Accelerated aging and biodegradation of PBSA with lignin for use in mulching films

• Grant number: 24/20167-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Silvia Helena Prado Bettini
• Grantee: Gabriel Delmonte Segredo
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The use of polymers to make mulching films in agriculture has grown in recent decades due to the advantages they bring during cultivation, including maintaining soil moisture and temperature, eliminating weeds and improving the use of fertilizers, among others. In most cases, they are made from polyethylene, which is inexpensive and meets the product's requirements. However, they degrade intensely during use and when they are removed, they can generate microplastics. As they are not biodegradable, according to current regulations, they take a long time to biodegrade and can lead to soil sealing. The use of biodegradable polymers is therefore an alternative, as it is possible to control biodegradation according to the type of crop, while maintaining the necessary properties during use. Degradation control can be achieved through the use of antioxidants and UV absorbers such as lignin, a product of plant origin and a by-product of the pulp and paper industry. The aim of this project is to investigate the degradation, in abiotic and biotic environments, of poly(butylene succinate-co-adipate), PBSA, a flexible biodegradable polymer, with different concentrations of lignin, in order to increase its shelf life and study the impact of biodegradation on the environment. To this end, films with various compositions of PBSA and lignin will be prepared by extrusion, degraded in accelerated aging equipment using xenon lamps and their products will be analyzed by Fourier transform infrared (FTIR), size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and samples will be selected for biodegradation analysis in soil by respirometry, following the ASTM D5988 standard.