Nanostructured epoxy—rubber network modified with mwcnt and ionic liquid: Electrical, dynamic‐mechanical, and adhesion properties

Soares, Bluma G.; Alves, Fabrício F.

doi:10.1002/pc.24852

Cited by 14 publications

(15 citation statements)

References 60 publications

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“…ER network modified with 5 phr of PBNCO presented an increase of E' rub , suggesting an increase of the CD on the ER networks. This behavior has been also reported for similar system cured with aliphatic amine 26 and confirms the ability of urethane groups in the modified ER in acting as an additional cross-linking agent. Increasing the amount of rubber, the E' rub and CD values decreased, but the values were still higher or similar to the neat ER network.…”

Section: Dynamic Mechanical Propertiessupporting

confidence: 85%

“…Evidences for the reaction between ER and PBNCO have been already reported in our previous work by using Fourier transform infrared analysis and size exclusion chromatography. 8,26 Quan and Ivankovic also observed an increase of Tg by adding core-shell based particles with special functionalized treatment to improve the interaction with epoxy matrix. 34 These results are very interesting from a technological point of view since it is possible to improve toughness without losing the stiffness and keeping good service temperature.…”

Section: Dynamic Mechanical Propertiesmentioning

confidence: 94%

“…According to the previous studies, the formation of block copolymer between ER and PBNCO resulted in a significant increase of the viscosity of the medium. 26 Thus, the cure with anhydride should make easier the processability and minimize the premature curing during the sample preparation. Although Kou et al worked with similar system, they employed a commercial dimer fatty acid diisocyanate to functionalize HTPB, whereas our system employed toluene diisocyanate (TDI).…”

Section: Introductionmentioning

confidence: 99%

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Toughened epoxy‐liquid polybutadiene networks cured with anhydride with outstanding thermal and mechanical properties

Soares

Silva

Lima

et al. 2020

J of Applied Polymer Sci

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Toughened epoxy systems cured with anhydride-based hardener were successfully prepared by incorporating nonpolar liquid polybutadiene (PB) previously functionalized with isocyanate groups (PBNCO). The NCO groups in PBNCO react with the hydroxyl and/or epoxy groups of the matrix forming a ER-PB-ER triblock copolymer. The block copolymer is evidenced by transmission electron microscopy (TEM). In fact the modified epoxy resin (ER) networks presented domains with cocontinuous-like morphology, composed by PB and ER phases in nanomeric dimensions. The effect of PBNCO on the curing process of ER was studied by rheometry. Also the resulting networks were characterized by mechanical and dynamic mechanical properties, differential scanning calorimetry, and TEM. By adding an amount of rubber as high as 20 phr, a great improvement of toughness (around 140%) and impact resistance as well as a good transparency were achieved without significantly affecting the modulus and stiffness. Also the glass transition temperature (Tg) increased around 10 C with the presence of 5 phr of PBNCO. Even with the addition of 20 phr of rubber, the Tg of the system was superior than that found for the neat epoxy network. The outstanding physic-mechanical performance is attributed to the peculiar morphology.

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Section: Dynamic Mechanical Propertiessupporting

confidence: 85%

Section: Dynamic Mechanical Propertiesmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Toughened epoxy‐liquid polybutadiene networks cured with anhydride with outstanding thermal and mechanical properties

Soares

Silva

Lima

et al. 2020

J of Applied Polymer Sci

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“…The work of Soares and Alves showed that both CNT and ionic liquids can accelerate the curing process of an epoxy matrix treated with a polyetheramine, Jeffamine D230. 82 Nanostructuration is due to the covalent interaction between the functionalized rubber and the epoxy resin, resulting in material with outstanding thermo-mechanical and adhesion properties as compared to neat resins. In this work, isocyanatemodified polybutadiene (PBNCO) was first functionalized by reacting the hydroxyl terminated polybutadiene with toluene diisocyanate, in an NCO/OH molar ratio of 2.82 under the catalytic action of dibutyltin dioctoate for 2 hours at 70 C in nitrogen atmosphere.…”

Section: Flexible and Formable Resinsmentioning

confidence: 99%

Multifunctionality in Epoxy Resins

2019

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Epoxy resin will continue to be in the forefront of many thermoset applications due to its versatile properties. However, with advancement in manufacturing, changing societal outlook for the chemical industries and emerging technologies that disrupt conventional approaches to thermoset fabrication, there is a need for a multifunctional epoxy resin that is able to adapt to newer and robust requirements. Epoxy resins that behave both like a thermoplastic and a thermoset resin with better properties are now the norm in research and development. In this paper, we viewed multifunctionality in epoxy resins in terms of other desirable properties such as its toughness and flexibility, rapid curing potential, self-healing ability, reprocessability and recyclability, high temperature stability and conductivity, which other authors failed to recognize. These aspects, when considered in the synthesis and formulation of epoxy resins will be a radical advance for thermosetting polymers, with a lot of applications. Therefore, we present an overview of the recent finding as to pave the way for varied approaches towards multifunctional epoxy resins.

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“…Imidazolium‐based ILs were also employed as additive in epoxy systems cured with conventional hardeners as amines or anhydride to improve the dispersion of carbon nanotube within the epoxy matrix, or reduce the friction coefficient and wear rate of the epoxy coatings . They also were used as additives for the curing process of epoxy resin cured with aromatic amine and also epoxy cured with anhydride…”

Section: Introductionmentioning

confidence: 99%

Epoxy/imidazolium‐based ionic liquid systems: The effect of the hardener on the curing behavior, thermal stability, and microwave absorbing properties

Carvalho

Santos

Soares

2019

J of Applied Polymer Sci

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A new transparent microwave absorbing coating was developed by compounding 1-butyl-3-methyl imidazolium tetrafluoroborate (bmim.BF 4 ) ionic liquid (IL) with diglycidyl ether of bisphenol A-type epoxy resin. The systems were crosslinked with the IL alone or combined with conventional hardeners, as anhydride or aromatic amine. The curing behavior was investigated by thermal and spectroscopic analysis performed at high temperatures. Neat bmim.BF 4 was able to cure epoxy resin, giving rise to networks with outstanding thermal stability compared with the systems cured with anhydride or aromatic amine. bmim.BF 4 accelerated the curing process in the presence of aromatic amine but retarded this event when anhydride was used as an external curing agent. The glass-transition temperature evaluated by dynamic mechanical analysis decreased when the amount of IL increased, which can be attributed to side reactions during the curing process, as well as the plasticizing effect of IL. The epoxy networks cured with bmim.BF 4 alone or in combination with anhydride or aromatic amine were transparent and presented considerable microwave absorbing properties in the X-band frequency range (8-12 GHz), being the best performance observed for the systems cured with bmim.BF4/anhydride curing system, with reflection loss value around −16 dB at 11.3 GHz.

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Nanostructured epoxy—rubber network modified with mwcnt and ionic liquid: Electrical, dynamic‐mechanical, and adhesion properties

Cited by 14 publications

References 60 publications

Toughened epoxy‐liquid polybutadiene networks cured with anhydride with outstanding thermal and mechanical properties

Toughened epoxy‐liquid polybutadiene networks cured with anhydride with outstanding thermal and mechanical properties

Multifunctionality in Epoxy Resins

Epoxy/imidazolium‐based ionic liquid systems: The effect of the hardener on the curing behavior, thermal stability, and microwave absorbing properties

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