Free volume manipulation of a 6FDA-HAB polyimide using a solid-state protection/deprotection strategy

POLYMER

卷:212

Article

Lin, Sharon¹  Joo, Taigyu¹  Benedetti, Francesco M.¹  Chen, Laura C.¹  Wu, Albert X.¹  Rodriguez, Katherine Mizrahi²  Qian, Qihui¹  Doherty, Cara M.³  Smith, Zachary P.¹ 

[1] MIT, Dept Chem Engn, 77 Massachusetts Ave,Room 66-466, Cambridge, MA 02139 USA

[2] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA

[3] Commonwealth Sci & Ind Res Org CSIRO Mfg, Private Bag 10, Clayton, Vic 3169, Australia

关键词: Thermal modification;    Gas transport;    Polyimide films;    Free volume modification;   

DOI  :  10.1016/j.polymer.2020.123121

来源: Elsevier

【 摘 要 】

Tert-butoxycarbonyl (t-BOC) is a thermally labile moiety that can be used to protect hydroxyl groups on polymers. In this study, t-BOC was appended onto a polyimide consisting of 2,2'-bis-(3,4-dicarboxyphenyl) hexafluompropane dianhydride (6FDA) and 3,3'-dihydroxy-4,4'-diamino-biphenyl (HAB), after which the polymer was formed into self-standing films. Solid-state thermal treatments were performed to systematically remove t-BOC moieties to alter the physical packing structure and concomitant gas transport properties of the polymer. Despite performing deprotection reactions well below the glass transition temperature of 6FDA-HAB (similar to 300 degrees C), this free volume manipulation (FVM) approach produced only subtle differences in polymer density, fractional free volume, average free volume element size, and gas transport properties relative to the unprotected polymer. While these findings suggest that thermally removing covalently bound functional groups from polymer films can be used to manipulate free volume and gas transport performance for glassy polymers, more robust polymer systems than linear polyimides are required to preserve the nascent free volume architecture generated from this approach.

【 授权许可】

Free