Investigation on the Polymerization Mechanism of N,N’-Bismaleimide-4,4’-diphenylmethane and Barbituric Acid
Date Issued
2009
Date
2009
Author(s)
Chao, Tai-Fong
Abstract
The polymerization mechanism of N,N’-(4,4’-diphenylmethane)bismaleimide (BMI) and barbituric acid (BTA) in N,N’-dimethylformamide (DMF) at 130°C was investigated by using 1H NMR, COSY, HSQC and MALDI-TOF techniques. The MALDI-TOF mass spectrum of the product which was prepared from BMI and BTA at a molar ratio of 1:1 showed the mass difference of main peaks exactly equals to the sum of the molecular mass of BMI and BTA, clearly indicating both BMI and BTA are the monomers of the final polymers. Moreover, the spectra of 1H NMR, COSY of the product from BMI-BTA and the DEPT135-1H NMR 2D spectrum of the product prepared from PMI and BTA at 1:1 molar ratio reveals the polymerization was carried out via the Michael addition. wo kinds of secondary carbon signals were observed in DEPT135-1H NMR 2D spectrum of the product of PMI-BTA, implying two reactive sites may present in BTA. Therefore, 5,5-dimethyl barbituric acid (5,5-DMBTA) and 1,3- dimethyl barbituric acid (1,3-DMBTA) were employed as reactant to react with BMI. The 1H NMR spectra showed that both molecules are reactive to BMI. These findings suggest that the –NH and –CH2 moieties of BTA are reactive to the double bond of BMI. Furthermore, the 1H NMR spectrum of the product prepared from PMI and BTA at a molar ratio of 1:5 indicated that the first reactive site of BTA is –CH2.
Subjects
Michael addition
Barbituric acid
1HNMR
MALDI-TOF
Type
thesis
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