A Practical Approach for Data Gathering for Polymer Cure Simulations

Abstract

Producing precision parts requires good control of the production parameters. When casting thermoset polymers an understanding of the curing process, with its heat release and associated temperature changes, is important. This paper describes how the cure of a polymer of unknown detailed chemical composition in a large part can be predicted and how the necessary material properties required for the predictions can be obtained. The approach given is a relatively simple method that a part manufacturer can perform. It will not characterize chemical reactions in detail, but it gives sufficient accuracy to describe the process. The procedures will be explained for an example of casting a large block of a filled two-component thermoset polyurethane. The prediction of the degree of cure, the associated heat and temperature increase during the curing of a polymer was successfully done using a standard finite element program with the input parameters reaction energy, the Arrhenius pre-factor and the kinetic function, which describes the chemical reaction. The three parameters could be obtained with standard Differential Scanning Calorimetry (DSC) equipment. The data were analyzed with the model-free isoconversional method combined with the compensation effect. The same set of parameters allowed the prediction of experimental cure behavior over two orders of magnitude of time and at a curing temperature range from room temperature up to 420 K.

Numerical Simulation of HTPB Resin Curing Process Using OpenFOAM and Study the Effect of Different Conditions on its Curing Time

“…At the moment, the progress of the curing reaction in the three geometries rectangular cube, cylindrical and spherical geometries is 0.35, 0.29, and 0.21, respectively (Figure 13). These values indicate that the speed of the curing process in the rectangular cube geometry is greater than the other two geometries [28].…”

Peroxide‐based crosslinking of solid silicone rubber, part II: The counter‐intuitive influence of dicumylperoxide concentration on crosslink effectiveness and related network structure

“…Alike, the exothermic event related to the DCP‐driven crosslinking reaction (step 4) was analyzed in terms of the curing enthalpy, calculated after considering baseline correction (step 8) of the heat flow . As advised by Heinze and Echtermeyer, 14 the melting () and crosslinking () enthalpies were calculated (mean value) as follows, considering the heating rate = 10 K.min −1 : …”

A Method to Derive the Characteristic and Kinetic Parameters of 1,1-Bis(tert-butylperoxy)cyclohexane from DSC Measurements

“…To resolve kinetic parameters from a single DSC measurement, we can use the method described in ASTM E2041, also known as the Borchardt and Daniels (B/D) method [23][24][25][26]. The process derives the kinetic parameters of the E a , A, n, and the reaction model f (α) = (1 − α) n [27,28].…”