Huiyuan Zhang,Hongxing Zhang,Wenchao Zhu,Hailing Xi,Bomou Ma,Yong He
Strippable film is effective for removing radioactive contamination. However, it still has some limitations, such as the long curing time (about 30 min~24 h) and the requirement of organic solvents. To address these issues, we report a simple protocol to prepare strippable decontamination films using liquid polybutadiene (LPB) and tert-butyl acrylate (TBA) as the raw materials without solvent and using camphorquinone/ethyl 4-dimethylaminobenzoate (CQ/EDB) as a photoinitiator, where the film was formed under household LED panel light or daylight irradiation for about 540 s. After a thorough study of viscosity, real-time Fourier transform infrared (RT-FTIR spectra), gel and volatile organic compound (VOC) contents, mechanical properties and decontamination efficiency, the optimum composition and curing conditions were determined for the decontamination strippable film. VOC content is as low as 12.7 ± 0.7% and the resultant strippable film exhibits good mechanical performances with a tensile strength of up to 5.4 ± 0.4 MPa and elongation of up to 66.6 ± 13%. Most important, the decontamination efficiencies of this strippable film for133CsCl on glass, ceramic and metal surfaces reach up to 98.1%, 94.3% and 97.6%, respectively.Keywords:visible light curing;strippable film;radioactive decontamination
Huiyuan Zhang,Hongxing Zhang,Wenchao Zhu,Hailing Xi,Bomou Ma,Yong He
In this research, solutions of styrene-butadiene-styrene block copolymer (SBS) in 2-ethoxyethyl methacrylate (EOEMA) were used to prepare strippable films via rapid visible-light curing, where the mixture of camphorquinone (CQ), diphenylsilane (DPS) and diphenyliodonium hexafluorophosphate (Iod) was employed as the photoinitiating system, LED@405 nm, sunlight or household LED panel light as the light source and no any solvent was involved. The double bond conversion for pure EOEMA under LED@405 nm was firstly monitored by real-time FTIR and it reached 72% within 300 s. The rapid-curing of SBS/EOEMA solutions were systematically investigated and it was found that the solution with 16 wt% SBS became completely dried at the presence of 2.16 mol% crosslinker and 3.6 wt% photoinitiating system after 240 s irradiation under LED@405 nm. The tensile strength , elongation at break and glass transition temperature of the resultant strippable film were determined to be about 4.4 ± 0.5 MPa, 130 ± 11.2% and 6.9 °C, respectively, by mechanical properties testing and DSC measurements. Also, the decontamination efficiencies (DE) of household LED panel light/sunlight cured-strippable film for uranium nitrate on stainless steel , glass, and ceramic surface were evaluated to be higher than 90%. These results indicate that this rapid-curing strippable films would be a good candidate material for large-scale radioactive decontamination.
Strippable film decontamination is critical for removing radioactive surface contamination during nuclear facility decommissioning and accident response. However, the conventional detergents perform poorly in film formation, freeze easily, and are hard to spray at low temperatures (below 0 °C). In this study, a novel ethyl cellulose-g-polyacrylate (EC-g-PA) detergent was successfully synthesized via benzoyl peroxide (BPO) initiated free-radical polymerization of ethyl cellulose (EC), methyl methacrylate (MMA), butyl acrylate (BA), ethyl methacrylate (EMA), and 2-ethylhexyl acrylate (2-EHA). The synthesized EC-g-PA was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). The film-forming and rheological properties of EC-g-PA detergents at low temperatures were systematically investigated and the mechanical properties of the EC-g-PA film were tested. Moreover, the decontamination efficiency of the EC-g-PA detergent on various plates within the temperature range from −10 °C to 25 °C was also investigated. The results demonstrate that the EC-g-PA detergent exhibits excellent low-temperature fluidity (below 0 °C) and colloidal stability. Notably, it demonstrates rapid film formation and complete peelability within 12 h under subzero conditions. The contamination decontamination rate (CDR) exceeds 90% on ceramic tiles (CT), glass (G), stainless steel (SS), and marble (M), while achieving 78.30% on concrete (C) at 0 °C. These results demonstrate that the EC-g-PA detergent shows significant potential for application in nuclear facility decommissioning and accident response at low temperatures.
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