| Autor: |
Baethge, Heike, Butz, Sören, Han, Chang-Hun, Schmidt-Naake, Gudrun |
| Zdroj: |
Die Angewandte Makromolekulare Chemie; June 1999, Vol. 267 Issue: 1 p52-56, 5p |
| Abstrakt: |
Poly(styrene-co-N-vinylcarbazole) copolymers with controlled molecular weights and narrow polydispersities were synthesized by N-oxyl-controlled free radical copolymerization using benzoyl peroxide as initiator and 2,2,6,6-tetramethylpiperidine-N-oxyl as terminating agent. To improve the low polymerization rates, the radical initiator dicumyl peroxide (DCP) was introduced and its effects on the polymerization rate, the molecular weight and the polydispersity were studied. It was demonstrated that the introduction of DCP leads to a significant enhancement of the polymerization rate and that copolymers with high N-vinylcarbazole contents as well as N-vinylcarbazole homopolymer can be obtained. The enhancement of the polymerization rate corresponds to a decrease in the number of chain breaking reactions which leads to polymers with lower polydispersities compared with those polymerized at the same monomer conversion without DCP. This could be proved via comparative chain-extension experiments with styrene leading to poly(styrene-co-N-vinylcarbazole)-block-poly(styrene) diblock copolymers. |
| Databáze: |
Supplemental Index |
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