Effect of Chlorinated Solvents on Some Mechanical Properties of Polyester Fibre.

Abstract

Purified polyester commonly referred to as polyethylene terephthalate (PET) fibres were treated in four chlorinated solvents: perchloroethylene (PCE), trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE) and tetrachloromethane (TCM) at room temperature for various time intervals of 30, 60, 150, 300, 450, 600, 750, 900 and 1800 seconds to induce structural modifications of the PET fibre. The effects of these treatments in a relaxed condition on the tensile properties of the treated polyethylene terephthalate (PET) fibres for modulus (MPa), tenacity (MPa) and extension at break (mm) were determined. A fall in the initial (Young’s) modulus of all the treated fibres compared to the control ones was noticed, this may be due to the reduction in stiffness of the phenyl residue on the terephthalate group. The increase in the tenacity and extension at break of the treated fibres compared to the control ones could be linked to the stability conferred on them by the solvent treatments and the convolution occurring from chain folds in the treated fibres. Tetrachloromethane (TCM) was found to give the highest stable equilibrium tenacity and extension at break values within the first 600 secs of the treatments while these two quantities continue to vary with increase in time of treatment for the other three solvents. The stability of these two quantities in TCM treated fibres at shorter treatment time is a useful indication of textile materials that would not be deformed easily during processing and dry cleaning operations.