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.
This study investigates the effect of using a multifunctional epoxide chain extender (Joncryl® ADR 4468) on the thermal stabilization and rheological properties of recycled polyethylene terephthalate (R-PET) and its blends with polybutylene terephthalate (PBT). The thermal stability of the melt blended samples was analyzed through small amplitude oscillatory shear (SAOS) rheological experiments. The structure of the samples was evaluated using a Fourier transform infrared (FTIR) spectrometer. While the dynamic rheological properties of R-PET were improved with the addition of Joncryl and by blending with PBT, during the SAOS rheological experiments, the complex viscosity of R-PET further increased due to the concurrent polycondensation of R-PET and the resumption of Joncryl reaction with R-PET molecules.These reactions during the rheological experiments were further expedited with increasing the testing temperature. On the other hand, in R-PET/PBT blends, the reactivity of Joncryl was more noticeable in blends with higher R-PET contents due to the higher available internal reactive sites of much shorter R-PET molecules. It was observed that the addition of only 0.2 wt.% Joncryl to the blends of R-PET/PBT (75w/25w) dramatically improves the thermal stability and dynamic rheological properties of R-PET and most likely its processability.
In this study, the composition of polylactide (PLA)/thermoplastic polyurethane (TPU) emulsion blends compatibilized with multifunctional epoxy-based Joncryl chain extender was regulated to tackle high impact resistant structures with improved ductility. PLA/TPU blends at different blending ratios of 95wt/05wt, 85wt/15wt, 75wt/25wt, and 65wt/35wt were first melt blended with 0.5 wt% of Joncryl. In all compositions, although the TPU droplets were significantly refined with the addition of Joncryl, the impact strength and ductility of the blends increased dramatically only at 75wt/25wt and 65wt/35wt blending ratios. The 75wt/25wt blend was then melt blended with various Joncryl contents of 0.25, 0.5, 0.75, and 1.0 wt%. It was illustrated that 0.5 wt% Joncryl was high enough to reach a blend with the highest impact strength and ductility of around 110 kJ/m 2 and 150%, respectively. This was while the tensile strength and modulus values remained comparable with those of neat PLA. The rheological experiments and the dynamic mechanical analysis confirmed that the complex viscosity and the storage modulus of the compatibilized blends were improved as a result of increased melt strength of PLA and the interfacial compatibilization through using Joncryl.
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