Epoxy/amine reactive systems for composites materials and their thermomechanical properties

Tcharkhtchi, Abbas; Nony, Fabien; Khelladi, Sofiane; Fitoussi, Joseph; Farzaneh, Sedigheh

doi:10.1016/b978-1-78242-307-2.00013-0

Cited by 19 publications

(18 citation statements)

References 70 publications

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“…560 μL of this mixture was then transferred to the rheometer using an Eppendorf pipette. The gel point was calculated from the intersection of the G ’ and G ’’ curves (determined graphically from recorded data) [ 29 , 30 ], by adding the stirring and transfer time. Details for the determination of the gel points can be found in Table S2 in the Supporting Information .…”

Section: Methodsmentioning

confidence: 99%

Multivalent Allylammonium-Based Cross-Linkers for the Synthesis of Homogeneous, Highly Swelling Diallyldimethylammonium Chloride Hydrogels

Mrohs

Weichold

2022

Gels

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N,N’-methylenebisacrylamide (BIS) is a very popular cross-linker for the radical polymerisation in water. It is highly reactive but prone to alkaline hydrolysis and suffers from a low solubility. This study shows that with slow polymerising systems such as N,N-diallyldimethylammonium chloride, only inhomogeneous networks are formed. As a consequence, gels with very low cross-linking densities, i.e., high swelling capacities, disintegrate during the swelling test and firm, coherent gels are not accessible due to the solubility limit. A promising alternative are multivalent tetraallyl-based compounds, of which tetraallylammonium bromide (TAAB), N,N,N’,N’-tetraallylpiperazinium dibromide (TAPB) and N,N,N’,N’-tetraallyltrimethylene dipiperidine dibromide (TAMPB) are the subject of this study. With these, the cross-linking polymerisation appears to be statistical, as gels formed at low monomer conversion have essentially the same swelling properties as those formed at high conversions. This is not observed with BIS. However, gelation with the tetraallyl cross-linkers is much slower than with BIS and follows the order TAPB < TAMPB < TAAB, but the differences become significantly smaller with increasing content. At low contents, all three allow the preparation of gels with high swelling capacities of up to 360 g/g.

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Section: Methodsmentioning

confidence: 99%

Multivalent Allylammonium-Based Cross-Linkers for the Synthesis of Homogeneous, Highly Swelling Diallyldimethylammonium Chloride Hydrogels

Mrohs

Weichold

2022

Gels

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“…Additionally, the gelation time (s), which was defined as the time at which the storage modulus (G′) reached a similar value to the loss modulus (G″), was also recorded. The gelation time or gel point represents the time when the material transformed from fluid-like behavior to solid-like or elastic behavior [ 24 , 25 ].…”

Section: Methodsmentioning

confidence: 99%

Rheological Properties, Surface Microhardness, and Dentin Shear Bond Strength of Resin-Modified Glass Ionomer Cements Containing Methacrylate-Functionalized Polyacids and Spherical Pre-Reacted Glass Fillers

Thepveera

Potiprapanpong

Toneluck

et al. 2021

JFB

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The aim of this study was to prepare experimental resin-modified glass ionomer cements (RMGICs) containing low levels of hydroxyethyl methacrylate (HEMA) for pulp protection. Liquid and powder phases of the experimental RMGICs were polyacid functionalized with methacrylate groups and spherical pre-reacted glass fillers (SPG). Two types of liquid phase containing 0 wt. % HEMA (CM liquid) or 5 wt. % HEMA (CMH liquid) were formulated. The experimental RMGICs were prepared by mixing SPG fillers with CM liquid (F1) or CMH liquid (F2). Rheological properties were examined using a strain-controlled rheometer (n = 5). The Vickers microhardness (n = 5) and dentin shear bond strength (SBS) (n = 10) of the materials were tested. Commercial pulp protection materials (Vitrebond and TheraCal LC) were used as comparisons. The viscosity and surface microhardness of F1 (22 m Pa·s, 18 VHN) and F2 (18 m Pa·s, 16 VHN) were significantly higher than those of Vitrebond (6 mPa·s, 6 VHN) and TheraCal (0.1 mPa·s, 7 VHN). The SBS of F1 (10.7 MPa) and F2 (11.9 MPa) was comparable to that of Vitrebond (15.4 MPa) but higher than that of TheraCal LC (5.6 MPa). The addition of 5 wt. % HEMA showed no significant effect on viscosity, surface microhardness, or SBS of the experimental RMGICs. The experimental materials showed higher viscosity and microhardness but similar SBS when compared with the commercial RMGIC.

