Development Of A Plastic Compounder By Volume Extension And Its Application On Process Of Different Viscosity Blends

Presently, polymer blending modification has been an important way to obtain excellent comprehensive properties in the industrial engineering field. Using blending mixer, making the polymer melt suffering extension flow field during processing, is a most simple and common method in polymer blending. Ultra High Molecular Weight Polyethylene(UHMWPE) has an excellent comprehensive performance, which is easily degradation under shear flow flied and long residence time. These make the UHMWPE low performance and the application of UHMWPE and UHMWPE composite limited in industry.In this thesis, we have developed vane polymer compounder, which is based on the structure of vane extruder, dominated by volume extension deformation when blending. Designing the non-circular bore in mixing stator to reduce the backflow of melt during mixing and simplifying the structure of the rotor to strengthen the volume extension during the polymer processing. Choosing HDPE/UHMWPE with different viscosity, and analyzing the properties of systems with the processing condition, structure parameters and the material properties. The main results show:(1)A compounder, with controlled residence time and the intensity of the flow field, based on volume extension has been developed. The process of the blends in this compound is not related to the material properties, and it can process the blends with different viscosity. It has simple structure and well self-cleaning.(2)The melt pressures in the process is cyclical fluctuation with the time, and the average pressures rise first and then fall, and finally tends to be stable. With increase of the eccentricity distance of stator and the matrix viscosity of the blends, the melt time reduces and the steady pressure and the peak pressure rise.(3)In the high matrix viscosity of the system, the rheological properties(storage modules, loss modules, complex viscosity)and the mechanical properties(tensile strength, elongation at break)rise with the increase of the mixing time. But in the low matrix viscosity, the rheological and the mechanical properties fall with the increase of the mixing. UHMWPE is easy to degradation in the high matrix viscosity, which will damage the outstanding performance of UHMWPE.(4)when rotor speed and mixing time are both keeping relatively low, the damage of UHMWPE chains is not obvious. In this process conditions, the rheological and mechanical properties of HDPE/UHMWPE blends is improved with the increase of the eccentricity distance of stator, and lower of the viscosity of matrix is, the more sensitive the change of the properties of the blends and the dispersion degree of UHMWPE in matrix are.