The Influence of the Molecular Architecture of the Peg: Ppg Triblock Copolymer on the Properties of Epoxy Nanocomposites

Abstract

This work focuses on characterizing the role of different triblock copolymers on the dispersion of nanoparticles in an epoxy matrix and in the thermal and mechanical properties of the resulting nanocomposites, using Poly (ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol) (PEG-b-PPG-b-PEG) with 30% PEG, and poly (propylene glycol) -block-poly (ethylene glycol) -block-poly (propylene glycol) (PPG-b-PEG-b-PPG) with 50% PEG. The nanoparticles employed have different geometries: carbon nanotubes, graphene nanoplatelets and carbon black (spherical). Both copolymers were miscible in epoxy. The results suggest that the copolymers viscosity may be interfering with the dispersion of the nanoparticles in the matrix: the PPG-b-PEG-b-PPG50% copolymer has a higher viscosity than the PEG b-PPG-b-PEG30%, which facilitates their dispersion and an increase in mechanical properties. The PEG fraction was an important factor in the dispersion of nanoparticles in the epoxy matrix. The higher the PEG content in the copolymer block, the greater the synergy shown in the mechanical properties, since the nanoparticles inhibited the plasticizing effect of the block copolymer.

Influence of miscibility of PEG-B-PPG-B-PEG/EPOXY systems on thermal, mechanical and fracture properties

“…Likewise, although the DSC test indicates that the BC58-10 and BC58-20 systems are not completely miscible blends, the copolymer may have selfarranged into nanophases or the microdomains were not discernible by microscopy. Similar results were obtained for this same copolymer but with a curing temperature of 60 °C (Silva et al, 2022b).…”

“…Through the values observed in Table 2, it is notable that adding a higher percentage of copolymer results in a lower glass transition temperature for the epoxy phase (Tg-R), which highlights the behavior of partially miscible material (Putz et al, 2008). Similar results were found in the literature for systems with the addition of block copolymers (Larrañaga et al, 2005;Schuster et al, 2023;Silva et al, 2022b).…”

Amphiphilic Block Copolymer Grafted Multiwalled Carbon Nanotube Based Hierarchical Nanohybrids for Effective Epoxy Toughening

“…The morphology studies of MWCNT- g -TBCP confirm that, similar to GO- g -TBCP, it is also capable of forming different nanostructures in epoxy (Figure ). The formation of hierarchical nanostructures or highly complex molecular architectures is responsible for the enhancement in toughness. , The grafting of TBCP enhances the dispersion of MWCNT well in the epoxy and is capable of forming a wormlike micellar structure. Generally, highly hierarchical nanostructures like wormlike morphologies can enhance the toughness to a great extent. , But in the case of neat and TBCP toughened epoxy, there is no evidence of formation of micellar structures as shown in Figure a,b, but in the graft, there is clear evidence for the formation of nanostructures which might be the reason behind the enhancement in toughness as well as tensile strength (Figure c).…”

“…26 The formation of hierarchical nanostructures or highly complex molecular architectures is responsible for the enhancement in toughness. 38,69 The grafting of TBCP enhances the dispersion of MWCNT well in the epoxy and is capable of forming a wormlike micellar structure. Generally, highly hierarchical nanostructures like wormlike morphologies can enhance the toughness to a great extent.…”

PPG-PEG-PPG/Epoxy systems cured at 100 °C: relationship between miscibility, microstructure, thermal and mechanical properties

“…Still in this context, the addition of the triblock copolymer poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) (PPG-PEG-PPG) can play a fundamental role in the curing kinetics of the mixture and, in thermomechanical properties of the modified material (LARRAÑAGA et al, 2007;SILVA et al, 2022b). However, the incorporation of the copolymer into the matrix causes a reduction in the value of the glass transition temperature (Tg)(SILVA; BELLO; COELHO, 2018).…”