Problem 3. The shear viscosity (n) of a thermosetting resin at Ty=90 C is n=3x1010. Find the viscosity values at 100, 110, 120 and 130 C. b) Plot the shift factor (at) as a function of temperature (i.e., Ln(at) vs 1/T) where at=n(T)(Trel). c) Plot n vs T and n vs 1/T. What do you observe? (Hint use the following VFT equation and assume that Tref=96 C): -CT Logar = A = log1 ) = log(; = ) = ni 'n tref ref (T-Tref) chef +T-Tref C1 = WLF constants, obtained at any reference temperature (Tr), can be used to calculate the corresponding values at Tg, using the following relationships (Ferry (1980)]: ch (5) Ca+Tg-T,' C2 = Ca+Tg-Tr, (6) where C1 and C2 are WLF constants at Tg, and C and C? are WLF constants at Tr. For VFT equation (when considering Tref= TG): C = Tref - T, and 2.303 c'ef cref =B =