ISSN:
0021-8995
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Copolymer compositions high in aliphatic isocyanate content cannot be determined by typical titration methods due to crosslinking during polymer workup. A quantitative method involving ultraviolet analysis of an isocyanate/absorbing amine adduct is presented. Agreement between the ultraviolet (UV) method and elemental analysis, in both composition data and reactivity ratios (r1r2, which are calculated from data obtained by the UV method) delineate a viable method of polymer analysis. Data from Fourier transform infrared (FTIR) analysis of the urea linkage is in good agreement with nitrogen analysis and the UV method, but is sufficiently biased to cause significant differences in r1r2 values. Bias in the infrared analysis may arise from the intra- or intermolecular interaction of C=O and N—H groups of the urea linkage. Hypochromic effects are observed in UV analysis in noncarbonylic solvents. Hypochromicity varied with copolymer composition and could be related to sequence distributions. The hypochromic effects observed were most pronounced in low amine adduct content polymers where the majority of phenyl chromophores are isolated between MMA units.
Zusätzliches Material:
13 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/app.1988.070360815
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