Bend, Twist, and Turn: First Bendable and Malleable Toughened PLA Green Composites

Abstract

The future of green electronics possessing great strength and toughness proves to be a promising area of research in this technologically advanced society. This work develops the first fully bendable and malleable toughened polylactic acid (PLA) green composite by incorporating a multifunctional polyhydroxybutyrate rubber copolymer filler that acts as an effective nucleating agent to accelerate PLA crystallization and performs as a dynamic plasticizer to generate massive polymer chain movement. The resultant biocomposite exhibits a 24‐fold and 15‐fold increment in both elongation and toughness, respectively, while retaining its elastic modulus at >3 GPa. Mechanism studies show the toughening effect is due to an amalgamation of massive shear yielding, crazing, and nanocavitation in the highly dense PLA matrix. Uniquely distinguished from the typical flexible polymer that stretches and recovers, this biocomposite is the first report of PLA that can be “bend, twist, turn, and fold” at room temperature and exhibit excellent mechanical robustness even after a 180° bend, attributes to the highly interconnected polymer network of innumerable nanocavitation complemented with an extensively unified fibrillar bridge. This unique trait certainly opens up a new horizon to future sustainable green electronics development.

Construction of Mechanically Reinforced Thermoplastic Polyurethane from Carbon Dioxide-Based Poly(ether carbonate) Polyols via Coordination Cross-Linking

“…T 10% and T max also decrease similarly, demonstrating the thermal stability of TPU decreases with the introduction of FeCl 3 . On the one hand, the coordination bonds rupture at a high temperature and the ferric compound evenly distributes in TPU, which is equivalent to a physical filler that weakens the interaction, resulting in the decrease in thermal stability [ 41 ]. On the other hand, many researchers have widely revealed that the interaction of such Lewis acid as transition metals in the polymer can boost thermal degradation of the organic matrix, leading to adverse effects [ 42 , 43 , 44 ].…”

Strong Interface via Weak Interactions: Ultratough and Malleable Polylactic acid/Polyhydroxybutyrate Biocomposites

“…PLLA and PHB are known for their biodegradability and high stiffness. However, amorphous PLLA and crystalline PHB are fragile under tension, [14,25] with low elongation at breaks 𝜖 = 3% and ≈6%, respectively. Most reported PLA blends/copolymers with high elongations used very ductile phases (elastomer such as PBS, PBAT, or rubbers), which often reduced their stiffness and strength.…”

“…The second strategy is to synthesize block copolymer containing a similar structural unit for better adhesion between matrix. [14][15][16][17] For example, Muiruri et al [15] utilized PLLA stereocomplexation effect with cellulose nanocrystal-rubber-PLLA copolymers to achieve 10-fold increase in elongation. The third way is adding plasticizers to reduce the glass transition temperature (T g ) of the PLLA/PHB-based blends.…”

Stereocomplex Crystallization Induced Significant Improvement in Transparency and Stiffness–Toughness Performance of Core‐Shell Rubber Nanoparticles Toughened Poly(l‐lactide) Blends

“…[ 6–8 ] In this condition, poly( l ‐lactide) (PLLA), as one typical member of bio‐based and biodegradable polymers, has gained a great development opportunity due to its good biocompatible, optical, and mechanical properties. [ 9–12 ] Unfortunately, the further development and industrial applications of PLLA are still impeded by its poor thermal stability, gas barrier properties, especially brittleness until now. [ 13–16 ] Using rubber particles to toughen PLLA has proved to be a simple and economical method.…”