Largely improved fracture toughness of an immiscible poly(l-lactide)/ethylene-co-vinyl acetate blend achieved by adding carbon nanotubes

Abstract

In this work, different contents of CNTs were introduced into an immiscible poly(L-lactide)/ethylene-covinyl acetate (PLLA/EVA) blend that exhibited a sea-island structure to further demonstrate the toughening probability of CNTs on the immiscible polymer blends. The fracture toughness was evaluated through impact measurements. The impact-fractured surface morphologies as well as the morphological changes of the blend induced by adding CNTs were characterized using scanning electron microscope. Furthermore, rheological properties and glass transition behaviors of samples were comparatively investigated to better understand the toughening mechanisms. The results demonstrated that although the presence of CNTs resulted in the formation of EVA particles with irregular shape and simultaneously increased diameters and matrix ligament thickness, which were usually thought to be unfavorable for the improvement of fracture toughness according to the Wu's toughening mechanism, the blend composites still exhibited largely enhanced fracture toughness compared with the binary blend, and the impact strength increased gradually with increasing content of CNTs. The plastic deformation ability of PLLA matrix during the fracture process was greatly enhanced, especially when CNTs formed the physical network structure. Further results demonstrated that the glass transition behavior of EVA particles was greatly influenced by CNTs. Then, the toughening mechanism was proposed on the basis of the morphological changes of EVA particles, the formation of CNT physical network structure and the glass transition behavior of EVA. The other mechanical properties were also measured and analyzed. This work further demonstrated the toughening effect of CNTs on the immiscible polymer blends, and the methodology can be widely adopted in industry application.

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

“…The use of inorganic fillers in the elastomer could toughen the polymeric system and further enhance the impact strength of the blends 34–37 . Wang et al reported that the addition of carbon nanotube (CNT) to the PLA/EVA can largely enhance its fracture toughness 34 . CNTs are placed near EVA particles and largely increased the plastic deformation ability of the PLA matrix upon fracture.…”

New, Effective, and Low-Cost Dual-Functional Binder for Porous Silicon Anodes in Lithium-Ion Batteries

“…Poly­(ethylene- co -vinyl acetate) (EVA) has drawn much attention because of its tunable physical and chemical characteristics. The mechanical properties of EVA are controlled by ethylene/vinyl acetate (VA) weight composition. − EVA, with higher VA units, shows rubber property and is always applied to improve the fracture toughness of rigid substrates. ,− Furthermore, EVA colloids act as host materials for electrolytes because of much of electrolyte permeating into the colloids. Inspired by the merits of PAA and EVA, we report a new binder PAA/EVA prepared by simply mixing low-cost PAA and EVA.…”

Influence of Protonic Ionic Liquid on the Dispersion of Carbon Nanotube in PLA/EVA Blends and Blend Compatibilization

“…Blending conducting fillers as carbon nanotube (CNT) expands the field of applications of these semi-biodegradable composite as antistatic, dielectric and microwave absorbing materials for utilization in electronic packaging. Most of the studies involving CNT-based PLA/EVA composites focused on the improvement of mechanical properties and toughness of the blends (Shi et al, 2011(Shi et al, , 2012Wang et al, 2015Wang et al, , 2016Liu et al, 2016). Studies related with the electrical properties of PLA/EVA blends loaded with CNT was reported by Shi et al (2013).…”