Rheological Properties In Processing Of Inorganic Rigid Particle Filled Polymer Composites Under Vibration Force Field

Polymer materials have been widely used in civil and industrial area for its excellent physical and chemical performance in place of traditional metal, glass, and wood. However its strength, hardness, thermal instability, abrasion resistance and so on often can not reach the standard required, and thus filling inorganic particles into polymer has been recognized as an effective modified methods to lower fabrication cost and endow the polymer with expected physical, mechanical, thermal, electro, and magnetic performance. Complex mechanical action will take place once the inorganic particles are filled into polymers, further lead to great changes in viscoelasticity of polymer matrix, and finally push forward the corresponding processing technique, process equipments and processing conditions to be developed and perfect.The introduction of vibration force field alters viscoelasticity of polymer and the motion modes of polymer chains in essence, resulting in a good dispersion of filled inorganic particles in polymer matrix. Therefore it is of great importance to investigate the effects of filler contents, particle diameter, temperature, shear rate of the screw, vibration frequency as well as vibration amplitude on the rheological properties and in the end offers a guideline for optimizing the dynamic moulding process.A physical and mathematical model for filled polymer composites during dynamic extrusion under axial vibration force field on the basis of the self-made multifunctional all-electro rheometer for polymer and polymer composites has been established. And the expressions for apparent shear viscosity, extrudate die swell ratio and first normal stress difference have also derived.The apparent shear viscosity and extrudate die swell ratio of CaCO3/PP composites have been measured with above mentioned rheometer under steady and vibration force field, with which the formal derived expressions were verified. Later SEM has been adopted to explore the effect of vibration force field on the dispersion of filled particles in polymer melt. The theoretical calculations agree well with the experimental results, and the theory developed herein is proved to be correct and effective to predict the dynamic rheological properties of filled polymer composites under vibration force field. Both the theoretical and experimental results show that the addition of inorganic particles into polymer matrix increases the apparent shear viscosity but decreases the elasticity of the composites. With the decrease of the filled particles the apparent shear viscosity goes up while the extrudate die swell ratio as well as the first normal stress difference declines. The introduction of vibration force field can greatly reduces both the apparent shear viscosity and elasticity of the composites, and improves the dispersion of the fillers in polymer matrix.The proposed theoretical model and experimental results can offers a valuable reference in exploring the mechanism of filled polymer composites moulding under vibration force field, optimizing dynamic moulding process and designing moulding equipments.