Tailored and Functionalized Polyolefin Structures via Metathesis Polycondensation Chemistry

University Of Florida, Gainesville FL

Investigators

Abstract

Acyclic diene metathesis polymerization will be employed in the pursuit of 4 research objectives: to define structure property relationships in branched polyethylene and related (functionalized) materials, to create a set of "Bio-Olefins" for tissue engineering and other bioapplications, to explore solid state metathesis chemistry, and to continue to expand the catalyst base for this metathesis oriented polycondensation chemistry. Precision synthesis techniques based on ADMET chemistry will be used to create branched polyethylene, where the branch identity and frequency can be controlled in an exact manner. Completely new functionalized versions of polyethylene will be made, and the structure/property relationships of these model ADMET polymers will be examined. Doing so will set clear goals for the generation of useful functionalized polyethylene structures. Collaborations on this aspect of the research are established with two industrial research laboratories in the USA in addition to the University of Pennsylvania and the Max Planck Institute for Polymer Research in Germany. Polyolefins containing amino acid and dipeptide branches have been made via this condensation chemistry, polymers which readily crystallize thus rendering them as durable materials for biomedical applications. Attaching known biologically active peptide sequences to the polyolefin backbone will advance this research. The biological activity of these materials will be examined in collaboration with two separate research groups, one at the University of Florida and the other at MIT; higher order structures within these polymers will be accessed via collaboration with Kyoto University in Japan. Solid-state metathesis polymerization thus far has produced the first known metathesis polycondensation chemistry occurring at room temperature. This facile method of polymer synthesis may prove useful in generating otherwise intractable polymer structures, some of which are conjugated in nature. Collaborations regarding this aspect of the work are in place with the research group at the University of Florida that investigates conjugated polymer systems. The catalyst base for ADMET chemistry will continue at a low level. Metathesis catalyst research, which is being done in several organometallic laboratories around the world, benefits ADMET chemistry; the metathesis catalyst work done within this project is being tailored especially for metathesis polycondensation. Polyethylene is the largest volume plastic made in the world, with a demand for more than 110 billion pounds produced in the year 2000 alone. Its impact on society is obvious and important, and so conducting research on polyethylene and related materials can influence a large number of people. This research is designed to strengthen the utility of polyethylene further by understanding fundamental issues associated with crystallization of this material, by synthesizing functionalized versions, and by expanding into tissue engineering, drug delivery, and other biomedical applications. Amino acids and peptides are being attached to the backbone of the plastic to create this new class of biomaterials. The research provides an intensive educational and training basis for undergraduate, Masters, and PhD students in chemistry and materials science. Included in the plan are several collaborations with other research groups in the USA, Germany, and Japan. These interactions will broaden the student's exposure beyond the University of Florida and our nation.