The mass manufacturing of composite products is hindered by long curing times, and composite manufacturers demand shorter curing cycles while keeping material properties. This requires reliable methods to predict the curing kinetics of each resin formulation. Isoconversional methods are easy to implement and able to deal with complex processes. However, scientists still limit their isoconversional predictions of curing degree to isothermal or constant heating programs. In this study, we perform combined dynamic and isothermal DSC measurements for two different commercial epoxies for aerospace applications (M18 and VTC401). Based on the isoconversional kinetic analysis, we show the feasibility of predicting the evolution of an epoxy resin cure for an arbitrary and complex temperature program using two different unexplored methods for this purpose. Because of the versatility of both prediction methods, they are especially suited to deal with actual conditions in industrial processes. The proposed approach is validated experimentally by comparing predictions against the curing degree of these epoxies during a temperature program that comprises isothermal and dynamic stages. These reliable and straightforward predictions open the door to optimize curing times and increase productivity in composites.
MasuelliMA. Polymers and Composites: Concepts, Properties and Processes. Fiber Reinforc Polym2013; 1: 24.
2.
GeramiGBagheriRDarvishiR. Investigation of isothermal and dynamic cure kinetics of epoxy resin/nadic methyl anhydride/dicyandiamide by differential scanning calorimetry (DSC). J Therm Anal Calorim2019; 137: 575–582. DOI: 10.1007/s10973-018-7961-9.
3.
HamedAASaadGRElsabeeMZ. Synthesis and characterization of modified epoxy resins and novel E-glass-/spectra-reinforced composites. High Perform Polym2017; 29(3): 328–340.
VyazovkinS.AchiliasD.Fernandez-FrancosX., et al.ICTAC Kinetics Committee recommendations for analysis of thermal polymerization kinetics. Thermochim Acta2022; 714: 179243. DOI: 10.1016/j.tca.2022.179243.
6.
SkordosAPartridgeI. Cure kinetics modeling of epoxy resins using a non-parametric numerical procedure. Polym Eng Sci2001; 41: 793–805. DOI: 10.1002/pen.10777.
7.
VyazovkinSBurnhamAKFavergeonL, et al.. ICTAC Kinetics Committee recommendations for analysis of multi-step kinetics. Thermochim Acta2020; 689: 178597. DOI: 10.1016/j.tca.2020.178597.
8.
VyazovkinS. The Handbook of Thermal Analysis & Calorimetry. In: BrownMEGallagherPK (eds) Recent Advances, Techniques and Applications, Vol. 5. Amsterdam, Netherlands: Elsevier, 2008, p. 503.
9.
VyazovkinSSbirrazzuoliN. Isoconversional kinetic analysis of thermally stimulated processes in polymers. Macromol Rapid Commun2006; 27: 1515–1532.
10.
BrownM.E.MaciejewskiM.VyazovkinS., et al.Computational aspects of kinetic analysis Part A: The ICTAC kinetics project-data, methods and results. Thermochim Acta2000; 355(1): 125–143. DOI: 10.1016/S0040-6031(00)00443-3.
VyazovkinSBurnhamAKCriadoJM, et al.ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data. Thermochim Acta2011; 520: 1–19. DOI: 10.1016/j.tca.2011.03.034.
13.
FarjasJRouraP. Isoconversional analysis of solid state transformations: A critical review. Part I. Single step transformations with constant activation energy. J Therm Anal Calorim2011; 105: 757–766. DOI: 10.1007/s10973-011-1446-4.
14.
WanJLiCBuZY, et al.A comparative study of epoxy resin cured with a linear diamine and a branched polyamine. Chem Eng J2012; 188: 160–172. DOI: 10.1016/j.cej.2012.01.134.
15.
StankoMStommelM. Kinetic prediction of fast curing polyurethane resins by model-free isoconversional methods. Polymers2018; 10: 698.
HuJShanJZhaoJ, et al.Isothermal curing kinetics of a flame retardant epoxy resin containing DOPO investigated by DSC and rheology. Thermochim Acta2016; 632: 56–63. DOI: 10.1016/j.tca.2016.02.010.
