Atomistic Modeling of Dual-Cured Thermosets Based on Glycidyl Methacrylate and Hardeners with Various Architecture and Functionality

Abstract

We report a versatile computational procedure for making and testing dual-cured thermosets based on a sequential chain-growth polymerization mechanism and step-growth polymerization mechanism, applicable to the generation of dual-cured thermosets with tunable macroscopic properties. The first stage involves a chain-growth polymerization of glycidyl methacrylate (GMA) monomers in the presence of hardeners, and the second stage is based on the step-growth polymerization of the epoxide bearing side chains of the polymerized GMA, p(GMA), with amine groups of the hardeners with various architecture and functionality, namely diethylenetriamine (DETA), isophoronediamine (IPDA), tris(2-aminoethyl)amine (TREN), and diethyltoluenediamine (DETDA). The mobility of the hardener in the once-cured samples determined the final density of the dual-cured samples. The faster the hardener is in the sample, the higher is the density of the dual-cured sample. Mechanical properties of the dual-cured samples showed a dependence on the architecture of hardener. The samples cured with linear aliphatic amines (DETA and TREN) obtained smaller Young's modulus values compared with the samples cured with cyclic (aliphatic or aromatic) amines (IPDA and DETDA).

A Computational Procedure for Atomistic Modelling of Polyphosphazenes towards Better Capturing Molecular-Level Structuring and Thermo-Mechanical Properties

“…Once the liquid samples were adequately equilibrated via the SA procedure, a homopolymerisation protocol reported in the literature was initiated [ 41 ]. In this protocol, 2% of monomers were randomly selected as initiators through which polymers chains were grown [ 27 , 28 ]. Once 1% of available monomers reacted, the polymerising sample was relaxed via a multi-step relaxation procedure.…”

“…First, the four repeat units ( Figure 1 ) were built, geometry optimised, and used for the calculation of partial atomic charges via the charge equilibration method [ 25 , 26 ]. Second, a simulation cell was generated for each system, and a simulated annealing (SA) procedure was applied to adequately equilibrate the systems [ 27 ]. Third, a chain growth polymerisation procedure [ 28 ] was applied to generate polymer samples.…”