Splat formation of polypropylene flame sprayed onto a flat surface

The oxy-acetylene flame process with external powder feeding was employed to spray form polypropylene (PP) splats onto a glass substrate. This work examines the influence of stand-off distance on PP splat morphology to establish a fundamental understanding of processing variables on microstructural characteristics. Optical microscopy, scanning electron microscopy (SEM), 2D profilometry, non-contact optical surface profilometry and VISION software were used to measure and quantify various morphological features that are descriptors for the splat metrics. Micro-Raman spectroscopy was used to examine the molecular structure of the PP splats. studies indicated that decreasing the stand-off distance from 35 to 15 cm produced coherent, integral disk-shaped splats that exhibited minimum splashing behavior. This observation has important fundamental implications concerning the structure–property relationships of polymer coatings since the design of these intrinsic building units also controls the composite nature of the coating.