Study on the thermal and structural properties of gamma-irradiated polyethylene terephthalate fibers

Abstract Polyethylene terephthalate (PET) fiber samples were irradiated using different gamma radiation doses. The physicochemical and structural properties of the irradiated PET samples, either the pristine sample or the sample chemically modified with polyethylene glycol (PEG), were assessed using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The surface morphology and characteristics of the irradiated PET fiber samples were investigated using scanning electron microscopy (SEM). The pristine and PEG-modified PET fibers were exposed to gamma radiation with doses ranging from 0.5 to 20 kGy. The FTIR analysis results showed certain degradation via irradiation, deduced from a decrease in the intensities of most of the PET original infrared bands. The XRD and DSC analysis results indicated the reduction of crystallinity upon irradiation of pristine and modified PET fibers. Conversely, an improvement in the crystallinity was observed at high doses compared with low doses. The crystallinity of the PEG-modified PET was found to be improved. Two types of morphological changes, wrinkles and small particles, were observed on the PET fiber surface due to gamma irradiation.