The Study Of The Extrusion Process Of PEX In Co-Rotating Twin-Screw

With abroad applications of plastics,in industry,performance of plastics has been paid more and more attention.But such as heat resistance,climate resistance,oil resistance,burning resistance,segregation resistance of plastics do not meet the need of hot water pipe for construction,so it is necessary to improve the performance of plastics.The movements of materials are complex movements.There are not only physical movements,but also chemical movements when PEX is extruded in co-rotating twin-screw extruders.The author made full use of theory of reactive extrusion,and plot out three models such as flow,reaction kinetic and heat tranfer to study.The main contents of this paper were as follows:1.The paper generally studied models such as flow,reaction kinetic and heat tranfer when PEX was extruded in co-rotating twin-screw extruders,the same time made use of ANSYS to compute flow,shear stress and shear rate.2.There was grafted reaction when PEX was extruded in co-rotating twin-screw extruders,so parameters of materials were not constant when PEX was extruded in co-rotating twin-screw extruders.The paper made use of ANSYS to set up the model of paramer of materials.3.Evaluating the mixing performance of a machine is important to evaluate distributive mixing and dispersive mixing.The paper analyzed distributive mixing and dispersive mixing of screws and k kneaders,and combine them in virtue of thei characters.4.By means of theory and experiment,the paper studied some factors on PEX such as combinations of screws and kneaders,parameters of materials,conditions of arts and crafts,machines and the ratio of length and dameter.5.The paper studied blending mechanism and the mean residece time of PEX in co-rotating twin-screw extruders,the results of theory and experiment were consistent.