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首页> 美国政府科技报告 >Thermal Degradation of an Aromatic Polypyromellitimide in Air and Vacuum. II. The Effect of Impurities and the Nature of Degradation Products
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Thermal Degradation of an Aromatic Polypyromellitimide in Air and Vacuum. II. The Effect of Impurities and the Nature of Degradation Products

机译：空气和真空中芳香族聚吡咯酰亚胺的热降解。 II。杂质的影响和降解产物的性质

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The effect of impurities on the thermal degradation of poly N,N'-(p,p'-oxydiphenylene) pyromellitimide (du Pont's 'H'-film) is discussed. Purification of the polymer in dimethylformamide decreases the rates of degradation both in air and in vacuum, but only slightly reduces the activation energies. Infrared and mass spectrometric data suggest the participation of polypyromellitamic acid (polyamide acid) impurity in the degradation process by thermal cleavage of its carboxyl and hydrolytic scission of its amide groups. As far as the vacuum pyrolysis of the main polyimide chains is concerned, the activation energy of 74 kcal/mole, bond dissociation energies, and elemental analysis of the residue remaining after pyrolysis suggest that the primary scission occurs at the imide bonds, most likely followed by a secondary cleavage resulting in the elimination of CO groups. (Author)

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