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A series of poly(butylene adipate-co-hexamethylene adipate) (PBHA) copolymers with different content of 1,4-cyclohexanedimethanol (CHDM) was synthesized via one-step melt polymerization. The PBHA copolymer with 5 mol% CHDM (PBHA-C5) exhibited a low melting point (Tm) and high enthalpy of fusion (∆Hm) of 35.7 °C and 43.9 J g−1, respectively, making it a potential candidate for an ambient temperature adjustment textile phase change material (PCM). Polybutylene terephthalate (PBT) was selected as the matrix and blended at different weight ratios of PBHA-C5, and the blended samples showed comparable Tm and ∆Hm after three cycles of cooling and reheating, indicating good maintenance of their phase changing ability. Samples were then processed via melt spinning with a take-up speed of 200 m min−1 at draw ratios (DR) of 1.0 to 3.0 at 50 °C. The fiber's mechanical strength could be enhanced to 2.35 g den−1 by increasing the DR and lowering the PBHA-C5 content. Infrared thermography showed that a significant difference of more than 5 °C between PBT and other samples was achieved within 1 min of heating, indicating the ability of PBHA-C5 to adjust the temperature. After heating for 30 min, the temperatures of neat PBT, blended samples with 27, 30, and 33 wt% PBHA-C5, and neat PBHA-C5 were 53.8, 50.2, 48.3, 47.2, and 46.5 °C, respectively, and reached an equilibrium state, confirming the temperature adjustment ability of PBHA-C5 and suggesting that it can be utilized in thermoregulating applications. [ABSTRACT FROM AUTHOR]

Abstract Three novel aliphatic long-chain comonomer-containing PA6 copolyamides were prepared via melt polycondensation reaction of novel bio-based N1, N6-bis(4-aminobutyl) adipamide derived polyamide salt, and ε-caprolactam. The goal of this study was to investigate the synthesis and the resulting crystal morphology, thermal, rheological and mechanical properties of copolyamides as a function of their comonomer composition. The long-chain based polyamide salt disturb the crystallization of the final copolyamides and lower the onset of melting and glass transition temperatures, which is the result of less stable γ-phase crystalline structure formation. Intriguingly, the thermogravimetric analysis measurements prove that the thermal stability of copolyamides can satisfy the requirement of multiple-processing without decomposition. Most notable is the fact that the tensile testing results exhibit outstanding mechanical behavior, i.e. elongation at break and tensile strength. Graphical abstract Image 107835 Highlights • A series of PA6-BABA/AA copolyamides were successfully synthesized from CPL and novel bio-based linear monomer BABA/AA. • Thermal properties of PA6-BABA/AA dependent on composition. • Copolyamides with thermal stability until 350 °C. • The elongation at break of PA6-BABA/AA is higher than that native PA6. • The PA6-BABA/AA is a potential polymer for industrial scale applications. [ABSTRACT FROM AUTHOR]

