Dynamic rheological behavior, crystallization and friction performance of ultrahigh molecular weight polyethylene/polypropylene blends by multi-step melt processing strategy

Abstract

The conventional polypropylene (PP) as a dispersed component was melt blended with ultrahigh molecular weight polyethylene (UHMWPE) in different proportions through a multi-stage melting processing strategy based on continuous rolling and forced kneading. The complex viscosity of blends was less affected by changing the content of PP under lower shearing, while it was significantly decreased in higher shearing range. Especially, by introducing a small amount of PP (5 wt%), the complex viscosity of the blend was only about 3% of original UHMWPE at 0.01 rad/s, and the crystallinity of UHMWPE component in the blend was 61.7% (about 14% higher than raw UHMWPE), which is conducive to maintaining the friction and mechanical properties of the blend. In addition, the possible different plasticization mechanisms related to the increased voids for molecular chain motion or microphase lubrication was also discussed in the present investigation.

Keywords

• UHMWPE-based blends
• Stretching deformation
• Rheological behavior
• Tribological properties
• Plasticization