Effect of the initiator content and temperature on the curing of an unsaturated polyester resin

Abstract

The influence of temperature and the initiator concentration on the curing of an unsaturated polyester resin was studied by means of differential scanning calorimetry (DSC) and Fourier‐transform infrared spectroscopy (FTIR). It was established that there is an isoconversional relationship of the type lnt = a − bln[I]0 between the curing time, t, and the initial initiator concentration, [I]0, at a given temperature. This relationship indicates that the degree of conversion curves vs. the logarithm of the curing time at different [I]0 may be superposed by displacement relative to a reference curve. It was confirmed that the reaction mechanism varies throughout the whole curing process, although it does not vary with the temperature and the [I]0 at each degree of conversion. It was established that there is a universal isoconversional relationship of the type lnt = d − bln[I]0 + E/RT that expresses the dependency of the curing time on the temperature, T, and the [I]0. The parameters a, b, and d depend on the reaction mechanism, and can be calculated on the basis of isothermal experiments at different temperatures and with different [I]0. The adjustment lnt = d − bln[I]0 + E/RT shows that there is an equivalence between the effect on the curing kinetics of the temperature and the initiator concentration. The same curing process can be achieved by using different combinations of curing temperatures and the [I]0. In the two adjustments established, it is not necessary to know the reaction mechanism, and the only assumption made is that for a given conversion the reaction mechanism is invariant with respect to the [I]0 and the temperature. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 751–768, 1999

The effect of cure history on the fluorescence behavior of an unsaturated polyester resin with a fluorescence probe

“…[5][6][7] The UP resins normally undergo rapid cure accompanying exothermic reaction. However, the cure of UP resin proceeds based upon a free radical reaction mechanism with initiation, propagation, termination, and transformation.…”

Prediction of the curing behavior for unsaturated polyester–styrene systems used for monitoring sheet moulding compounds (SMC) process

“…Even though DSC is a good way of studying simple systems made of ''resin + inhibitor + initiator'' [12,13], it is less representative for heterogeneous systems containing anti-shrinkage agents, fillers [14] and glass fibres [15]. Indeed, filled mixtures are relatively heterogeneous and their study by DSC with samples of a few milligrams is generally not sufficiently representative.…”

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Study on Microwave Curing of Unsaturated Polyester Resin and Its Composites Containing Calcium Carbonate

“…However, the UPR is a poor thermal conductor and unable to be cured evenly inside and outside using the thermal curing method. In addition, the curing rate of this method is slow, and its energy consumption is large [13]. Different from the thermal curing method, microwaves are electromagnetic energy wave that has a strong penetrating ability.…”