Correlation between phase separation and rheological behavior in bitumen/SBS/PE blends.

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Bitumen modification enhances road material performance.
• Polymer blends offer tunable properties for bitumen modification.
• Immiscibility issues complicate phase structure evolution in bitumen/polymer systems.

Purpose of the Study:

• Investigate the phase structure evolution of bitumen modified with styrene-butadiene-styrene (SBS) and polyethylene (PE) blends during annealing.
• Determine the influence of different SBS/PE compositional ratios on phase morphology and rheological behavior.
• Understand the role of crystalline polymers and elastomers in bitumen modification.

Main Methods:

• In situ optical microscopy for observing phase structure evolution during annealing.
• Preparation and characterization of bitumen/SBS/PE blends with varying SBS/PE ratios.
• Rheological testing to evaluate the impact of phase morphology on bitumen properties.

Main Results:

• Phase morphology evolution is significantly dependent on the compositional ratio of the SBS/PE blend.
• The compositional ratio influences the formation and evolution of SBS-rich droplets.
• Immersion of SBS-rich droplets into the bitumen matrix effectively enhances rheological properties.

Conclusions:

• The compositional ratio of the polymer blend is critical for controlling phase structure and optimizing bitumen rheology.
• SBS/PE blends offer a viable route to enhance bitumen's complex modulus and viscosity.
• Understanding phase evolution is key to designing high-performance bitumen modifiers.