Study on the Photo-degradable Properties of Degradable Mulching Film under Natural Conditions

The degradable properties of 3# and 4# film containing photo sensitizer(3.43%,0.44%,respectively) were studied by natural exposure test.The course of photo-degradation was studied from viscosity-average molecule weight,carbonyl index,mechanical properties(tensile strength and elongation at break) and crystallinity.The results indicated that carbonyl index rose insignificantly at the early exposure stage and then increased quickly,viscosity-average molecule weight,crystallinity,tensile strength,and elongation at break decreased accordingly.The viscosity-average molecule weight of 3# film degraded to 5,493 after 5 weeks,meeting the requirement of biodegradation.