Ring Opening Metathesis Polymerization of Low Ring Strain Monomers to Investigate Desirable Precision and Structural Properties

This thesis communicates the research of two projects: the investigation of the structural properties in polycyclododecene and the precision of polypentenamers with highly isotactic branching on every five carbons. High molecular weight polycyclododecene (P_CdDE) is synthesizes using ring opening metathesis polymerization (ROMP) in the presence of a ruthenium catalyst producing moderate dispersity’s. By varying the time of the polymerization, the trans content in the polymer backbone can be controlled. Using this method, a series of P_CdDE polymers were synthesized with trans content ranging from 56 to 70%. We also show that the stereochemistry has a linear influence on the melting temperature. Furthermore, through mechanical testing this polymer showed properties that behaves like a ductile material. A series of allylic substituted cyclopentene monomers with increasing steric bulk are investigated by ring opening metathesis polymerization to understand the effects of these substituents on the microstructural outcomes of the resulting polypentenamers. 3-Triethylsiloxycyclopentene is discovered to polymerize to a highly regular microstructure with up to 96% trans olefins and 92% head-to-tail positional isomers. Dynamic resolution after synthetic modifications produced an enaniopure version (~92% ee) of this monomer which subsequently produced a precision isotactic and regioregular polypentenamer for the first time. Synthetic investigations, mechanistic aspects, and basic thermal properties are discussed.