Effect of water on relaxations in the glassy and liquid states of poly(propylene oxide) of molecular weight 4000

The complex relative permittivity of poly(propylene oxide) (PPO) of molecular weight 4000 containing 1.23 wt% water has been measured in the temperature range 77 to 325 K and frequency range 12 Hz to 500 kHz, and the results are compared with the corresponding study of pure PPO-4000. On the addition of water, all the three processes, namely the β-process (at T < T g) and the α- and α′-processes (at T > T g), are shifted to higher temperatures. The strength of the β-process remained unchanged but that of the α and α′-processes increased. The halfwidths of the three processes remained unchanged on dilution with water. The decrease in the relaxation rate of the β-process is suggested to be due to hydrogen bonding of the CH(CH 3)OCH 2 group with water molecules. Water antiplasticizes PPO-4000 and this is interpreted as due to the increased chain length when the chain ends become linked via hydrogen bonds. The static permittivity is increased by ∼30% on addition of 1.23 wt% water.