Synthesis and impact of polyethylene terephthalate nanoparticles on the stability of polypropylene exposed to electron beam irradiation

Adsorption behaviors of perfluorooctanoic acid on aged microplastics

The presence of perfluoroalkyl substances (PFAS) in the environment poses a significant threat to ecological safety and environmental health. Widespread microplastics (MPs) have been recognized as vectors for emerging contaminants due to human activities. However, the adsorption behaviors of PFAS on MPs, especially on aged MPs, have not been extensively investigated. This study aimed to investigate the adsorption behaviors of perfluorooctanoic acid (PFOA) on aged MPs (polystyrene, polyethylene, and polyethylene terephthalate) treated with UV irradiation and persulfate oxidation under salinity and dissolve organic matter (DOM) condition. Carbonyl index values of MPs increased after the aged treatment, indicating the production of oxygen-containing groups. The PFOA adsorption on aged MPs was impacted by the co-existence of Na+ ions and DOM. As PFOA adsorption onto aged MPs was mainly controlled by hydrophobic interaction, the electrostatic interaction also made a contribution, but there was no significant change in PFOA adsorption behavior between the pristine and aged MPs. While these findings provide insight into PFAS adsorption on aged MPs, further research is necessary to account for the complexity of the real environment. PRACTITIONER POINTS: Adsorption behaviors of perfluorooctanoic acid (PFOA) on aged microplastics were investigated. Hydrophobic interaction mainly controlled PFOA adsorption on aged microplastics (MPs). Co-existence dissolve organic matter and salinity influenced PFOA adsorption behaviors on aged MPs.

Short nylon tire cord and gamma irradiation impact on SBR/ultrasonic and mechanochemical devulcanized rubber blends

Devulcanization of discarded tire rubber (WR) has remained of prior attention to numerous researchers, aiming for unlimited commercial profits upon modification, especially to serve as a substituent for virgin rubber. In this concern, composites of styrene butadiene rubber (SBR) and devulcanized waste rubber, developed via two techniques: mechanochemical (DRm) and ultrasonic (DRus), and reinforced with short nylon tire cord (SNF), namely at a filling ratio of 3 and 5 phr were fabricated. All prepared specimens were exposed to various gamma radiation doses, namely 50, 100, and 150 kGy. The post-radiation characterization was investigated by FTIR and SEM techniques. Radiation-induced crosslinking density of the polymer composites was calculated and correlated with the different mechanical features. Furthermore, the TGA technique and activation energy measurement were implemented in studying the thermal behavior of the products. Incorporation of 5 phr SNF set out the thermal stability order: SBR/DRm/5 SNF > SBR/DRus/5 SNF > SBR/5 SNF. Ionizing irradiation of all composite–SNF formulations derived to a marked improvement in TS data as a result of creating further crosslinking within the polymeric matrix, reaching a maximum by the integral dose 150 kGy. The results were appreciably compared to a recently published study that applied reinforced tire fiber with polyester, as another cord utilized in the manufacture of tires. It is found that TS data observed by irradiation with 150 kGy of SBR/3 SNF, SBR/DRm/3 SNF, and SBR/DRus/3 SNF are respectively as follows: 3.7, 2.5, and 2.4 MPa, whereas the corresponding reported values for PTC reinforced counterpart blends were: 2, 1.7 and 1.8 MPa. Similarly, the TS respective values of SBR/5 SNF, SBR/DRm/5 SNF and SBR/DRus are 2.5, 1.9, and 2.2 MPa, whereas their counterparts reinforced with 5 phr PTC recorded 1.6, 1.8, and 1.2 MPa. SNF-reinforced SBR, SBR/DRm, and SBR/DRus were superior in their properties to PTC-reinforced counterpart specimens.