Aliphatic polyester block polymers that behave as thermoplastic elastomers can be prepared from straightforward sequential ring-opening transesterification polymerizations of cyclic esters. Poly(lactide) is an attractive hard block for these materials because of its ready availability, renewable origins, relatively high glass transition temperature, ability to crystallize in the isotactic form, and the capacity to be industrially composted. We have focused our work on the development of suitable low glass transition temperature, non-crystalline, soft midblocks that can also be synthesized from renewable resources and that are compostable. To that end, we have focused our attention on poly(4-methyl caprolactone). The monomer, 4-methyl caprolactone, can be prepared from cresols, which in turn can come from renewable lignin, in an economical manner and the corresponding polymer is industrially compostable. In this presentation I will discuss our recent efforts to prepare block polymers from these hard and soft components and focus on architecture control (e.g., triblocks, star blocks, and graft blocks), the influence of tacticity in the poly(lactide) segments, the ultimate properties of these thermoplastic elastomers, and the environmental fate in soils and compost.
Marc Hillmyer received his B.S. in Chemistry from the University of Florida in 1989 and his Ph.D. in Chemistry from the California Institute of Technology in 1994. After completing a postdoctoral research position in the University of Minnesota’s Department of Chemical Engineering and Materials Science he joined the Chemistry faculty at Minnesota in 1997. He is currently the McKnight Presidential Endowed Chair in Chemistry and leads a research group focused on the synthesis and self-assembly of multifunctional polymers. In addition to his teaching and research responsibilities, Marc served as an associate editor for the ACS journal Macromolecules from 2008-2017 and is currently the editor-in-chief of Macromolecules. He is also the director of the Center for Sustainable Polymers headquartered at the University of Minnesota, a National Science Foundation Center for Chemical Innovation.