Preparation, characterization and dielectric properties of polycyanurate films cyclotrimerized in the presence of different catalysts

The article deals with the preparation and characterization of a series of functional polycyanurate (PCN) films obtained from bisphenol E dicyanate (BDECy) by thermal cyclotrimerization in the presence of four different catalysts. Thermal, structural, and dielectrical analyses of PCN films are performed as well as some physical properties such as solubility, adhesion, hardness, and contact angle measurements are studied. Fourier transform infrared spectroscopy results reveal that cyclotrimerized structure is formed from BDECy not only in the presence of catalyst but also free of catalyst. While 55.5% of BDECy is cylotrimerized without catalyst, the conversion of BDECy into triazine significantly increases and reaches to 82.1% and 84.8% for PCNPh1-2 and PCNPh3-2, respectively. Thermogravimetric analysis results reveal that PCN films prepared in the presence of catalyst are thermally stable up to 240°C and exhibit two degradation steps. Dielectric constant and dielectrical breakdown strength of the PCN film cyclotrimerized with 1 wt% phenol as catalyst are found to be 3.16 at 1 MHz and 194 kV/mm, respectively, while the catalyst-free PCN film has the dielectric constant of 4.92 at the same frequency. On the other hand, chemical stability, hardness, and adhesion properties of the prepared films are found to be excellent. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.