EVIDENCE OF ELECTRON-ACCEPTOR - ELECTRON-DONOR INTERACTIONS IN THERMOPLASTIC POLYMER BLENDS BY USING FTIR - ATR SPECTROSCOPY

Specific interactions in binary blends of ethylene/vinyl acetate copol ymer (EVA) with various low molecular weight terpene-phenol tackifying resins (TPR) were systematically investigated, as a function of the c omposition of the blend and of the electron-acceptor ability of the re sin, by using attenuated total reflection-Fourier transform infrared ( ATR-FTIR) spectroscopy. Molecular acid-base were evidenced between TPR hydroxyl groups and EVA carbonyl groups. Quantitative information on the fraction of acid-base bonded entities, the enthalpy and the equili brium constant of pair formation were obtained. A crystalline transiti on of the EVA copolymer is observed and is discussed in terms of entha lpy and entropy considerations based on FTIR and calorimetric differen tial scanning calorimetry (DSC) investigations. Fundamental results ar e then summarized in order to predict the interfacial reactivity of su ch polymer blends towards acid or basic substrates.