Polyvinyl chloride (PVC) is a predominantly amorphous thermoplastic polymer produced through the free-radical polymerization of vinyl chloride monomer (VCM, CH₂=CHCl), with a repeating structural unit of –[CH₂–CHCl]–. The presence of polar carbon-chlorine bonds along the polymer backbone contributes to strong intermolecular interactions, relatively high rigidity, and resistance to numerous chemicals. Commercial PVC is predominantly manufactured through suspension polymerization, with emulsion and bulk polymerization employed for specific resin grades and processing requirements. Unplasticized PVC is inherently rigid and exhibits limited flexibility at ambient temperatures, whereas the incorporation of plasticizers modifies chain mobility and produces flexible formulations. PVC is commercially supplied primarily as a white powder, with its molecular weight, particle morphology, porosity, and thermal characteristics determining resin selection for extrusion, injection molding, and calendaring.