No abstract

With a high melting temperature and good crystallization ability, poly­(neopentyl glycol 2,5-furandicarboxylate) (PNF), a polyester derived from bio-based 2,5-furandicarboxylic acid and neopentyl glycol, has been proposed and proved to be a promising hard segment for the development of novel bio-based thermoplastic poly­(ether-ester) elastomer (TPEE). The resulting TPEE, namely PNF–PTMG, has high performance comparable to the petroleum-based counterpart PBT–PTMG (i.e., Hytrel, Dupont). Among all of the existing polyesters derived from bio-based 2,5-furandicarboxylic acid (FDCA), PNF has perfectly balanced properties, namely, a high melting temperature of 200 °C and a good crystallization ability to easily grow medium to large-size crystalline spherulites. Characterizations based on dynamic mechanical analysis and small-angle X-ray scattering suggest that there are two domains in PNF–PTMG, the crystalline PNF and a mixture of amorphous PNF and PTMG. These two domains form microphase separation induced mainly by the crystallization of PNF. By adjusting the PTMG soft segment from 30 to 60 wt%, PNF–PTMG shows a melting temperature, tensile modulus (E), and elongation at the break (εb) ranging from 180 to 134 °C, 738 to 56 MPa, and 38 to 1089%, respectively. More importantly, the shape recovery ratios increase from 57 to 90% at 200% strain when the amount of PTMG increases from 50 to 70 wt%, indicating excellent elastic property. These results indicate that PNF is an excellent hard segment to serve as a strong physical cross-link so that PNF–PTMG is able to display high performance comparable to extensively commercialized PBT–PTMG.

Improving the phase separation and stability of the hard segment domains at the same time is the novel method reported here to improve the recovery of thermoplastic shape memory polyurethanes (SMPUs) at high strain (>1000%). The shape recovery of the corresponding SMPUs with a more than 1000% strain can reach about 96% at room temperature in 3 min, the recoverable strain (3 max À 3 permanent ) is more than 960%, which is nearly 2.5 times that of the best value (400%) previously reported.