The structural characteristics of PVC film can be summarized from aspects such as chemical composition, physical form, multilayer construction, and classification methods as follows
Chemical and Basic Structure
Main component: Polyvinyl chloride (PVC), chemical formula −(CH2−CHCl)n−, is an amorphous polymer material formed by free radical polymerization of vinyl chloride monomers.
Additives: To improve performance, plasticizers (10%~50%), stabilizers (1%~10%), fillers (1%~30%), colorants (1%~10%), and other additives are usually added.
Microstructure: PVC is a linear polymer with a small amount of crystalline regions, with molecular chains arranged in a zigzag pattern, and carbon atoms are all sp³ hybridized.
Physical and Macroscopic Structure
Thickness range: Generally 0.08~0.2 mm; sheets thicker than 0.25 mm are called PVC sheets.
Appearance: Light yellow and semi-transparent, glossy; transparency is better than polyethylene and polypropylene but worse than polystyrene.
Surface structure (taking decorative films/adhesive films as example)
Upper layer: Paint layer or functional coating (e.g., PVDF, PVF for self-cleaning or UV resistance);
Middle layer: PVC substrate;
Lower layer: Back-coated adhesive (high-energy affinity agent to ensure firm adhesion to the substrate).