http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Calle, Mariola,Jo, Hye Jin,Doherty, Cara M.,Hill, Anita J.,Lee, Young Moo American Chemical Society 2015 Macromolecules Vol.48 No.8
<P>The incorporation of small amounts of 3,5-diaminobenzoic acid (DABA) comonomer (usually 5–20 mol %) into an <I>ortho</I>-hydroxypolyimide (HPI) precursor constitutes a new methodology to easily improve the gas transport performance of thermally rearranged (TR) polymer membranes. Thermogravimetric analysis (TGA) profiles of HPI with DABA copolyimides (HPID) suggests that there is an overlap between the temperature ranges of two processes: the degradation of DABA carboxyl groups and the actual thermal rearrangement process. During thermal treatment at 450 °C, carboxyl pendant groups in DABA degrade while a more rigid biphenyl cross-linked structure is formed either following or at the same time as the rearrangement of imide to benzoxazole. Mixed-gas CO<SUB>2</SUB>/CH<SUB>4</SUB> (1:1) experiments proved this new series of cross-linked TR poly(benzoxazole-<I>co</I>-imide) (XTR-PBOI) membranes as superior materials for CO<SUB>2</SUB>/CH<SUB>4</SUB> separation applications, with enhanced permeability and selectivity, as well as high resistance to plasticization up to 40 bar.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2015/mamobx.2015.48.issue-8/acs.macromol.5b00298/production/images/medium/ma-2015-00298a_0006.gif'></P>
Cross-Linked Thermally Rearranged Poly(benzoxazole-<i>co</i>-imide) Membranes for Gas Separation
Calle, Mariola,Doherty, Cara M.,Hill, Anita J.,Lee, Young Moo American Chemical Society 2013 Macromolecules Vol.46 No.20
<P>A novel strategy to tune the cavity size and free volume of thermally rearranged polybenzoxazole (TR-PBO) copolymer membranes by transesterification cross-linking reaction of <I>o</I>-hydroxy polyimide precursors with 1,4-butylene glycol in the solid state is demonstrated in this study. During the thermal rearrangement (TR) process at high temperatures, loose diester interchain cross-linkers are prone to degrade while formation of a much more rigid cross-linked structure occurs following or alongside the imide-to-benzoxazole rearrangement. As a result, a synergistic effect of high permeability and high selectivity appeared to be created in one step, and the newly synthesized cross-linked TR-PBO membranes exhibited outstanding gas separation performance, surpassing the so-called 2008 upper bound for CO<SUB>2</SUB>/CH<SUB>4</SUB> separation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2013/mamobx.2013.46.issue-20/ma4014115/production/images/medium/ma-2013-014115_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma4014115'>ACS Electronic Supporting Info</A></P>