The screw rotation speed on the properties of alloy
when the screw rotation speed in 30 system formed the obvious layered structure, PA6 is structured in the HDPE matrix of layered distribution, so this kind of layered structure has the very good barrier property. When the screw rotation speed greater than 30, due to the increase of shear rate, shear PA6 times divided into tiny particles, scattered in the HDPE matrix, the scattered granular structure does not have the barrier property. So the screw rotation speed influence dispersion effect, not only will change polyolefin-g-mah/morphological structure, will ultimately affect the some characteristics of the alloy.
in the case of screw combination must have, the higher the speed of the screw, the greater the shear stress. Through the screw in the process of blending of shearing action, will the dispersed evenly dispersed in the matrix, the greater the shear force, the size of the dispersed phase is more thin, the performance of the alloy. But the screw rotation speed is too large, the friction easy cause thermal degradation of polymers, the screw rotation speed but also reflect the length of the residence time of material in the screw.
the screw rotation speed small stay long, material for easy hot oxygen polymer can have adverse effect, speed is too high, stay time too short material mixing effect between the components. Above is the macroscopic Angle to discuss the important role of the screw rotation speed. In addition the screw rotation speed has a great influence on the blending system of microstructure. In the preparation of layered polyolefin-g-mah /, have very strict request for the screw rotation speed and the change of the screw rotation speed, can change polyolefin-g-mah/microstructure and performance.
screw speed on the properties of injection molding products processing blocks. For HDPE/PA6, cambium structure besides reasonable formula, the screw rotation speed plays a very important role, blend morphology related to screw shear rate. With the increase of screw speed, the barrier property of alloy,; OuGan speed at 30, the transmittance of the gas is very low and that the speed the formation of the structure has the barrier property. The screw rotation speed is low, the shear rate is relatively small, does not make its orientation on PA6 effective shear extension.
plasticizing and mixing degree effect on the properties of alloy. Say rising temperatures, which is beneficial to both total mixture of polymers, is advantageous to the dispersed phase dispersed. Bear high temperature, besides bring high temperature degradation problems, because the two polymer liquidity to temperature dependence is not consistent, can produce non-uniform fluid, the uneven distribution of dispersed phase in the matrix, and thus affect the mechanical properties of the alloy. Adopt what kind of temperature distribution in the form, it is low before and after high and low before or after, or two head low high, middle or set up one or more of the high temperature, should be based on the property to determine the blend components.
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