Volatile and non-volatile compounds in irradiated semi-rigid crystalline poly(ethylene terephthalate) polymers

Abstract

In this study two different semi-rigid crystalline and oriented polyethylene terephthalate materials were used and were irradiated at 25-kGy dose at room temperature by using a caesium137 radiator. Volatile and non-volatile compounds present in the irradiated materials were identified and quantified. The qualitative results obtained from HS/GC/TCD/FID analysis at room temperature showed volatiles could not be identified. The HS/GC/MSD analysis performed at 106 degrees C showed that the irradiation generated 668-742 micrograms/kg formic acid, 868-922 micrograms/kg acetic acid, 17-32 micrograms/kg 1,3-dioxolane, and 47-71 micrograms/kg 2-methyl-1, 3-dioxolane based on PET weight. The results obtained from the thermal desorption and GC/MSD performed at 200 degrees C showed that 10-12 mg/kg acetaldehyde, 479-975 micrograms/kg 1,3-dioxolane, and 6.6-11.2 mg/kg methyl-1, 3-dioxolane were detected after irradiation. The concentrations of the two dioxolanes found from thermal desorption were much higher than those observed in the HS, although formic and acetic acids were not detected. It is possible that the formic and acetic acids produced by irradiation underwent further reactions with ethylene glycol during thermal desorption to form the dioxolanes. The soluble solid extracted from various PET specimens before and after irradiation were in a range of 0.67-0.78%. PET cyclic trimer is the major component and is present at 0.41-0.50%, accounting for more than 50% of the percent total solid in PET. Statistically, irradiation did not increase the soluble solid and cyclic trimer. The overall results suggest that 25-kGy irradiation had a significant effect on increasing the volatile but not the non-volatile compounds detected in the PET specimens.

Radiation‐induced oxygen scavenging activity in EVOH copolymers

“…Concerning this last aspect, plastics are affected in various ways when exposed to high‐energy radiation. The polymer chains may exhibit scission, crosslinking,8 free radical production,9, 10 formation of gases and low molecular weight radiolysis products,11 discoloration and formation of unsaturated bonds 12. The dominant effect depends on the particular material, additives used in the plastic, radiation dose and irradiation conditions 13…”

Multi-variate multi-objective optimization of production conditions for electro-spun skin scaffold using RSM and investigation of gamma irradiation effects on the properties of the optimized sample

“…Some absorbances between 2000 and 2500 cm −1 in the FTIR spectrum are related to forming CO 2 band after gamma irradiation. The overall results suggest that the gamma irradiation had a significant effect on increasing the volatile compounds such as CO 2 detected in the Polycaprolactane specimens and the formed band is related to the CO 2 that was formed at these irradiation dosages [ 35 ].

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Effects of electron beam sterilization on polyethylene terephthalate: Physico-chemical modifications and formation of non-volatile organic extractables

“…As retention time increases, more apolar or larger compounds are separated. Whenever retention times exceed 25 minutes, the major peaks appear with regular 7-8 minutes approximative time intervals (25,32,41 and 48 min), while their dose-dependant intensities increase markedly. Such peaks result most likely from the presence of oligomers with increasing polymerization order as their 3D chromatograms display the same UV spectrum.…”

“…Several papers have been published on radiation effects on PET by means of high energy ions beam [30][31][32][33][34][35][36] and gamma rays [28,29,[37][38][39][40][41], but electron-beam 12 sterilization on PET is less described in the literature. Apel et al [36] and Buchalla et al [37] mentioned the formation of a large amount of polar lowmolecular weight compounds.…”

“…Villain et al [50] reported aldehyde formation following PET thermal degradation. Komolprasert et al [41] argued that a 25 kGy gamma irradiation on PET triggered a significant volatile compound increase, as opposed to non-volatile compounds. 50 and 150 kGy doses used in our investigations induced weight increase up to 0.056 ± 0.003 g. Chain scission-related oligomers formation may indeed account for such an upward trend.…”