Variable Temperature AFM Observation of Phase Separation in NR/BR Blend

摘要

The phase images of natural rubber / poly(butadiene) (NR/BR) blend were observed at various temperatures by the dynamic force mode AFM at 370 Hz. The phase separated structure of NR/BR blend was observed in the temperature range between -70 and 30 ℃, which corresponded to rubbery BR and glassy NR phases. The phase separated structure scarcely changed with temperature, however the phase contrast between BR and NR phases changed with temperature. The phase angle difference of NR and BR domains which was normalized by the phase angle of ZnO, shifted continuously with temperature. The glass transition temperatures (Tg) of each domain were obtained from the temperature dependency of the phase angle difference. The relationship between the frequency and the reciprocal Tg values, which were evaluated by AFM (370 kHz), dynamic mechanical analysis (2-10 Hz) and dielectric relaxation spectroscopy (10~2 - 10~5 Hz), showed Vogel-Fulcher relationship.