Effect of Aminosilane Coupling Agents with Different Chain Lengths on Thermo-Mechanical Properties of Cross-Linked Epoxy Resin

Abstract

In this paper, a molecular dynamics simulation method was used to study the thermo-mechanical properties of cross-linked epoxy resins doped with nano silica particles that were grafted with 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-[2-(2-aminoethylamino)ethylamino]-propyl-trimethoxysilane with different chain lengths. Firstly, a set of pure epoxy resin models, and four sets of SiO2/EP composite models were established. Then, a reasonable structure was obtained through a series of optimizations using molecular dynamics calculations. Next, the mechanical properties, hydrogen bond statistics, glass transition temperature, free volume fraction, and chain spacing of the five models were studied comparatively. The results show that doped nano silica particles of surfaces grafted with 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-[2-(2-aminoethylamino)ethylamino]-propyl-trimethoxysilane with different chain lengths enhanced mechanical properties such as elastic modulus, shear modulus, and volume modulus obviously. The glass transition temperature increased by 15–16 K, 40–41 K, and 24–27 K, respectively. Finally, the data show that the cross-linked epoxy resin modified by nanoparticles grafted with N-(2-aminoethyl)-3-aminopropyl trimethoxysilane had better effects for improving thermo-mechanical properties by the comparatively studying the five groups of parameter models under the same conditions.

Effects of Different Grafting Density of Amino Silane Coupling Agents on Thermomechanical Properties of Cross-Linked Epoxy Resin

“…Bisphenol A epoxy resin (DGEBA) and 1,3 benzenediamine (BD) were selected respectively as the monomer and curing agent molecule of epoxy resin in this paper, and an epoxy resin composite model was established by Materials Studio (MS) software [18]. The C atom and N atom in the reaction between the epoxy resin monomer and curing agent molecule are respectively marked as R1 and R2.…”

“…Next, geometric optimization and molecule dynamics running were performed in order to make the established model reach the balance conformation, and finally, the cross-linked reaction was completed by using Perl language. COMPASS was selected as the force field for calculations in all dynamic simulations; Nose and Berendsen were used for temperature control and pressure control, respectively [18].…”

“…Next, geometric optimization and molecule dynamics running were performed in order to make the established model reach the balance conformation, and finally, the cross-linked reaction was completed by using Perl language. COMPASS was selected as the force field for calculations in all dynamic simulations; Nose and Berendsen were used for temperature control and pressure control, respectively [18]. According to the literature [18], the N-(2-aminoethyl)-3-Aminopropyl trimethoxy silane coupling agent was selected to study the influences of the N-(2-aminoethyl)-3-Aminopropyl According to the literature [18], the N-(2-aminoethyl)-3-Aminopropyl trimethoxy silane coupling agent was selected to study the influences of the N-(2-aminoethyl)-3-Aminopropyl trimethoxy silane coupling agent with different grafting densities on the surface of the nano silicon dioxide particle on the thermomechanical performance of cross-linked epoxy resin in the paper.…”

“…According to the literature [ 18 ], the N-(2-aminoethyl)-3-Aminopropyl trimethoxy silane coupling agent was selected to study the influences of the N-(2-aminoethyl)-3-Aminopropyl trimethoxy silane coupling agent with different grafting densities on the surface of the nano silicon dioxide particle on the thermomechanical performance of cross-linked epoxy resin in the paper. The diameter of the nano silicon dioxide particles is 6.6 Å [ 19 ].…”

“…Reference [30] mentioned that the hydrogen bond grid among polymers will greatly affect the mechanical performance and aging resistance of the polymers. The hydrogen bond was defined by using the geometric rule [18] in the paper. The schematic diagram of the hydrogen bond is shown in Figure 7 relation between the temperature and hydrogen bond number at grafting density values of 3%, 6%, 9% and 12% is shown in Figure 8.…”