Effect of TPU hard segment content on the rheological and mechanical properties of PLA/TPU blends

Abstract

Blends of an amorphous polylactide (PLA) with three different thermoplastic polyurethane (TPU) grades having various hard segment (HS) contents are prepared at the blending ratio of 85/15 wt% through a twin‐screw extruder (TSE) at processing temperatures of 150 and 190°C. Blends of a semicrystalline PLA with 15 wt% of the noted TPU grades are also processed in the TSE at 190°C to investigate the matrix crystallization effect on the morphology and property enhancements. The rheological experiments reveal that the increase in TPU HS content significantly increases the phase compatibility between PLA and TPU as also suggested by the finer morphology of the TPU phase, although the use of lower HS TPUs is more favorable to enhance the ductility and impact properties of the blends.

Mechanical and viscoelastic properties of polyethylene‐based microfibrillated composites from 100% recycled resources

“…The processing type and parameters also influence the blends morphology due to the changes in the applied shear and elongational forces as well as the changes in the viscoelastic properties and the viscosity ratios 42–44 . Therefore, besides processing at 250°C in TSE, the rPE/rPET system was also melt processed in TSE at 275°C where the PET phase could also completely melt and flow better.…”

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

“…Several studies have investigated the morphological and mechanical properties of PLA/TPU blends with and without using a compatibilizer 43–61 . Although some studies have reported that PLA and TPU are not compatible, 43–45 a few studies have shown that the ductility and impact strength of the PLA/TPU blends could be improved to some extent without the use of a compatibilizer while the strength and modulus were also decreased 44–49 .…”

Toughening Modification of Polylactic Acid by Thermoplastic Silicone Polyurethane Elastomer

“…Thermoplastic polyurethane (TPU) is an elastomeric polymer with a unique combination of properties, such as high ductility, toughness, durability, flexibility, biocompatibility and biostability [51]. The molecular structure of TPU includes hard segments and soft segments.…”

“…TPU obtains rigidity and hardness from the crystalline domain of the hard segment, while the amorphous soft segment provides its flexibility and elastic behavior [52][53][54]. Several studies explored how the tensile strength and elastic modulus of the blends made by TPU-toughened PLA gradually decreased with the increase of TPU content, while the elongation at break and impact strength were greatly increased [47,50,51,[55][56][57][58][59]. Han et al [58] prepared PLA/TPU blends by melt blending, and the mechanical test results showed that the elongation at break of the blend increased greatly, while the yield strength decreased.…”

“…Jing et al [56] used TPU as a toughening modifier to melt blend with PLA, the results showed that the PLA/TPU blend was an incompatible system and had an obvious island structure. Nofar et al [51] blended PLA with three different TPU grades with different hard segment content to study the effect of matrix crystallization on morphology and performance. Rheological experiments showed that the increase in hard segment content significantly improves the compatibility between PLA and TPU, although the use of TPU with lower hard segment was more conducive to enhancing the ductility and impact properties of the PLA.…”