Differences in Nanoplastic Formation Behavior Between High-Density Polyethylene and Low-Density Polyethylene
Hisayuki Nakatani,
Teruyuki Yamaguchi,
Mika Asano,
Suguru Motokucho,
Anh Thi Ngoc Dao,
Hee-Jin Kim,
Mitsuharu Yagi,
Yusaku Kyozuka
Affiliations
Hisayuki Nakatani
Graduate School of Integrated Science and Technology, Chemistry and Materials Engineering Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Teruyuki Yamaguchi
Graduate School of Engineering Chemistry and Materials Engineering Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Mika Asano
Graduate School of Integrated Science and Technology, Chemistry and Materials Engineering Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Suguru Motokucho
Graduate School of Integrated Science and Technology, Chemistry and Materials Engineering Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Anh Thi Ngoc Dao
Graduate School of Integrated Science and Technology, Chemistry and Materials Engineering Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Hee-Jin Kim
Graduate School of Integrated Science and Technology Fisheries Bioresources Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Mitsuharu Yagi
Graduate School of Integrated Science and Technology Fisheries Bioresources Program, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Yusaku Kyozuka
Organization for Marine Science and Technology, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
High-Density Polyethylene (HDPE) and Low-Density Polyethylene (LDPE) films were used to create nanoplastic (NP) models, with the shape of delamination occurring during degradation. In the case of HDPE, selective degradation occurred not only in the amorphous part, but also in the crystalline part at the same time. Some of the lamellae that extend radially to form the spherulite structure were missing during the 30-day degradation. The length of these defects was less than 1 µm. HDPE disintegrated within units of spherulite structure by conformational defects in lamellae, and the size of the fragments obtained had a wide distribution. LDPE was synthesized by radical polymerization, so it contained a cross-linked part. The part was not sufficiently fused, and when it degraded, it delaminated and separated preferentially. The zeta potential reached a minimum value of approximately −20 mV at the degradation time of 21 days, and then increased. This complex dependence on degradation time was due to NP particle aggregation. The addition of 1% Triton(R) X-114 surfactant was effective in stabilizing the NP dispersion. The particle size remained constant at around 20 nm for degradation times of 15–30 days.
