MSE Seminar: Dr. Mohamad Al-Sheikhly, UMD
Wednesday, December 6, 2023
Room 2108 Chemical and Nuclear Engineering Building
Radiation Graft Polymerization Synthesis of Novel Fabrics for Harvesting Uranium and Lithium Ions, Capturing CO2 From the Atmosphere, and Fabricating Proton Conductive Membranes for High Temperature Fuel Cells
Abstract: Ionizing radiation has become the most effective way to modify natural and synthetic polymers through crosslinking, degradation, and graft polymerization. For decades, low linear energy transfer (LLET) ionizing radiation, such as gamma rays, X-rays, and up to 10 MeV electron beams, has been the primary tool to produce many products through graft polymerization reactions. Over the past decade, grafting new chemical functionalities on polymers by radiation-induced polymerization (also called RIG for Radiation-Induced Grafting) has been widely exploited to develop innovative materials in coherence with actual societal expectations. These novel materials have been used in advanced technologies such as tissue engineering, proton conductive polymers for fuel cells, numerous specific adsorbents and membranes for environmental remediation and harvesting metals ions such as uranium and lithium.
The radiolytically produced C-centered radicals of polymer substrates and vinyl monomers undergo various homopolymerization, copolymerization, and crosslinking reactions. Many parameters influencing RIG that control the yield of the grafting process and the grafting mechanisms such as monomer reactivity, irradiation dose and dose rate, solvent, presence of inhibitor of homopolymerization, grafting temperature, etc. As radiation penetration depths can be varied, this technique can be used to modify polymer surface or bulk. Today, the general knowledge of RIG can be applied to any solid polymer and polymer solutions, and may predict, to some extent, the grafting locations on the backbone of polymer chains.
Bio: Mohamad Al-Sheikhly is a Professor at the Department of Materials Science and Engineering.