Oyeleke G.O.^1,, Adetoro R.O.², Ishola A.D.¹, Salam M.A.¹

Perchloroethylene (PCE), trichloroethylene (TCE), 1,1dichloroethylene (1,1DCE) and tetrachloromethane (TCM) with solubility parameter values of 9.76, 9.30, 9.28 and 8.65 respectively were used to pretreat polyethene terephthalate (PET) fibre in relaxed condition for varying times. Dyed polyester fabrics with known amount of dye uptake were also laundered in the chlorinated solvents at room temperature. The treated and untreated PET fibres were examined using critical dissolution time (CDT) technique in 100% phenol at 60°C in order to characterize the relative changes in their structure as a result of the treatments. The quantity of dye removed from the surface of the dyed fabric during laundering was determined spectrophotometrically while the washed surfaces were characterized by the use of X- ray diffractography (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM) techniques. The TCM treated fibres gave the highest CDT value followed by TCE, 1,1 DCE and PCE treated fibres in that order. A trend of 1,1 DCE > PCE > TCE > TCM obtained for the level of liquid retained after treatments pointed to the closeness of solubility parameter values of the solvents to that of the PET as a major influence. TCM as solvent also gave the highest value of dye wash from the surface of the dyed fibre which may be explained in terms of its wider solubility parameter value to that of PET compared to PCE, TCE and 1,1 DCE with closer solubility parameter values. The low liquid retention values of TCM treated fibre is an indication of better dimensional stability as revealed by SEM and XRD results in terms of minimal swelling ability both in thickness and width while its high CDT value was an evidence of stability to deformation during processing and solvent cleaning where the fibre will be expected to become wet.

PET, solubility parameter, liquid retention, CDT, SEM, XRD, IR, dry cleaning