In-situ cure monitoring of epoxy/graphene nanocomposites by several spectroscopic techniques

Yuste-Sánchez, V.; Santana, Marianella Hernández; Ezquerra, Tiberio A.; Verdejo, Raquel; López–Manchado, Miguel A.

doi:10.1016/j.polymertesting.2019.106114

Cited by 13 publications

(17 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are several measuring methods for observing the curing progress of thermosets: differential scanning calorimetry (DSC), dielectric analysis (DEA), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), [ 1–3 ] and ultrasonics. [ 4 ] Based on the amount of heat released from crosslinking reactions, DSC is a classical method to analyze the relationship among crosslink density, temperature, and time, [ 5–8 ] which is often expressed in an empirical model termed reaction kinetics (Equation 5).…”

Section: Introductionmentioning

confidence: 99%

“…Applications of the DEA technique exist in the polymer field, such as for analyzing relaxation properties that depend on temperature and frequency [ 9–13 ] and for monitoring the curing process in a thermosetting material. [ 3,12–19 ] Changes in dielectric responses, such as dielectric conductivity, dielectric loss, and ion viscosity, are related to the material properties' changes during curing, like glass‐transition temperature, [ 16,18 ] cure reaction onset, and cure end. [ 14 ] The application of DEA for online‐monitoring was reported in the autoclave process [ 14 ] and during the pressing process.…”

Section: Introductionmentioning

confidence: 99%

“…During curing, pure epoxy resin has a similar conductivity as resins with fiber contents between 20% and 40%. [ 19 ] Yuste‐Sanchez et al [ 3 ] have investigated the curing behavior at 80°C and the post‐curing behavior at 140°C of a pure resin and composite using DEA combined with FTIR and Raman spectroscopy. Based on molecular changes, FTIR and Raman spectroscopy were used to determine the crosslink density, which was compared with the degree of crosslinking calculated according to DEA signal (permittivity and dielectric loss).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

In‐situ investigation of dielectric properties and reaction kinetics of a glass‐fiber‐reinforced epoxy composite material using dielectric analysis

Yan

Zeizinger

Merten

et al. 2021

Polymer Engineering & Sci

View full text Add to dashboard Cite

Monitoring the curing behavior of a thermosetting material is a key issue for ensuring a stable manufacturing process (e.g., injection molding). Dielectric analysis (DEA), which is applicable for online‐monitoring, is used to investigate the curing behavior of a glass‐fiber‐reinforced epoxy molding compound. At first, the influences of experimental settings (pressure, temperature, and frequency) on dielectric responses (dielectric loss and ion viscosity) are characterized in a fully crosslinked material. Results show a significant impact of temperature and frequency on dielectric responses. Furthermore, DEA is combined with differential scanning calorimetry (DSC) to investigate dielectric properties depending on crosslink density under non‐isothermal and isothermal conditions. The results show that DEA can detect cure changes only for a crosslink density <80%. Finally, reaction kinetics, which can predict the crosslink density, is derived using DSC and validated through DEA for determining the best suitable kinetic expression for the investigated material. The crosslink density, estimated by reaction kinetics, can be correlated with the dielectric properties.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In‐situ investigation of dielectric properties and reaction kinetics of a glass‐fiber‐reinforced epoxy composite material using dielectric analysis

Yan

Zeizinger

Merten

et al. 2021

Polymer Engineering & Sci

View full text Add to dashboard Cite

show abstract

“…There are several methods that allow us to calculate and optimize cure kinetics in idealized laboratory conditions (Differential Scanning Calorimetry DSC, Dynamical Mechanical Analysis DMA, rheology), but only a few methods are suitable for online cure monitoring: infrared, ultrasonic wave propagation, and Raman and dielectric spectroscopy [ 4 , 5 , 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Online Cure Monitoring and Modelling of Cyanate Ester-Based Composites for High Temperature Applications

