Abstract. Poly(butylene succinate) (PBSu), poly(2-methyl-1,3-propylene succinate) (PMPSu), and PBSu-rich copolyesters were synthesized using an effective catalyst, titanium tetraisopropoxide. Measurements of intrinsic viscosity (1.20-1.28 dl/g) and gel permeation chromatography demonstrated the success of the preparation of polyesters with high molecular weights. The compositions of the copolyesters were determined in three approaches from 1 H and 13 C NMR (nuclear magnetic resonance) analyses, and good agreement between the results was obtained. The distributions of the comonomers were found to be random from the spectra of carbonyl carbon. Their thermal properties were elucidated using a differential scanning calorimeter and a thermogravimetric analyzer. No marked difference exists among the thermal stabilities of these polyesters. However, the window between the glass transition and the melting temperatures becomes narrower with the increase in the concentration of 2-methyl-1,3-propylene succinate in the copolymers. Additionally, the cold crystallization ability decreases considerably. Finally, PMPSu is an amorphous homopolymer. Wide-angle X-ray diffractograms of isothermally crystallized copolyesters also follow the same trend.

Novel miscible ternary blends comprising poly(ethylene azelate) (PEAz) and poly(ε-caprolactone) (PCL), which are biodegradable polymers, and catechin, a natural polyphenol, were discovered. The inherent biodegradability of PEAz and PCL and the biocompatibility of catechin enable these blends to be used for manufacturing functional polymeric materials. The PEAz/catechin/PCL blends exhibit homogeneous phase morphology and one single T g for each of the ternary compositions, demonstrating that the blends are with ternary miscibility. The phenomenon of melting point depression found in the blends confirmed that the PEAz/catechin/PCL blends are inherently miscible with thermodynamically favorable interactions. It also revealed that catechin formed hydrogen-bonding interactions with the polyesters PEAz and PCL in the ternary blends. Ternary miscibility in the PEAz/catechin/PCL blends might be mainly attributed to two factors: (1) a negligible ΔK effect resulting from the symmetric hydrogen-bonding interactions between catechin and PEAZ and between catechin and PCL, and (2) a minimal Δχ effect caused by a slight difference in the solubility parameters of PEAz and PCL in the blends. In these miscible ternary blends, the nonisothermal crystallization of crystalline polyesters was retarded as the catechin content was increased.

Abstract:The green blends of an ionic liquid, 1-ethyl-3-propylimidazolium bis(trifluoromethanesulfonyl) imide { [EPrI][TFSI]}, and a biodegradable polymer, poly(3-hydroxybutyrate) (PHB), were investigated in this study. The influence of an ionic liquid on the crystallization behaviors of a biodegradable polymer was explored. In the blends, the presence of [EPrI]

Recently, ionic liquids (ILs) and biodegradable polymers have become crucial functional materials in green sustainable science and technology. In this study, we investigated the influence of a novel IL, 1-ethyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imide ([EPrI][TFSI]), on the crystallization kinetics of a widely studied biodegradable polymer, poly(ε-caprolactone) (PCL). To obtain a comprehensive understanding, both the isothermal and nonisothermal crystallization kinetics of the PCL blends were studied. Incorporating [EPrI][TFSI] reduced the isothermal and nonisothermal crystallization rates of PCL. Regarding isothermal crystallization, the small k and 1/t0.5 values of the blend, estimated using the Avrami equation, indicated that [EPrI][TFSI] decreased the rate of isothermal crystallization of PCL. The Mo model adequately described the nonisothermal crystallization kinetics of the blends. Increasing the [EPrI][TFSI] content caused the rate-related parameter F(T) to increase. This indicated that the crystallization rate of PCL decreased when [EPrI][TFSI] was incorporated. The spherulite appearance temperature of the blending sample was found to be lower than that of neat PCL under a constant cooling rate. The analysis of the effective activation energy proposed that the nonisothermal crystallization of PCL would not be favorited when the [EPrI][TFSI] was incorporated into the blends. The addition of [EPrI][TFSI] would not change the crystal structures of PCL according to the results of wide angle X-ray diffraction. Fourier transform infrared spectroscopy suggested that interactions occurred between [EPrI][TFSI] and PCL. The crystallization kinetics of PCL were inhibited when [EPrI][TFSI] was incorporated.

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