CPVC is PVC (polyvinyl chloride) that has been chlorinated via a free radical chlorination reaction. This reaction is typically initiated by application of thermal or UV energy utilizing various approaches. In the process, chlorine gas is decomposed into free radical chlorine which is then reacted with PVC in a post-production step, essentially replacing a portion of the hydrogen in the PVC with chlorine. Depending on the method, a varying amount of chlorine is introduced into the polymer allowing for a measured way to fine tune the final properties. The chlorine content may vary from the base PVC 56.7% to as high as 74%, although most commercial resins have 63 to 69% chlorine. As the chlorine content in CPVC is increased, its glass transition temperature (Tg) increases significantly. Various additives are also introduced into the resin in order to make the material processable. These additives may consist of stabilizers, impact modifiers, pigments and lubricants.
CPVC shares most of the features and properties of PVC. It is also readily workable, including machining, welding, and forming. Because of its excellent corrosion resistance at elevated temperatures, CPVC is ideally suited for self-supporting constructions where temperatures up to 200°F (93°C) are present. The ability to bend, shape, and weld CPVC enables its use in a wide variety of process applications including tanks, scrubbers, and ventilation systems. It exhibits excellent fire resistance, chemical resistance, and is readily available in sheets, rods, and tubing. |
