Electric resistance of chitosan derivatives

Direct compression of partially deacetylated chitin (DAC) and its derivativ es gave tablets, which were found to be very convenient for the simple and swift estimation of the specific resistance under the various temperature a nd moisture conditions. The specific resistance (rho) value of the 86% deac etylated chitin (DAC-86) tablet decreased with increasing the water content and temperature. The presence of metal chloride in the DAC-86 acetate tabl et decreased the rho value. The utilization of polyionic DAC derivatives su ch as N-carboxymethylated DAC-86, N,O-sulfated DAC-95, and O-methyl-N-trime thylated DAC-86 chloride gave improved rho values (ca. 10(6)-10(7) Ohm cm a t 20 degrees C and RH = 40%) without the addition of acidic dopant and inor ganic salts that would be easily lost by dissolution in water. These chitos an derivatives might be regarded as polyelectrolytes, which partially showe d ionic conductivity. (C) 1999 Elsevier Science Ltd. All rights reserved.