The Effect of Processing Parameters on the Crystalline, Orientation, and Mechanical Properties of Two-Stage Die-Drawn Polypropylene

An investigation specifically focusing on the relationship among processing parameters, structure, and mechanical properties of solid two-stage die-drawn polypropylene (PP) has been done in this study, which aimed at providing a reliable reference in the choose of appropriate conditions that can be able to meet a specific processing requirement. PP sheets were drawn through a self-design solid two-stage die-drawing apparatus to various drawing ratios (DRs) at different speeds and with different die-exit thicknesses. The results showed that tensile strength, modulus, and the degree of orientation significantly increased with the nominal DR and could be further improved by increasing the drawing speed. While the crystallinity increased prior and decreased to near a constant value when the drawing speed was over 150 mm/min in the researched scope. Larger the die-exit thickness was, lower the orientation degree was but higher the crystallinity could be obtained. Compared with crystallinity, orientation degree plays a leading role in the final product properties during a two-stage solid die-drawing process.
INTRODUCTION Polymer and polymer composites have been widely applied in various fields like commodity, engineering, medical materials, and so on [1], As known, the inner structure and morphology are decisive [...]