Abstracts Chemistry

Studies in Sustainable Polymers: Strategies for Feedstock Incorporation and Enhanced Polymer Si–O Bond Cleavage

by Ethan Gormong

The development of sustainable polymers is a significant undertaking and is best accomplished using a wide variety of complimentary techniques and chemical approaches. The body of work put forth by the NSF Center for Sustainable Polymers embodies this style of collaborative research, aspects of which will be summarized in Chapter 1. A promising avenue toward sustainable polymers is the development of new monomers derived from renewable carbohydrate resources (Chapter 2). The isohexides, including isosorbide, isomannide, and isoidide, can be readily converted into their corresponding bis-propargyl ethers, which can be polymerized using Cu(I) and Ni(II) catalysts. The resulting diyne polymers can be readily converted to their saturated polyether analogs by catalytic hydrogenation. Sustainable polymers are an excellent avenue to excite the next generation of scientists through chemistry laboratory curriculum. Dibutyl itaconate and -myrcene were copolymerized using two different reaction conditions to produce two polymeric materials with vastly different physical properties, suitable for student analysis (Chapter 3). The introduction of degradable linkages into commercial but environmentally persistent polymers, such as silicones, could be an important step toward sustainability. Though usually robust, the Si–O bonds in the polymer backbone can be activated toward cleavage by the introduction of tethered basic functional groups such as dimethyl amides and amines. The effect of tether length of the cleavage of the alkoxydisiloxanes was studied experimentally by 1H NMR analysis of small-molecule analogs and by computation (Chapter 4). These small-molecule findings are currently being applied to other classes of Si–O bonds (carbodisiloxanes) and to macromolecular systems in ongoing research efforts (Chapter 5).