ± 6 £ p - ET = 0 9.6 ± 0.56
- , ethyl ester - , methyl ester
41 29.7 19.7 31.8 ±2.5
12.3 22.2 -0 20.1 ±0.8
-, methyl oc-acetoxy ester
35.5
46.8
-, methyl a-butoxy ester
30.5
25.1
Acrylonitrile
17.2 16.2
22.6 15.5
107 108
109 By PLP; temperature range: 288-328 K 110 Thermally induced solid state polymerization; 87 two methods to find Ep: (1) ESR, (2) DSC; temperature range: 60-160 0 C Polymerized with styrene-arsenic sulfide 114 complex initiator in DMF Initiated with an As2S3-styrene complex in 115 DMSO at 363 K 8 At 20% conversion 26 From PLP-GPC; temperature range: 116 (208-266 K); bulk polymerization 109 From PLP; temperature range: (298-353 K); 117 conversion range: (10-80%); bulk polymerization; P = 1 bar. From PLP; conversion = 30% in bulk 118 polymerization By PLP-GPC; bulk polymerization with 119 photoinitiators: benzoin and 2,2dimethoxy-2-phenylacetophenone; temperature range: 298-303 K 109 Gamma ray induced solid state polymerization; temperature range: 243-283 K
40.7 31.8
-, 1,3-hydroxyneopentyl ester
Initiation with APS; temperature range: 309.5-324.5 K; solution polymerization at pH 0 4.38 Precipitation polymerization; temperature range: 313-333 K
5.9 8.5
109 Measured by dilatometry in both benzene 120 and 1,4 dioxane (kp/k®-5 higher in dioxane) By ESR; temperature range: 303-333 K; 121 solution polymerization in 1,1,2-trichloroethane; initiator: 2,2 '-azobis(4-methoxy-2,4dimethylvaleronitrile) (V-70) By ESR; assuming Ed = 109.5; 121 solution polymerization in 1,1,2-trichloroethane; initiator: 2,2 /-azobis(4-methoxy-2, 4-dimethylvaleronitrile (V-70) In water solvent 25 In DMF solvent 32
References page II - 424
TABLE 3. cont'd Monomer
Ep
Et
Ep — \Et
Acrylonitrile {cont'd)
26.8
~0
6.8 21.4
29.6
7.0
Remarks In DMF solvent Estimated from data on solution copolymerization with styrene as azeotrope
42.7
D-Fluoroacrylic acid -, methyl ester
23.9
Polymerization in NaSCN solution with Mn(CsH702)2 as free radical initiator; temperature range: 295-313 K; value estimated from overall activation energy with Ed = 58.6 kJ/mol
9.6
Solution: acrylonitrile; initiator: AIBN; (assume Ed = 128 kJ/mol)
Refs. 37 109 122 123 124
71
TABLE 4. METHACRYLIC DERIVATIVES Monomer
Ep
Et
Methacrylamide
15.5 22.1
16.7
Methacrylic acid
17.7
-, butyl ester - , butyl ester
17.4 18.4 20.4 20.9 21.8 ± 0.27 22.9 ±1.1
4.6 12.7 8.8
Ev -\Et 7.1
16.1 14.1 16.7
23.3 20.4 20.5 ± 0.24 - , i-butyl ester
22.5 ± 0.42 21.5 ± 0.35
-, f-butyl ester
27.7 ± 2.5
-, chloromethyl ester
5.5
-, cyanomethyl ester
~ 8.4
- , dodecyl ester (lauryl ester)
15.5 29.8 21.5 ±0.34 13.7 16.2
- , ethyl ester
23.2
8.9
18.0
21.3
7.1
17.7 16.5
Remarks Solvent: water By PLP; temperature range: (288-328 K); pH 1 By PLP-GPC; 33% monomer in methanol; temperature range: 293-333 K
Refs. 34 110 125
109 Gamma ray initiation 27 Kinetics from calorimetry 55 Temperature range: 35-27°C Quoted in 58 By PLP 131 By PLP-GPC; P = 1000 bars; temperature 141 range: - 10 to 6O0C Temperature range: 25-55°C; by PLP bulk 135 polymerization; photoinitiator: benzoin 126 By PLP-MWD; bulk polymerization; 127 pressure: 1 bar; photoinitiator: benzoin 131 By PLP-MWD; bulk polymerization; 127 pressure: 1 bar; photoinitiator: benzoin Temperature range: 9-66°C; by PLP with 128 benzoinethyl ether as free rapid initiator Ampoule and emulsion polymerization; 78 AIBN initiator Solution: acetonitrile AIBN initiator 87 calculated, assuming Ed of AIBN= 128 kJ/mol from overall activation energy; temperature range: 50-70 0 C Quoted in 58 Bulk polymerization with BPO initiator; 66 temperature range 60-80 0 C; maximum conversion 1% ByPLP 131 135 By PLP-MWD; bulk polymerization; 135 photoinitiator: benzoin Gamma ray initiation; temperature range: 52 — 30 to 55 0 C; kinetics from calorimetry Quoted in 58 Data from bulk and solution (50% DMF); 63 AIBN initiator; kinetics from GLC and gravimetry
TABLE 4. cont'd Monomer Methacrylic acid, ethyl ester {cont'd)
Ev
Et
27.0 22.8 ±0.35 20.46
- 6.6
Ev-\Et 30.4
27.0 22.9 ± 0.46 22.2 16.3 -, hexadecyl ester - , hexyl ester - , methyl ester
20.1 18.0 26.4 18.4 24.3 20.9
18.8 11.9 0 2.1 0-16.7
10.5 ~ 8.4 20.5 18.4 23.2 20.9-12.6
18.8 22.4 22.8
13.2
11.2
22.6 ± 2.5
Tends to 0
22.6 ± 2.5 13.0
19.7 18.2 ± 0.2
3.3 2.9 ± 0.0
18.0 16.7 ± 0.2
23.4 20.4
~ 10.5
15.1
20.9 ±3.3
1.6 ± 0.4
20.1 ±3.6
31.3 21.3 ±0.25 18.2 26.4
11.7
29.1
3.55 22.6 18.9 15.7 18.0 18.2 24.2 18.3 31.3
0 ± 2.5 2.93
2.9 26.9 2.94 21.1 36 -14 ±8 - 1 6 ±15
22.2 ±0.3
Remarks
Refs.
