Glass fiber reinforced modified PA process, such as vacuum waved off is very important, if in the blending system of volatilization of removal, will affect the stability of the extrusion drawstring, prone to break belt and note with a loose, rough surface, which leads to mechanical performance degradation products.
The conditions of the guarantee waved off completely is in screw exhaust period of formation pressure.
Maximize the melt surface.
Should be set at into the exhaust section reverse thread element or reverse kneading block, in reverse thread component upstream small lead positive screw elements should be adopted;
Vent the corresponding position, big lead screw elements should be adopted.
the blending body in the screw shape change rule along the axial direction.
To seek the measures to improve the effect of mixing is quite important.
Studies show that different polymer morphology changes in screw extruder is not the same.
In the molten zone after kneading block with a reverse thread element, the better dispersion of the EPDM in PP matrix and homogenization, and the melt conveying zone, the screw configuration of EPDM dispersion effect is small.
PA6 dispersed phase particle size in soften or melt phase change is very big, when the polymer melt completely, it is the dispersed phase size.
glass fiber mixed with mouth is downstream area.
In the mixed zone, on the one hand, should the fibre bundle is opened, and the fiber must be cut off and the dispersion in the injection molding processing of polymer melt.
Mixed areas, therefore, the main function is to realize the change of the glass fiber length and homogenization.
Glass fiber length and distribution depends on polymer performance, glass fiber content, depends more on screw shear mixing effect.
In general for high viscosity and high glass fiber content system can use the combination of low shear;
For short glass fiber reinforced system, adopting the combination of secondary shear can kneading block is suitable for medium thickness;
For low content of glass fiber, liquid polymer system, can be combined using high shear;
For flame retardant reinforced blend system, mixed areas shear strength should be moderate, shoulds not be too large, scattered distribution effect should be considered at the same time.
the main feature of glass fiber reinforced effect screw combination is how to satisfy the mixing and dispersing may see from the front.
This combination can be considered a flexible combination of shear, fused segment USES multiple sets of kneading block/thread element combination, ensure the screw uniform temperature distribution;
In the mixed section using moderate shear, mixed with multiple sets of pipeline components, guarantees a certain shear have very good mixing effect.
the mixed effect comes from the reasonable combination of the double screw.
Principle of screw combination is provided with polymer melt and break the dispersed phase components required in the process of injection molding processing and stress.
In numerous alloy research, we are very pay attention to the compatibility of polymer research, and the process conditions.
And in the process of blending extrusion, blend morphology change and the screw structure, the relationship between operating conditions is little research.
the process of preparing polymer alloy, melting and mixing is happening at the same time, in the melting zone, due to the strong shear stress, to disperse polymer.
Therefore, for preparation of polymer alloy double screw extruder, the melting and blending section of the structure is essential.
in polymer polyolefin-g-mah/manufacturing process, between the continuous phase and dispersed phase component rent include chemical reactions and physical tangles, interaction between polymer reactive groups of the former to form a chemical combination.
Due to the concentration can be reactive groups in macromolecular chain is very small, the probability of interactions in a short time is very small, the reaction condition is reached between the two polymer molecular hybrid, mutual contact and collision response group.
Two polymer physics tangles need macromolecular chain segment of mutual penetration, especially the size of dispersed phase of polymer component refinement.
No matter what kind of role, jun need to be a successful combination of dispersion and distribution mix.
more wonderful words: double screw configuration feature, click directly.
HTML nantong on suye's official website: http://www.