74 research outputs found
Otimização da interface/interfase de compósitos termoplásticos de fibra de carbono/PPS pelo uso do poli(ácido âmico) do tipo BTDA/DDS
New thermostable polymers with semiconductor properties -poly(arolylene-bis-benzimidazoles)
X-Ray photoelectron spectroscopic studies of polyquinazolones: An assessment of the degree of cyclization
Prepolymers of polyquinazolone have been prepared from 4, 4′-diaminodiphenyl-3, 3′-dicarboxylic acid and aromatic diacetoamido compounds by melt condensation. Optimum preparative conditions were established for each individual system on the basis of reduced viscosity and thermogravimetry (TG) results. The soluble prepolymers were converted to the quinazolone structure by thermal cyclization under two heating programmes. A significant amount of uncyclized carboxylic groups have been identified by X-ray photoelectron spectroscopy (XPS). Quantitative measurements of the C=O/COOH ratio at the surface of the resultant polymers have been carried out by XPS, which provide a reliable measure of the degree of cyclization. Comparison of XPS results with TG data indicates a direct correlation between degree of cyclization on the polymer surface and thermooxidative stability of the bulk polymer. © 1990 The Society of Polymer Science, Japan.Link_to_subscribed_fulltex
Preparation and evaluation of isocyanate-based polyimides as liquid phase for gas chromatography
Preparation and properties of polyamide-imides derived from 1,3-bis(4-aminophenoxy)benzene, trimellitic anhydride, and various aromatic diamines
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