抄録
In accordance with the newly developed homogeneous periodate oxidation procedure, we prepared high cleavage level 2, 3-dialcohol cellulose (DAC) which gives off a clear and transparent film. Viscoelastic properties of DAC were investigated in relation to those of cellulose. Dynamic mechanical measurements for DAC at 110Hz over the temperature range from -150°C to 150°C revealed two kinds of relaxation processes, which were respectively centered around -70°C and 112°C. The first process at -70°C was related to dielectric relaxion, and was regarded to be, similar to the process in cellulose, due to the motion of methylol groups. On the other hand, the cleavage of C2-C3 bonds of the glucopyranose ring resulted in the process at around 112°C, while no comparable process has been reported for cellulose in the similar region. This process was ascribed to the micro- Brownian motion along the main chain. From the temperature variation of the stress-elongation diagrams, the glass transition temperature Tg for DAC was estimated to be about 80°C. The DAC film above Tg showed a marked elongation reaching 200% at 112°C.