This study investigates melt spinnability of ethylene vinyl alcohol (EVOH) copolymers with various ethylene contents, which exhibits excellent biocompatibility but cannot easily undergo single-component fiber spinning. The chemical, thermal and rheological properties of EVOH were examined herein. Three EVOH copolymers, EV-32, 38 and 44, with different ratios of ethylene to vinyl alcohol (EV ratio), were used to evaluate the influence of the ratio on melt spinnability. The EV ratios of EV-32, EV-38 and EV-44 examined by nuclear magnetic resonance were 0.64, 0.82 and 1.0, respectively. The experimental results reveal that the melting temperature (Tm) and crystallinity (Xc) of EVOH decreased in the order EV-32 (178.9℃, 46.6 wt%) > EV-38 (171.9℃, 41.8 wt%) > EV-44 (166.0℃, 40.0 wt%). The thermal stability, however, increases in the order EV-32 < EV-38 < EV-44. The viscosity decreases in the order EV-32 > EV-38 > EV-44. EV-44 has much higher flow activation energy than EV-32 and EV-38, indicating that it has a temperature sensitivity higher than EV-32 and EV-38. The pellets of EV-32, EV-38 and EV-44 were melt spun. Three as-spun fibers, EV-32, EV-38 and EV-44 have cross-sectional diameters of 151.3, 150.9 and 154.1 µm and tensile stresses (strain (%) at breaking point) of 123.1 (205.2%), 121.4 (202.0%) and 131.1 MPa (180.2%), respectively. Most importantly, EV-44 can easily be spun at a relatively low temperature, 245℃, while the other two, EV-38 and EV-32, can hardly be made on condition that the spinning temperatures are higher than 255℃ and 265℃, respectively. Notably, once the spinning temperature of EVOH polymers was higher than 258℃, the degradation of vinyl alcohol segments would cause fuming and broken filaments to eventually terminate the entire spinning process. Ultimately, a brand new fiber, EVOH, with an EV ratio of 1.0, was successfully melt spun and mechanically characterized in this study. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Unsaturated poly (butylene adipate-co-butylene itaconate) (PBABI) copolyesters were synthesized through melt polymerization composed of 1,4-butanediol (BDO), adipic acid (AA), itaconic acid (IA) and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a cross-linking modifier. The melting point, crystallization and glass transition temperature of the PBABI copolyesters were detected around 29.8–49 °C, 7.2–29 °C and −51.1 and −58.1 °C, respectively. Young's modulus can be modified via partial cross-linking by BTCA in the presence of IA, ranging between 32.19–168.45 MPa. Non-isothermal crystallization kinetics were carried out to explore the crystallization behavior, revealing the highest crystallization rate was placed in the BA/BI = 90/10 at a given molecular weight. Furthermore, the thermal, mechanical properties, and crystallization rate of PBABI copolyesters can be tuned through the adjustment of BTCA and IA concentrations. [ABSTRACT FROM AUTHOR]

A series of copolyesters, poly(butylene adipate-co-butylene itaconate) (PBABI), was synthesized using melt polycondensation from adipic acid (AA), itaconic acid (IA), 1,4-butanediol (1,4-BDO), and ethylenediaminetetraacetic acid (EDTA). 1H-NMR, FT-IR, GPC, DSC, TGA, DMA, XRD, Shore D, and tensile test were used to systematically characterize the structural and composition/physical properties of the copolyesters. It was found that the melting point (Tm) and crystallization temperature (Tc) of the copolyesters were, respectively, between 21.1 to 57.5 °C and −6.7 to 29.5 °C. The glass transition (Tg) and the initial thermal decomposition (Td-5%) temperatures of the PBABI copolyesters were observed to be between −53.6 to −55.8 °C and 313.6 and 342.1 °C at varying ratios of butylene adipate (BA) and butylene itaconate (IA), respectively. The XRD feature peak was identified at the 2θ values of 21.61°, 22.31°, and 23.96° for the crystal lattice of (110), (020), and (021), respectively. Interestingly, Shore D at various IA ratios had high values (between 51.3 to 62), which indicated that the PBABI had soft plastic properties. The Young's modulus and elongation at break, at different IA concentrations, were measured to be at 0.77–128.65 MPa and 71.04–531.76%, respectively, which could be attributed to a close and compact three-dimensional network structure formed by EDTA as a crosslinking agent. There was a significant bell-shaped trend in a BA/BI ratio of 8/2, at different EDTA concentrations—the ∆Hm increased while the EDTA concentration increased from 0.001 to 0.05 mole% and then decreased at an EDTA ratio of 0.2 mole%. Since the PBABI copolymers have applications in the textile industry, these polymers have been adopted to reinforce 3D air-permeable polyester-based smart textile. This kind of composite not only possesses the advantage of lower weight and breathable properties for textiles, but also offers customizable, strong levels of hardness, after UV curing of the PBABI copolyesters, making its potential in vitro orthopedic support as the "plaster of the future". [ABSTRACT FROM AUTHOR]