et al. 2021

View full text Add to dashboard Cite

A cure kinetics investigation of a high temperature-resistant phenol novolac cyanate ester toughened with polyether sulfone (CE-PES blend) was undertaken using non-isothermal differential scanning calorimetry. Thin ply carbon fiber prepreg, based on the CE-PES formulation, was fabricated, and plates for further in-situ cure monitoring were manufactured using automated fiber placement. Online monitoring of the curing behavior utilizing Optimold sensors and Online Resin State software from Synthesites was carried out. The estimation of the glass transition temperature and degree of cure allowed us to compare real time data with the calculated parameters of the CE-PES formulation. Alongside a good agreement between the observed online data and predicted model, the excellent performance of the developed sensors at temperatures above 260 °C was also demonstrated.

show abstract

“…As documented, the characteristics of the epoxybased composites strongly depend on the curing reactions and the extent of 3D network formation during the curing process [2,[16][17][18][19]. Curing dramatically alters the thermal, physical, and mechanical features of the system depending on the kinetics of the curing process [1,20,21]. The curing process includes a series of complex reactions whose complete investigation requires considering the reactants, curing agent, crosslinkers, catalysts, and products.…”

Section: Introductionmentioning

confidence: 99%

The Curing Kinetics of Multiscale [Ni(EDTA)]-2 Intercalated Zn-Al Layered Double Hydroxides: Glass Fiber–Epoxy Composite Prepreg

Darvishi

Moshkriz

2021

International Journal of Polymer Science

View full text Add to dashboard Cite

In the present research, the effect of Zn2Al layered double hydroxides (LDH) and nickel (II)-EDTA complex intercalated LDH (LDH-[Ni(EDTA)]-2) on the cure kinetics of glass fiber/epoxy prepreg (GEP) was explored using nonisothermal differential scanning calorimetry (DSC). The results showed that LDH caused a shift in the cure temperature toward lower temperatures while accelerating the curing of epoxy prepregs. The use of LDH-[Ni(EDTA)]-2 more profoundly influenced the acceleration of the curing process. The curing kinetics of prepregs was assessed through the differential isoconversional Friedman (FR) technique and the integration method of Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS). A decrease was detected in the E α value of glass fiber/LDH-[Ni(EDTA)]-2/epoxy (GELP) and glass fiber/LDH-[Ni(EDTA)]-2/epoxy (GELNiP) prepregs at small cure degrees relative to GEP, suggesting the catalytic effect of LDH or LDH-[Ni(EDTA)]-2 on the initial epoxy/amine reaction. Furthermore, LDH-[Ni(EDTA)]-2 performed better due to the catalyst role of nickel (II). Moreover, the activation energy exhibited lower reliance on the degree of conversion in the cases of GELP and GELNiP rather than pure epoxy prepregs. An autocatalytic model was used to evaluate the curing behavior of the system. Based on the results, the curing reaction of the epoxy prepreg can be described by the autocatalytic Šesták-Berggren model even after the incorporation of LDH or LDH-[Ni(EDTA)]-2. The kinetic parameters of the autocatalytic model (such as E α , A , m , n ) and the equations explaining the curing behavior of prepregs were introduced as well whose predictions were in line with the experimental findings.

show abstract

In-situ cure monitoring of epoxy/graphene nanocomposites by several spectroscopic techniques

Cited by 13 publications

References 34 publications

In‐situ investigation of dielectric properties and reaction kinetics of a glass‐fiber‐reinforced epoxy composite material using dielectric analysis

In‐situ investigation of dielectric properties and reaction kinetics of a glass‐fiber‐reinforced epoxy composite material using dielectric analysis

Online Cure Monitoring and Modelling of Cyanate Ester-Based Composites for High Temperature Applications

The Curing Kinetics of Multiscale [Ni(EDTA)]-2 Intercalated Zn-Al Layered Double Hydroxides: Glass Fiber–Epoxy Composite Prepreg

Contact Info

Product

Resources

About