Effect of electron beam irradiation on thermal and mechanical properties of epoxy polymer (original) (raw)
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Journal of Composite Materials, 2012
In this study, epoxy/clay nanocomposites with different content of nanoclay were prepared by shear mixing followed by ultrasonication. In order to study electron beam irradiation effects, nanocomposites were exposed to electron beam irradiation in 100, 500 and 1000 KGy doses. X-ray diffraction and transmission electron microscopy were used to study the morphology of nanocomposites. The mechanical and thermal behaviors of nanocomposites were studied by tensile test and thermo-gravimetric analysis. The results showed that the irradiation brought about improvement in mechanical properties in most specimens and the most improvement was achieved in 100 KGy irradiation doses.
Gamma-irradiation influence on the mechanical and electrical properties of epoxy and nanocomposites
ASAT 20 Conference, 2023
The space environment hazards are becoming harsh as they affect both the mechanical and electrical properties of the polymer-based reinforced fiber materials in spacecraft. The structure materials changes by Gamma-irradiation often deteriorate the epoxy matrix or the epoxy/nano-composite properties. As a result, the effect of gamma irradiation on the mechanical and electrical properties of the selected materials were evaluated. The mechanical properties and electrical resistivity of nanocomposites were studied by a universal testing system (UTS) and Keithley 2635A System Source Meter respectively. Fourier transform infrared (FTIR) functioned to assess the chemical structural variation due to the gamma-ray exposure. Dynamic Mechanical Analysis (DMA) was conducted to obtain the Tan delta, loss and storage modulus of each sample. The result showed enrichment in both the mechanical properties and the electrical conductivity of Epoxy/MWCNT's nanocomposites.
Polymers, 2018
The effects of electron beam irradiation on the properties of ethylene propylene diene monomer (EPDM)/butyl rubber composites in presence of a polyfunctional monomer were investigated by means of differential scanning calorimetry (DSC), thermal analysis, scanning electron microscopy (SEM), attenuated total reflection absorption infrared spectroscopy (ATR-IR), and mechanical and surface energy measurements. The samples were exposed over a wide range of irradiation doses (20-150 kGy). The EPDM matrix was modified with butyl rubber, chlorobutyl rubber, and bromobutyl rubber. The gel content and crosslink density were found to increase with the electron beam irradiation dose. The values of the hardness and modulus increased gradually with the irradiation dose, while the tensile strength and elongation at break decreased with increasing irradiation dose. The EPDM/butyl rubber composites presented a higher thermal stability compared to the initial EPDM sample. The incorporation of butyl rubbers into the EPDM matrix led to an increase in material hydrophobicity. A similar trend was observed when the irradiation dose increased. The greatest change in the surface free energy and the contact angles occurs at an irradiation dose of 20 kGy. The Charlesby-Pinner plots prove the tendency to crosslinking as the irradiation dose increases.
Effect of high gamma irradiation doses on structure and morphology properties for Epoxy resins
Optik, 2021
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Polymer Bulletin, 2012
High volume fraction carbon nanotube (CNT) composites (7.5-16% vol.) were fabricated by the impregnation of CNT buckypapers into epoxy resin. To enhance the interfacial reaction with the epoxy resin, the CNTs were modified by two different treatments, namely, an epoxidation treatment and a chemical oxidation. The chemical treatment was found to result in CNT length severance and to affect the porosity of the buckypapers, having an important impact on the physico-mechanical properties of the nanocomposites. Overall, the mechanical, electrical, and thermal properties of the impregnated buckypapers were found to be superior of the neat epoxy resin, offering an attractive combination of mechanical, electrical, and thermal properties for multifunctional composites.
Degradation of epoxy resins under high energy electron beam irradiation: Radio-oxidation
Polymer Degradation and Stability, 2007
The degradation of two epoxy systems exposed to electron beam irradiation in oxygen atmosphere has been studied and compared to our previous results obtained under helium atmosphere. A multi-scale approach to the degradation has been carried out using a variety of analytical methods including solid state NMR spectroscopy, 2D-WISE experiments, SEC measurements and infrared spectroscopy associated with chemical derivatisation treatments. It is shown that the degradation of both polymers is governed by radiolytic processes which involve chain scissions. The formation of oxidation products, mainly carboxylic acid chain ends, was shown at the surface of the irradiated film. Oxidative degradation is limited to the first 20 mm of the film due to the low oxygen diffusion coefficient in epoxy polymers combined with the high dose rates of irradiation.
Journal of Applied Polymer Science, 2009
Because of the complexity of the electron beam (EB) curing process, current understanding of EB curing of polymer resins and composites is limited. This article describes an investigation of different factors affecting EB curing of epoxy resin such as dose rate, time interval between irradiation doses, moisture, and photoinitiator concentration using a calorimetry technique. Results show that higher dose rate resulted in a higher and faster temperature increment in the uncured resin samples, and thus a higher degree of cure. In the multiple-step EB irradiation, a shorter time interval between irradiation doses resulted in higher temperature in the resin samples and therefore higher degree of cure. Results indicate that moisture could delay crosslinking reaction in the early stages of the cure reaction, but accelerates it later in the curing process. Given a reasonable percentage of photoinitiator, experiments confirmed that samples with higher photoinitiator concentration reach higher degree of cure under same EB irradiation conditions. V
European Polymer Journal, 2001
The eect of irradiation on the tensile and dynamic mechanical properties of ENR50 (ENR: epoxidized natural rubber) was investigated. ENR50 was irradiated using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. The in¯uence of several additives such as trimethylolpropane triacrylate (TMPTA), Irganox1010 and tribasic lead sulfate (TBLS) on the irradiation-induced changes of ENR50 was investigated. The general improvement on the tensile, as well as dynamic mechanical properties with irradiation indicates the formation of irradiation-induced crosslinks. An appreciable increase in T g is observed with irradiation while the enhancement in stress at break is found to be marginal. This observation agrees well with the relatively small increase in storage modulus occurred beyond the T g of the irradiated ENR. This in return reveals that only a small degree of crosslinking is achieved through irradiation. Based on these factors it can be inferred that the gradual increase in T g upon irradiation of ENR50 could be associated with the occurrence of irradiation-induced ring opening side chain reaction of the oxirane group and irradiationinduced oxidation at the cis double bond along with the irradiation-induced crosslinking. From the observation in the properties studied it con®rms that TMPTA is ecient in enhancing the irradiation-induced crosslinking of ENR50. The addition of Irganox1010 and TBLS are found to impart considerable stability to ENR50, although the antioxidant did cause some inhibition of crosslinking. The acceleration of crosslinking by the TMPTA as well as the inhibition of crosslinking the added stabilizing additives were further con®rmed by using gel fraction data. However, the studies did not reveal the exact nature of irradiation-induced reactions involved in ENR. Ó
2009
In the present work, the changes in physicochemical, morphological and thermal properties of electron-beam irradiated ethylene–vinyl alcohol copolymer (EVOH) resin and EVOH resin reinforced with piassava (Attalea funifera Mart) fiber, as a function of radiation dose, were investigated. The materials were irradiated up to 90 kGy using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. The changes in properties of the EVOH and of the reinforced EVOH, after irradiation, were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and sol-gel analysis. The correlation between the properties of the EVOH and of the EVOH-piassava, both irradiated and non-irradiated samples, were discussed. The results showed that there were no significant differences (p < 0.05) in the enthalpy, crystallinity percentage variation and initial degradation temperature of the non-irradiated and irradiated EVOH....