Aromatic Hyperbranched Polyester/RTM6 Epoxy Resin for EXTREME Dynamic Loading Aeronautical Applications

Abstract

The effects of the addition of an aromatic hyperbranched polyester (AHBP) on thermal, mechanical, and fracture toughness properties of a thermosetting resin system were investigated. AHBP filler, synthesized by using a bulk poly-condensation reaction, reveals a glassy state at room temperature. Indeed, according to differential scanning calorimetry measurements, the glass transition temperature (Tg) of AHBP is 95 °C. Three different adduct weight percentages were employed to manufacture the AHBP/epoxy samples, respectively, 0.1, 1, and 5 wt%. Dynamical Mechanical Analysis tests revealed that the addition of AHBP induces a negligible variation in terms of conservative modulus, whereas a slight Tg reduction of about 4 °C was observed at 5 wt% of filler content. Fracture toughness results showed an improvement of both critical stress intensity factor (+18%) and critical strain energy release rate (+83%) by adding 5 wt% of AHBP compared to the neat epoxy matrix. Static and dynamic compression tests covering strain rates ranging from 0.0008 to 1000 s−1 revealed a pronounced strain rate sensitivity for all AHBP/epoxy systems. The AHBP composites all showed an increase of the true peak yield compressive strength with the best improvement associated with the sample with 0.1 wt% of AHBP.

Thermal and Mechanical Characterization of an Aeronautical Graded Epoxy Resin Loaded with Hybrid Nanoparticles

“…Great efforts have been made to overcome the epoxy resins drawbacks without sacrificing their original performances: the most common approach consists of the addition of different typologies of fillers [ 4 , 5 ]. In the last few decades, many fillers have been employed as modifiers for epoxy resins, such as inorganic nanoparticles (NPs) [ 6 ], graphene nanoplatelets [ 7 ], rubber NPs [ 8 ], hyperbranched polymers [ 9 ] and CSNPs [ 5 ].…”

Effect of Strain Rate and Silica Filler Content on the Compressive Behavior of RTM6 Epoxy-Based Nanocomposites

“…The high strain rate compression experiments were performed using the split Hopkinson pressure bar (SHPB) facility available at MST-DyMaLab at Ghent University. The details of the setup were explained in previous work [11]. Figure 4 shows a schematic of the SHPB setup used.…”

“…However, because of the high cross-linking density, epoxy resins are generally very brittle with a very low fracture strain and have poor resistance to impact and crack propagation [2]. For this reason, efforts were made to improve the mechanical performance of the epoxy resins by the addition of different types of fillers, such as inorganic particles [3][4][5], elastomer particles [6,7], carbon nanotubes [8,9], hyperbranched polymers [10][11][12] and recently graphene nanoplatelets [2,13]. Compared to other filler types, silica nanoparticles are widely studied as fillers to epoxy resins.…”

A modified peridynamic method to model the fracture behaviour of nanocomposites

“…As a result, improving the fracture resistance of epoxy resin is important, and adding particle materials is one of the promising solutions [3]. According to existing investigations, introducing polylactide [4], graphene oxides [5], nanoparticles [6] and hyperbranched polyester (HBP) [7] to epoxy resin can greatly increase its fracture toughness. In particular, neat epoxy or composites, which contain HBP, show not only outstanding fracture properties [7,8] but also excellent thermal properties along with an increased glass transition temperature.…”

“…According to existing investigations, introducing polylactide [4], graphene oxides [5], nanoparticles [6] and hyperbranched polyester (HBP) [7] to epoxy resin can greatly increase its fracture toughness. In particular, neat epoxy or composites, which contain HBP, show not only outstanding fracture properties [7,8] but also excellent thermal properties along with an increased glass transition temperature. Additionally, HBP particles are also a low-cost option for industrial applications.…”