From Nanofibrillar to Nanolaminar Poly(butylene succinate): Paving the Way to Robust Barrier and Mechanical Properties for Full-Biodegradable Poly(lactic acid) Films

Abstract

The traditional approach toward barrier property enhancement of poly(lactic acid) (PLA) is the incorporation of sheet-like fillers such as nanoclay and graphene, unfortunately leading to the sacrificed biocompatibility and degradability. Here we unveil the first application of a confined flaking technique to establish the degradable nanolaminar poly(butylene succinate) (PBS) in PLA films based on PLA/PBS in situ nanofibrillar composites. The combination of high pressure (10 MPa) and appropriate temperature (160 °C) during the flaking process desirably enabled sufficient deformation of PBS nanofibrils and retention of ordered PLA channels. Particularly, interlinked and individual nanosheets were created in composite films containing 10 and 20 wt % PBS, respectively, both of which presented desirable alignment and large width/thickness ratio (nanoscale thickness with a width of 428±13.1 and 76.9±8.2 μm, respectively). With the creation of compact polymer "nano-barrier walls", a dramatic decrease of 86% and 67% in the oxygen permeability coefficient was observed for the film incorporated with well-organized 20 wt % PBS nanosheets compared to pure PLA and pure PBS (1.4 and 0.6×10(-14) cm3·cm·cm(-2)·s(-1)·Pa(-1)), respectively. Unexpectedly, prominent increases of 21% and 28% were achieved in the tensile strength and modulus of composite films loaded 20 wt % PBS nanosheets compared to pure PLA films, although PBS intrinsically presents poor strength and stiffness. The unusual combination of barrier and mechanical performances established in the fully degradable system represent specific properties required in packaging beverages, food and medicine.

Self-nanofibrillation strategy to an unusual combination of strength and toughness for poly(lactic acid)

“…Prominent peaks centered at q ¼ 0.259 nm À1 and 0.273 nm À1 were recorded exclusively for the 1D-SAXS intensity curves of MD PLA and HD PLA, respectively, yielding the values of 24.3 nm and 23.0 nm for the long period, respectively. 40 The decrease of 1.3 nm in the long period as increasing the drawing ratio was presumably due to the chain packing of higher order under the intensied stretching ow, 39,41 in line with the SEM observation ( Fig. 3a and b).…”

Influence of Polylactide (PLA) Stereocomplexation on the Microstructure of PLA/PBS Blends and the Cell Morphology of Their Microcellular Foams

“…The calculated PLLA crystallinity in Table 2 present slightly increase when more PBS was added into PLLA matrix. This phenomenon is consistent with the study of PLA/PBS blends in the literature [ 42 ]. Besides, the introduction of PBS has improved the chain mobility of PLA due to the high flexibility of the PBS phase, resulting in a slight decrease of T g of the PLLA matrix.…”

The Innovation Research of Biodegradable Polymers for Sustainable Packaging

“…1. Lan Xie et al [17] used a confined flaking technique to establish the degradable nanolaminar poly(butylene succinate) (PBS) in PLA films, which created compact polymer with "nano-barrier walls" (shown in Fig. 2).…”