Thermal stability and gamma ray shielding properties of tungsten borides/epoxy micro-composites. (December 2021)

• Record Type: Journal Article
• Authors: Al Hassan, Mohamadou; Wang, Zhicheng; Liu, Wen-bin; Wang, Jun; Zhigang, Yuan; Khan, Muhammad; Ali, Mohsen M.M.; Geldiyev, Rejep; Diaby, Mahamady; Derradji, Mehdi
• Is Part Of: Radiation physics and chemistry. Volume 189(2021)
• Publication Date: 2021-12
• Subjects: Epoxy E51 -- Tungsten borides -- FTIR spectra -- Thermal stability -- Gamma shielding; Radiation chemistry -- Periodicals; Radiometry -- Periodicals; Radiation -- Periodicals; Chimie sous rayonnement -- Périodiques; 539.2
• DOI: 10.1016/j.radphyschem.2021.109769
• Languages: English
• ISSNs: 0969-806X

Abstract

Abstract: Particle reinforced epoxy matrix composites have recently been intensively prepared and investigated in numerous publications as a promising alternative gamma ray shielding materials. In this work, a DDM (4, 4′-diaminodiphenylmethene) hardener modified by AA (acrylic acid) was used to cure the epoxy resin (E51) at room temperature. To obtain high performance epoxy composites, 30% by weight of tungsten borides WB and WB2 microparticles treated with a KH-560 silane coupling agent were incorporated into the epoxy matrix (EP0) and the composites were coded as EP30WB and EP30WB2, respectively. SEM (scanning electron microscopy) analysis confirmed the good dispersion of these fillers within the polymeric matrix. The structure of the synthesized epoxy matrix and its related composites were characterized using the FTIR (Fourier transform infrared) analysis. According to the FTIR spectra, the epoxy matrix as well as the micro-composites were effectively cured in less than 4 h. This rapid curing process can be justified by the reaction of the epoxy and acrylamide groups as well as the strong reactivity of DDM with AA. The thermal stability of the samples was evaluated by DSC (differential scanning calorimetry) and TGA (thermal gravimetric analysis). DSC analysis revealed that EP30WB2 has a high exothermic peak (166.68 °C) compared to EP30WB (154.48 °C). In addition, the TGA analysis showed that T5% (temperature of 5% weight loss) increased from 207.01 °C for EP0 to 339.65 °C for EP30WB and 346.92 °C for EP30WB2 . Meanwhile, the char yield (Yc) at 800 °C has increased from 23.85% for EP0 to 40.36% for EP30WB and 45.99% for EP30WB2, respectively. Moreover, using a Cs-137 radioactive source, the linear and mass attenuation coefficients ( μ, μ m ), half-value layer ( HVL ), ten-value layer ( TVL ) and radiation protection efficiency ( RPE ) for the epoxy matrix EP0, EP30WB and EP30WB2 micro-composites were experimentally determined. The shielding efficiency for EP0 was 17% and it was improved to 32% and 35% by filling EP0 matrix with WB and WB2, respectively. Highlights: Epoxy matrix and its related micro-composites were cured in less than 4 h. DSC test revealed that EP30WB2 has a high exothermic peak compared to EP30WB. TGA analysis showed that EP30WB2 possess the highest T5% value (346.92 °C). EP30WB2 displayed the maximum value of Yc (45.99%). The RPE for EP0 was 17% and improved to 32% for EP30WB and to 35% for EP30WB2 .