JOPSS - Search Results

Journal Articles

Plastic-associated metal(loid)s in the urban river environments of Mongolia

Battulga, B.; Atarashi-Andoh, Mariko; Koarashi, Jun; Bolormaa, O.*; Kawahigashi, Masayuki*

Ecotoxicology and Environmental Safety, 261, p.115100_1 - 115100_10, 2023/08

https://doi.org/10.1016/j.ecoenv.2023.115100

Times Cited Count：1 Percentile：16.92(Environmental Sciences)

The widespread distribution of plastic debris in the riverine environment is one of the major concerns of environmental pollution because of its potential impact on the aquatic ecosystem. In this study, we investigated accumulation of metal(loid)s on polystyrene foam (PSF) plastics collected from the Tuul River shore of Mongolia. Sorbed metal(loid)s on plastics have been extracted from collected PSF by sonication after peroxide oxidation. Size-dependent association of metal(loid)s indicated that PSFs act as vectors for the pollutants in the urban river environment. In addition, images from scanning electron microscopy (SEM) indicated not only the degraded surface of plastics showing fractures, holes, and pits, but also adhered mineral particles and microorganisms on PSFs. Interaction of metal(loid)s with plastics may be facilitated by altered surface physical and chemical properties of the plastics through photodegradation followed by an increase in surface area by size reduction and/or biofilm development in the aquatic environment. Enrichment ratio (ER) of metals on PSF samples suggested continuous accumulation of heavy metals on plastics. Our results demonstrate that the widespread plastic debris could be one of the carriers for hazardous chemicals in the environment. Since the influences of plastic debris on environmental health are major concerns to be solved, the fate and behavior of hetero-aggregates of plastics in aquatic environments should be continuously studied.

Journal Articles

Complexation of syndiotactic polystyrene with branched molecules

Kaneko, Fumitoshi*; Radulescu, A.*; Iwase, Hiroki*; Takata, Shinichi; Nishiura, Masayoshi*; Hou, Z.*

Macromolecular Symposia, 386(1), p.1900008_1 - 1900008_5, 2019/08

https://doi.org/10.1002/masy.201900008

Times Cited Count：0 Percentile：0.00(Polymer Science)

Journal Articles

Experimental investigation of the glass transition of polystyrene thin films in a broad frequency range

Inoue, Rintaro*; Kanaya, Toshiji*; Yamada, Takeshi*; Shibata, Kaoru; Fukao, Koji*

Physical Review E, 97(1), p.012501_1 - 012501_6, 2018/01

https://doi.org/10.1103/PhysRevE.97.012501

Times Cited Count：10 Percentile：61.90(Physics, Fluids & Plasmas)

In this study, we investigate the process of a polystyrene thin film using inelastic neutron scattering (INS), dielectric relaxation spectroscopy (DRS), and thermal expansion spectroscopy (TES). The DRS and TES measurements exhibited a decrease in glass transition temperature ( $T_{rm g}$ ) with film thickness. On the other hand, an increase in $T_{rm g}$ was observed in INS studies. In order to interpret this contradiction, we investigated the temperature dependence of the peak frequency ( $f_{rm m}$ ) of the process probed by DRS and TES. The experiments revealed an increase in the peak frequency ( $f_{rm m}$ ) with decreasing film thickness in the frequency region. This observation is consistent with the observed decrease in $T_{rm g}$ with thickness. The discrepancy between INS and DRS or TES descriptions of the process is likely to be attributed to a decrease in the apparent activation energy with film thickness and reduced mobility, due to the impenetrable wall effect.