Ethylene Succinate Research Articles

The Effect of Poly(Ethylene Succinate) on Mechanical Properties of PLLA/PES Blend Prepared by Melt-Blending

Fully biodegradable poly(L-lactide) and poly(ethylene succinate) (PLLA/PES) blends were prepared via melt-blending using PLLA and PES as reactants in a stainless steel chamber. The prepared PLLA/PES blend, as well as neat PLLA and PES, was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD) to confirm the structure and the crystallization of PLLA in the blend. The mechanical properties of PLLA/PES blends were determined by bending and tensile tests and the effects of PES content on the mechanical properties of PLLA/PES blends were investigated. It was found that blending some amount of PES could significantly improve the elongation at break while still keeping considerably high strength and modulus. With increasing PES content, both strength and modulus gradually decreased; however the elongation at break significantly increased. SEM was used to examine the morphology of fracture surfaces of PLLA/PES blends.

Fabrication of Mixed Monolayer of Biodegradable Polymers and Organo-modified Montmorillonite

We investigated formation of ultrathin hybrid films composed of a biodegradable polymers (ex. poly(ethylene succinate), poly(L-lactide), and poly(e-caprolactone)) and organo-modified montmorillonite nanosheet at an air/water interface. When a chloroform solution of the biodegradable polymer was spread onto a surface of an pure water in a Langmuir trough, a mixed monolayer of biodegradable polymer was formed by hybridization with the clay nanosheets at the air/water interface. These results indicated that some ammonium cations spread onto the clay suspension were dissolved into the aqueous subphase before the hybridization with the clay nanosheets. The hybrid monolayers were transferred onto a mica substrate by Langmuir-Blodgett method to form a mixed monolayer. Interestingly, the densities of dimethyl dioctadecyl (DMDO) ammonium determined by the thermogravimetric analysis were constant in the hybrid multilayers prepared from the clay suspensions at the same concentration, regardless of the concentrations of the amphiphilic ammonium salt solutions. Out-of plane and in-plane XRD profiles of the films showed that the cations of DMDO would lie down on the clay layer in the hybrid film.

Crystallization kinetics and morphology of biodegradable poly(butylene succinate-co-ethylene succinate) copolyesters: effects of comonomer composition and crystallization temperature

The crystallization kinetics and morphology of a series of biodegradable poly(butylene succinate-co-ethylene succinate) (P(BS-co-ES)) with ethylene succinate (ES) comonomer composition ranging from 13 to 28 mol% were investigated with various techniques and compared with those of the homopolymer poly(butylene succinate) (PBS) in this work. The crystal structures of P(BS-co-ES) are the same as that of neat PBS, but the crystallinity decreases slightly with increasing the ES composition. The glass transition temperature increases slightly while the nonisothermal melt crystallization peak temperature and melting point decrease for P(BS-co-ES) with increasing the ES composition; moreover, the equilibrium melting point temperature of P(BS-co-ES) is also reduced. The overall isothermal crystallization kinetics of P(BS-co-ES) was studied and compared with that of neat PBS. The crystallization mechanism does not change for either neat PBS and P(BS-co-ES) while the overall crystallization rates of P(BS-co-ES) decrease with increasing ES composition and crystallization temperature. The spherulite growth rates of P(BS-co-ES) also decrease with increasing ES composition and crystallization temperature. Both neat PBS and P(BS-co-ES) exhibit a crystallization regime II to III transition independent of ES composition; moreover, the crystallization regime transition temperature shifts to lower temperatures with increasing the ES composition.

The effect of poly(ethylene succinate) on mechanical properties of PLLA/PES blend prepared by melt-blending

The effect of poly(ethylene succinate) on mechanical properties of PLLA/PES blend prepared by melt-blending

Phase diagrams in blends of poly(3-hydroxybutyric acid) with various aliphatic polyesters

Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3- hydroxybutyric acid) (PHB) with aliphatic polyesters such as poly(butylene adipate) (PBA), poly(ethylene adipate) (PEA), poly(trimethylene adipate) (PTA), or poly(ethylene succinate) (PESu), respectively, were explored mainly using differential scanning calorimeter (DSC) and polarized-light optical microscopy (POM). Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST) is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ring- banded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST) at 180~221°C depending on blend composition. UCST with reversibility was verified.

