Polymerization of chloro-p-xylylenes, quantum-chemical study
The p-xylylene monomers of parylene N, C and D have similar high polymerization reactivity. For effective copolymerization processes this fact is basically a draw- back and for instance the copolymerization with styrene doesn't go at all (Corley et al. J Pol Sc 13(68):137156, 1954). Substitution of terminal hydrogen atoms by chlorine atoms reduces reactivity dramatically. 7,7,8,8-tetrachloro-p- xylylene and 2,5,7,7,8,8-hexachloro-p-xylylene can be iso- lated as yellow crystals. These crystals can be kept without any change in temperature below 0 C, but they polymerize slowly at room temperature. Perchloro-p-xylylene is sta- ble even at elevated temperatures and does not polymerize under any conditions. Both 7,7,8,8-tetrachloro-p-xylylene and 2,5,7,7,8,8-hexachloro-p-xylylene copolymerize with various vinyl monomers, such as styrene and others. In this work the polymerization reactions of different chloro- derivatives of p-xylylene were modeled by means of the DFT method with hybrid correlation functionals (B3LYP and PBE0) and, for comparison, by means of the Hartree Fock methods. We inquired both initiation as well as elongation polymeric reactions for each of the reactants.
Cezary Czaplewski, Krzysztof Smalara, Artur Giełdoń, Maciej Bobrowski. (2017). Polymerization of chloro-p-xylylenes, quantum-chemical study, 23(40), 1-20. https://doi.org/10.1007/s00894-016-3179-6
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