Comparison of Glass-Transition Temperatures for Epoxy Polymers Obtained by Methods of Thermal Analysis

Старцев, О. В.; Vapirov, Yu. M.; Лебедев, М. П.; Кычкин, А. К.

doi:10.1007/s11029-020-09875-5

Cited by 29 publications

(17 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Under reasonable test parameters, including a frequently used standard frequency of 1 Hz and a heating rate of 3°C/min, the DMA T g obtained trends higher than the values obtained by DSC 25 . When the frequency and heating rate are significantly reduced, the DMA results appear to provide similar values to those obtained from DSC 12–13,26–27 . The frequency and heating dependence of DMA data found in previous studies is further explored here.…”

Section: Resultssupporting

confidence: 75%

“…25 When the frequency and heating rate are significantly reduced, the DMA results appear to provide similar values to those obtained from DSC. [12][13][26][27] The frequency and heating dependence of DMA data found in previous studies is further explored here. However, changing these test parameters in order to achieve identical T g values in DMA and DSC is not always practical because it leads to long measurement times and poor data quality, which is demonstrated and discussed below.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Deeper insights into the thermal properties of epoxy thermoset resins using torsion measurements

Smith

Lazzara

Fernando

2021

J of Applied Polymer Sci

View full text Add to dashboard Cite

The glass transition temperature (T g ) of epoxy thermosets is a critical material property that depends on the component chemistry, the final cross-link density, and processing conditions. This study incorporates dynamic mechanical analysis (DMA) testing with a torsion clamp geometry on a TA Instruments DHR-2 and differential scanning calorimetry (DSC) to characterize five different two-component epoxy-amine systems. Investigation of the T g dependence on DMA frequency and heating shows that lowering the frequency from 1 to 0.01 Hz results in a T g very similar to that measured using DSC, while a heating rate of 0.3 C/min using DMA gives a T g comparable to the DSC measured value at 30 C/min. The DMA technique reveals secondary relaxation transitions and peak broadening in the tan(δ) plots of poorly mixed epoxy blends, quantified using full width at half maximum (FWHM) of tan(δ) peaks, and are indicative of a non-homogeneous cross-linked network and off-ratio blending, respectively. The increase in the FWHM due to poor mixing ranges from 8% to 96%. These parameters are easily measurable and quantifiable in DMA, but are not observed in DSC. The additional DMA insights are valuable for process development and failure analysis, and can improve the understanding of epoxies.

show abstract

Section: Resultssupporting

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Deeper insights into the thermal properties of epoxy thermoset resins using torsion measurements

Smith

Lazzara

Fernando

2021

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…The expansion work due to the compound evaporation is typically linked to a loss of heat at relatively low temperatures (usually below the temperature at which true degradation occurs). While epoxy resins are thermosetting materials, they still undergo a slight softening upon heating [ 87 , 88 ]. The endothermic peak shown in all of the plots is indicative of glass transition events, as one does not observe a related peak in the TGA curves, meaning that such an endothermic peak is not associated with mass loss, but rather with the fact that the material has reached a glass transition temperature.…”

Section: Resultsmentioning

confidence: 99%

Fabrication and Thermo-Electro and Mechanical Properties Evaluation of Helical Multiwall Carbon Nanotube-Carbon Fiber/Epoxy Composite Laminates

et al. 2021

View full text Add to dashboard Cite

The development of advanced composite materials has taken center stage because of its advantages over traditional materials. Recently, carbon-based advanced additives have shown promising results in the development of advanced polymer composites. The inter- and intra-laminar fracture toughness in modes I and II, along with the thermal and electrical conductivities, were investigated. The HMWCNTs/epoxy composite was prepared using a multi-dispersion method, followed by uniform coating at the mid-layers of the CF/E prepregs interface using the spray coating technique. Analysis methods, such as double cantilever beam (DCB) and end notched flexure (ENF) tests, were carried out to study the mode I and II fracture toughness. The surface morphology of the composite was analyzed using field emission scanning electron microscopy (FESEM). The DCB test showed that the fracture toughness of the 0.2 wt.% and 0.4 wt.% HMWCNT composite laminates was improved by 39.15% and 115.05%, respectively, compared with the control sample. Furthermore, the ENF test showed that the mode II interlaminar fracture toughness for the composite laminate increased by 50.88% and 190%, respectively. The FESEM morphology results confirmed the HMWCNTs bridging at the fracture zones of the CF/E composite and the improved interlaminar fracture toughness. The thermogravimetric analysis (TGA) results demonstrated a strong intermolecular bonding between the epoxy and HMWCNTs, resulting in an improved thermal stability. Moreover, the differential scanning calorimetry (DSC) results confirmed that the addition of HMWCNT shifted the Tg to a higher temperature. An electrical conductivity study demonstrated that a higher CNT concentration in the composite laminate resulted in a higher conductivity improvement. This study confirmed that the demonstrated dispersion technique could create composite laminates with a strong interfacial bond interaction between the epoxy and HMWCNT, and thus improve their properties.

show abstract

“…The phase transition from glassy to rubbery occurs in the polymer matrix at a temperature of glass transition (Tg) 14 . It is also an indicator of the status of curing of the polymer matrix 15 . The polymer composites subjected to a temperature beyond Tg remarkably reduced their strength, stiffness, fracture toughness.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical Properties of Carbon Fabric Reinforced Epoxy Laminates with h-BN and MoS2 Fillers

et al. 2021

View full text Add to dashboard Cite

Comparison of Glass-Transition Temperatures for Epoxy Polymers Obtained by Methods of Thermal Analysis

Cited by 29 publications

References 59 publications

Deeper insights into the thermal properties of epoxy thermoset resins using torsion measurements

Deeper insights into the thermal properties of epoxy thermoset resins using torsion measurements

Fabrication and Thermo-Electro and Mechanical Properties Evaluation of Helical Multiwall Carbon Nanotube-Carbon Fiber/Epoxy Composite Laminates

Thermomechanical Properties of Carbon Fabric Reinforced Epoxy Laminates with h-BN and MoS2 Fillers

Contact Info

Product

Resources

About