Super Toughened Poly(lactic acid)-Based Ternary Blends via Enhancing Interfacial Compatibility

Abstract

Novel super toughened bioplastics are developed through controlled reactive extrusion processing, using a very low content of modifier, truly a new discovery in the biodegradable plastics area. The super toughened polylactide (PLA) blend showing a notched impact strength of ∼1000 J/m with hinge break behavior is achieved at a designed blending ratio of PLA, poly(butylene succinate) (PBS), and poly(butylene adipate- co -terephthalate) (PBAT), using less than 0.5 phr peroxide modifier. The impact strength of the resulting blend is approximately 10 times that of the blend with the same composition without a modifier and ∼3000% more than that of pure PLA. Interfacial compatibilization among the three biodegradable plastics took place during the melt extrusion process in the presence of a controlled amount of initiator, which is confirmed by scanning electron microscopy and rheology analysis. The synergistic effect of strong interfacial adhesion among the three blending components, the decreased particle size of the most toughened component, PBAT, to ∼200 nm, and its uniform distribution in the blend morphology result in the super tough biobased material. One of the key fundamental findings through the in situ rheology study depicts that the radical reaction initiated by peroxide occurs mainly between PBS and PBAT and not with PLA. Thus, the cross-linking degree can be controlled by adjusting renewable sourced PLA contents in the ternary blend during reactive extrusion processing. The newly engineered super toughened PLA with high stiffness and high melt elasticity modulus could reasonably serve as a promising alternative to traditional petroleum plastics, where high biobased content and biodegradability are required in diverse sustainable packaging uses.

Morphology and performance relationship studies on biodegradable ternary blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polylactic acid, and polypropylene carbonate

“…Heat deection temperature (HDT) is important for materials because it determines the highest temperature a material can withstand before deformation. 7 It is well known that PLA exhibits rather low HDT ($55 C) and the addition of PLA normally leads to a decrease of HDT of blends. 8 In this study, the addition of 35% PLA did not weaken the HDT of PHBV dramatically.…”

“…PLA exhibits high modulus and strength, yet, it is brittle and fractures easily, greatly hindering its potential for high performance applications. [7][8][9] PHBV is a linear aliphatic polyester bioplastic that is nontoxic, biodegradable, and biocompatible. It is produced by bacteria and is a good substitute for petroleum-based polymers.…”

Improvement of Interlayer Adhesion and Heat Resistance of Biodegradable Ternary Blend Composite 3D Printing

“…However, PLA has limitations of brittleness and low heat resistance. Research has shown that blending with ductile polymers, i.e., poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene succinate) (PBS), polycaprolactone (PCL) [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], and incorporating with particulate fillers and reinforcing fibers [ 25 , 26 , 27 , 28 , 29 ], can improve the limitations of PLA. From our previous study, the binary blend composites from PLA and PBAT blends (PLA/PBAT) and composites with nano talc (PLA/PBAT/nano talc) at 70/30/0/10 exhibited good toughness and printability, and can be presented as alternative filaments in FDM 3D printing [ 28 ].…”

Novel tunable super-tough materials from biodegradable polymer blends: nano-structuring through reactive extrusion

“…Several goals are achieved in our current research: (i) by carefully choosing the polymer pairs, nano-blends can be obtained by reactive extrusion and the mechanism of the nanoblends formation has been discussed here to guide the future nano material designing; (ii) the effects of the peroxide usage and its reaction with the polymer components is discussed; (iii) high impact strength and high melt strength PBS nano-blends can be processed like traditional blending without the need to change the current equipment or production speed; (iv) the low contents of peroxide initiator in this research meets the development of industrial environmentally-friendly processes; and furthermore biodegradable blends are expected to be developed base on the formulation and concept proposed here. 24…”