Analysis and characterization of rubbery polymers using FT-IR and FT-IR imaging spectroscopy

The changes in orientation of polymer chains during latex drying have been studied using Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) technique. The variable angle ATR technique was used to profile the dichroic ratio changes at different depths of in the films. Using the dichroic ratio and the Hermans orientation function, the orientation changes of the polymer chains during latex drying were monitored in real time. According to the Hermans orientation function, the general trend of the transition moment change of the polymer chain was as follows: the polymer chains were normal to the crystal surface in the top layer and isotropic at the middle and bottom layers.; Interfacial reaction between styrene/maleic anhydride copolymer (SMA) and amine terminated butadiene-acrylonitrile copolymer (ATBA) was observed using FT-IR imaging spectroscopy. The anhydride (1601 cm−1) and amine (2237 cm−1) reacted to form imide (1701 cm −1). FT-IR images were taken as reaction proceeded at 150, 160, 170, and 180°C. Images were taken at the interface and absorbance profiles were extracted. Using the absorbance profiles, the amount of reaction at the interface were calculate. At low temperatures (150 and 160°C), diffusion-controlled kinetics was observed and interdiffusion didn't occur at the images between reactants. On the other hand, interdiffusion and reaction-controlled kinetics was observed at high temperatures (170 and 180°C).; The diffusion of a binary solvent mixture into cross-linked poly (butadiene) (PBD) was observed using fast scan FT-IR imaging spectroscopy. Benzene and cyclohexane diffused into PBD in similar fashion but toluene and methanol showed completely different behavior. Toluene (good solvent) aggressively diffused in the polymer, while methanol (poor solvent) hardly penetrated in the polymer. Because of the high temporal resolution of fast FT-IR imaging, the competitive ingress of benzene and cyclohexane at the beginning of the diffusion process could be observed. Boltzmann transformed concentration profiles allowed us to analyze the diffusion process independent of time and position of the polymer boundary.