Effect of polymerization modification of filler on viscosity and viscoelasticity of polystyrene melts

1. Expansion of the spectrum of viscoelastic relaxation times H(λ) in the direction of higher λ is clearly expressed for compositions with a PMF as compared with an ummodified filler. The appearance of a maximum for H(λ) in the region of small λ is associated with the narrow MMD of a polymer synthesized on the surface of the filler. 2. Filling increases the activation energy ΔH α of viscoelastic relaxation negligibly. For practical computations, one can set ΔH α of the composition equal to the ΔH α of the matrix. 3. With the same volumetric filling, the viscosity in the region of low strain rates is higher with a PMF than the viscosity of a composition in which the bond between the polymer and the surface of the filler particles is physical in nature. The differences between the viscosity properties of both types of compositions decrease and approach the viscosity values of the matrix as the shear rate increases. 4. Values of the modulus GL are greater for compositions with a PMF than those for compositions in which the bond between the polymer and matrix is physical in nature. For a selected matrix and filler, the presence of the filler depresses the high elasticity of compositions in the region of high shear rates. In the region of low q, the values of the moduli of the compositions are lower than GL of the matrix. 5. It is possible to predict the improvement of a number of physicomechanical properties of similar compositions on the basis of apparent characteristic features of the rheological properties of melts of polymerization-filled polystyrene as compared with traditionally filled polymers; this is their advantage, despite certain difficulties that arise in reworking compositions into articles.