Gang Zhang,Dongsheng Li,Guangming Yan,Han Wang,Yu Zhang,Zhefu Wu,Suilin Liu,Xiaojun Wang,Jie Yang
In this study, a novel bisphenol-containing cyclohexane group [4,4′-(cyclohexane-1,1-diyl)bis(2-methoxyphenol) (CDBMP)] was synthesized. It was reacted with 4,4′-dichlorodiphenylsulfone to synthesize polyether sulfone-containing −OCH3 groups (PES–OCH3). Then, PES–OCH3 was reacted with BBr3 and (t-Boc)2O to yield PES–OH and PES–Boc, respectively. The glass transition temperatures of PES–OCH3 and PES–OH were found to be 177.6 and 240.7 °C, respectively. The resultant resins exhibited good tensile strength and solubility (dissolved in N-Methyl-2-Pyrrolidine, dimethylformamide, and so on). Interestingly, PES–Boc showed excellent foam property, and the density of the foam decreased from 1.23 to 0.012 g/cm3. Also, we found that the dielectric constant and dielectric loss values (107 Hz) of the foaming sample were in the range of 1.9–2.7 and 4.22 × 10–3 to 7.99 × 10–3, respectively. The introduction of hydroxyl-Boc-assisted modification provides a controllable process to fabricate porous and ultra-light materials, and it can be potentially applied in these fields such as microelectronics and high speed communication systems.
Liuqun Gu,Meifeng Wang,Hui Li,Kai Ni Teh,Yiqun Li,Ye Liu
A new type of modified lignin, lignin-p-Boc, was obtained through reaction with di- tert -butyl dicarbonate (Boc 2 O) in aqueous media catalyzed by 4-dimethylaminopyridine (DMAP). Boc modification occurred regardless of type of lignin, was tunable, and proceeded well in recovering lignin at high purity from sodium lignosulfonate (a common byproduct from pulping industry; lignin content: 60%). Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic and as a potential crosslinker in design of bioresorbable composite polymeric implants. Furthermore, the effect of the modification on breakdown rate of alkali lignin by microbes was investigated, and results showed that the modification substantially decreases the breakdown rate. The tunable Boc modification process was designed via a system thinking, including availability of raw lignin, economical/green modification, potentiality of drop-in-change to current thermoplastic processing, modification impact on microbial degradability/disposed environment at the end of use life; hence the holistic consideration makes this alternative method for upgrade of technical lignins very practical for future industrial application. Via “ in-situ ” forming “easily breakable covalent bonds” with existing thermopolymers inside, Lignin-p-BOCs are also promising to play an important role as both excellent binders via “random match” and reductants in transforming linear plastic waste into circular plastics.
危险品化学品经营许可证（带存储）