| Autor: |
Davison, A., Dewar, M. J. S., Hafner, K., Heilbronner, E., Hofmann, U., Niedenzu, K., Schäfer, Kl., Wittig, G., Boschke, F., Rubin, M. B., Jones, L. B., Jones, V. K., Sonntag, C., Koerner von Gustorf, E., Grevels, F.-W., Williams, J. L. R. |
| Zdroj: |
Photochemistry; 1969, p227-250, 24p |
| Abstrakt: |
It appears that at least three processes can take place when systems containing photopolymerizable monomers or photocrosslinkable polymers are exposed to light. They are photopolymerization, photocrosslinking and photografting. These three processes lead to the formation of networks of crosslinks which provide the rigidity and stability of structure that permit photopolymerization and photocrosslinkable polymers to be of practical importance in image formation. The differences between photopolymerization and the photocrosslinking of polymers for practical applications are not great and lie only in the details of the photocrosslinking mechanism. Photopolymerization could more correctly be termed photoinitiation since the primary act of initiation is the only step which is light dependent. During long irradiation times photografting could occur during the propagation and after the termination steps leading to crosslinking or branching. The presence of two radical species appearing during photocrosslinking of poly(vinyl cinnamate) lends credence to the idea that two processes could be occurring, one due to a radical at the cinnamate unit and the other due to a radical on the polymer chain. The two radical sites would result in photodimerizing-type crosslinking and radical reactions of the backbone chain. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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