No abstract

The purpose of this brief communication is to demonstrate how near infrared (NIR) spectroscopy can be used to study specific interactions in miscible polymer blends. We will first demonstrate, using model systems and blends of polycaprolactone (PCL) and phenoxy [ poly (hydroxypropylether of bisphenol-A) 1, that information obtained from the OH stretch overtone absorption in the NIR is consistent with the information obtained from the OH stretch fundamental in the mid-IR region. We will then illustrate the advantages of NIR analysis of specific interaction with spectra obtained, over a range of temperatures, from thick ( 2 mm) films of blends of Nylon-6 and the zinc salt of sulfonated polystyrene ( ZnSPS) .

Near infrared spectroscopy (NIR) was used to characterize the nature of specific interactions in blends of lightly sulfonated polystyrene ionomers (M-SPS where M ¼ Zn 12 , Mn 12 , or Li 1 ) and polycaprolactam (PA6). The assignments of the NIR overtone bands that arise due to the interactions between the cation of the ionomer, and the amide groups were made using spectra of model compounds. The relative populations of the different environments of the NÀ ÀH groups were qualitatively determined by deconvoluting the NIR spectra into five absorbances representing hydrogen-bonded NÀ ÀH in crystalline and amorphous phases and an ion-amide complex. The ion-amide complex was specific for the blends. The interpolymer interactions were sensitive to composition and temperature, but qualitatively the behavior was the same for all three ionomer salts investigated.