Tailored flexibility in inherently brittle epoxy-based composites through gradient interphase formation with bio-based thermoplastic elastomer grades

Zweifel, Lucian; Kupski, J.A.; Brauner, Christian

doi:10.1016/j.compositesa.2023.107679

Cited by 3 publications

(1 citation statement)

References 36 publications

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“…Epoxy resins are widely utilized in various industries due to their excellent processability, high strength, good dielectric properties, and chemical stability. − However, the inherent brittleness of cured epoxy resins, attributed to their highly cross-linked network, has prompted research into effective methods for toughening these resins. − Despite promising results in toughening epoxy resins through the incorporation of second phases such as rubber elastomers, thermoplastic materials, liquid crystal polymers, and block copolymers, the challenge lies in minimizing the reduction in thermal stability and processability as a result of these modifications. − In the context of modifying epoxy resins, researchers have explored the use of hyperbranched polymers as modifiers due to their unique branched topologies, abundant functional terminal groups, and flexible designability. − Various studies have investigated the impact of incorporating hyperbranched polymers into epoxy resins. For instance, Pan et al synthesized an epoxy-terminated hyperbranched polysiloxane (EPTS-12) for toughening epoxy resins through a silylation reaction.…”

Section: Introductionmentioning

confidence: 99%

Designing Schiff-Based Hyperbranched Polysiloxane for Simultaneously Enhancing Epoxy Resin with Mechanical Properties, Thermal Stability, and Recyclability

Li,

Liu,

Zhang

et al. 2024

ACS Appl. Polym. Mater.

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It is indeed challenging to simultaneously enhance the toughness, thermal stability, and recyclability of epoxy resins. This study presents an approach utilizing a hybrid hyperbranched polysiloxane (STHPSi) structure, which incorporates Schiff base structures (comprising two benzene rings bonded to imines), Si–O–Ar (aryl group) segments, and abundant terminal sulfhydryl groups. This structure was employed to fabricate high-quality hybrid epoxy resins (STHPSi/EP). Experimental techniques including universal testing machines, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were utilized to assess the performance of the resulting materials. The incorporation of the STHPSi structure imparted a rigid-flexible nature to the epoxy resins, leading to remarkable mechanical properties. Notably, STHPSi not only significantly improved the impact strength by 59.8% and flexural strength by 20.6% but also contributed to enhanced thermal properties. With a 6 wt % addition of STHPSi, the thermal decomposition temperature at 5% weight loss (T d,5%), glass transition temperature (T g), and char residues of the hybrid resins increased to 351.0 °C, 128.06 °C, and 9.55%, respectively. Furthermore, the STHPSi/EP composites exhibited complete degradation in 1,3-diaminopropane and the degraded substance was successfully reintroduced into the epoxy matrix as a curing agent, facilitating the recycling of waste epoxy resins. The recycled epoxy resins demonstrated excellent mechanical properties, with the impact strength and flexural strength reaching up to 15.3 kJ/m2 and 149.22 MPa, respectively, and interesting luminescent characteristics. This study presents an effective approach for the preparation and reutilization of high-performance epoxy resins, addressing the critical challenges in enhancing their properties and promoting sustainable materials development.

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