Effect of silk nano‐disc dispersion on mechanical, thermal, and barrier properties of poly(lactic acid) based bionanocomposites

Abstract

Exacerbated environmental concerns about petroleum‐based plastics provide the impetus to foster sustainable poly(lactic acid) (PLA) based food packaging. Nonetheless, PLA has its foibilities such as its brittleness, higher gas permeability, and slow crystallization. With the intent to mitigate the above shortcomings, we report a maiden effort for the fabrication of PLA/crystalline silk nano‐discs (CSNs) based bionanocomposites by melt‐extrusion for high temperature engineering and food packaging applications. Acid hydrolyzed silk fibroin from muga silk (Antheraea assama) yields CSNs, a crystalline hydrophobic discotic nanofiller with diameter of ∼50 nm and thickness ∼3 nm. At optimum loadings of 1 wt % uniform dispersed CSNs with percolated network structures covering the entire matrix can be seen. Due to enhanced crystal nucleation density, water vapor, and oxygen permeability reduced by ∼30% and ∼70%, respectively. Enhancement in toughness, percentage elongation, and tensile strength up to ∼65%, ∼40%, and ∼10%, respectively, is obtained. Onset of thermal decomposition for the PLA/CSN improved ∼10 °C, confirming the role of CSN in enhancing melt stability. Accordingly, this investigation renders a novel non‐invasive approach for increasing the crystallinity with improvement in thermomechanical and barrier properties which make this bionanocomposite, a promising candidate for food packaging applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46671.

UV-Blocking, Transparent, and Antioxidant Polycyanoacrylate Films

“…Inspecting Figure 7 c and d also reveal that both pure PECA and PECA/PPC blends with or without caffeic acid display competitive WVP values compared to conventional polymers such as HDPE, PCL, and PLA. Moreover, OTR values of the blends are superior to common food packaging LDPE films (including improved LDPE films with antioxidants) and reasonably close to PCL, PLA, and chitosan biopolymers [ 65 , 66 , 67 , 68 , 69 , 70 ]. As such, these films can be implemented in food packaging applications either as single-layer films or in combination with other polymers in the future.…”

“…All data represent the mean ± SME of three measurements. ( c ) Comparison of water vapor permeability (WVP) and ( d ) oxygen transmission rate with other polymers: high-density polyethyelene (HDPE) [ 64 ], poly(lactic acid) (PLA) [ 67 , 68 ], polycaprolactone (PCL) [ 66 , 69 ], chitosan [ 42 , 66 ], polyhydroxybutyrate (PHB), low-density polyethylene (LDPE), LDPE with 1% wt. of linanool (LDPE*) [ 64 ].…”

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“…These results indicate that nanoparticle can promote the compatibility between the PLA matrix and dispersed phases. It could be expected the organic nanoparticle to act as a bridge between the two immiscible components, leading to a better stress transfer and thus an improvement of the mechanical properties of the materials [42].…”

Mussel-Inspired Approach to Constructing Dual Network Coated Layered Clay for Enhanced Barrier and Antibacterial Properties of Poly(vinyl alcohol) Nanocomposites

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