Current Position: ExxonMobil
Hydrogenated ring-opened polynorbornene (hPN) has been shown to exhibit a transition between two monoclinic lattices at its crystal-crystal transition temperature (Tcc) around 110 °C. The transition was described by John Bishop of this group as between “a conventional three-dimensionally ordered structure” and a structure where “individual chains are rotationally disordered and show a hexagonal packing transverse to the chain axes, but with reduced order along the chain axis….”(Bishop and Register, 2010) The cited paper proceeded to explore how the tacticity of the polymer affects its Tcc.
As changes in structure can have serious effects on the properties of a material, it behooves us to fully understand what can change the structure of hPN, and how. The polymer has both been used as the prototype for studies in polymers produced by ring-opening metathesis polymerization and also has important commercial applications. These include its use as an oil spill cleaner due to its affinity to hydrocarbons, as well as use in race car bumpers, tires, sealing, and transmission belts.
If we add a comonomer (like hexylnorbornene) to hPN, we expect Tcc to additionally depend on the comonomer content because of disruptions to crystal packing. As Bishop did with tacticity, my research seeks to investigate the effect of changing comonomer content on Tcc and the resulting crystal structure.