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Rate mechanisms of a novel thiol‐ene photopolymerization reaction
Author(s) -
Reddy Sirish K.,
Cramer Neil B.,
O' Brien Allison K.,
Cross Tsali,
Raj Rishi,
Bowman Christopher N.
Publication year - 2004
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200450228
Subject(s) - photoinitiator , photopolymer , monomer , polymerization , polymer chemistry , copolymer , materials science , ene reaction , polymer , photochemistry , thiol , chemistry , organic chemistry , composite material
A novel thiol‐ene photopolymerization reaction involving copolymerization of tetrathiol monomer with vinyl silazane is experimentally characterized and is modeled successfully. The overall polymerization rate is found to be controlled by the ratio of the propagation to chain transfer kinetic parameters. The polymerization rate of this mixture, in the presence of added photoinitiator, is approximately first order in ene functionality and is independent of thiol functional group concentration. Initiation rates in this system, when cured utilizing a light centered around 365 nm light, and in the presence of no added photoinitiator, are shown to be proportional to the ene monomer concentration. When the mixture is polymerized utilizing light centered at 254 nm light, and without photoinitiator, the initiation rates are proportional to the thiol monomer concentrations. This novel reaction scheme is further utilized to form ultra rapidly polymerizable polymer derived ceramic structures with high aspect ratios.