Quoted in 79 ByPLP 131 By PLP; temperature range: 298-328 0 C; 135 bulk polymerization; photoinitiator: benzoin Evaluated for emulsion polymerization 129 By PLP-GPC; bulk polymerization, 127 pressure: 1 bar; photoinitiator: benzoin Bulk polymerization; initiator: AIBN 130 Solution polymerization in benzene; 130 initiator: AIBN Quoted in 58 Quoted in 58 4 7 28 Termination by combination or 30 disproportionation 47 In emulsion 31 Gamma ray induced; temperature range: 48 - 25 to 55 0 C; used a combination of DCS and inhibition with DPPH to find kinetic parameters Polymerization in benzene; DMDM initiator; 49 temperature range: 50-80 0C Bulk polymerization; DBPO initiator; 53 maximum conversion 25%; ESR used to find kinetic parameters Isothermal bulk; polymerization with AIBN 56 initiator; DCS used to follow reaction; value found assuming E& AIBN= 128 kJ/mol Quoted in 58 Bulk polymerization; AIBN initiator 64 temperature range 15-3O 0 C; reaction followed by spatially intermittent polymerization; DP 10000-15000 Bulk polymerization; AIBN initiator; 65 1-butanethiol used as CTA; value assumes Ed AIBN= 128 kJ/mol Solution: benzene; AIBN initiator; kinetic 68 data from molecular weight data; maximum conversion 5% Emulsion data; particle sizes from turbidity; 72 potassium persulfate initiator Solution: benzene; AIBN initiator; kinetic 77 parameters from intermittent illumination Bulk polymerization 85 ByPLP 131 132 133 109 Temperature range: 293-353 K 156 Suspension polymerization 134 Spatially intermittent polymerization/ 164 emulsion polymerization 135 136 137 Solution polymerization in toluene 138 139 1 Bar; temperature range: 323-353 K, 140 low conversion 100 bars 1000 bars 141
References page II - 424
TABLE 4. cont'd Monomer
Ep
Methcrylic acid, methyl ester (cont'd)
22.4
Et
Ev-\Et
Remarks PLP plus GPC for bulk polymerization; temperature range: 272-363 K
22.2 23.9
22.2
nonyl ester octyl ester phenyl ester o-methylphenyl ester 0-ethylphenyl ester 6>-iso-propylphenyl ester /7-methylphenyl ester p-ethylphenyl ester /7-iso-propylphenyl ester /?-te7t-butylphenyl ester ethyl a-Benzoyloxymethyl ester
17.2 15.9
13.0 12.1
- , ethyl a-acetacetoxymethyl ester - , 2-(3-chloro-3-methylcyclobutyl)-2hydroxyethyl ester Methacryloyl fluoride
Methacrylonitrile
10.4
20.9
- , «-Phenyl-a-methylene-p-lactam
TABLE 5.
10.9 9.7 9.2 9.6 12.2 14.4 10.6 9.3 13.2 9.5 11.5 24.55 30.68
48.1 29.7 ±1.5
142 143 144 145
2.9
-, -, -, -, -, -, -, -, -, -, -,
Refs.
37.7
22.8
By PLP-GPC; bulk polymerization; pressure: 1 bar; photoinitiator: 2-hydroxy-2,2-dimethylacetophenone; temperature range: 272-363 K By PLP-GPC; bulk polymerization; 146 pressure: 1 bar; photoinitiator: benzoin; temperature range: 272-363 K Quoted in 58 Quoted in 58 147 147 147 147 147 147 147 147 By ESR, assuming E& = 129; solution 148 polymerization in benzene; initiator: AIBN 149 Polymerization in dioxane using BZ2O2 as 150 initiator Solution: MEK; AIBN initiator; calculated 81 using Ed AIBN = 128 kJ/mol; temperature range: 50-70 0 C 20 By PLP; solution polymerization in 151 benzylactone; temperature range: 283-333K Solution polymerization in n-methyl-2152 pyrrolidone with AIBN (calculated from £ O v assuming Ed of AIBN= 129 kJ/mol)
VINYL HALOGENS
Monomer
Ev
Tetrafluoroethylene
17.4 5.4 30.0 16.0
Vinyl bromide Vinyl chloride
Vinylidene chloride
27.6 104 37.7 ± 5.9
Et 13.6 0.8 16.3 17.6
18.2 167 20.9 ± 10.5
Ep-\Et 10.6 5.0 21.8 7.4 12
20.5 27.2 ±11.1
Remarks
Validated for model of suspension polymerization For suspension polymerization Solvent: hexane Solution: N-methylpyrrolidone; AIBN used as photoinitiator; most runs < 1% conversion
Refs. 46 43 42 17 153 154 9 67
TABLE 6. VINYL ETHERS AND VINYL ESTERS Monomer
Ep
Et
Butyl vinyl ether
Vinyl acetate
E9-\Et 46.4
18.0 30.6 13 18 18 39±3 19.6 ± 2.9
O 21.9 0
