Etude par spectroscopie infrarouge d'alcanes ramifiés et de polymères modèles — application à la determination du taux de ramifications dans les polyéthylènes basse densité

The absorption band at 1378 cm−1 was used for the quantitative determination of branching in polyethylene. Using various models with different alkyl groups (12‐alkyltriacosanes, 11,20‐dialkyltriacontances, alkylcyclohexanes, homopolymers), new absorption coefficients, depending on their branching, were obtained. The degrees of branching of a series of copolymers deriving from α‐olefins (15 compounds) determined by infrared spectroscopy with the new coefficients and by 13C NMR spectroscopy were compared.