Chain length dependent termination in pulsed-laser polymerization. 9. The influence of solvent on the rate coefficient of bimolecular termination in the polymerization of styrene
Olaj, OF; Zoder, M; Vana, P
| HERO ID | 1596899 |
|---|---|
| In Press | No |
| Year | 2001 |
| Title | Chain length dependent termination in pulsed-laser polymerization. 9. The influence of solvent on the rate coefficient of bimolecular termination in the polymerization of styrene |
| Authors | Olaj, OF; Zoder, M; Vana, P |
| Journal | Macromolecules |
| Volume | 34 |
| Issue | 3 |
| Page Numbers | 441-446 |
| Abstract | The chain length dependence of bimolecular termination in the solution polymerization of styrene was examined at 25 degreesC with the solvents (50% per volume) toluene, cyclohexane, bis(3,5,5-trimethylhexyl)phthalate, and ethyl acetate. Irrespective of which method was applied, the ""good"" solvent systems with toluene and ethyl acetate exhibited a chain length dependence comparable to or even greater than that observed for the bulk polymerization of styrene, while a markedly weaker chain length dependence was observed with the ""bad"" solvents cyclohexane and bis( 3,5, 5-trimethylhexyl)phthalate. This is documented by the exponent b in the power law (k) over bar (t) = A . nu'(-b) connecting the average termination coefficient (k) over bar (t) and the chain length nu' of the radical chains at the moment of undergoing bimolecular termination: b approximate to 0.2 for styrene tin bulk) and in toluene solution, b approximate to 0.3 in ethyl acetate solution and 0.10 to 0.14 in cyclohexane and bis (3,5,5-trimethylhexyl)phthalate solution, respectively. Only in the case of the bad solvents the bulk viscosity and BL or the prefactor A are inversely correlated. In the case of the good solvents, the bulk viscosities were too close to detect such a relationship. The observed values of the parameter b (with the exception of the ethyl acetate system) are consistent with the idea of a chain length dependent shielding exercised by the rest of the chains on the two radical chain ends (some sort of ""kinetic"" excluded volume effect) which is much weaker in bad solvents. |
| Doi | 10.1021/ma0012651 |
| Wosid | WOS:000166601100017 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Source: Web of Science WOS:000166601100017 |
| Is Public | Yes |