Curing of a thermosetting powder coating by means of DMTA, TMA and DSC

Abstract:In this work, the characterisation of reaction kinetics of a methylene diphenyl diisocyanate (MDI)-based fast curing polyurethane resin (PUR) and the mathematical description of its curing process are presented. For the modelling of the reaction process isoconversional methods, which are also called model-free approaches, are used instead of model-based approaches. One of the main challenges is the characterisation of a reactive system with a short pot life, which already starts to crosslink below room temperature. The main focus is the evaluation of the applicability of isoconversional methods for predicting the reaction kinetics of fast curing polyurethane resins. In order to realise this, a repeatable methodology for the determination of time-and temperature-dependent reaction curves using differential scanning calorimetry (DSC) is defined. The cure models defined by this method serve as the basis for process simulations of PUR processing technologies such as resin transfer moulding (RTM) or reactive injection moulding (RIM) and reactive extrusion (REX). The characterisation of the reaction kinetics using DSC measurements is carried out under isothermal and non-isothermal conditions. Within this work isoconversional methods have been applied successfully to experimentally determined DSC data sets. It is shown that the reaction kinetics of fast curing polyurethane resins can be predicted using this methods. Furthermore, it is demonstrated that the time-dependent change of conversion of the considered polyurethane under isothermal curing conditions can also be predicted using isoconversional methods based on non-isothermal DSC measurements. This results in a significant reduction in the experimental effort required to characterise and model the curing process of polyurethanes.

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“…Some of these kinetic models are listed in Table 1. Other kinetic models can be found in the literature, such as in [26][27][28]. Table 1.…”

Section: Reaction Kinetic Modellingmentioning

confidence: 99%

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Stanko

Stommel

2018

Polymers

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“…Isothermal curing was carried out several times at temperatures between 1108C and 1508C. The degree of shrinkage in TMA was calculated as follows 16 :…”

Section: Thermomechanical Analysismentioning

confidence: 99%

Kinetic study of the curing of mixtures of DGEBA and five‐membered cyclic carbonates with lanthanum triflate as cationic initiator

Cervellera¹,

Ramis²,

Salla³

et al. 2006

J of Applied Polymer Sci

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Mixtures of diglycidylether of bisphenol A (DGEBA) with 1,3-benzodioxolane-2-one (CC) or 4-phenoxymethyl-1,3-dioxolane-2-one (PGEC) were cured in the presence of lanthanum triflate. FTIR/ATR was used to study the evolution of carbonate and epoxide groups to follow the reactive processes that take place during curing. DSC was applied to study the thermal characteristics of the curing process and to determine the glass-transition temperatures of the cured materials. The kinetics of the curing was studied isothermally by means of FTIR and the kinetic model was selected through the isokinetic relationships. DSC experiments were used to study the kinetics in nonisothermal conditions by means of isoconversional procedures and the Coats-Redfern and Criado methodologies. By TMA we could monitor the evolution of the shrinkage during isothermal curing.

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“…Triglycidyl isocyanurate (TGIC) has been a widely used curing agent for the curing of carboxylic acid-functional resins. 1,7,[17][18][19] Besides reaction with carboxylic acids, TGIC can also react with hydroxyl groups and amines. However, its use in Europe is declining because of its toxicity.…”

Section: Introductionmentioning

confidence: 99%

Amorphous polyamide coating resins from sugar-derived monomers

2016

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In this article, the synthesis of bio-based polyamides for powder coating applications and their evaluation in a solventborne coating system are reported. The M n values of the resins were between 3000 and 4000 g mol À1 and the resins displayed T g values from 60 to 80°C. Both amine and carboxylic acid functionalities (total $0.6 mmol g À1 ) were introduced for curing purposes. The resins were cured with triglycidyl isocyanurate (TGIC) or N,N,N¢,N¢-tetrakis(2-hydroxyethyl)adipamide (Primid XL-552). The curing reaction was followed using rheology which indicated that TGIC achieved higher reaction rates and higher gel contents. The DSC analysis of the cured disks showed that all cured samples were amorphous as is desired for the targeted coating application. The resins required a curing temperature higher than 150°C. Aluminum panels were coated using a solventborne approach and the coatings were cured at 180°C during 1 h. Dewetting was observed on all panels. Network formation was adequate for an amine-functional resin cured with TGIC as indicated by solvent resistance testing. In conclusion, the developed biobased polyamide resins are promising materials to be used as binder resins in powder coating applications.

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Curing of a thermosetting powder coating by means of DMTA, TMA and DSC

Cited by 118 publications

References 43 publications

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Kinetic study of the curing of mixtures of DGEBA and five‐membered cyclic carbonates with lanthanum triflate as cationic initiator

Amorphous polyamide coating resins from sugar-derived monomers

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