Partial to complete wetting transitions in immiscible ternary blends with PLA: the influence of interfacial confinement

Abstract

In this study it is shown that the three different intermediate phases in melt blended ternary PLA/PHBV/PBS, PLA/PBAT/PE and PLA/PE/PBAT systems all demonstrate partial wetting, but have very different wetting behaviors as a function of composition and annealing. The interfacial tension of the various components, their spreading coefficients and the contact angles of the confined partially wet droplets at the interface are examined in detail. A wetting transition from partially wet droplets to a complete layer at the interface is observed for both PHBV and PBAT by increasing the concentration and also by annealing. In contrast, in PLA/PE/PBAT, the partially wet droplets of PE at the interface of PLA/PBAT coalesce and grow in size, but remain partially wet even at a high PE concentration of 20% and after 30 min of quiescent annealing. The dewetting speed of the intermediate phase is found to be the principal factor controlling these wetting transitions. This work shows the significant potential for controlled wetting and structuring in ternary polymer systems.

Nucleation modalities in poly(lactide), poly(butylene succinate), and poly(ε‐caprolactone) ternary blends with partial wetting morphology

“…Moreover, the size of PLA spherulites at a given time is larger for the second sample (Figure 4(D–F)), which means nucleation occurs at earlier times in the 45/10/45 PLA/PCL/PBS blend. Therefore, under the assumption that the surface‐nucleation events highlighted in Figure 4 are actually occurring at the interface with partially wet droplets, and considering the interfacial areas with PLA are similar in the two blends (or higher for the 45/10/45 PLA/PBS/PCL, as expected on the basis of the interfacial tensions for PBS/PLA and PCL/PLA pairs 53–54 ), these results on the nucleation of the PLA major phase confirm the higher apparent nucleation efficiency of molten PCL surfaces with respect to the PBS melt. Similar results have been previously reported by us for PLA partially wet droplets in the 45/10/45 PBS/PLA/PCL blend 43 …”

Ductility and Toughness Improvement of Injection-Molded Compostable Pieces of Polylactide by Melt Blending with Poly(ε-caprolactone) and Thermoplastic Starch

“…In addition to binary blends, a wide variety of ternary blends based on PLA have been proposed to tailor the desired properties, particularly in terms of improved toughness [35,36,37]. On the one hand, PCL is a well-known synthetic aliphatic biopolyester, characterized by a high crystallinity, relatively fast biodegradability, and high ductility.…”

Environmentally Friendly Compatibilizers from Soybean Oil for Ternary Blends of Poly(lactic acid)-PLA, Poly(ε-caprolactone)-PCL and Poly(3-hydroxybutyrate)-PHB

“…Due to the low miscibility of PLA with most polymers, the use of compatibilizers and/or reactive extrusion have been proposed as technical solutions to improve compatibility in binary PLA-based blends [ 30 , 33 ]. Moreover, ternary blends with PLA have also given good results in terms of improved toughness as tailored properties can be obtained by selecting the appropriate components and/or compatibilizers [ 24 , 34 , 35 , 36 , 37 , 38 , 39 ].…”