Powder Flowability Study to Optimize Mixing and Predict Final Product Properties: A study on PVC Formulations

摘要

The rheology of granular flow has recently been a topic of interest for additive manufacturing, 3D printing and laser sintering applications where the polymer is directly processed in a powder form. In this work, we study the effect of impact modifier, filler type and level on the rheology of PVC compounds. In particular, the aggregation and demixing of CaCO3 particles from the PVC matrix has been observed at certain CaCO3 concentrations leading to reduced impact performance. Dynamic powder testing was performed on 25 different PVC compounds with varying concentrations of CaCO3. The data showed a good correlation between powder flow properties (BFE, SI and FRI) and formulation ingredients (IM, CaCO3, and Ti02). Temperature and humidity effects on powder flowability were also studied. A strong correlation was shown between powder flow properties (BFE and SI) and humidity. Finally, the correlation between properties-structure and performance will be investigated.