Applications of compaction testing to the processability of rigid PVC compounds

A compaction test has been developed to examine the lubrication and fusion characteristics of PVC compounds. A model of the compaction process at low pressures is proposed which involves two distinct modes of compaction. Initial densification quickly reaches a plateau density, the magnitude of which is determined primarily by frictional properties and the elastic deformability. of the resin particles. A second slower rate densification is attributed to fusion within the PVC resin grains, as well as diffusion between grains. It is shown that compaction alone is insufficient for grain boundary destruction. As a result, significantly higher temperatures are needed to achieve a given state of elasticity development by compaction when compared to material produced by shear processing.