Melting Behaviors of Bio-Based Poly(propylene 2,5-furan dicarboxylate)-b-poly(ethylene glycol) Co Polymers Related to Their Crystal Morphology

In this experiment, a series of poly(propylene 2,5-furan dicarboxylate)-b-poly(ethylene glycol) (PPFEG) copolymers with different ratios were synthesized using melt polycondensation of dimethylfuran-2,5-dicarboxylate (DMFD), 1,3-propanediol (PDO) and poly(ethylene glycol) (PEG). The effect of PEG content on the crystallization behavior of the poly(propylene 2,5-furan dicarboxylate) (PPF) copolymers was investigated. For PPF, the nucleation density of the β-crystals was higher than that of α-crystals. As Tc increases, the β crystals are suppressed more, but at Tc = 140 °C, the bulk of PPF has already been converted to α crystals, which crystallize faster at higher nucleation densities, resulting in a difference in polymer properties. For this case, we chose to add a soft segment material, PEG, which led to an early multi–melt crystallization behavior of the PPF. The addition of PEG led to a decrease in the crystallization temperature of PPF, as well as a decrease in the cold crystallization peak of PPF. From the crystalline morphology, it can be seen that the addition of PEG caused the transformation of the PPF crystalline form to occur earlier. From the crystalline morphology of PPF at 155 °C, it can be observed that the ring-banded spherical crystals of the PPF appear slowly with increasing time. With the addition of PEG, spherical crystals of the ring band appeared earlier, and even appeared first, and then disappeared slowly.