Introduction to Epoxy Composites

Pulikkalparambil, Harikrishnan; Siengchin, Suchart

doi:10.1002/9783527824083.ch1

Cited by 13 publications

(7 citation statements)

References 101 publications

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“…Thermosetting epoxy systems are commonly used as a matrix component of carbon fiber-reinforced polymers (CFRPs) due to their high mechanical properties and ease of processing . However, epoxies display inherently brittle behavior with poor crack resistance and low fracture toughness at room temperature. , To overcome these drawbacks, strategies have been developed to successfully enhance the fracture toughness of epoxies. , A strategy to toughen the epoxy resins is the addition of a second microphase (i.e., thermoplastic, rubber, nanofiller, block copolymer, etc.)…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…In particular, when rheological percolation is reached, viscosity of the resin changes to a certain point that the curing is affected. Thus, in highly demanding applications or in composite manufacturing processes where resin viscosity is crucial, e.g., RTM and vacuum infusion, it is necessary to understand the influence that these particles have on the curing process since the final properties of the composite significantly depends on the initial conditions of the resin 5–7 …”

Section: Introductionmentioning

confidence: 99%

“…Thus, in highly demanding applications or in composite manufacturing processes where resin viscosity is crucial, e.g., RTM and vacuum infusion, it is necessary to understand the influence that these particles have on the curing process since the final properties of the composite significantly depends on the initial conditions of the resin. [5][6][7] A poor chemical interaction is a significant obstacle to the effective dispersion of carbonaceous nanoparticles such as GN and CNT in liquids and resins. This is related to the van der Waals forces, that promote their agglomeration, and the polar groups in their structure, that enable hydrogen bonds and yield stable suspensions.…”

Section: Introductionmentioning

confidence: 99%

Rheology, curing and time‐dependent behavior of epoxy/carbon nanoparticles systems

Bianchi,

Cruz,

Paim

et al. 2023

J of Applied Polymer Sci

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This study delved into the characterization of epoxy nanocomposites containing diglycidyl ether of bisphenol‐A (DGBEA), graphene nanoplates (GN), and carbon nanotubes (CNT) across a range of weight percentages (0.05% to 2%). The nanocomposites were produced through a process involving mechanical stirring and ultrasonication. To assess compatibility, three‐dimensional solubility parameters (3DSP) were employed. CNT demonstrated superior compatibility with epoxy and triethylenetetramine (TETA), due to its higher amount of oxygenated species in nanoparticle surface compared to GN. A rheological percolation phenomenon occurred in CNT systems at concentrations above 0.2%, while GN did not display percolation even at 2% concentration. Incorporating nanoparticles led to increased curing enthalpy due to surface functional groups. As the percolation network formed, viscosity rose, and a reduced glass transition temperature (Tg) indicated restricted molecular mobility. Surprisingly, Tg consistently increased by approximately 27°C during composite annealing, regardless of nanoparticle type or concentration. This was attributed to forming a three‐dimensional network structure potentially originating from reactions between nanoparticle‐oxygenated groups and the epoxy matrix. This phenomenon was crucial in heightened creep and irreversible deformations, setting these nanocomposites apart from pure resin behavior.

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“…The epoxy system is a well-known material due to its low processing temperatures, low shrinkage, cost-effective production, good chemical resistance, absence of volatiles, and suitability for mass production. 1 However, epoxy resin systems are vulnerable to ultraviolet damage. 2 The ability to customize the properties of epoxy composites, such as thermal and electrical conductivity, makes them well-suited for various applications.…”

Section: Introductionmentioning

confidence: 99%

Revolutionizing epoxy performance: A new flame retardant with phosphorus and maleimide for enhanced cure behavior, thermal stability, flame retardancy, and mechanical properties

Ranjith,

Mahendran,

Rajkumar

2023

Polymer Engineering & Sci

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A novel phosphorus‐based maleimide, tris[4‐(2,5‐dioxopyrrol‐1‐yl)phenyl] phosphite (TDPPI), was employed as a flame retardant in epoxy with moderate transparency, enhanced thermal stability, and improved mechanical strength. SEM studies ascertained the uniform dispersion of TDPPI and its compatibility with the epoxy. Differential scanning calorimetry showed that the epoxy compounded with 2.5 wt% of TDPPI achieved 100% curing with the glass transition temperature of 43.8°C. The thermogravimetric study revealed that the presence of 2.5 wt% of TDPPI in epoxy increased the residual mass found at 600°C by 23%. The epoxy thermoset compounded with 2.5 wt% of TDPPI passed the Underwriter's Laboratory (UL‐94) test with V‐1 classification and achieved the limiting oxygen index of 30.7% with a reduced burning rate of about 58.7%. At 1.5 wt% of the TDPPI, the resulting epoxy thermoset exhibited an enhancement in the tensile strength (23%), Young's modulus (37%), flexural strength (9%), and Izod impact strength (37%) relative to the neat epoxy. In conclusion, 2.5 wt% of TDPPI is adequate for imparting flame retardancy to epoxy composites with improved mechanical strength because of the maleimide‐phosphorus synergistic effect.Highlights TDPPI is a phosphorus and maleimide containing flame retardant. TDPPI improves thermal stability, flame retardancy and mechanical strengths. Only 2.5 wt% of TDPPI is required for epoxy to achieve high flame retardancy. Maleimide presence lowers phosphorus requirement for epoxy flame retardancy. TDPPI is a promising new flame retardant material for epoxy.

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Introduction to Epoxy Composites

Cited by 13 publications

References 101 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

Rheology, curing and time‐dependent behavior of epoxy/carbon nanoparticles systems

Revolutionizing epoxy performance: A new flame retardant with phosphorus and maleimide for enhanced cure behavior, thermal stability, flame retardancy, and mechanical properties

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Introduction to Epoxy Composites

Cited by 13 publications

References 101 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

Rheology, curing and time‐dependent behavior of epoxy/carbon nanoparticles systems

Revolutionizing epoxy performance: A new flame retardant with phosphorus and maleimide for enhanced cure behavior, thermal stability, flame retardancy, and mechanical properties

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