m,m′-二氨基二苯酮与均苯四酸二酐的微波辐射聚合

研究 m,m′-二氨基二苯酮 (m,m′- DABP)与均苯四酸二酐 (PMDA)的缩聚及亚酰化 ,并运用微波辐射和常规加热两种方式对反应进行了比较。考察了微波辐射时间 (功率 )、单体浓度、单体配比和温度等因素对缩聚物的特性粘数、转化率的影响。用红外光谱对亚酰化度进行了表征 ,并用简并四波混频技术首次测量了该缩聚物的三阶光学非线性极化率系数及其响应时间。实验结果表明 ,微波辐射对提高聚合物的特性粘数和转化率都有显著作用 ;合成的缩聚物具有较大的三阶光学非线性极化率系数 (聚酰亚胺的 χ(3) =1.642× 10 -13 esu)和较快的时间响应

微波辐射合成三元共聚高吸水性树脂

以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,以丙烯酸(AA)、丙烯酰胺(AM)、2-丙烯酰胺基2-甲基丙磺酸(AMPS)为单体,在不加引发剂和无氮气保护的情况下,微波辐射合成AA/AM/AMPS共聚高吸水性树脂。通过单因素实验得出了反应的最佳条件为:n(AMPS):n(AA):n(AM)=1:2:1,pH=2.25,w (NMBA)=0.025%;采用FT-IR、AFM和DSC-TGA等对树脂结构、表面形态及热稳定性进行了表征。结果表明,在优化条件下高吸水性树脂其吸蒸馏水倍率为1 819 g/g,耐热性表明在60℃的环境中树脂吸水率高达745 g/g;在305℃之前树脂较稳定,且重复使用性好。

SYNTHESIS OF MPt/C (M=La, Nd) CATALYSTS BY MICROWAVE RADIATION

In this paper, MPt/C (M= La, Nd) catalysts of PEMFC were synthesized by microwave radiation process. The crystallinity and structure of catalysts were respectively analyzed by XRD and nitrogen adsorption tests. The activity of catalysts was investigated by electrochemistry experiment. The results showed that: 1) compared with Pt/C catalyst prepared by typical impregnation-reduction process, the size of MPt/C catalyst particle decreased and the available crystal for O2 reduction increased; 2) the MPt/C catalysts had relatively high BET surface areas; and 3)these crystal transformations of the MPt/C catalyst brought high the electrocatalytic activity, and as a result, improved the power of PEMFC.