Assessment of aliphatic–aromatic copolyester biodegradable mulch films. Part II: Laboratory simulated conditions

• Published in: Chemosphere (Oxford) Vol. 71; no. 9; pp. 1607 - 1616
• Main Authors: Kijchavengkul, Thitisilp, Auras, Rafael, Rubino, Maria, Ngouajio, Mathieu, Fernandez, R. Thomas
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2008; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Aliphatic–aromatic copolyester; Application fields; Applied sciences; Biological and medical sciences; Biopolymers; Compostability; composts; Cropping systems. Cultivation. Soil tillage; crosslinking; Degradation; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; Global environmental pollution; metabolism; Microscopy, Electron, Scanning; Molecular Weight; Mulch films; plastic film mulches; Plasticulture; Pollution; polyesters; Polyesters - metabolism; Polymer industry, paints, wood; Spectroscopy, Fourier Transform Infrared; Technology of polymers; Tensile Strength; Ultraviolet Rays; X-Ray Diffraction; Degradation; Plasticulture; Compostability; Biopolymers; Aliphatic–aromatic copolyester; Mulch films; Laboratory study; Photochemical crosslinking; Biodegradability; Mechanical properties; Aliphatic-aromatic copolyester; Environmental factor; Protected cultivation; Plastic film; Pollution; Ultraviolet radiation; Selfpurification; Mineralization; Butene terephthalate copolymer; Risk assessment; Environment; Agriculture; Solar radiation; Adipate copolymer; Organic compounds
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2008.01.037

In a previous paper, we demonstrated that the main mechanism of degradation of poly(butylene adipate- co-terephthalate) (PBAT) biodegradable mulch films when exposed to field conditions was crosslinking due to the photodegradation from solar radiation. The aim of this work was to determine the effect of crosslinking on the biodegradability of PBAT samples. PBAT films were subjected to UV photodegradation in laboratory simulated conditions to investigate the effects of crosslinking and other major changes in the structure and mechanical properties of the films. Crosslinking caused the films to become more brittle and produced a reduction of the tensile strength and percent elongation. Besides the crosslinking degradation mechanism, chain scission also occurred in the samples. After 45 d of biodegradation test, the non-crosslinked PBAT sample reached 60% of mineralization. However, the percent mineralization was reduced when samples were crosslinked. The percent mineralization of samples with 10%, 30%, 50%, and 70% gel content was 36%, 43%, 21%, and 24%, respectively. Our results indicate that crosslinking is a key process underlying the degradation of the PBAT film and did affect the biodegradability of the films, since the samples with greater amount of gel content generally showed less percent mineralization in the biodegradation tests.