Unprecedented Access to Strong and Ductile Poly(lactic acid) by Introducing In Situ Nanofibrillar Poly(butylene succinate) for Green Packaging

Abstract

The notion of toughening poly(lactic acid) (PLA) by adding flexible biopolymers has generated enormous interest but has yielded few desirable advances, mainly blocked by the sacrifice of strength and stiffness due to uncontrollable phase morphology and poor interfacial interactions. Here the phase control methodology, that is, intense extrusion compounding followed by "slit die extrusion-hot stretching-quenching" technique, was proposed to construct well-aligned, stiff poly(butylene succinate) (PBS) nanofibrils in the PLA matrix for the first time. We show that generating nanosized discrete droplets of PBS phase during extrusion compounding is key to enable the development of in situ nanofibrillar PBS assisted by the shearing/stretching field. The size of PBS nanofibrils strongly dependent on the PBS content, showing an increased average diameter from 83 to 116 and 236 nm for the composites containing 10, 20, and 40 wt % nanofibrils, respectively. More importantly, hybrid shish-kebab superstructure anchoring ordered PLA kebabs were induced by the PBS nanofibrils serving as the central shish, conferring the creation of tenacious interfacial crystalline ligaments. The exceptional combination of strength, modulus, and ductility for the composites loaded 40 wt % PBS nanofibrils were demonstrated, outperforming pure PLA with the increments of 31, 51, and 72% in strength, modulus, and elongation at break (56.4 MPa, 1702 MPa, and 92.4%), respectively. The high strength, modulus, and ductility are unprecedented for PLA and are in great potential need for packaging applications.

Three‐dimensional printing of poly(lactic acid) bio‐based composites with sugarcane bagasse fiber: Effect of printing orientation on tensile performance

“…Polymers derived from renewable resources are considered promising alternatives to traditional petroleum‐based polymers, which can mitigate current environmental and energy issues . In this regard, poly(lactic acid) (PLA) has long been the focus of research in biomass polymers because of its favorable mechanical properties, reproducibility, and biodegradability . Nevertheless, brittle nature and unfavorable crystallization property of PLA restrict its widespread applications …”

“…19 In this regard, poly(lactic acid) (PLA) has long been the focus of research in biomass polymers because of its favorable mechanical properties, reproducibility, and biodegradability. [20][21][22] Nevertheless, brittle nature and unfavorable crystallization property of PLA restrict its widespread applications. 23 Traditional processing methods of PLA include hot pressing, screw extrusion, injection molding, and solution casting.…”

Morphology Evolutions and Mechanical Properties of In Situ Fibrillar Polylactic Acid/Thermoplastic Polyurethane Blends Fabricated by Fused Deposition Modeling

“…In contrast, in situ fibrillation provides a novel way for overcoming the flexible fiber shrinkage problem through self‐compatibilization, which can induce an unexpectable combination of strength, modulus, and ductility . The interface transcrystalline nucleation and growth of the matrix polymer can effectively improve the mechanical performance of the in situ fibrils, as compared to nanofillers .…”

Effect of halloysite on structure and properties of melt-drawn PCL/PLA microfibrillar composites

“…Friedrich et al [34] and Kimble et al [35] prepared PLA/ poly(glycolic acid) melt-drawn MFC for medical application. The recently reported PLA/ poly(butylene succinate) system melt-drawn with insitu formed PLA short fibres could not be processed using thermoplastic processing technique due to the similarity of the components' melting points [36]. The MFC concept was also applied to PLA microfibrils preparation [37].…”