Chemical and Physical Treatment of Poly (Ethylene Terephthalate)(PET) Fibre and Its Characterization

Abstract

The effect of heat and solvent treatments on the chemical degradation of the polyester fibres was investigated and their effects inducing structural and properties changes were thoroughly reviewed. Drawn poly( ethylene terephthalate) fibres (D.R. 5:1) were treated relaxed and tensed in dimethylformamide (DMF) and benzaldehyde at 95°C for varying periods of time. The PET fibres were also pre-crystallized at 160°C, 180^oc and 200°C for 1 min., 1 h and 3 h, using dry hot air prior to liquid treatment study at 95°C and retention at 60^oc. Thus resulting in a linear increase in the amount of liquid retained in the polymer as a function of time until equilibrium was attained. Specific functional groups were introduced on the surface of the untreated and pretreated polymer samples through aminolysis with primary amines such as methylamine, propyl amine and ethylamine; also polymer samples were treated with ethanol and water. Chemical reaction of PET with primary amines resulted in chain degradation and molecular weight lowering of the polymer. On complete degradation, the corresponding amide of terephthalic acid was obtained.