Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents.

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Bio-based unsaturated poly(butylene adipate-co-butylene itaconate) (PBABI) aliphatic copolyesters were synthesized with pentaerythritol (PE) as a modifier, observing the melting point, crystallization, and glass transition temperatures were decreased from 59.5 to 19.5 °C and 28.2 to −9.1 °C as an increase of itaconate concentration, and Tg ranged from −54.6 to −48.1 °C. PBABI copolyesters tend to the amorphous state by the existence of the BI unit above 40 mol%. The yield strength, elongation, and Young’s modulus at different BA/BI ratios were valued in a range of 13.2–13.8 MPa, 575.2–838.5%, and 65.1–83.8 MPa, respectively. Shear-thinning behavior was obtained in all BA/BI ratios of PBABI copolyesters around an angular frequency range of 20–30 rad s−1. Furthermore, the thermal and mechanical properties of PBABI copolyesters can be well regulated via controlling the itaconic acid contents and adding the modifier. PBABI copolyesters can be coated on a 3D air mesh polyester fabric to reinforce the mechanical property for replacing traditional plaster applications.

Nonisocyanate polyurethane (NIPU) was synthesized using different concentrations of C36‐alkylenediamine (C36DDA), hexamethylene diamine, and a cyclic carbonate monomer synthesized from bisphenol A epoxy resin and carbon dioxide. The structures, molecular weights, thermal behaviors, and stabilities of the NIPU copolymers were evaluated using 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry measurements. All synthesized NIPUs were amorphous and exhibited good Td−5% thermal stabilities above 250°C; Tg decreased from 73 to 51°C as C36DDA content increased from 0% to 10% based on dynamic mechanical analysis tests. Furthermore, ethylenediamine (EDA) as a chain extender incorporating a small amount of crosslinker 1,2,4,5‐benzenetetracarboxylic acid (PMA) can enhance the melt strength of a partially three‐dimensional network, and the attained NIPU showed elastic properties. Thus, the NIPU synthesized with 7.5% and 10% C36DDA containing small amounts of EDA and PMA were suitable choices for supercritical CO2 foaming; their morphologies and mechanical behaviors were examined by scanning electron microscopy and DMA, and the densities of foamed NIPU with 7.5% and 10% C36DDA were calculated as 432 and 215 kg m−3 with pore sizes of 10–20 μm, respectively. The maximum stresses were attained at 149.5 and 123.4 kPa, and the foamed NIPU displayed rigid foam behaviors owing to the compression behaviors of the stress–strain curves.

A series of polyurethane (PU) copolymers was synthesized by 4,4-Methylene diphenyl diisocyanate (MDI) with different polyols of polyether, polyether carbonate (PEC), and polycarbonate with the same molecular weight via a one-step copolymerization process. The synthesized PU containing the ether carbonate groups exhibited a relatively higher glass transition temperature (T g ) above 45 C; in comparison, a value of 12.4 C for the polycarbonate sample and À22 C for the polyether sample was observed. The film made of PEC samples produced by solvent indicated an increment of T g from 14.6 to 59.6 C after annealing for 6 h, which might be due to the rearrangement of chain structure, which led to an assembling of carbonate groups and resulted in a hindrance of chain mobility. For shape memory examination of the PU copolymers, all samples showed remarkable ability as recovery rate above 91% after 3 cycles test. PEC-type PU polymers reveal potential high-temperature micro shape memory material applications.