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Thermoplastic polyurethane is one of the most versatile thermoplastic materials being used in a myriad of industrial and commercial applications. Thermoplastic polyurethane foams are finding new applications in various industries including the furniture, automotive, sportswear, and packaging industries because of their easy processability and desirable customizable properties. In this study, three methods of manufacturing injection molded low density foams were investigated and compared: (1) using chemical blowing agents, (2) using microcellular injection molding with N2 as the blowing agent, and (3) using a combination of supercritical gas-laden pellets injection molding foaming technology and microcellular injection molding processes using co-blowing agents CO2 and N2. Thermal, rheological, microscopic imaging, and mechanical testing were carried out on the molded samples with increasing amounts of blowing agents. The results showed that the use of physical blowing agents yielded softer foams, while the use of CO2 and N2 as co-blowing agents helped to manufacture foams with lower bulk densities, better microstructures, and lower hysteresis loss ratios. Chemical blowing agent-foamed thermoplastic polyurethane showed an earlier onset of degradation. The average cell size decreased and the cell density increased with the use of co-blowing agents. A further increase in gas saturation levels showed a degradation of microstructure by cell coalescence. [ABSTRACT FROM AUTHOR]

While position emission tomography (PET) is an important molecular imaging technique for both preclinical research and clinical disease diagnosis/prognosis, chelator-free radiolabeling has emerged as a promising alternative approach to label biomolecules or nanoprobes in a facile way. Herein, starting from bottom-up synthesized WS 2 nanoflakes, this study fabricates a unique type of WS 2 /WO x nanodots, which can function as inherent hard oxygen donor for stable radiolabeling with Zirconium-89 isotope ( 89 Zr). Upon simply mixing, 89 Zr can be anchored on the surface of polyethylene glycol (PEG) modified WS 2 /WO x (WS 2 /WO x -PEG) nanodots via a chelator-free method with surprisingly high labeling yield and great stability. A higher degree of oxidation in the WS 2 /WO x -PEG sample (WS 2 /WO x (0.4)) produces more electron pairs, which would be beneficial for chelator-free labeling of 89 Zr with higher yields, suggesting the importance of surface chemistry and particle composition to the efficiency of chelator-free radiolabeling. Such 89 Zr-WS 2 /WO x (0.4)-PEG nanodots are found to be an excellent PET contrast agent for in vivo imaging of tumors upon intravenous administration, or mapping of draining lymph nodes after local injection., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)