The effects of pretreatment reagents on the hydrolysis and physical properties of PET fabrics were investigated under various alkaline hydrolysis treatment and pretreatment conditions. Before alkaline hydrolysis, solvent treatment with pretreatment reagents, including benzyl alcohol (PET-b) or 2-phenyl ethanol (PET-p), modified the structure of the PET fabric, thus affecting the hydrolysis and physical properties of the PET fabrics. Fabric weight loss increased with increasing hydrolysis time. The rate constant (k) increased markedly with increasing rnethyl groups in the pretreatment reagents. The activation energy (E-a) of untreated fabrics was higher than those of the treated fabrics. The crystallinity of the PET fabrics increased with increasing hydrolysis times (t) and methyl groups in the pretreatment reagents. The weight loss of PET-b increased with increasing pretreatment temperature (T). However, the weight loss of PET-p increased up to 100 degrees C but decreased above 120 degrees C. The shrinkage of all samples increased with increasing hydrolysis times (t). Shrinkage of PET-b and PET-p was greater than that of untreated fabrics. PET-b displayed greater shrinkage than PET-p because byproducts polluted the PET fibers. Both the initial and maximum water absorption of the fabrics increased with increasing hydrolysis times (t). (c) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3071-3078, 2009