Development And Application Of Vane Plasticization Mixing Device Dominated By Tensile Deformation

The melt blending is not only an effective method to improve polymer comprehensiveproperties but also an important way to develop new materials. Experimental and theoreticalstudies had shown that extensional deformation had higher mixing efficiency compared withshear deformation at the same deformation rate. A vane compounder dominated withextensional deformation was developed and related researches were carried out on the device.The dynamic extensional deformation dominated the mixing process generated by theconvergence/divergence flow. The research results provided experimental data and theoreticalbasis for reasonable selection of mixing process parameters and structure optimization ofmixing device. The research is of important significance in science and reality.This paper described the structure, working principle of the vane blending unit consist ofstator, rotor, vane and baffle. The effect of eccentricity, rotor radius and clearance on thevolume changing rate and the ratio of the protruding length of the adjacent two vanes werediscussed respectively. The volume changing rate was optimized by genetic algorithm and theoptimal parameters were obtained with in the given ranges. Appropriate structure parameterswere selected according to the design intention.The PS/HDPE blend was molded with vane compounder. Research of the effect ofrotating speed, mixing time and component on properties were discussed in terms ofmechanical testing, SEM and rheological testing. The experimental results show that:(1)Continuous extrusion and intermittent blending experiments showed that materialsformed circulation flow and achieved extensional deformation dominated plasticizing mixingprocess. The materials suffered dynamic entensional deformation during the mixingprocedure.(2) The mechanical properties, rheological properties and SEM results indicated that thedistribution and dispersion mixing effects enhanced, the particles were refined and thedispersed phase was more evenly dispersed with the increase of mixing time and rotatingspeed. The dispersive mixing process occurred mainly at the initial stage of blending whiledistributive mixing occurred mainly in the final stage.(3)The values of average particle diameter and polydispersity index obtained at the sameprocessing conditions from vane compounder and Brabender rotor internal mixerdemonstrated that finely particle dispersion, narrow particle diameter distribution and betterhomogeneity can be gotten by vane compounder. The mixing efficiency of the vanecompounder is high.