Degradation of PLA and PLA in composites with triacetin and buriti fiber after 600 days in a simulated marine environment

作者：Pelegrini Kaue; Donazzolo Indianara; Brambilla Vanessa; Coulon Grisa Ana Maria; Piazza Diego; Zattera Ademir Jose^*; Brandalise Rosmary Nichele

来源：Journal of Applied Polymer Science, 2016, 133(15): 43290.

DOI：10.1002/app.43290

• biopolymers and renewable polymers
• composites
• degradation
• differential scanning calorimetry
• packaging

Poly(lactic acid) (PLA), the polymer object of this study, degrades by a biotic process after an abiotic hydrolysis process. Its degradation was evaluated after 600 days of exposure in a simulated marine environment (SME), as buriti fiber-reinforced composites having triacetin as coupling agent. Composites were obtained by extrusion and films were produced by compression molding. After between 60 and 600 days of exposure, PLA had a weight loss of 2.5%, PLA/T of 1.5%, and 10-12% of weight loss for PLA/B and PLA/B/T, respectively. PLA intercalates reduction, increase, and decrease of its crystallinity attributed to hydrolysis (up to 15 days), impairment of amorphous segments (45 days), and loss of integrity of the matrix (100-600 days), respectively. In the PLA/T composites, triacetin inhibited the diatom colonization process, having its crystallinity values increased after nearly 100 days of exposure with subsequent reduction. For samples with buriti fiber, changes in crystallinity were attributed to absorption of water and exposure of matrix amorphous segments. PLA degradation in a SME is evidently favored by the use of natural fibers since they make easier water access to the matrix and colonization by the protists group, diatoms, showing that the polymer can have reduced post-use shelf life as composites, with benefits while in use and at the same time post-use environmental benefits. Triacetin inhibits PLA colonization and degradation up to 45 days after exposure, after which it no longer influences the degradation process.

• 出版日期2016-4-15