An overview of viscoelastic phase separation in epoxy based blends

Surendran, Anu; Joy, Jomon; Parameswaranpillai, Jyotishkumar; Anas, S.; Thomas, Sabu

doi:10.1039/c9sm02361e

Cited by 29 publications

(20 citation statements)

References 71 publications

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“…18 This phase inversion is attributed to the viscoelastic phase separation phenomenon, as already observed for different epoxy/thermoplastic blends. 34 The size of these epoxy droplets was observed to decrease gradually toward the pure PEI region due to the increase in PEI content. A similar gradient morphology was observed for the samples cured at higher dwell temperatures (160 and 180 °C).…”

Section: Methodsmentioning

confidence: 96%

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High T_g Epoxy System

Farooq

Heuer

Teuwen

et al. 2021

ACS Appl. Polym. Mater.

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Epoxies are inherently brittle materials and to overcome this brittleness, a second microphase (i.e., thermoplastic) is typically added. This modification of epoxy resin using thermoplastics results in reaction-induced phase separating morphologies in the micrometer range. In this study, the influence of the curing history, beyond phase separation, on the interphase formation and final morphology of PEI and the high T g epoxy system is investigated. Several cure cycles were examined, each with a first dwell temperature ranging from 120 to 180 °C for a given time up to the onset of phase separation (OPS) or up to the 80% degree of cure (80% DOC) and then with a second dwell at 200 °C for 20 min to complete the cure cycle. Hot-stage microscopy experiments were carried out at several first dwell temperatures before final conversion at the second dwell. The morphologies and resulting droplet size distribution at the interphase, after the final cure, were analyzed through scanning electron microscopy. Results showed that the diffusion distance was significantly higher in the case of OPS as compared to the 80% DOC case, particularly at lower first dwell temperatures. This behavior was attributed to the fact that, in the case of OPS, polymeric chains were still in a mobile state and diffused further during the second dwell curing stage, while at 80% DOC, polymeric chains were completely bound but still diffuse due to non-stoichiometric curing. This restricted mobility of polymeric chains after phase separation (80% DOC) resulted in a larger number of smaller droplets as compared to the OPS case.

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Section: Methodsmentioning

confidence: 96%

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High T_g Epoxy System

Farooq

Heuer

Teuwen

et al. 2021

ACS Appl. Polym. Mater.

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“…The toughening by reaction induced phase separation was extensively explored by many researchers. [5][6][7][8] An important strategy that was developed for toughening epoxy resin involved addition of low molecular weight rubbers, [9] thermoplastics, [10,11] block copolymers, [12][13][14] etc. Kim et al [15] explored the morphology development during reaction induced phase separation in epoxy/poly(ether sulfone) (PES) blends.…”

Section: Introductionmentioning

confidence: 99%

“…The toughening by reaction induced phase separation was extensively explored by many researchers. [ 5–8 ] An important strategy that was developed for toughening epoxy resin involved addition of low molecular weight rubbers, [ 9 ] thermoplastics, [ 10,11 ] block copolymers, [ 12–14 ] etc. Kim et al.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Thermal Properties of Epoxy/Poly(Styrene‐co‐Acrylonitrile) (SAN)/Organoclay Nanocomposites

Surendran

Geethamma

Kalarikkal

et al. 2021

Macromolecular Symposia

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This article focuses on the investigations on mechanical and thermal properties of the epoxy/poly(styrene-co-acrylonitrile) (SAN)/cloisite 20A nanocomposites. The analysis is performed in two particular compositions of epoxy/SAN blends to study the effect of nanoclay addition. The compositions of blends, epoxy/5 phr SAN and epoxy/15 phr SAN, are selected based on the difference in phase separation mechanism and microstructure. An increment in tensile strength is observed for epoxy/5 phr SAN/1 wt% cloisite 20A nanocomposite. Young's modulus is increased in epoxy/15 phr SAN/cloisite 20A nanocomposites. A surge in the toughness and impact properties is observed for the nanocomposites. Beneficial increment in activation energy for thermal degradation is observed for epoxy/SAN blends and epoxy/SAN/cloisite 20A nanocomposites. The nanocomposites are suitable for high temperature applications without much compromise in the mechanical properties.

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“…Thermoplastic resins including polysulfone, 22 polyurethane, 23 polyethersulfone, 24 polyetheretherketone, 25 were used as fillers to balance this contradiction. However, in the process of combining thermoplastic resin with epoxy resin, it is difficult to handle solvent residue and polymerization‐induced phase separation 26,27 . Thus, it is still challenging to achieve synergetic improvements of mechanical and thermal properties by simply blending with thermoplastic resins.…”

Section: Introductionmentioning

confidence: 99%

Synergistic improvement of mechanical and thermal properties in epoxy composites via polyimide microspheres

2021

J of Applied Polymer Sci

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Achieving synergetic improvements of mechanical strength, toughness, and thermal stability of epoxy resin has been a crucial but very challenging issue. Herein, to explore a new solution for circumventing this issue, polyimide microspheres were successfully prepared through the inverse nonaqueous emulsion process, and the structure, size distribution and morphologies of polyimide (PI) microspheres were comprehensively investigated. Then the PI microspheres were incorporated in epoxy resin matrix to systematically investigate the mechanical and thermal properties of obtained epoxy/PI microspheres composites. It was found that the PI microspheres can not only enhance the mechanical strength of epoxy resin, but also significantly improve the toughness. Specially, the epoxy‐based composites containing 3 wt% PI microspheres exhibit a 47% increase in tensile strength, while the GIC and Charpy impact strength increase by 106% and 200%, respectively. The toughing mechanism of epoxy/PI microspheres composites was discussed. Moreover, the PI microspheres can also endow the epoxy resin with excellent thermal stability and heat resistance. Thus, this work may open a new opportunity to synergistically enhance the mechanical and thermal properties of epoxy‐based composites and may also give some valuable inspiration for the rational design of other high‐performance thermosetting composites.

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An overview of viscoelastic phase separation in epoxy based blends

Abstract: The viscoelastic effects during reaction induced phase separation play an important role in toughening epoxy-based blends.

Cited by 29 publications

References 71 publications

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High T_g Epoxy System

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High T_g Epoxy System

Mechanical and Thermal Properties of Epoxy/Poly(Styrene‐co‐Acrylonitrile) (SAN)/Organoclay Nanocomposites

Synergistic improvement of mechanical and thermal properties in epoxy composites via polyimide microspheres

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An overview of viscoelastic phase separation in epoxy based blends

Abstract: The viscoelastic effects during reaction induced phase separation play an important role in toughening epoxy-based blends.

Cited by 29 publications

References 71 publications

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High Tg Epoxy System

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High Tg Epoxy System

Mechanical and Thermal Properties of Epoxy/Poly(Styrene‐co‐Acrylonitrile) (SAN)/Organoclay Nanocomposites

Synergistic improvement of mechanical and thermal properties in epoxy composites via polyimide microspheres

Contact Info

Product

Resources

About

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High T_g Epoxy System

Effect of a Dwell Stage in the Cure Cycle on the Interphase Formation in a Poly(ether imide)/High T_g Epoxy System