Abstract By using the modified suspension polymerization of vinyl chloride, samples of poly(vinyl chloride) (PVC) were prepared with a high content of unprocessible particles which were isolated and subjected to a morphological investigation. Their structure was examined viscometrically, by the light‐scattering method, GPC, IR spectroscopy, and X‐ray analysis; the specific surface area of the particles was measured, and their heat stability was determined. The results lead to a conclusion that the unprocessibility of the particles compared with the usual particles of suspension PVC is not caused by differences on the level of molecular structure, but ensues from the difference in their morphology.