Dicyanate Resin Research Articles

Kinetics and rheology characterization during curing of dicyanates

Reaction kinetics and viscosity rise of a liquid dicyanate ester monomer, 1,1-bis(4-cyana-tophenol)ethane, are characterized and fitted several models. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) are used to obtain the isothermal reaction kinetic data. The liquid dicyanate resin shows second-order reaction kinetics in the early stage and approaches a plateau conversion at longer times with each curing temperature. Experimental data show that the diffusion limitation for dicyanate resin occurs well before the vitrification point. A two-step kinetic model and a Williams-Landel-Ferry-(WLF-) type diffusion-controlled kinetic model are developed to describe the entire range of curing. For the temperature range we studied (140°C–200°C), the WLF-type diffusion-controlled kinetic model gives a better prediction than the two-step kinetic model does. The viscosity rise during isothermal curing is characterized using disposable parallel plates. A Castro-Macosko type of equation is used to describe the isothermal viscosity rise. © 1996 John Wiley & Sons, Inc.

A simple dilatometer for thermoset cure shrinkage and thermal expansion measurements

AbstractA simple capillary and bulb mercury dilatometer designed for specific volume measurements on thermoset resin systems during the curing reaction and as a function of temperature is described. The design, calibration, operation, data treatment, and error analysis are presented in detail, with data on the bisphenol A dicyanate resin system used as an example. Particular attention is directed at experimental difficulties such as monomer/prepolymer degassing, filling the dilatometer under vacuum, adhesive distortion of the curing resin on the dilatometer bulb, and the dilatometer bulb to capillary connection problem. © 1994 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.

Phase structure and toughening mechanism of a thermoplastic-modified aryl dicyanate

A high temperature thermosetting aryl dicyanate resin was modified with thermoplastic polysulfone and/or poly(ether imide) at various compositions. Differential scanning calorimetry was used to characterize the phase behaviour, while the morphologies and continuities of the thermoplastic/dicyanate networks were investigated by using dynamic mechanical analysis, scanning electron microscopy, fracture toughness testing, and solvent sorption studies. The phase structure was found to change from a thermosetting continuity to a co-continuity of both thermoplastic and thermosetting domains. The mechanical and physical properties of the modified polycyanates exhibited a step change at the shift of the phase structure.

Cure kinetics of dicyanate matrix polymers

AbstractThe cure kinetics of two dicyanate resins were investigated by differential scanning calorimetry under isothermal and nonisothermal conditions. An autocatalytic kinetic model was proposed and a set of general kinetic parameters was calculated from the isothermal experiments. Good agreement between experimental data and the kinetic model has been obtained under different processing conditions, which demonstrated the validity and the usefulness of the analytical procedure and of the kinetic expression employed. Consequently, in its current form, the modeling methodology is capable of describing the degree of cure during a typical processing cycle and has the potential for comparing different resin formulations as well as the manifestations of cure in property development. Specifically, in this work the modeling methodology was tested using two distinct dicyanate resin systems while the development of the cure was also observed through dielectric analysis (DEA).