Polymer Chemistry

Polymers in and Around You

What is Saran® Wrap?

Saran® Wrap is a trade name (another held by the Dow Chemical Company) for polyvinylidene chloride. If two of the hydrogen atoms on every other carbon in polyethylene are replaced by chlorine atoms (note yet again that this is not how this material is actually made!), you get PVDC, or polyvinylidene chloride. It was discovered by accident in 1933 by Ralph Wiley, who was having trouble washing this strange material out of the bottom of a piece of glassware. The actual polymer they were trying to make was poly(perchloroethylene)—where every hydrogen is replaced by a chlorine atom. It was just before WWII that a breakthrough was made that allowed the scientists to make film from this new material. It was quickly adopted by the Army to wrap equipment being transported by sea in order to prevent corrosion from saltwater and other applications to keep soldiers dry in jungle environments. After WWII, Dow found a new use for the material and introduced a PVDC film product for wrapping food called Saran® Wrap. The clingy food wrap you buy today is not PVDC, however. This material was phased out due to environmental and health concerns of those chlorine atoms, and low-density polyethylene took its place.



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