Polymerization of chloro-p-xylylenes, quantum-chemical study
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- 作者：Cezary Czaplewski ; Krzysztof Smalara ; Artur Giełdoń…
- 关键词：Parylene ; Chloro ; p ; xylylene ; CVD ; Polymerization ; DFT ; B3LYP ; PBE0
- 刊名：Journal of Molecular Modeling
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：23
- 期：2
- 全文大小：3625KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Computer Applications in Chemistry; Molecular Medicine; Computer Appl. in Life Sciences; Characterization and Evaluation of Materials; Theoretical and Computational Chemistry;
- 出版者：Springer Berlin Heidelberg
- ISSN：0948-5023
- 卷排序：23
文摘
The p-xylylene monomers of parylene N, C and D have similar high polymerization reactivity. For effective copolymerization processes this fact is basically a drawback and for instance the copolymerization with styrene doesn’t go at all (Corley et al. J Pol Sc 13(68):137–156, [15]). 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 isolated 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 stable 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. We survied their reactivity analytically examining energetics and configurations in Szwarc-like process. The quantitative influence of chlorine atoms on the reactivity in polymerization steps, their location in the reactants’ structure (aromatic and/or aliphatic) as well as their number, were reviewed. The polymerizations of p-xylylenes with chlorine atoms as terminal aliphatic substituents yet revealed one more access path for parylenes’ in situ functionalization.