High performance engineering polymers continue to play a vital role in emerging technologies, especially for materials that must withstand harsh environments (radiation, flame, chemical, and thermal). The Long research group has maintained vibrant working relationships with diverse engineering polymer companies to develop next generation materials and establish guiding structure-property-processing relationships for future discovery. These efforts led to joint intellectual property arrangements and opportunities to translate university compositions for larger scale production. This lecture will focus on discoveries of next generation poly(arylene ether sulfones) and polyimides to enable advanced performance. For example, the design of linear high performance polyetherimides comprising 3,3’- and 4,4’-bisphenol-A dianhydride (bis-DA) and m-phenylene diamine (mPD) provided an opportunity to elucidate the influence of dianhydride regiochemistry on thermomechanical and rheological properties. Step-growth polymerization enabled the production of high molecular weight PEIs for subsequent thermal and mechanical analysis. Monofunctional phthalic anhydride as an end capper and monomeric stoichiometric imbalances enabled predictable number-average molecular weights ranging from 3,600 – 35,400 g mol^-1, as confirmed with size exclusion chromatography coupled with light scattering detection for absolute molecular weight determination. Moreover, melt rheological analysis revealed a two-fold increase in M_efor 3,3’-PEI, which pointed to the origin of the differences in mechanical and rheological properties as a function of PEI backbone geometry. An industrial feasible polymeric salt approach to the design of photoreactive polyimide precursors now allows facile design of polyimides for additive manufacturing.

A collaborative academic-industrial relationship is vital to translate novel polymer chemistry to the manufacturing scale for broader impact

Josh Wolfgang

Appearances