pH Determination

An alternative process is used to complement and verify results of solvent extractions and provide added indications of PVC binder condition. As previously explained, dehydrohalogenation of PVC produces HC1, whilst hydrolysis of PE-U produces carboxylic acids. Acids are normally measured on an inverse logarithmic scale of H+ ion concentration simply called pH. A technique commonly used for testing film supports 10 involves soaking finely chopped tape samples in distilled H20, then measuring pH. In our initial trials we arrived at H20:tape ratio of 10:1 w/w, over an immersion time of 2 hours with constant agitation (Fig. 6).