Absolute rate theory for spherulite growth of polymeric substances

The rate of spherulite growth has been measured for various polymers. Several authors have developed the theory for the rate with emphasis on its temperature dependence but without reference to its absolute value. In this paper, a theory of the absolute rate of growth is put forward on the basis of the perfect crystal growth mechanism of Volmer‐Frenkel and the absolute reaction rate theory of Eyring. The linear rate of growth, G is given by For typical polymers, this equation is approximated by where d1 is the diameter of the polymer molecular, d3 the length of the segment, ηL the local viscosity near the crystal surface, ΔHm the heat of fusion for a mole of segments, Tm° the equilibrium melting temperatures, and ΔT = Tm° – T. The glass temperature for the local viscosity is assumed to be lower by δTg than that for usual viscosity, and the equilibrium melting temperature Tm° is assumed to be 5° higher than the apparent melting point Tm. The values of G calculated by this theory show good agreement with observed values for polyethylene succinate and nylon 6.