Stabilization of Polylactic Acid and Polyethylene with Nutshell Extract: Efficiency Assessment and Economic Evaluation

Abstract

Recovery of functional molecules from byproducts of agro-food industries is an appealing approach to waste reduction and to obtain safe and value-added phytochemicals with antioxidant and antimicrobial properties. However, more information about the operational costs is needed for successful industrial scale-up. In this study, the potential of pecan (Carya illinoinensis) nutshell (NS) as a source of antioxidants was investigated. To this aim, a hydroalcholic NS extract (NSE) was thoroughly characterized, and its effect was investigated on thermo- and photo-oxidative stability of two polymers widely used in food packaging, polylactic acid (PLA) and polyethylene (PE). Twenty-six phenolic constituents, including proanthocyanidins, were identified in NSE, and its effective radical scavenging capacity was assessed. NSE acted as a thermal stabilizer for PLA and PE films, both in an oxygen-depleted environment (i.e., during melt processing) and in the presence of oxygen during polymer service life. NSE showed great potential as a PLA stabilizer, due to the compatibility with the polyester matrix. Under UV-light irradiation, NSE was more effective in protecting PE than PLA, due to combination of peroxy radical scavenging and inhibition of Norrish-type photolytic cleavage. Finally, from the experimental data, an economic evaluation of batch and continuous mode NSE manufacturing was performed, demonstrating that the process is technically and economically viable. Overall, these results emphasize the potential of NSE as a low-cost, safe, and sustainable additive for the stabilization of polymer films in packaging and other applications.

Natural compounds from Punica granatum peel as multiple stabilizers for polyethylene

“…The presence of phenolic hydroxyl group was evidenced by the broad band at 3280 cm −1 . The peaks at 2926 and 1614 cm −1 were attributed to the CH (sp 2 ) vibration and CC vibration on the aromatic ring 27,37 . The peak at 1348 cm −1 was related to the stretching or deformation vibration of COH (phenolic compound) 36 .…”

“…Figure 1 shows the FTIR spectrum of PPE. The peaks at 1731, 1444, and 1343 cm −1 were derived from the vibration of CO, the deformation vibration of CH and the plane bending of OH, respectively 26,27 . The band at 1048 to 1219 cm −1 included the stretching vibration of COH side groups of polysaccharide and COC of glycosidic linkage 36 .…”

“…Tomato waste, 18,19 grape seeds, 18,20 pine bark tannin, 21 cork, 22 chestnut burs, 23 flax fibers, 24 and green tea 25 were reported to be beneficial to the thermo‐oxidative improvement of PP and PE. Grape marc and nutshell showed great potential as UV‐light stabilizer for PP and PE, respectively 26,27 . Effectiveness of agro‐waste (grape pomace, turmeric waste, orange peel waste, and coffee grounds) in protecting PE from processing degradation was also reported 28 .…”

High Tg and tough poly(butylene 2,5‐thiophenedicarboxylate‐co‐1,4‐cyclohexanedimethylene 2,5‐thiophenedicarboxylate)s: Synthesis and characterization

“…Nowadays, many studies about bio‐based polymers have begun in the last decade due to an increasing environmental awareness and the depletion of oil resources . Specially, sustainable materials with high‐performance or biodegradability have become the research hot spot, such as poly(ethylene 2,5‐furandicarboxylate) (PEF), poly(1,4‐butylene 2,5‐furandicarboxylate), poly(lactic acid), and poly(butylene 2,5‐thiophenedicarboxylate) (PBTF) …”

Partially bio-based and tough polyesters, poly(ethylene 2,5-thiophenedicarboxylate-co-1,4-cyclohexanedimethylene 2,5-thiophenedicarboxylate)s

“…[1][2][3][4][5][6][7] Specially, sustainable materials with high-performance or biodegradability have become the research hot spot, such as poly(ethylene 2,5-furandicarboxylate) (PEF), [8][9][10][11][12][13][14] poly(1,-4-butylene 2,5-furandicarboxylate), 15,16 poly(lactic acid), [17][18][19] and poly(butylene 2,5-thiophenedicarboxylate) (PBTF). [1][2][3][4][5][6][7] Specially, sustainable materials with high-performance or biodegradability have become the research hot spot, such as poly(ethylene 2,5-furandicarboxylate) (PEF), [8][9][10][11][12][13][14] poly(1,-4-butylene 2,5-furandicarboxylate), 15,16 poly(lactic acid), [17][18][19] and poly(butylene 2,5-thiophenedicarboxylate) (PBTF).…”