Comparison of aging properties of starch/ PBAT degradable mulching film in different environments

In order to develop a biodegradable mulching film to reduce the pollution of traditional mulching film, thermoplastic starch (TPS) and polyadipate/butylene terephthalate (PBAT) were used as raw materials to prepare two biodegradable mulching films TPS/PBAT-A and TPS/PBAT-B with a ratio of raw materials, and study their thermal aging (60℃, 80℃, 100℃) and multi-factor aging (temperature, humidity, and light intensity are 40℃-65%-310 W/m², 60℃-65%-310 W/m² and 60℃-65%-648 W/m²). Before aging, the tensile strength of the two mulching films TPS/PBAT-A and TPS/PBAT-B are 16.3 MPa and 20.8 MPa, respectively, and the elongation at break is 1222.7% and 564.5%, respectively. After high temperature thermal aging, the mechanical properties of the two mulching films decreased. After thermal aging at 100℃, the tensile strength of the two mulching films TPS/PBAT-A and TPS/PBAT-B decreased to 11.2 MPa and 18.2 MPa, respectively; TPS/PBAT-B mulching films have relatively few surface defects after thermal aging, and their properties are well preserved. In the comparative environment of 60℃-65%-310 W/m² and 60℃-65%-648 W/m², the tensile strength of the two mulching films decreased by 23.0% and 22.4% after 24 days, respectively. When the two kinds of mulching films are aged, the amorphous area of the mulching films decomposes first, the molecular chain structure is destroyed, the existence of internal voids after molecular fracture reduces the bonding quality, and there are many holes and cracks on the surface.