502-55-6Relevant articles and documents
Dual roles of a xanthate as a radical source and chain transfer agent in the photoinitiated RAFT polymerization of vinyl acetate
Khan, Mohd Yusuf,Cho, Min-Soo,Kwark, Young-Je
, p. 1929 - 1934 (2014)
A high level of control over the photoinitiated RAFT polymerization of vinyl acetate (VAc) was achieved using a specifically designed xanthate, S-2-cyano-2-propyl-O-ethyl xanthate (CPEC), which acted as a radical source and a chain transfer agent simultaneously. Unlike other RAFT processes, the present system did not use any additional radical initiator, while achieving greater control over the polymerization than the photoiniferter process. The molecular weight of the resulting polymer could be modulated by changing the initial [VAc]0/[CPEC]0 ratio, but the control over the polymerization was lost with a very low initial [VAc]0/[CPEC] 0 ratio. The intensity of UV irradiation affected the polymerization by reducing the induction period and increasing the rate of polymerization but did not affect the molecular weight of the resulting polymer.
Poly(ethylene glycol)-block-poly(N-vinylformamide) copolymers synthesized by the RAFT methodology
Shi, Lianjun,Chapman, Toby M.,Beckman, Eric J.
, p. 2563 - 2567 (2003)
The radical polymerization of N-vinylformamide was followed and found to proceed in a controlled manner if an appropriate RAFT agent is employed. Use of a poly(ethylene glycol) macro-RAFT agent allowed for the generation of block copolymers of PEG and PNVF.
Activating ATRP Initiators to Incorporate End-Group Modularity into Photo-RAFT Polymerization
Hakobyan, Karen,McErlean, Christopher S. P.,Müllner, Markus
, p. 10357 - 10365 (2020/12/23)
Heterogeneous photocatalysis is increasingly used in reversible deactivation radical polymerization (RDRP). In this study, we found that alkyl bromide redox chemistry typically found in atom transfer radical polymerization (ATRP) can be incorporated in concert with dithiocarbonyl disulfide chemistry into the reversible addition-fragmentation chain transfer (RAFT) process via bismuth oxide photocatalysis. This amalgamation of mechanisms introduces end-group modularity - a new layer of control - into RAFT polymers uniquely enabled by photoredox catalysis. We found that a diversity of functionality can be installed at the α-end group via alkyl bromides, while the molecular weight distribution can be tuned seamlessly at the ω-end group through the simultaneous addition of multiple disulfides.
Coupling of gem-difluorinated organozinc reagents with S-electrophiles
Ashirbaev, Salavat S.,Levin, Vitalij V.,Struchkova, Marina I.,Dilman, Alexander D.
, p. 143 - 148 (2016/10/24)
gem-Difluorinated organozinc reagents, which were prepared by insertion of CF2-fragment into C[sbnd]Zn bond, couple with diethyl dixanthogen, di(benzothiazolyl) disulfide, and tetraethylthiuram disulfide. The reaction is promoted either by a copper(I) catalyst or by irradiation with blue light in the presence of Eosin Y disodium salt.
