New Dicyano-Containing Cyclopolymers Having High Stereoregularity Dervied From Dimethacrylmalononitrile
Polymers and High Performance Materials
New monomers for cyclopolymerization were synthesized through phase transfer catalyzed reaction between methyl or ethyl alpha-(chloromethyl)acrylate and malononitrile. The dicyano-containing diacrylates obtained undergo AIBN-initiated or spontaneous thermal polymerization in bulk to give soluble cyclopolymers with virtually complete cyclization (cyclization efficiency f(c) > 0.99) and eta(sp)/c of 0.15-0.50 dL/g. Solution C-13 NMR in CDCl3 confirmed cyclic structures for the repeat units and suggested exclusive six-membered ring formation with cis-dominated configurations (70-95%) of the recurring cyclohexane ring. Kinetic consideration of the temperature dependence of cis/trans ratios indicated that a lower activation energy for cis formation is responsible for the cis-dominated configuration despite a smaller collision frequency factor for cis than for trans formation. DSC thermograms showed high glass transition temperatures for both the methyl ester (239-degrees-C) and ethyl ester (195-degrees-C) derivatives. No evidence of crystallization was evident. The high glass transition temperatures apparently result from the high stereoregularity of the cyclic units and the inherent stiffening effect of the cyclic groups in the polymer backbones. UV curing of the diacrylate ethyl ester using a photoinitiator gave clear, rigid films which were soluble in methylene chloride. These new monomers and polymers incorporate functionality suitable for piezoelectric applications.
Mathias, L. J.
(1993). New Dicyano-Containing Cyclopolymers Having High Stereoregularity Dervied From Dimethacrylmalononitrile. Macromolecules, 26(24), 6359-6363.
Available at: http://aquila.usm.edu/fac_pubs/6693