Evaluating the influence of chemical composition and morphology of waxes on the fusion behaviour of rigid PVC

A set of linear Fischer-Tropsch (FT) waxes were oxidized to various degrees by utilizing an ozonolysis method. These waxes were comprehensively characterized in tenns of their chemical composition, thennal behaviour, molecular weight distributions, and overall polarity using various analytical techniques, including Fourier transfonn infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), high temperature size exclusion chromatography (HT-SEC) along with nonnal and reverse-phase high temperature solvent gradient interaction chromatography (HT-SGIC). Application-based studies were perfonned by evaluating the behaviour of these waxes in unplasticized polyvinyl chloride (uPVC) fonnulations. Analyses included hot melt mixing, single screw extrusion, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), and torque rheometry. Through a combination of these techniques, the lubrication mechanism of these waxes could be explained by the Rabinovitch model. It was found that a combination of molecular size and degree of polarity play a vital role in the migration of the waxes and therefore ultimately impacts the fusion behaviour of the overall polyvinyl chloride (PVC) fonnulation. Results indicate that fusion times can greatly be altered when using oxidised waxes, and this could be promising for the development of multifunctional lubricant systems.