Synthesis and properties of novel poly(meth)acrylates containing tricyanocyclopropyl groups for piezoelectric applications

o-(2,2,3-Tricyano-3-carbomethoxycyclopropyl)phenoxyethyl acrylate (5a) and o-(2,2,3-tricyano-3-carbomethoxycyclopropyl)phenoxyethyl methacrylate (5b) were prepared by reactions of bromomalononitrile with methyl o-(2-acryloyloxyethoxy)benzylidenecyanoacetate and methyl o-(2-methacryloyloxyethoxy)benzylidenecyanoacetate respectively. The dipole moments of 5a and 5b, calculated by atom superposition and electron delocalization molecular orbital method, were 2.75-3.47 D. Monomers 5a and 5b were polymerized with free-radical initiators to obtain the polymers with tricyanocyclopropane ring as a piezoelectric chromophore in the pendant group. The resulting polymers 6a and 6b were soluble in common organic solvents such as acetone and DMF. Polymers 6a and b showed thermal stability up to 280degreesC in TGA thermograms. T-g values obtained from DSC thermograms were in the range 125-140degreesC. Piezoelectric coefficients (d(31)) of the poled films were 1.2-1.4 pC N-1. These polymers showed good temporal and long-term thermal stabilities which are acceptable for piezoelectric device applications. (C) 2003 Society of Chemical Industry.