Formulation selection of aliphatic aromatic biodegradable polyester film exposed to UV/solar radiation

• Published in: Polymer degradation and stability Vol. 96; no. 10; pp. 1919 - 1926
• Main Authors: Kijchavengkul, Thitisilp, Auras, Rafael, Rubino, Maria, Selke, Susan, Ngouajio, Mathieu, Fernandez, R. Thomas
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2011; Elsevier
• Subjects: antioxidants; Applied sciences; biodegradability; Biodegradation; butylated hydroxytoluene; Composites; crop production; crosslinking; Exact sciences and technology; Forms of application and semi-finished materials; free radicals; gels; Michigan; microorganisms; molecular weight; mulches; PBAT; Photodegradation; photolysis; Poly(butylene adipate-co-terephthalate); polyesters; Polymer industry, paints, wood; Response surface methodology; selection criteria; solar radiation; soot; Technology of polymers; tensile strength; weight loss; Michigan; Photodegradation; PBAT; Biodegradation; Response surface methodology; Poly(butylene adipate-co-terephthalate); Transparency; Composite material; Optimization; Property formulation relationship; Additive; Optical properties; Reaction mechanism; Photochemical degradation; Carbon black; Mechanical properties; Crosslinking; Antioxidant; Experimental study; Tensile strength; Ester copolymer; Ultraviolet radiation; Stabilizer agent; Butene terephthalate copolymer; Butylated hydroxytoluene; Phenols; Photochemical stability; Artificial ageing; Adipate copolymer
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2011.07.001

Aliphatic aromatic copolyester films, poly(butylene adipate- co-terephthalate) or PBAT, are susceptible to photodegradation, leading to main chain scission and crosslinking. The presence of crosslinked structures not only decreased the mechanical properties of the film due to embrittlement, but also hindered the biodegradation process by limiting access of water and microorganisms to the polymer chains. This has limited the use of PBAT for outdoor applications, such as mulch films. In this study, response surface methodology (RSM) was used to determine the optimal concentrations of carbon black (CB) and the chain breaking antioxidant butylated hydroxytoluene (BHT) for the design of mulch films that can prevent the formation of crosslinked structures from recombination of free radicals. An overlaid contour plot of suitable concentrations of CB and BHT for the formulation of mulch film for crop production in Michigan or regions with similar solar radiation was established using selection criteria of light transmission of less than 20%, final tensile strength of at least 6.35 MPa, maximum gel fraction of 0.30, and positive number average molecular weight reduction sensitivity in the early stage of degradation.