Synthesis and characterization of interpenetrating polymer networks (IPNs) from acrylated soybean oil α-resorcylic acid: Part 2. Thermo-mechanical properties and linear fracture mechanics

Abstract

The thermo-mechanical properties and linear fracture mechanics of acrylated soybean oil and the triglycidylated ether of α-resorcylic acid interpenetrated networks as a function of their weight composition are the focus of Part 2 of this article. Thermo-mechanical characterization showed that the obtained materials behave as thermoset amorphous polymers, and that both the modulus and glass transition are extremely dependent on the epoxy/acrylate weight ratio. Modulus values ranged from 0.7 to 3.3 GPa at 30 °C, and glass transition temperatures ranged from around 58 °C to approx. 130 °C. No synergistic effect on these two properties was observed. Interpenetrating networks containing equivalent weight proportions of the parent resins showed the highest fracture toughness of the series, exhibiting a KIc value of around 2.1 MPa·m1/2. The results showed that the KIc values did not increase as Mc increased, which seems to suggest that a different mechanism is responsible for the increase in the fracture toughness displayed by IPNs. Also, there seems to be an exponential-type increase in the fracture energy with the Mc1/2 for the materials containing the epoxy phase.