What gives PVC fabrics their flexibility?

The flexibility of PVC fabrics primarily comes from the use of plasticizers during the manufacturing process. Plasticizers are chemical additives that are blended with PVC to modify its properties, making it more flexible and pliable. Without plasticizers, PVC would be rigid and inflexible like a hard plastic.
When PVC is in its natural state, it is quite rigid due to its amorphous molecular structure and the strong forces of attraction between its polymer chains. The addition of plasticizers disrupts these strong intermolecular forces, allowing the PVC chains to move more freely and increasing the space between them. This results in a softer and more flexible material.

The plasticizers effectively act as lubricants between the PVC polymer chains, reducing the stiffness and enabling the material to bend, stretch, and fold easily. The type and amount of plasticizer used can be adjusted during the manufacturing process to achieve the desired level of flexibility for a specific application.
Different types of plasticizers can be used, and each has its own set of characteristics. Some common plasticizers used in PVC fabric include phthalates and adipates, among others. However, there has been increasing interest in developing alternative plasticizers that are more environmentally friendly and have less potential impact on human health.
It's worth noting that the flexibility of PVC fabric can vary depending on the type and amount of plasticizer used, as well as the base fabric material used in the composite structure. Different combinations of PVC and fabric can yield varying levels of flexibility, allowing manufacturers to tailor the fabric to suit specific applications, from rigid structures like PVC pipes to soft and flexible materials used in inflatable products and flexible packaging.