The PBAT (poly (butylene adipate- co-terephthalate) is a promising biodegradable material. However, it is often blend with hydrophilic polymers since its degradation rate in the aquatic environment is still limited. In this study, the blend PBAT/TPS (thermoplastic starch) films, namely BFs, were prepared by a blow extrusion approach, and evaluated for hydrolysis in four studied mediums acid (HCl, 1 M, 2 M, and 3 M), alkaline (NaOH, pH = 9, 11, and 13), phosphate buffer (pH = 7.4), and artificial seawater. The hydrolyzed BFs were characterized by weight loss, mechanical properties, scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), and differential scanning calorimetry (DSC). A larger starch content in the BFs caused hydrolysis more quickly. The highest hydrolytic rate was found in the alkaline solution, followed by the acid medium. The complete abiotic hydrolysis of the BFs was 3 M HCl for 14 days or NaOH (pH 13) for 35 days. After 180 days of incubation, the film containing 70.5 % PBAT/TPS granules has been associated with the highest biodegradation rate of 76.31 % in composting.

Residual plastic films in soils are posing a potential threat to agricultural ecosystem. However, little is known about the impacts of microplastics (MPs) derived from biodegradable and non-biodegradable plastic films on plant-soil systems. Here, we carried out a pot experiment using soil-cultivated lettuce treated by two types of MPs, degradable poly(butylene adipate-co-terephthalate) (PBAT-MPs) and non-biodegradable polyethylene (PE -MPs). MPs resulted in different degrees of reduction in shoot biomass, chlorophyll content, photosynthetic pa-rameters, and leaf contents of nitrogen (N), phosphorus (P), and potassium (K), accelerated accumulation of hydrogen peroxide and superoxide, and increased malondialdehyde content in lettuce leaves. Moreover, MPs obviously decreased contents of total N, nitrate, ammonium, and available K in soils, and increased available P, thus altering soil nutrient availability. MPs also significantly decreased proportions of macroaggregates, and decreased soil electrical conductivity and microbial activity. PBAT-MPs had significantly greater impacts on oxidative damage, photosynthetic rate, soil aggregation, microbial activity, and soil ammonium than those of PE -MPs. Our results suggested that MPs caused oxidative damages, nutrient uptake inhibition, soil properties alteration, ultimately leading to growth reduction, and PBAT-MPs exhibited stronger impacts. Therefore, it is urgent to further study the ecological effects of MPs, especially biodegradable MPs, on soil-plant systems.