Effect of an Anhydride Excess on the Curing Kinetics and Dynamic Mechanical Properties of Synthetic and Biogenic Epoxy Resins

Altuna, Facundo Ignacio; Riccardi, C. C.; Quintero, Diana Catalina Marin; Ruseckaite, Roxana Alejandra; Stefani, Pablo Marcelo

doi:10.1155/2019/5029153

Cited by 9 publications

(7 citation statements)

References 30 publications

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“…[38] The sudden drop in T g above R = 0.90 might be due to unreacted rosin-based anhydride in the network, which exerts a plasticizing effect and forms pendant chains. [39] The storage modulus G′ stays in the range of 0.97 GPa and 1.15 GPa over the entire range of stoichiometric ratios. The fact that the storage modulus G′ remains approximately the same at T = 30 °C might be because the decreasing network density is compensated by the steric hindrance of unreacted groups in the cured material.…”

Section: Dynamic Mechanical Analysismentioning

confidence: 91%

Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride

Rothenhäusler,

Kettenbach,

Ruckdaeschel

2023

Macro Materials & Eng

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Bio‐based alternatives for petroleum‐based epoxy resin curing agents, such as maleopimaric acid (MPA), are indispensable for sustainable fiber reinforced polymer composites with thermosetting matrices. However, previous investigations disregarded the importance of choosing the right stoichiometric ratio R between the anhydride groups in the rosin‐based curing agent and the epoxy groups in the resin. Therefore, the influence of R on the curing kinetics and mechanical properties of an epoxy resin cured with a rosin‐based anhydride is studied. Here, Fourier‐transform infrared spectroscopy (FT–IR) indicates that for R ⩾ 0.9 unreacted anhydride groups are present in the thermoset. Consequently, the network density decreases and the glass transition temperature Tg drops by about 40 °C. On the other hand, the steric hindrance of unreacted functional groups for R ⩾ 0.9, increases the flexural modulus and the reduced network density improves fracture toughness. The results indicate that the best R for overall high mechanical performance and good processability is preferably low (R ⩽ 0.7). Here, a low R results in a high Tg and good processability due to a low viscosity. However, the latency of the mixtures is low and therefore, the mixtures are not fit for processing via prepreg technology.

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Section: Dynamic Mechanical Analysismentioning

confidence: 91%

Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride

Rothenhäusler,

Kettenbach,

Ruckdaeschel

2023

Macro Materials & Eng

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“…Glass transition values similar to those of the thermosets developed in this study are specified for commercial resins such as Solvay Cycom ® 977-3 (T g = 178-190 • C), Dow Voraforce™ TW 103/TW 158 (T g = 175-185 • C), Henkel Hysol Benzoxazine 99110 (T g = 161-191 • C), Hexcel ® HexPly ® 8552 (T g = 154-200 • C), Park Aerospace Nelco ® N4000-29 (T g = 185 • C), etc. (based on MatWeb database), but also to the TGPh-based resins (T g = 178-211 • C) [11], and superior to DGEVA-based resins (T g = 93-107 • C) synthetized in the previous work [11] or to DGEBA-based resins (T g = 46-155 • C) [35,[47][48][49].…”

Section: Thermomechanical Performances Investigation By Dmamentioning

confidence: 94%

Development of Sustainable High Performance Epoxy Thermosets for Aerospace and Space Applications

Dinu

Lafont

Damiano³

et al. 2022

Polymers

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There is an imperative need to find sustainable ways to produce bisphenol A free, high performance thermosets for specific applications such as the space or aerospace areas. In this study, an aromatic tris epoxide, the tris(4-hydroxyphenyl)methane triglycidyl ether (THPMTGE), was selected to generate high crosslinked networks by its copolymerization with anhydrides. Indeed, the prepared thermosets show a gel content (GC) ~99.9% and glass transition values ranged between 167–196 °C. The thermo-mechanical properties examined by DMA analyses reveal the development of very hard materials with E′ ~3–3.5 GPa. The thermosets’ rigidity was confirmed by Young’s moduli values which ranged between 1.25–1.31 GPa, an elongation at break of about 4–5%, and a tensile stress of ~35–45 MPa. The TGA analyses highlight a very good thermal stability, superior to 340 °C. The Limit Oxygen Index (LOI) parameter was also evaluated, showing the development of new materials with good flame retardancy properties.

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“…Related to the influence of DEH 35 and the curing temperature, at 110 C ESO 87:10 showed α 40% higher than ESO 87:5; at 180 C 87:10 ESO had α = 96.1%, while for 87:5 ESO α = 90.5%. It is reported 40 that the increase in the amine catalyst content induced higher degrees of conversion in thermoset based on epoxidized linseed oil. Increasing the heating rate from 3 to 20 C/min displaced the exothermic peaks to higher temperature, as illustrated in Figure 8 a.…”

Section: Ftir Measurementsmentioning

confidence: 99%

Effect of hardener and catalyst contents on curing and degradation of epoxidized soybean oil

Albuquerque

Almeida

Barreto

et al. 2022

J of Applied Polymer Sci

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Epoxidized soybean oil (ESO) compounds were cured with methyl tetrahydrophthalic anhydride (MTHPA) as hardener and 2,4,6-tris (dimethylaminomethyl) phenol (DEH 35) as catalyst. To figure out MTHPA and DEH 35's influence during curing and degradation, ESO/MTHPA/DEH 35 compounds were investigated using Fourier-Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetry (TG).FTIR spectra of uncured resin showed the secondary interactions among ESO's carbonyl groups with MTHPA and DEH 35's hydroxyls and amines. Curing progress was followed tracking the evolution of reactive groups, that is, epoxy and carbonyl bands and corroborated with released heat of DSC scans. ESO 87:5 and ESO 87:10 compounds cured using higher heating rates presented higher released enthalpy suggesting denser reticulation, and they also displayed lower activation energy E a ð Þ for curing, which was evaluated using the Friedman model. Increasing the hardener and catalysts contents promoted higher thermal stability and lower degradation rates, while higher E a for degradation was verified.

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Effect of an Anhydride Excess on the Curing Kinetics and Dynamic Mechanical Properties of Synthetic and Biogenic Epoxy Resins

Cited by 9 publications

References 30 publications

Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride

Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride

Development of Sustainable High Performance Epoxy Thermosets for Aerospace and Space Applications

Effect of hardener and catalyst contents on curing and degradation of epoxidized soybean oil

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