18.
BudrugeacPCucosADascăluR, et al.The use of thermal analysis methods for predicting the thermal endurance of an epoxy resin used as electrical insulator. J Therm Anal Calorim2021; 146: 1791–1801. DOI: 10.1007/s10973-020-10156-5.
19.
DunneRCSitaramanSKLuoS, et al.Investigation of the curing behavior of a novel epoxy photo-dielectric dry film (ViaLuxTM 81) for high density interconnect applications. J Appl Polym Sci2000; 78: 430–437.
20.
LiSYVuorimaaELemmetyinenH. Application of isothermal and model-free isoconversional modes in DSC measurement for the curing process of the PU system. J Appl Polym Sci2001; 81: 1474–1480.
21.
GranadoLTavernierRFoyerG, et al.Comparative curing kinetics study of high char yield formaldehyde and terephthalaldehyde-phenolic thermosets. Thermochim Acta2018; 667: 42–49.
22.
WuzellaGMahendranARBeucC, et al.Isoconversional cure kinetics of a novel thermosetting resin based on linseed oil. J Therm Anal Calorim2020; 142: 1055–1071.
23.
VafayanMHosain BeheshtyMGhoreishyMHR, et al.Advanced integral isoconversional analysis for evaluating and predicting the kinetic parameters of the curing reaction of epoxy prepreg. Thermochim Acta2013; 557: 37–43. DOI: 10.1016/j.tca.2013.01.035.
24.
ShuyanLVuorimaaELemmetyinenH. Application of isothermal and model-free isoconversional modes in DSC measurement for the curing process of the PU System. J Appl Polym2001; 81: 1474–1480. DOI: 10.1002/app.1574.
25.
VyazovkinSDrancaIFanX, et al.Kinetics of the thermal and thermo- oxidative degradation of a polystyrene-clay nanocomposite. Macromol Rapid Commun2004; 25(3): 498–503.
26.
FarjasJRouraP. Isoconversional analysis of solid state transformations: A critical review. Part II. Complex transformations. J Therm Anal Calorim2011; 105: 767–773. DOI: 10.1007/s10973-011-1447-3.
27.
FarjasJRouraP. Isoconversional analysis of solid-state transformations: A critical review. Part III, Isothermal and non isothermal predictions. J. Therm. Anal. Calorim2012; 109: 183–191. DOI: 10.1007/s10973-011-1642-2.
28.
RasiSRoura-GrabulosaPFarjasJ. Application of thermal analysis and kinetic predictions to YBCO films prepared by chemical solution deposition methods. J. Therm. Anal. Calorim2020; 142: 2077–2086. DOI: 10.1007/s10973-020-10103-4.
29.
FriedmanHL. Kinetics of thermal degradation of char-forming plastics from thermogravimetry. Application to a phenolic plastic. J Polym Sci, Part C: Polym Symp2007; 6: 183–195.
30.
VyazovkinS. Modification of the integral isoconversional method to account for variation in the activation energy. J Comput Chem2001; 22: 178–183.
31.
SbirrazzuoliNVincentLBouillardJ, et al.Isothermal and non-isothermal kinetics when mechanistic information available. J Therm Anal Calorim1999; 56: 783–792.
32.
HardisRJessopJLPPetersFE, et al.Cure kinetics characterization and monitoring of an epoxy resin using DSC, Raman spectroscopy, and DEA. Compos. Part A Appl. Sci Manufact2013; 49: 100–108. DOI: 10.1016/j.compositesa.2013.01.021.
33.
Sánchez-RodríguezDEloussifiHFarjasJ, et al.Thermal gradients in thermal analysis experiments: Criterions to prevent inaccuracies when determining sample temperature and kinetic parameters. Thermochim Acta2014; 589: 37–46. DOI: 10.1016/j.tca.2014.05.001.
34.
SbirrazzuoliN. Interpretation and physical meaning of kinetic parameters obtained from isoconversional kinetic analysis of polymers. Polymers (Basel)2020; 12(6): 1280. DOI: 10.3390/polym12061280.
