A series of thermoplastic poly(ester urethane)s (PUs) containing poly(butylene 1,4-cyclohexanedicarboxylate) (PBC) as a soft segment were prepared for shape memory materials via a two-step synthesis, with isophorone diisocyanate and 1,4-butanediol as its hard segments. The isomerization of the 1,4-cyclohexylene ring moiety (CHRM) happened during the preparation of PBC oligomers with molecular weight of 1700, 2300 and 3300 g mol−1, but such phenomenon was not observed during the reaction for the synthesis of PU. The three PBC oligomers could all crystallize, but their crystallization ability was depressed after incorporation of PUs. Thermo, thermo-mechanical and mechanical properties of the corresponding PUs were studied to understand their structural information. It was found that the PU containing PBC1700 was an elastomer at elevated temperatures, and its shape memory properties were evaluated by DMA procedures. Regardless of its low degree of micro-phase separation, it was very interesting to find that the shape recovery ability of such PU was excellent, which was in contrast to traditional findings.
Xiansong Wang,Qingyin Wang,Shaoying Liu,Gongying Wang
A series of bio-based copolyesters, poly(ethylene 2,5-furandicarboxylate-co-ethylene 1,4-cyclohexanedicarboxylate)s (PEFCs) were synthesized from ethylene glycol (EG), 2,5-furandicarboxylic acid (FDCA) and 1,4-cyclohexanedicarboxylic acid (CHDA) through a two-step melt polycondensation procedure. The chemical structure , compositions and sequence distributions were determined by 1 H NMR. The molecular weight , thermal properties, thermal stabilities, crystal structure and mechanical properties were investigated by GPC , DSC , TGA , WAXD , and tensile testing , respectively. All PEFCs showed the characteristic of random copolymer , and their composition could be controlled by the feed molar ratio of FDCA to CHDA. DSC results showed that PEFCs were amorphous , while increasing the content of the CHDA unit, the glass transition temperatures (Tg) of PEFCs decreased. Moreover, the thermal stabilities of all PEFCs remained unchanged. The tensile testing demonstrated that PEFC-30 was a toughened plastic with tensile modulus 801 MPa and elongation 667%.
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