Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Ping Liu


This study was mainly concerned with rheological properties of composites of recycled high density polyethylene (HDPE) with recycled tire rubber particles at shear rates from 1.167 to 116.7 s-1. The viscosity was investigated in terms of effects of shear rate, shear stress, temperature, concentration of recycled tire rubber particles and heating duration. The temperature was in the range from 160 to 250 °C and the rubber particle concentration was between 0 and 25%. The heat duration for the composites was up to 240 minutes before testing.

The viscosities of composites were decreased with increase in shear rate and shear stress. The change was considerably noticeable when the shear rate was less than 7.5 s-1. Increasing the temperature could also decrease the viscosity of composites of recycled HDPE and recycled tire rubber particles. The effect of temperature was more obvious at lower shear rate. The higher viscosity due to increased content of recycled tire rubber particles was explained in terms of increased interaction between recycled HDPE and recycled tire rubber particles. There was little change in viscosity after recycled HDPE and the composites were held up to 240 minutes at 220 °C.