Unsubstituted vinyl-addition polynorbornene (VAPNB) possesses many outstanding properties, such as high thermal, chemical, and oxidative stabilities, which makes it a promising candidate for engineering and high-performance applications. However, VAPNB’s limited solubility in common organic solvents, brittleness, and narrow service window between its glass-transition temperature (Tg) and decomposition temperature (Td) limit its processability and overall utility. While studies have shown that the solubility of VAPNB may be dramatically enhanced by the introduction of side-chain moieties, thereby facilitating solvent processing to yield robust films, their overall industrial appeal would be enhanced if they could be melt-processed into various form factors. Herein, we describe our efforts to develop melt-processable VAPNBs (service window &gt; 100 °C) via monomer design. In this work, a systematic series of VAPNBs with various functional groups were synthesized using a Pd-based vinyl-addition catalyst. This library of materials is used to examine the relationship between molecular structure and thermal properties. The Tg and Td of homopolymers and copolymers were characterized by multiple techniques, including modulated DSC, DMA, ellipsometry, and TGA. Furthermore, Tg prediction curves were also constructed and compared to experimentally determined values. We found that the resulting (co)polymers possessed sufficiently suppressed Tg’s and consistently high Td values to yield a tailored service window of &gt; 100 °C while maintaining a Tg &gt; 150 °C. Finally, we demonstrated the melt processibility of select VAPNBs by melt extrusion and characterized their mechanical properties via tensile testing.

Design, synthesis, and characterization of melt-processible vinyl-addition polynorbornenes

ACS Spring Meeting 2021

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