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“…Therefore, deep knowledge about how composites and their polymer matrices change their properties during application over time and under the influence of water, moisture, and different temperatures is required. Numerous studies have already dealt with the durability in case of water absorption (Gagani et al, 2019;Humeau et al, 2018) or various operating temperatures in the past (Kraus and Trappe, 2021;Tcharkhtchi et al, 2015). Most of them have in common that, due to slow diffusion rates at moderate ambient temperatures, they rely on accelerated aging processes at elevated temperatures for prediction of property development (Ilioni et al, 2019;Bordes et al, 2009;Jaksic et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Hygrothermal Aging History of Amine-Epoxy Resins: Effects on Thermo-Mechanical Properties

et al. 2022

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Epoxy systems are widely used as matrix resins for fiber reinforced polymers (FRP) and, therefore, often have to withstand harsh environmental conditions. Especially in marine and offshore environments, moisture or direct water contact leads to water absorption into the epoxy resin. As a result, the mechanical properties change during application. Since diffusion at room or colder temperatures is slow, industry and academia typically use accelerated aging methods at elevated temperatures for durability prediction. However, as the water-polymer interaction is a complex combination of plasticization, physical aging, and molecular interaction, all of these mechanisms are expected to be affected by the ambient temperature. To reveal the impact of aging time and temperature on the thermo-mechanical properties of an amine-epoxy system, this publication includes various hygrothermal aging conditions, like water bath and relative humidity aging at temperatures ranging from 8°C to 70°C and relative humidity from 20% to 90%. Thus, it is demonstrated via long-term aging, DMTA and FTIR investigations that, e.g., strength, stiffness, strain to failure, and the glass transition temperature (Tg) can differ significantly depending on aging time and temperature. For example, it can be shown that water absorption at cold temperatures leads to the strongest and longest-lasting reduction in strength, although the maximum water absorption amount is lower than at higher temperatures. For the application, this means that strength differences of up to 26% can be obtained, depending on the aging method selected. Furthermore, it can be shown that conventional prediction models, such as Eyring correlation, which consider the mobility of the molecular structure for the prediction of thermo-mechanical properties, can only be used to a limited extent for prediction in hygrothermal aging. The reasons for this are seen to be, in particular, the different characteristics of the water-polymer interactions depending on the aging temperature. While plasticization dominates in cold conditions, relaxation and strong water-molecule bonds predominate in warm conditions.

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Epoxy/amine reactive systems for composites materials and their thermomechanical properties

Abstract: Advances in Composites Manufacturing and Process Design. http://dx.

Cited by 19 publications

References 70 publications

Multivalent Allylammonium-Based Cross-Linkers for the Synthesis of Homogeneous, Highly Swelling Diallyldimethylammonium Chloride Hydrogels

Multivalent Allylammonium-Based Cross-Linkers for the Synthesis of Homogeneous, Highly Swelling Diallyldimethylammonium Chloride Hydrogels

Rheological Properties, Surface Microhardness, and Dentin Shear Bond Strength of Resin-Modified Glass Ionomer Cements Containing Methacrylate-Functionalized Polyacids and Spherical Pre-Reacted Glass Fillers

Hygrothermal Aging History of Amine-Epoxy Resins: Effects on Thermo-Mechanical Properties

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