Characterization, crystallization kinetics, and melting behavior of poly(ethylene succinate) copolyester containing 10 mol % butylene succinate

Abstract

Copolyester was synthesized and characterized as having 89.9 mol % ethylene succinate units and 10.1 mol % butylene succinate units in a random sequence, as revealed by NMR. Isothermal crystallization kinetics was studied in the temperature range (T c ) from 30 to 73 C using differential scanning calorimetry (DSC). The melting behavior after isothermal crystallization was investigated using DSC by varying the T c , the heating rate and the crystallization time. DSC curves showed triple melting peaks. The melting behavior indicates that the upper melting peaks are associated primarily with the melting of lamellar crystals with various stabilities. As the T c increases, the contribution of recrystallization slowly decreases and finally disappears. A Hoffman-Weeks linear plot gives an equilibrium melting temperature of 107.0 C. The spherulite growth of this copolyester from 80 to 20 C at a cooling rate of 2 or 4 C/min was monitored and recorded using an optical microscope equipped with a CCD camera. Continuous growth rates between melting and glass transition temperatures can be obtained after curve-fitting procedures. These data fit well with those data points measured in the isothermal experiments. These data were analyzed with the Hoffman and Lauritzen theory. A regime II ! III transition was detected at around 52 C.

Biodegradable poly(ethylene succinate) blends and copolymers containing minor amounts of poly(butylene succinate)

“…In the 13 C‐NMR spectrum of PEBSA 50/50, the carbonyl carbons were split into four peaks, which areas were utilized for the determination of the triads possibility, composition and the ester sequence distribution in this copolyester. Based on the analysis of carbonyl carbons, PEBSA 90/10 copolyester was characterized as having 89.9 mol % ethylene succinate (ES) units and 10.1 mol % BS units in a random sequence 34. Only enlarged 13 C‐NMR spectrum of the carbonyl carbons of PEBSA 90/10 copolymer is replotted in Figure 1 for the comparison with PES/PBS 90/10 blend.…”

“…Detailed studies of isothermal crystallization kinetics of PEBSA copolymers were reported in our most recent works 34, 35. For brevity, only the kinetic analysis of PES/PBS 90/10 blend is presented here.…”

“…In previous studies, it was found that the incorporation of trimethylene succinate units into PES significantly inhibited the crystallization behavior of PES and decreased its melting temperature 32. To increase the biodegradation rate without sacrificing the melting temperature of succinates, PES copolymers with minor amounts of butylene succinate (BS) were synthesized in this work 33–35. Blends of PES and PBS were prepared in chloroform with the weight ratios of PES/PBS: 98/02, 95/05, and 90/10 for the comparison with the copolymers.…”

Synthesis and characterization of biodegradable poly(butylene succinate)‐co‐oligo(L‐valine) copolyesters via direct melt transesterification

“…In the past two or three decades, there has been considerable interest in the development of biodegradable and biocompatible polymers. Among the synthetic biodegradable polymers, aliphatic polyesters, poly(butylene succinate) (PBS),1 polylactide (PLA),2 and Poly(amino acid)3, 4 have been thoroughly investigated and use in the field of pharmaceutical, agricultural, and biomedical materials 5–7…”

Crystal growth rates and master curves of poly(ethylene succinate) and its copolyesters using a nonisothermal method

“…Combining self‐nucleation and nonisothermal temperature programs facilitates the expansion of the temperature range where growth rate data are measurable. Using this approach, Lu et al recently estimated the G values of PETSA 80/2012 and PEBSA 90/1018 between the melting ( T m ) and the glass transition ( T g ) temperatures, where PEBSA is a copolymer of ethylene succinate and butylene succinate. Those continuous growth rates fitted well with the data points measured in the isothermal experiments.…”