Plastic molds in the production of polymers in most of the molecules and their segments or crystalline polymer microcrystalline particles under the action of the formation of the order is called the orientation structure.
1. Orientation classification
according to the nature of different stress points
Tensile orientation - caused by tensile stress, the orientation direction and the direction of stretching consistent
Flow orientation - formed under shear stress along the melt flow direction
According to the different nature of the flow, the orientation structure can be divided into
Uniaxially oriented - oriented structural elements are arranged in a flow direction in an orderly manner
The multi-axis orientation - the structural elements can be ordered in two or more directions of flow
by crystallization and non-crystalline polymer points
2. Effect of orientation on the performance of plastic parts
The influence of orientation on the mechanical properties of plastic parts
For uniaxial orientation, the tensile strength in the direction parallel to the orientation is greatly enhanced, while the tensile strength in the direction perpendicular to the orientation axis is weakened; and the biaxially oriented sheet or film is in any direction of the plane Have a higher tensile strength, elongation at break and impact toughness, tear resistance has also increased.
orientation to make plastic parts with anisotropy (in light, heat, electricity, etc.)
The impact of orientation on other performance
The glass transition temperature of the polymer increases with the degree of orientation; the greater the degree of orientation, the greater the retraction or heat shrinkage.
In summary, the orientation of the polymer has a great influence on the properties of the plastic parts. In the plastic molding production, the use of polymer orientation can be used to improve the performance of plastic parts, such as blown film is the use of polymer biaxial orientation principle to improve its performance, but not to say that the polymer orientation of plastic parts are Benefits, in the production of larger plastic parts, it should try to eliminate the orientation phenomenon, so that plastic parts will not occur warping deformation or cracks, so as to ensure the quality of plastic parts.
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