Super toughened and highly ductile PLA/TPU blend systems by in situ reactive interfacial compatibilization using multifunctional epoxy‐based chain extender

Abstract

This study investigates the influence of using multifunctional epoxy Joncryl ADR 4468 chain extender (CE) on the properties of various polylactide (PLA)/thermoplastic polyurethane (TPU) (75 wt/25 wt) blend systems. The blends were based on two different TPU grades with ether‐ and ester‐based soft segment as the dispersed phase (i.e., TPUether and TPUester) and an amorphous and a semicrystalline PLA grades as the matrix (i.e., aPLA and scPLA). PLA appeared to be more compatible with the TPUester, which caused the enhancement of the impact strength and strain at break values of the blends more remarkably. The dynamic rheological experiments also confirmed that the CE revealed a better reactivity with TPUester than TPUether. This further enhanced the interfacial compatibility between the PLA and TPUester and thereby dramatically improved the impact strength and ductility of the PLA/TPUester blends, specifically those with 0.5 wt% CE. Meanwhile, aPLA as the matrix reflected the TPUs toughening effect more efficiently than scPLA. This was due to the possible shrinkage caused by the crystallization of scPLA matrix, which could deteriorate the interfacial interactions between the phases in the corresponding blends.

Insight into roles of different types of additives on mechanical and crystalline properties of polylactic acid

“…It is inferred that few reactive groups, that is, O═C═N , in TPU potentially due to the incomplete polymerization can react with terminal OH and COOH groups of PLA molecules forming crosslinking-grafting structures, 20,33 as marked by the red dotted circles. With respect to the ADR4468 chain extender, it is a co-polymer containing multifunctional epoxy groups, 19 which can react with the terminal groups of PLA, crosslinking to form molecular structures with branched chains, and the possible ringopening mode of epoxy groups and reaction procedure are also illustrated in Figure 3.…”

“…[1][2][3][4][5][6]8,[10][11][12][13][14][15] Comparing with distinct modification methods, including physical blending, 3,5,8,10,[15][16][17] co-polymerization, 1,11,14 nanofilling 4,18 and so forth, the reactive extrusion 14,[19][20][21][22][23] is the most economical and effective method which can adjust the size of dispersion phase and improve comprehensive performance of the polymer blends. In particular, the effective method widely used to improve the toughness and ductility is blending with flexible polymers, such as epoxy-based chain extender, [23][24][25][26] PBAT, 10,14 poly(ε-caprolactone) (PCL), 3 thermoplastic polyurethane (TPU) 16,17,19 and polyolefin polymers, 2,5 and so forth. Moreover, many mineral fillers, such as talc 27,28 and calcium carbonate, 12 have been used for many years as the nucleating agents in commercial polymers, and furthermore talc has been attested efficient to enhance the crystallinity of P...…”

Thermal Stabilization of Recycled PET Through Chain Extension and Blending with PBT

“…Depending on the chemical nature and number of available functional groups of CEs, linear chain extension and/or branching of PET molecules could be observed. So far, several CEs such as bis-oxazolines [24], pyromellitic dianhydride (PMDA) [22], organic phosphites [25][26][27], isocyanides [28,29] and epoxides [4,5,[29][30][31][32][33][34][35] have been proposed to extend the molecules of polyesters. Among these CEs, multifunctional epoxides better known under the trade name of Joncryl® ADR are the most commonly used CEs to enhance the melt properties of PET [36].…”

Composition design ofPLA/TPUemulsion blends compatibilized with multifunctional epoxy‐based chain extender to tackle high impact resistant ductile structures

“…2 In PLA/TPU blends, the inherent molecular structure of TPU such as hard segment content, soft segment molecular weight and having ether or ester backbone soft segment [72][73][74][75] could influence the phase compatibility and the final mechanical performance in PLA blends. [62][63] Overall, it has been reported that PLA/TPU blends are not compatible systems. 53,54,61,76,77 Hence, compatibilizers should be incorporated to generate blends with strong interfacial interaction, which could cause the achievement of desired ductility, toughness, and impact resistance.…”