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Well-aligned, 1D CdSe quantum dot (QD) fibers (0.3µm to 2.5µm) containing up to 20wt% fluorescent quantum dots (QDs) were prepared by near-field electrospinning (NFES) process. Electrospun solutions were prepared using PVAc as the matrix polymer, dimethyl formamide (DMF) solvent and colloidal QDs in chloroform (CHCl 3 ). The diameter of the fibers decreased as the ratio of DMF/CHCl 3 is varied. QDs showed good dispersion and a linear relationship between QD loading and fiber diameter, as determined by the morphology measurements taken using TEM and SEM, respectively. Fluorescence microscopy shows that there is light attenuation throughout the fibers. Results also show that the NFES process may be used as a method to create aligned, 1D fibers of QDs and potentially other nanofibers.

The degradation of polyethylene (PE) from radiation sources with both thermal and nuclear interactions show sensitivities towards oxygen and air. Characterization of the sensitivities in both inert and oxygenated atmospheres can be characterized by thermogravimetric analysis (TGA). Under argon, the thermal degradation of PE follows a random scission pathway that has activation energy of ~229 kJ mol -1 . The activation energy of PE is reduced by ~30% when 1% air is added to the inert argon atmosphere, illustrating the impact of oxygen on the degradation of PE. This effort seeks to diminish degradation of PE waste containment bags and extend their lifetime, thereby, reducing the cost and worker exposure risk. The project evaluated the use of oxygen scavenger nanoparticles to mitigate the deteriorating effects of oxygen on polymer physical properties and reduce polymer degradation. The thermal degradation of PE composites with various additives were tested and two additives showed promising results approaching the activation energy of pristine PE in an inert atmosphere. This activity was sponsored by the EM Office of Technology Development through SRNL's Technical Task Plan SR091701.

In the process of decontaminating and decommissioning (D&D) older nuclear facilities, special precautions must be taken with removable or airborne contamination. One possible strategy utilizes foams and fixatives to affix these loose contaminants. Many foams and fixatives are already commercially available, either generically or sold specifically for D&D. However, due to a lack of revelant testing in a radioactive environment, additional verification is needed to confirm that these products not only affix contamination to their surfaces, but also will function in a D&D environment. Several significant safety factors, including flammability and worker safety, can be analyzed through the process of headspace analysis, a technique that analyzes the off gas formed before or during the curing process of the foam/fixative, usually using gas chromatography-mass spectrometry (GC-MS). This process focuses on the volatile components of a chemical, which move freely between the solid/liquid form within the sample and the gaseous form in the area above the sample (the headspace). Between possibly hot conditions in a D&D situation and heat created in a foaming reaction, the volatility of many chemicals can change, and thus different gasses can be released at different times throughout the reaction. This project focused on analysis of volatile chemicals involved in the process of using foams and fixatives to identify any potential hazardous or flammable compounds. Resources 1: http://www.arl.noaa.gov/faq_ac14.php SRNL-STI-2017-00492 2: http://principia-scientific.org/at-whatconcentration-does-co2-becomes-toxic-to-humans/ Appendix: EP-102 Part A GC-MS Spectrum and TIC* *A m/z threshold of 29 was used for this sample 1.809 minute propylene oxide match 4.710 minute toluene match SRNL-STI-2017-00492 EP-102 Part B GC-MS Spectrum and TIC SRNL-STI-2017-00492 SRNL-STI-2017-00492 EP-102 Curing GC-MS Spectrum and TIC CC Epoxy GC-MS Spectrum and TIC Foam-iT! 8 GC-MS Spectrum and TIC