[Degradation Characteristics of PBAT Fully Biodegradable Mulch Film]

Replacing traditional plastic mulch with fully biodegradable mulch is an important research direction to solve the problem of "white pollution," but whether it can truly realize biodegradation is still the focus of many scholars. In this study, field and indoor experiments were carried out in Pingluo County, Ningxia Hui Autonomous Region, using poly（butyleneadipate-co-terephthalate） （PBAT） fully biodegradable mulch film and ordinary polyethylene （PE） mulch film, with no mulch film （CK） as the control. Macroscopic characteristics such as the degree of apparent cracking of the mulch film, loss of the mulch film area, and the rate of weight loss were observed, and the results were combined with the results of scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, and thermogravimetry （TGR）. Combined with microscopic features such as SEM, FTIR, thermogravimetric analysis （TG）, and CO₂ release, the degradation characteristics of PBAT in the irrigation area of Yinbei District were comprehensively investigated, and data support was provided for the promotion of PBAT on a large scale. The results showed that, macroscopically, the PBAT film had begun to rupture after 60d of covering, the loss rate of film area was 27.92%, and the mass loss rate reached 19.04% after 110d of PBAT treatment, which was much larger than those of PE film. Microscopically, the SEM, FTIR, and thermogravimetric analyses showed that there was no obvious change in PE film after 110d of embedding, while the surface structure of PBAT changed greatly, with a more obvious lamellar structure, altered ester base structure, and deteriorated thermal stability. The indoor simulation test showed that the mineralization rate of PBAT film was 18.30% after 90d of incubation, which was close to that of leaves, while PE film had almost no mineralization.