On the correlation equations of liquid and solid C-13-NMR, thermomechanical analysis, T-g, and network strength in polycondensation resins

Wide-scope mathematical relationships have been established between the C-1 3-NMR of liquid polycondensation resins, such as urea-formaldehyde and phen ol-formaldehyde resins, and the strength of the network formed by the same resin when hardened under well-defined conditions, the thermomechanical ana lysis deflection, the number average molecular mass and the number of degre es of freedom of the average polymer segment between crosslinking nodes in the hardened resin network, the resin network glass transition temperature, its solid-phase C-13-NMR proton-rotating frame spin-lattice relaxation tim e, and the homogeneous and heterogeneous polymer segment/polymer segment in terfacial interaction energy calculated by molecular mechanics. These mathe matical relationships allow the calculation of any of these parameters from any of the techniques listed, provided that all of the systems are used un der well-defined conditions. Under different conditions, the values of the numerical coefficients involved change; and, whereas the equations are stil l valid, a different set of coefficients needs to be recalculated. (C) 1999 John Wiley & Sons, Inc.