Control of gel time and exotherm behaviour during cure of unsaturated polyester resins

Cook, Wayne D.; Lau, Michelle; Mehrabi, Mansour; Dean, Katherine; Zipper, M. D.

doi:10.1002/1097-0126(200101)50:1<129::aid-pi598>3.0.co;2-c

Cited by 38 publications

(33 citation statements)

References 11 publications

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“…Thus to estimate the constants KA and KA for the Arrhenius equation using Equations (9) and (14) from the constants K and K for the Linear Exponential Temperature Relationship or vice versa it is necessary to know the limits or the range of temperatures, T K1 -T K2 , from which the primary constants have been obtained.…”

Section: Comparison Of the Temperature Influence On The Gel Time Usinmentioning

confidence: 99%

Simplified Modeling of the Dynamic Gel Time and/or the Dynamic Gel Temperature for a Thermosetting Resin or Composite

Sudduth¹

2003

Journal of Composite Materials

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The simple analytical model developed in this study has been found to give a successful engineering estimate of when gel will occur during the cure cycle of a thermosetting resin. This simple analytical model provides a quick result that appears to be equivalent to similar results obtained with much more complicated computer programs. The replacement of the Arrhenius activation energy with the reaction release energy in the relationship between the isothermal temperature and the time to reach gel significantly contributed to the simple analytical solution that was able to be developed in this study.Resins used in both autoclave processing and Vacuum Assisted Resin Transfer Molding (VARTM) processing were evaluated in this study. It was found that the calculated Dynamic Gel Temperatures were much higher and the calculated Dynamic Gel Times were much longer for the autoclave resins than for the VARTM resins at the same heating rate. The VARTM resins also appeared to be more exothermic on a relative scale than the autoclave resins.Several multiple step cure cycles were evaluated for two Hercules resins. In general the agreement between the measured and calculated Dynamic Gel Temperatures was very good. In addition, two cure cycles for Hexcel F-263 composites were calculated and autoclave evaluated for dynamic gel time and the resulting mechanical properties. For Cure Cycle I the autoclave pressure was not applied until after dynamic gel had been reached. For Cure Cycle II the dynamic gel was achieved after the pressure was introduced into the autoclave. The short beam shear strength Cure Cycle I was nearly one-half the strength of the composite generated with Cure Cycle II. In addition, the void content of the composite for Cure Cycle I was approximately four times higher than the composite for Cure Cycle II.This study has clearly shown that if the time-temperature history of a cure cycle is known, then the dynamic gel analysis developed in this study should be able to predict when a particular resin formulation will gel. The importance of the correct prediction of when the gel time occurs in a cure cycle was also clearly shown.

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Section: Comparison Of the Temperature Influence On The Gel Time Usinmentioning

confidence: 99%

Simplified Modeling of the Dynamic Gel Time and/or the Dynamic Gel Temperature for a Thermosetting Resin or Composite

Sudduth¹

2003

Journal of Composite Materials

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“…Besides, the curing reaction is a very complicated process that is affected by many different things, such as weather, humidity, storage conditions and so on [4]. Cook et al [5] stated that, decreasing gel time in a reciprocal fashion and increased rate of polymerisation of an unsaturated polyester resin may be due to increasing concentrations of initiator (either MEKP or acetyl acetone peroxide)…”

Section: Introductionmentioning

confidence: 99%

Curing behaviour of unsaturated polyester resin and interfacial shear stress of sugar palm fibre

et al. 2017

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Studies on the effect of cobalt of unsaturated polyester resin and the effect of treated sugar palm fibre with sodium hydroxide on single fibre strength and interfacial shear strength (IFSS) are presented in this paper. 1% of methyl ethyl ketone peroxide was used as the initiator, while cobalt of variable percentages (0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8% and 1%) was used as the hardener. The effects on glass transition and exothermic reaction of unsaturated polyester were studied for post curing temperature determination using differential scanning calorimetry by heating the samples at 10ºC/min heating rate from 30ºC to 120ºC with flowing of purge nitrogen gas atmosphere. For the single fibre test and IFSS, the treatment was carried out using sodium hydroxide solution with 1% concentration for one hour soaking time. Based on the optimisation percentage of cobalt, it was found that the higher the percentage of cobalt, the faster the sample tested to gel and cured. Treated sugar palm fibre exhibited better single fibre strength and IFSS between the matrices compared to untreated fibre due to the effectiveness of the alkali treatment. This can be attributed to the rearrangement of fibrils along the direction of tensile force and the removal of the coating layer and impurities after the alkaline treatment.

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“…Styrene is usually incorporated into the coating formulations as a reactive diluent to increase the crosslink density, reduce viscosity, and decrease cost. 3 There are two methods to cure UPEs: conventionally by initiation with an organic peroxide 4 and photochemically by using a photoinitiator. 5 Conventional curing can be performed at ambient temperature via a metal salt catalyst.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the properties of UV-curing acrylate-terminated unsaturated polyester coatings by utilizing an experimental design methodology

Nebioglu

Soucek

2007

J Coat Technol Res

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The effect of the extent of internal unsaturation and branching on the properties of the acrylated polyester films was investigated. Polyester acrylate resins were prepared based on adipic acid, maleic anhydride, neopentyl glycol, trimethylolpropane, and acrylic acid. As the reactive diluent, trimethylolpropane triacrylate (TMPTA) was used. Experiments were planned according to the threefactor, three-level Box-Behnken design. Coating film properties were evaluated in terms of the independent variables, amount of branching, internal unsaturation, and reactive diluent.

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Control of gel time and exotherm behaviour during cure of unsaturated polyester resins

Cited by 38 publications

References 11 publications

Simplified Modeling of the Dynamic Gel Time and/or the Dynamic Gel Temperature for a Thermosetting Resin or Composite

Simplified Modeling of the Dynamic Gel Time and/or the Dynamic Gel Temperature for a Thermosetting Resin or Composite

Curing behaviour of unsaturated polyester resin and interfacial shear stress of sugar palm fibre

Investigation of the properties of UV-curing acrylate-terminated unsaturated polyester coatings by utilizing an experimental design methodology

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