Permeation Studies of PVC Pipes with Near Infrared Spectroscopy

Polyvinyl chloride (PVC) is commonly used for §drinking water pipes. Although PVC is resistant to §natural environmental conditions, organic solvents §may attack the pipe wall causing swelling, §softening, water lines failure and drinking water §pollution. Permeation is linked to underground §storage tanks and random accidental spills of §organic solvents or fuel derivates. Although rare, §several cases have been reported. The aim for this §research was developing new laboratory methods for §permeation testing and helping pipe companies in §assessing about pipe selection in zones of high §risk. Near infrared spectroscopy (NIRs) was selected §as the methodology. NIR is already used in both §organic solvents and polymer fields for both §discriminative and quantitative analysis of organic §compounds. The objective of the first study was to §track the permeation of PVC pipes by two major §organic solvents (toluene and benzene) at different §concentrations developing partial least squares §(PLS) calibrations. The second study lead to the §correlation of the pipe permeation susceptibility in §pure toluene to the pipe spectra using§locally weighted regression (LWR).