An investigation of rheological properties of polypropylene single-polymer composites

Polypropylene single-polymer composites (PP SPCs), whose matrix and reinforcement came from identical type of polymers, were fabricated by an approach of applying undercooled polymer melt. The undercooling method could enlarge the processing temperature windows and realize the fabrication of SPCs without destroying the whole reinforcement. Rheology could be used in the processing of the SPCs, however there is a little investigations. This work was done with the aim to investigate the effects of undercooling compaction temperature from 125 ^oC to 145 ^oC on rheological properties of PP SPCs by dynamic rheological measurements. The linear viscoelastic range (LVE) was measured for strain sweep. It was found that the viscosity and modulus of PP SPCs at different compaction temperature had markedly differences during frequency sweep. With different processing temperatures, the interface between the matrix and the fiber was diverse, so it had a great influence on the rheological properties of SPCs. Moreover, the photography of morphology before and after rheological tests revealed a positive correlation between the degree of shrinkage and the compaction temperature.