Ionizing radiation induced curing of epoxy resin for advanced composites matrices

Alessi, Sabina; Calderaro, E.; Parlato, Aldo; Fuochi, P.G.; Lavalle, Marco; Corda, U.; Dispenza, Clelia; Spadaro, G.

doi:10.1016/j.nimb.2005.03.250

Cited by 14 publications

(13 citation statements)

References 5 publications

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“…2a and b) always two relaxation peaks in tan d/T curves can be observed. As already discussed for the same epoxy resin radiation cured in absence of the thermoplastic (Alessi et al, 2005), this is an indication of an ''heterogeneous'' structure, consisting of portions having different crosslinking densities, which relax at two different temperatures. This phenomenon can be related to vitrification effects occurring when the T g of the cured material reaches the processing temperature.…”

Section: Resultssupporting

confidence: 56%

“…In fact, the heating of the irradiated system can be due to both the radiation absorption and the exothermic curing reactions, the resulting temperature being determined by the balance between the heat production rate and the heat delivering rate toward the environment (Alessi et al, 2005). Then the temperature of the irradiated systems strongly depends on the processing conditions, which affect the kinetics of all the phenomena occurring during irradiation.…”

Section: Introductionmentioning

confidence: 99%

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E-beam curing of epoxy-based blends in order to produce high-performance composites

Alessi

Dispenza

Fuochi

et al. 2007

Radiation Physics and Chemistry

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Section: Resultssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

E-beam curing of epoxy-based blends in order to produce high-performance composites

Alessi

Dispenza

Fuochi

et al. 2007

Radiation Physics and Chemistry

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“…This effect prevents a direct knowledge of the network and sometimes leads to artifacts causing a misinterpretation of the results . This is the case for instance of polymeric systems having a wide range of cross‐linking densities, which produce a broad peak or even more than one well‐defined peak in the Tan_δ curve . In fact in these circumstances, it is very difficult to distinguish the real response of the sample to the applied stress from the effect of the thermal treatment on the less cross‐linked parts, that can evolve towards higher cross‐linking density during the thermal test.…”

Section: Introductionmentioning

confidence: 99%

Study of the Curing Process of DGEBA Epoxy Resin Through Structural Investigation

Alessi

Caponetti

Güven

et al. 2015

Macro Chemistry & Physics

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In this work, a multi-scale approach with different analytical methods is applied to study the\ud curing process and the structural properties of a diglycidyl ether of bisphenol A (DGEBA) epoxy\ud resin. This monomer, thermally cured using 4,4′-diaminodiphenilsulfone (DDS) as hardener,\ud is analyzed after 10, 45, 90, and 120 min of reaction time at 180 °C to obtain information on\ud samples with different cross-linking densities. Samples are also characterized after extraction\ud in acetone in order to obtain structural information on the insoluble parts. For this purpose, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), solid-state nuclear magnetic resonance (ss-NMR), and positron annihilation lifetime spectroscopy (PALS) are\ud employed. The importance of this multi-method approach lies in the possibility to obtain a more complete knowledge of the investigated system, overcoming the limits inherent to the use of a single technique, through the correlation among results obtained from different structural investigation\ud methodologies

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“…However, when utilizing high-energy radiation, a careful balance must exist between the two possible simultaneous reactions that may occur, resulting in chain scission and/or cross-linking during irradiation of the polymer network. 11,12 In the last few decades, there have been successful attempts at utilizing both gamma and e-beam radiation for the cure of epoxies and acrylateepoxy systems for use in composite manufacture. 13,14 However, the phenomena involved in radiation degradation of polymers are quite complex and many times lead to varying final results.…”

Section: Introductionmentioning

confidence: 99%

“…However, the literature describes numerous other examples of difunctional epoxies exhibiting degradation as evidenced by decreased Tg temperatures and reduced mechanical performance. [11][12][13][14][15] In this investigation, we have utilized a replicated radiation-cured epoxy composite to manufacture high-quality mirrors. The replicated layer (RL) was exposed to varying degrees of radiation using a 60 Co radiation ranging from 0 to 50 Mrad.…”

Section: Introductionmentioning

confidence: 99%

Effect of gamma radiation on the stability of UV replicated composite mirrors

2018

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Composite replicated mirrors are gaining increasing attention for space-based applications due to their lower density, tailorable mechanical properties, and rapid manufacturing times over state-of-the-art glass mirrors. Ultraviolet (UV)-cured mirrors provide a route by which high-quality mirrors can be manufactured at relatively low processing temperatures that minimize residual stresses. The successful utilization of these mirrors requires nanometer scale dimensional stability after both thermal cycling and hygrothermal exposure. We investigate the effect of gamma irradiation as a process to improve the stability of UV replicated mirrors. Gamma radiation exposure was shown to increase the cure state of these mirrors as evidenced by an increase in modulus, glass transition temperature, and the thermal degradation behavior with dosage. Gas chromatography-mass spectroscopy also showed evidence of consumption of the primary monomers and initiation of the photosensitive agent with gamma exposure. The gamma-exposed mirrors exhibited significant improvement in stability even after multiple thermal cycling in comparison with nonirradiated composite mirrors. Though improvements in the cure state contribute to the overall stability, the radiation dosage was also shown to reduce the film stress of the mirror by over 80% as evidenced using Stoney replicated specimens. This reduction in residual stress is encouraging considering the utilization of these structures for space applications. This paper shows that replicated composite mirrors are a viable alternative to conventional optical structures. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Ionizing radiation induced curing of epoxy resin for advanced composites matrices

Cited by 14 publications

References 5 publications

E-beam curing of epoxy-based blends in order to produce high-performance composites

E-beam curing of epoxy-based blends in order to produce high-performance composites

Study of the Curing Process of DGEBA Epoxy Resin Through Structural Investigation

Effect of gamma radiation on the stability of UV replicated composite mirrors

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