@article{gupta_saquing_afshari_tonelli_khan_kotek_2009, title={Porous Nylon-6 Fibers via a Novel Salt-Induced Electrospinning Method}, volume={42}, ISSN={["1520-5835"]}, DOI={10.1021/ma801918c}, abstractNote={Porous nylon-6 fibers are obtained from Lewis acid-base complexation of gallium trichloride (GaCl3) and nylon-6 using electrospinning followed by GaCl3 removal. DSC and FTIR results reveal that the electrospun fibers, prior to GaCl3 removal, are amorphous with no hydrogen bonds present between nylon-6 chains. GaCl3 being a Lewis acid interacts with the Lewis base sites (CdO groups) on the nylon-6 chains, thereby preventing the chains to crystallize via intermolecular hydrogen bonding. Subsequent removal of GaCl3 from the as-spun fibers by soaking the electrospun web in water for 24 h leads to the formation of pores throughout the fibers. While the average fiber diameter remains effectively the same after salt removal, the average surface area increases by more than a factor of 6 for the regenerated fibers. The dual use of a metal salt (Lewis acid) to (a) facilitate fiber formation by temporary removal of polymer interchain interactions and (b) act as a porogen provides a facile approach to obtain porous fibers via electrospinning.}, number={3}, journal={MACROMOLECULES}, author={Gupta, Amit and Saquing, Carl D. and Afshari, Mehdi and Tonelli, Alan E. and Khan, Saad A. and Kotek, Richard}, year={2009}, month={Feb}, pages={709–715} }
 @article{afshari_gupta_jung_kotek_tonelli_vasanthan_2008, title={Properties of films and fibers obtained from Lewis acid-base complexed nylon 6,6}, volume={49}, ISSN={["0032-3861"]}, DOI={10.1016/j.polymer.2008.01.038}, abstractNote={A nylon 6,6 complex with GaCl3 in nitromethane (4–5 wt% nylon 6,6) was prepared at 50–70 °C over 24 h for the purpose of disrupting the interchain hydrogen bonding between nylon 6,6 chains, resulting in amorphous nylon 6,6, and increasing the draw ratio for improving the performance of nylon 6,6 fibers. After drawing, complexed films and fibers were soaked in water to remove GaCl3 and regenerate pure nylon 6,6 films and fibers. FTIR, SEM, DSC, TGA, and mechanical properties were used for characterization of the regenerated nylon 6,6 films and fibers. The amorphous complexed nylon 6,6 can be stretched to high draw ratios at low strain rates, due to the absence of hydrogen bonding and crystallinity in these complexed samples. Draw ratios of 7–13 can be achieved for complexed fibers, under low strain rate stretching. This study indicates that nylon 6,6 fibers made from the GaCl3 complexed state, using a high molecular weight polymer, can reach initial moduli up to 13 GPa, compared to initial moduli of 6 GPa for commercial nylon 6,6 fibers. Lewis acid–base complexation of polyamides provides a way to temporarily suppress hydrogen bonding, potentially increasing orientation while drawing, and following regeneration of hydrogen bonding in the drawn state, to impart higher performance to their fibers.}, number={5}, journal={POLYMER}, author={Afshari, M. and Gupta, A. and Jung, D. and Kotek, R. and Tonelli, A. E. and Vasanthan, N.}, year={2008}, month={Mar}, pages={1297–1304} }
 @article{said_schur_gupta_mock_seyam_theyson_2004, title={Giant vehicles}, volume={3}, number={4}, journal={Journal of Textile and Apparel Technology and Management}, author={Said, M. and Schur, W. W. and Gupta, A. and Mock, G. N. and Seyam, A. M. and Theyson, T.}, year={2004} }