中文摘要 液態核磁共振技術是一種可以應用於分析分子級微觀化學結構的方法。综合核磁共振圖譜的化學位移(chemical shift)、J偶合(J-coupling)、定量積分值(quantitative integration)、擴散係數值(Diffusion coefficient)二維相關頻譜(2D correlation spectroscopy)依其功能而設計的實驗結果可推論出樣品的分子立體結構。液態核磁共振技術具備:(一)多樣性脈衝程序、(二)高解析度(NMR可分辨小於1Hz的能量解析度,而IR的分辨率比1 cm-1=3×1010 Hz還大)、(三)可分辨混合物(利用COSY鑑定或依據不同的Diffusion coefficient值)、(四)可同時定性及定量決定分子特性的特點。除了熱力學上確定分子結構的功能之外,核磁共振技術亦可應用在動力學方面的探討。藉由反應前後反應物與生成物的圖譜可推論化學反應所進行的反應機制。這些 NMR 技術亦廣泛應用在高分子材料之分子量與鍵結形態之判定。 本篇研究雙馬來亞醯胺(4,4’-Bismaleimidodi-phenylmethane)和巴比妥酸(Barbituric acid)在二甲基甲醯胺(N,N-Dimethylformamide)溶劑中,進行聚合反應(Polymerization)後的結構探討。在分子結構鑑定上,藉由改變不同的(一)磁場強度、(二)進行NMR實驗的溫度、(三)反應物比例、(四)產物動力學比較,以解析出產物結構。 傳統上高分子合成注重其功能及表現,而對於其微結構並無深入探討,本篇利用核磁共振技術佐以其他測量技術(MS)對BMI-BTA聚合物進行分子結構鑑定,並經由改變反應物比例對BMI-BTA聚合反應做微觀調控以得到不同比例之產物,以期未來針對BMI-BTA聚合反應做改質、微觀調控,並應用在不同領域。
Abstract Nuclear magnetic resonance technology can confirm the thermodynamics molecular structure of the sample by chemical shift, J-coupling, quantitative integration, and diffusion coefficient. Liquid nuclear magnetic resonance has following characteristics: high resolution( 1 cm-1 equals to 3*1010 Hz in resolution,) mixture compounds identification( by using COSY or Diffusion coefficient experiments,) simultaneous qualitative and quantitative analysis , and diversified pulse sequence( 1D and 2D homonuclear and 2D heteronuclear pluse sequence.) Therefore, NMR is important to the molecular-level identification. Beside the identification of the molecular structures, NMR can be used in dynamic study of possible reaction mechanisms by analyzing the spectrums of reactant active sites and structures of products. In this study, we proposed possible mechanisms of the polymerization in which BMI( 4,4'-Bismaleimidodi-phenylmethane) reacted with BTA ( Barbituric acid) at 90°C in DMF( N,N-Dimethylformamide) solvent system. The polymerization reaction of the structural identification, by changing the different (a) magnetic field , (b) temperature of the NMR experiments, (c) the proportion of reactants, (d) the product of dynamics, in order to parse out the products structures. Traditionally, polymer chemists focus on the behaviors and utility functions of polymers, which does not have deep discussion to its molecular structure. In this paper we identified the structures of BMI-BTA polymer by mainly NMR technology and some complementary measurements. It is our wish to improve reaction efficiency, to fine tune the modification of BMI-BTA polymer in the future and hopefully applied this technique to different domains.