Design of PLA/ENR thermoplastic vulcanizates with balanced stiffness‐toughness based on rubber reinforcement and selective distribution of modified silica

Abstract

Elastomer-toughened PLA has incubated plenty outstanding achievements. Principally, increasing elastomer content will immolate vast rigidity in exchange for toughness. In this work, silane coupler KH550-treated SiO 2 and ENR were used to synergistically enhance and toughen PLA via dynamic vulcanization. It is found that the PLA/ENR/SiO 2 TPV with balanced stiffness and toughness exhibited a bicontinuous phase structure. Thereinto, the hydrophobic SiO 2 nanoparticles were regulated to uniformly disperse in the ENR phase, which played an essential role in reinforcing the rubber and bracing the symmetrical rubber network, so as to toughen the PLA with retaining high stiffness at an acceptable plastic-to-rubber ratio. By incorporating nano-SiO 2 modified with 10 phr KH550, the TPV could obtain an impact strength of 23.7 kJ/m 2 at 0 C while maintain a tensile strength of 42.1 MPa, which were 1.62-fold and 1.03-fold of those before modification, respectively. The synergistic enhancing and toughening mechanism of nano-SiO 2 and ENR was revealed through a series of test and analysis, which furnished a succinct and effective proposition of fabricating high-performance PLA materials.

Synergistic toughening of poly(lactic acid)/poly(ethylene vinyl acetate) (PLA/EVA) by dynamic vulcanization and presence of hydrophobic nanoparticles

“…However, it seems that blending with a rubbery polymer is the most convenient, economic, and efficient method to toughen the PLA. For this purpose, different nonbiodegradable or biodegradable rubbery polymers have been tried as toughening agent: acrylate copolymer (ACR), 13 poly(caprolactone) (PCL), 8 nitrile rubber (NBR), 14 epoxidized natural rubber (ENR), 15 poly(butylene succinate) (PBS), 16 thermoplastic polyurethane (TPU), 17,18 polycarbonate (PC), 19 poly(ethylene‐co‐vinyl acetate) (EVA) copolymer, 20,21 and poly (ethylene oxide) PEO 22–24 . As most of these polymers are incompatible with PLA, their blending with PLA leads to weak and inferior mechanical properties.…”

Dynamically vulcanized polylactic acid/natural rubber/waste rubber blends: Effect of the crosslinking agent on the morphology and tensile properties

“…GTR rubber wastes can further be used as partial substitute of fresh rubber in thermoplastic elastomers, beneficiating from the abovementioned strategies to design NR/GTR or PLA/GTR blends using compatibilization between of fresh rubber, wastes rubber, and plastics. This is of particular interest for the design of bio‐based brittle plastics such as PLA conventionally dynamically vulcanized with natural rubber, 22–24 where compatibilization by dynamic vulcanization was used to improve the tensile and impact properties of PLA/NR blends 25,26 or PLA/NR‐based blends 27,28 . However, these PLA/NR blends still contain wide amount of PLA and hence remain expensive materials that do not necessarily widely lower the cost of common commodity plastics.…”

“…This is of particular interest for the design of bio-based brittle plastics such as PLA conventionally dynamically vulcanized with natural rubber, [22][23][24] where compatibilization by dynamic vulcanization was used to improve the tensile and impact properties of PLA/NR blends 25,26 or PLA/NR-based blends. 27,28 However, these PLA/NR blends still contain wide amount of PLA and hence remain expensive materials that do not necessarily widely lower the cost of common commodity plastics. Hence, there is still a necessity to design novel strategies for PLA impact elastomeric modifiers.…”

Simultaneously Toughening and Reinforcing Polylactide by Regulating the Distribution of Core–Shell Rubber Particles with Carbon Black

“…Adding rigid nanoparticles (such as silica dioxide (SiO 2 ), carbon black (CB), clay) into rubber toughened polymer blends has proved to be an effective way to compensate strength and modulus losses. [21,[37][38][39][40] Moreover, rigid nanoparticles can also maintain or even further enhance the toughness. For example, rigid nanoparticles could act as compatibilizers to greatly reduce the size of dispersed rubber phase and thus contribute to a significant enhancement in toughening efficiency.…”