This study examined the effect of the phase-transfer catalysts tetrabutylammonium bromide (TBAB), tetrabutylammonium hydrogen sulfate (TBAHS) on the chemical modification of poly(vinyl chloride) (PVC) by ubstitution with thiocyanate as a nucleophile. TBAB accelerated the clechlorination of PVC SCN/ethylene glycol (EG) solution. Furthermore, the addition of TBAB to SCN/EG solution improved substitution of the C1 in PVC with SCN in solution. The addition of TBAB or TBAHS to SCN/H2O solution promoted the clechlorination of PVC, whereas clechlorination did not occur without the catalyst. catalysts preferred substitution to the elimination of HCI in SCN/H2O solution, and TBAB was slightly superior to TBAHS in terms of the degree and selectivity of the substitution. The addition of nitrobenzene to SCN/H2O solution with TBAB increased the degree of substitution. Consequently, phase-tran catalysts, particularly TBAB, were very effective at promoting the substitution of Cl in PVC with SCN/H2O solution. (C) 2009 Elsevier B.V. All rights reserved.