Gamma-irradiation influence on the mechanical and electrical properties of epoxy and nanocomposites (original) (raw)

Effect of Gamma Radiation on the Physico-Mechanical and Electrical Properties of Jute Fiber-Reinforced Polypropylene Composites

Journal of Reinforced Plastics and Composites, 2008

Hessian cloth (jute fiber)-reinforced polypropylene (PP) composites were prepared by compression molding. The fiber content in the composites was about 50%. The resulting composites and also PP sheets were irradiated under gamma radiation of various total doses (250—1000 krad) at the rate of 600 krad/h. It was found that by using gamma radiation, the mechanical properties of the PP sheets and composites were improved. Gamma radiation dose of 500 krad showed better mechanical properties than that of other doses. Tensile strength and tensile modulus of the PP sheets improved 28% and 26%, respectively, and for composites 16% and 45%, respectively. On the other hand, bending strength and bending modulus of the PP sheet improved 16% and 125%. For composites, bending strength, bending modulus, and impact strength improved 12%, 38%, and 62%, respectively. Water uptake of the composites at 25°C was measured and it was found that treated samples had lower water uptake properties. It was foun...

Degradation of Epoxy–Particles Composites Exposed to UV and Gamma Radiation

Chemistry

In the design and fabrication of any structural system for space application, balance between mass, stiffness and strength is crucial. Structures in space environments are exposed to high radiation levels and thermal shock, due to the sun irradiance and rotation around Earth. Therefore, accurate determination of the thermal and radiation properties is a key issue for the materials used in such applications. This study reports the thermal and mechanical performance of particle composites (epoxy resin and ZnO particles) after gamma and UV radiation. Composites are exposed to gamma and UV radiation at rates of 1 kGy and 10 kGy and characterized after exposure. For the evaluation, DMA, TGA and three-point bending mechanical test are performed to determine thermal properties and possible material degradation after radiation exposure. The incorporation of the filler in the thermal, radiation and mechanical response of the epoxy system improves as a function of its concentration. Then, epo...

RADIATION BEHAVIOUR OF NANOCOMPOSITE EPOXY MATERIAL

Acoperirile epoxy modificate cu dioxid de titan (rutil) şi silice la diferite concentraţii până la 10%, au fost investigate pentru evaluarea rezistivităţii electrice şi modificarea calităţii suprafeţei după expunerea la îmbătrânire accelerată în câmp de radiaţii gamma. Au fost înregistrate schimbările de proprietăţi după iradieri la diferite doze de radiaţii gama (0, 10, 20, şi 50 kGy). Influenţa mediilor de degradare în care se face expunerea la radiaţii a fost realizată în două medii (aer şi apă distilată) la iradieri de energie ridicată, pentru a evalua comparativ, contribuţia produselor de radioliză a apei asupra materialului supus testării.

Some physical behavior of Epoxy/Lead composites for various doses of radiation

The researchers analyzed the possible effect (pause-long and tensile strength) of gamma irradiation on certain physical properties utilizing an Instron Tensile test.. A series of composites has been prepared by adding lead powder and lead shots with different masses to the epoxy resin. The influence of gamma radiation on the traction behavior of the composite's mechanical characteristics given the damage of the radiation-related reactions was analyzed.. The observed results remarks that the changes in the color of epoxy composites, color varied from yellow up to dark brown gradually as a result of different radiation doses effect of radiation exposure to the composites. Gamma radiation's effect on mechanical properties was also studied. Gamma radiation improved the mechanical properties up to a certain level, and then started to decrease.

Effects of Gamma Radiation Doses on the AC Electrical Properties of Epoxy Reinforced with Nano-Silica Composites

Journal of Composites Science

This study reports the effects of gamma radiation on the AC electrical properties of epoxy nano-silica composite sheets with an average thickness of 3 mm. Epoxy reinforced with different nano-silica concentrations of 0, 5, 10, and 15 wt.%. The epoxy nano-silica composites were exposed to different gamma radiation dosages of 1, 3, and 5 kGy. The data were analyzed before and after gamma irradiation and the results showed that the AC electrical properties of the gamma-irradiated epoxy nano-silica composites varied from those of the non-irradiated samples. We found that there were significant changes in the impedance, dielectric constant, dielectric loss, and AC electrical conductivity values of the epoxy nano-silica composites after irradiation, and the AC electrical conductivity and dielectric constant values of the nano-silica composites were enhanced by exposing the samples to gamma radiation because more free electrons were released inside the epoxy nano-silica composites. The AC ...

Influence of electron accelerator irradiation on epoxy nanocomposites materials for spacecraft structure

Arab Journal of Nuclear Sciences and Applications, 2020

a Space Technology Center, Cairo, Egypt b Polymer Chemistry Department, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Cairo, Egypt c Solid State Physics and Accelerators Department, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority (AEA), Cairo, Egypt d Materials Science and Technology Department, Military Technical College (MTC), Cairo, Egypt

Lifetime estimation of epoxy based composite materials on irradiating with gamma radiation for shielding applications

Polymer Testing, 2021

The extensive application of polymer composites in the ionizing radiation conditions leads to durability issues where performance for a long run under the radiation environment is related. For the products, such as space applications; it is expected to have about 20 to 30 years of durability. In the case of polymer composites, the reactive intermediates like free radicals present in the polymers are capable of initiating chemical reactions resulting in scission and cross-linking on irradiation. It may result in the failure of material under the application. In the current work, polymer composites are developed to withstand such chemical reactions prepared by using different fillers and stabilizers and carried out decomposition studies to predict the stability of developed materials under ionizing radiation conditions. The lifetime is estimated by studying decomposition kinetics. The lifetime estimated for all developed samples is found around 20 to 45 years at 50 • C which is desired for a device under the nuclear environment.

Effects of gamma irradiation on resistivity and absorption currents in nanocomposites based on thermoplastic polymers

2013 8TH INTERNATIONAL SYMPOSIUM ON ADVANCED TOPICS IN ELECTRICAL ENGINEERING (ATEE), 2013

The functional characteristics depend strongly on the chemical structure of polymer and on the formulation of material, as well. In the present work, the effects of gamma irradiation at different doses on the resistivity and on the absorption currents in nanocomposites of thermoplastic polymers, such as low density polyethylene (LDPE), polypropylene (PP) and ethylene-propylene-diene monomer rubber (EPDM) are analysed. The influences of the polymer structure as host matrix (LDPE, PP, EPDM) and nanoSiO 2 concentration (between 2 and 5 wt.%) on electrical features are discussed. A correlation between electrical and thermal properties is illustrated for all formulations.

The influence of stabilisers on resistance to gamma radiation for epoxy based polymeric composite material

Composites Part B: Engineering, 2014

In certain applications plastic materials are getting irradiated while in end use. High energy irradiation leads to the auto-oxidation and degradation. The primary approach for stabilization against post irradiation degradation is to use appropriate stabilisers. In this research work, an experimental analysis of the effect of dose rate of gamma irradiation on epoxy resin based samples prepared by using combinations of primary and secondary stabilisers is presented. The chemistry, reaction mechanisms and morphology changes are studied and its effect on mechanical properties is observed. The results show an improvement of mechanical strength as dose increases, indicating cross-linking over oxidative degradation.