国务院办公厅出台意见 加快推进重要产品追溯体系建设

Synthesis and Properties of Polyimides Derived from 9,9-Bis （4-Aminophenyl） Fluorene

本报讯中国政府网12日发布了《国务院办公厅关于加快推进重要产品追溯体系建设的意见》。意见指出,近年来,围绕食用农产品、食品、药品、稀土产品等重要产品,各地区、部门积极推动应用物联网、云计算等现代信息技术建设追溯体系,取得积极成效。但是,也存在统筹规划滞后、制度标准不健全、推进机制不完善等，

A series of polyimide （PI） containing fluorene groups were synthesized by polycondensation of the diamine monomer 9,9-bis （4-aminophenyl） fluorene （BAF） with six dianhydrides, i. e. , pyromellitic dianhydride （PMDA）, 3,3＇, 4,4＇ -oxydiphthalic anhydride （0DPA）, 3,3＇, 4,4＇-biphenyltetracarboxylic dianhydride （BTDA）, 3,3＇, 4, 4 ＇-bisphenyltetracarboxylic dianhydride （BPDA）, 4, 4 ＇-（hexafluoroisopropylidene） diphthalic anhydride （6FDA）, 1,2,3,4-cyelobutanetetracarboxylic dianhydride （CBDA）, and subsequent chemical imidization step. The chemical structures and properties of the PIs were characterized by FT-IR, DSC, TGA, solubility test and gas separation These PIs show good solubility in some aprotic polar organic solvents such as N-methyl pyrrolidone （NMP）, etc. These PIs exhibit high Tg value above 300℃, and aromatic PIs show initial thermal decomposition temperature above 500℃. By thermal treatment at 600℃ for 30 rain, these PIs with high thermal stability membrane show high gas permeability, while the gas permeability of PI-CBDA is poor.