Suspension polymerisation, step by stepAs a first step in the production of suspension PVC, also known as S-PVC, VCM is fed into the polymerisation reactor alongside water and suspending agents. Through high-speed agitation, small droplets of VCM are formed. It is these droplets that eventually become PVC.As a next step in PVC manufacture, an initiator or catalyst soluble in VCM is fed into the reactor. It is here, under pressure and at temperature ranging from 40 to 60°C, that the VCM droplets are turned into PVC. The PVC obtained through this method is suspended in water and appears as slurry particles of 50~200 μm diameter.At the final stage of the S-PVC process, the slurry discharged from the polymerisation reactor is stripped of un-reacted VCM; most of the water is removed, usually by centrifugation, and the solid is dried. The end result is PVC in the form of a white powder, or resin, which is non-toxic, odourless and inert. Importantly, all un-reacted VCM is recovered and recycled as raw material.
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