PVC is a polar polymer with strong intermolecular forces, therefore it is rigid at room temperature. On the other hand, when a plasticiser is added upon fabrication, flexible PVC products are obtained. This versatility is a major advantage of PVC.
PVC products without any plasticisers are called rigid PVC products, while PVC products that include plasticisers are called flexible PVC products. The softness of the flexible PVC products is obtained as a result of plasticisers coming between molecules to separate them, reducing intermolecular forces.
The graph shows the correlation between plasticiser concentration and tensile strength and tensile elongation of the moulded product. It can be seen that as the concentration of plasticiser increases, the softness of the flexible PVC products is enhanced, resulting in a soft state that is easier to stretch. Since rubber-like elasticity or pliable texture of leather is obtainable, flexible PVC is used for packaging, hoses, automobile parts, synthetic leather and surfaces.
Effect of plasticisers (tensile strength, elongation)