Evaluating UV/H 2 O 2 exposure as a DEHP degradation treatment for plasticized PVC

Abstract

Millions of tons of plasticized poly(vinyl chloride) (PVC) materials are disposed every year. A biologically sustainable and green method for removal of toxic plasticizers from polymer systems after disposal is highly desired since plasticizers can leach out into the environment over decades. Here we compare the surface and bulk structural changes of DEHP‐plasticized PVC after two treatments intended to degrade bis‐2‐ethylhexyl phthalate (DEHP) in PVC plastic: short wave (254 nm) UV with and without the addition of 35 wt % H 2 O 2. Sum frequency generation vibrational spectroscopy (SFG) reveals the addition of aqueous H 2 O 2 decreases CH 3 signals on the surface of the films up to 8 h, due to increased molecular disorder and the removal of alkyl chains. Secondary ion mass spectrometry demonstrates that the degradation of DEHP after 8 h of reaction is similar with and without the use of H 2 O 2 . However, FTIR results reveal that the introduction of H 2 O 2 reduces bulk DEHP degradation and leads to competing radical chain scission reactions with PVC. Therefore, simple short wave UV exposure may be an effective means to degrade DEHP within and on PVC plastic and the addition of H 2 O 2 is only beneficial if additional degradation of PVC is needed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40649.