Poly(vinyl chloride) (“PVC”) is commonly utilized as a material of construction for consumer and industrial goods. PVC possesses the advantageous features of low cost, durability, moisture resistance, tailored stiffness, dimensional stability, and flame retardancy. Virgin PVC is readily processed into sheet, tubes, and other forms using conventional processing equipment such as extruders and thermal compression bonding equipment. The reported density of poly(vinyl chloride) is 1.45 g/cm3.
Plasticizers can be added to PVC, which is known to be rigid in the absence of such additives, to make it more flexible and more suitable for an even broader range of applications, including but not limited to applications such as plumbing and electrical cable insulation. The addition of plasticizers and other such flexibilizing agents will lower the modulus and the density of the PVC.
The use of chemical and physical inert gas blowing agents can also be used to lower the density of PVC substrates.
While PVC is attractive for many first life commercial uses, the opportunities to reclaim and reuse PVC for subsequent future life applications are limited. The recycling of reclaimed PVC possesses inherent challenges due both to the processing difficulties caused by the various and often unknown additives and fillers that may have been used during the first life and to the sorting and separation of reclaimed PVC to generate a more homogenous raw material for use in future applications. Specifically, a significant amount of reclaimed PVC sources incorporate mixtures of other materials or components, for example pigments, colorants, fillers, plasticizers and the like, that limit PVC's potential reuse in future applications. Reclaimed PVC materials introduce feedstock variability for which conventional melt processing may be ill-suited and which limits the commercial utility for future life applications of PVC. This challenge becomes more acute as one tries to use a high fraction of reclaimed PVC within conventional processing methods.