流動性破壊過程に及ぼす時間,温度,濃度の影響

抄録

Fluid fracture processes were considered from time, temperature and concentration dependence of the ultimate property during the course of an investigation of fracture processes of polymeric liquids, rubberlike and hard plastic polymers. The samples were liquid polybutadiene (PBD)-benzen solutions with six different volume fractions of PBD (v₂) ranging from 0.374 to 0.782. The method and an apparatus used for the experiment are described in a previous report.¹⁾ The drop weight W and the breaking time t_b were measured with various drop sizes at four different temperatures from 25°C to 40°C for each sample. The results may be summarized as follows:
(1) Time and temperature dependence; (i) Weight vs. time curves a_t different temperature for each sample can be superposed into an almost unified master curve by the horizontal shift along the time axis. (ii) The shift distance loga_T seem to follow the prediction of the Arrhenius equation. (iii) The apparent activation energy for the viscoelastic process from a plot of loga_T against l/T systematically increases with decreasing v₂.
(2) Time and concentration dependence; (i) Time-concentration superposition is possible on a plot of W vs. logt_b at each temperature, but it is impossible on a plot of W(ρ_s/ρ) vs. log t_b, where ρ is weight of PBD per unit volume of the solution, ρ_s is a ρ selected arbitrarily as reference. (ii) The shift distance loga_c was examined from the following two equations; -1/loga_c=f(v_s)+[f(v_s)]²/γ(v₁-v_s)…(1), loga_c=log(η/η_s)={b(v₂-v_s)+c(v₂²-vs²)}/RT…(2), where v₁=1-v₂, v_s is a reference volume concentration, b, c are constants. The Eq. (1) has been presented by Fujita and Kishimoto³⁾, and corresponds to WLF equation. The E_q. (2) was lead from Andrade's viscosity equation η=A exp (U/RT), where U is replaced by interaction energy between polymer chain elements and solvent molecules in the from U=a+bv₂+cv₂² which was obtained form thermo-dynamical consideration of polymer solution. The present temperature-concentration region may be divided into three parts where loga_c obtained from experiment follow approximately the Eq>. (1) only, the Eq. (2) only, and both the Eqs.