l-Arginine as Bio-Based Curing Agent for Epoxy Resins: Temperature-Dependence of Mechanical Properties

Abstract

The precise characterization of new bio-based thermosets is imperative for the correct assessment of their potential as matrix material in fiber-reinforced polymer composites. Therefore, the mechanical properties of diglycidyl ether of bisphenol a (DGEBA) cured with l-arginine were investigated to determine whether the bio-based thermoset possesses the required mechanical properties for application as a matrix material. The cured thermoset is called Argopox. The mixture of amino acid and epoxy resin was prepared via three-roll milling and cured in the presence of an urea-based accelerator. The tensile, compression, flexural and toughness properties of Argopox were characterized at T=−40 ∘C, 22 ∘C and 80 ∘C to determine the temperature-dependence of the thermoset’s mechanical properties in its service temperature range. The glass transition temperature Tg was analyzed via dynamic mechanical analysis (DMA) and is approximately 119 ∘C. The tensile, compression and flexural strength at 22 ∘C are about 56 MPa, 98 MPa and 85 MPa, respectively. The critical stress intensity factor KIC and fracture energy GIC at 22 ∘C are roughly 1.1 MPam0.5 and 510 Jm−, respectively. Consequently, Argopox possesses mechanical properties that reach performance levels similar to that of materials which are already used as matrix for fiber reinforced composites.

Amino Acids as Bio-Based Curing Agents for Epoxy Resin: Correlation of Network Structure and Mechanical Properties

“…In a previous investigation, Rothenhäusler et al [ 18 ] characterized the mechanical properties of DGEBA cured with l -arginine, called Argopox, in the presence of a urea-based accelerator. Here, the thermoset’s was about 119 , which is significantly lower than the of 162 that results from using 2-ethyl-4-methyl-imidazole as accelerator.…”

“…The build-up of internal stresses was prevented by cooling down the molds to room temperature over 4 . This curing cycle was already employed in the previous investigation about epoxy resins cured with amino acids and proved to be effective [ 18 ]. The specimens for dynamic mechanical analysis, compression tests, three-point bending tests, and compact tension tests were prepared with a Mutronic DIADISC5200 diamond plate saw from MUTRONIC Präzisionsgerätebau GmbH & Co. KG (Rieden am Forggensee, Germany) according to the test methods’ standards.…”

“…Rothenhäusler et al [ 18 ] investigated the mechanical behavior of DGEBA cured with l -arginine at T = , 22 , and 80 . Here, the tensile, compression and flexural strength at 22 are about 56 , 98 and 85 , respectively.…”

Curing Regime-Modulating Insulation Performance of Anhydride-Cured Epoxy Resin: A Review

“…Epoxy resin is the general name of a class of compounds that contain two or more epoxy groups in the molecule and can form a three-dimensional cross-linking network structure with the participation of appropriate chemical reagents [ 25 , 26 ]. The epoxy group has high reactivity, which is attributed to the strong deformation ability of the ternary ring and the shift of the charge in the epoxy ring.…”

“…At room temperature, epoxy resin is usually a viscous liquid or brittle solid and only by adding the appropriate chemical agents for cross-linking reaction can insoluble thermosetting resin be formed, which has practical application value [ 25 ]. This kind of chemical agent that can react with epoxy resin is called the curing agent, and this kind of chemical reaction is called the curing reaction.…”