INFLUENCE OF GAMMA-IRRADIATION ON THE RHEOLOGICAL PROPERTIES OF GELS OF THE POLOXAMINE, SYNPERONIC-T908

Aqueous solutions of the poloxamine, Synperonic (Tetronic) T908 formed thermally reversible gels at concentrations greater-than-or-equal-to 30% w/w, which exhibited plastic flow properties at temperatures exceeding 27-degrees-C. The yield stress increased with increasing concentration of T908 over the range 30-40% w/w and with increase of temperature between 27 and 42-degrees-C. Gamma irradiation of the gels produced a progressive increase of yield stress with radiation dose up to 0.4 Mrad. At radiation doses exceeding 0.8 Mrad, flow was pseudoplastic and conformed to the empirical relationship, log(shear stress) = log K + n log(shear rate). Values of the flow index, n, were < 1 indicating shear thinning behaviour. The consistency index, K, increased with increase of temperature between 27 and 42-degrees-C, with concentration over the range 30-40% w/w and with radiation dose up to 2.4 Mrad.