Unique Crystalline/Crystalline Polymer Blends of Poly(ethylene succinate) and Poly(p-dioxanone): Miscibility and Crystallization Behaviors

Miscibility and crystallization behaviors of poly(ethylene succinate)/poly(p-dioxanone) (PES/PPDO) blends were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). PES/PPDO blends are completely miscible as proved by the single grass transition temperature (T(g)) dependence of composition and decreasing crystallization temperature of the blends in comparison with the respective component. POM observation suggests that simultaneous crystallization of PES and PPDO components in the blends took place, spherulites of one component can crystallize inside the spherulites of the other component, and the unique interpenetrated crystalline morphology has been formed for the blends in the full composition range. Isothermal crystallization kinetics of the blends was studied by DSC and the data were analyzed by the Avrami equation. The results suggest that the crystallization mechanisms of the blends were unchanged but the overall crystallization rates were slowed down compared with neat PES and neat PPDO. WAXD results indicate that the crystal structures of PES and PPDO did not change in the blends.

High-Pressure Analysis of the Multiple Melting Endotherms of Poly(ethylene succinate) and Poly(butylene succinate)

The origin of the multiple melting peaks in two linear polyesters, poly(ethylene succinate) (PES) and poly(butylene succinate) (PBS), of isothermally crystallized samples was investigated by differential scanning calorimetry (DSC) at atmospheric pressure and high-pressure differential thermal analysis (HP-DTA) at elevated pressures. In PES, the DSC melting curves showed three endothermic peaks at slow heating rates, which decreased to two with increasing heating rates. The HP-DTA curves showed that the area (qualitative) and peak height of the high-temperature peak decreased with increasing pressure and merged with the low-temperature peak at pressures above 450 MPa. This behavior supported the melting, recrystallization, and remelting model for the observed multiple melting endotherms. In PBS, the DSC melting curves were similar to those seen in PES. The HP-DTA curves were also similar to PES up to 400 MPa, but above this pressure the area and the peak height of the high-temperature peak and the temperature difference between the high- and low-temperature peaks remained unchanged. This observation suggested that the two peaks in PBS were due to the melting of two populations of crystals with different lamellar thickness originally present in the sample. The multiple melting behavior in isothermally crystallized PBS is proposed to incorporate both the melting of two populations of crystals and melting, recrystallization, and remelting.

Immiscibility-miscibility phase transformation in blends of poly(ethylene succinate) with poly(L-lactic acid)s of different molecular weights

Using differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and Fourier transformed infrared spectroscopy (FTIR), upper critical solution temperature (UCST) phase behavior with immiscibility–miscibility transformation in blends of poly(ethylene succinate) (PESu) with poly(lactic acid)s (PLAs), such as poly(D,L-lactic acid) (PDLLA), poly(L-lactic acid) (PLLA), poly(D-lactic acid) (PDLA), differing in D/L configurations and molecular weights were investigated. All three binary blends of PDLLA/PESu, PLLA/PESu, and PESu/PDLA exhibit UCST behavior, which means they are immiscible at ambient temperature but can become miscible upon heating to higher temperatures at 240–268 °C depending on molecular weights. The PLLAs/PESu blends at UCST could be reverted back to the original phase-separated morphology, as proven by solvent redissolution. The blends upon quenching from above UCST could be frozen into a quasi-miscible state, where the Flory-Huggins interaction parameter (χ12) was determined to be a negative value (by melting point depression technique). The interaction between PDLLA and PESu in blend resulted in significant reduction in spherulite growth rate of PESu. Furthermore, blends of PESu with lower molecular weight PLLA or PDLA (Mw of PLLA and PDLA are 152,000 and 124,000 g/mol, respectively), instead of the higher Mw of PDLLA (Mw of PDLLA = 157,000 g/mol), are immiscible with UCST phase behavior, which are affected by molecular weights rather than the ratio of L/D monomer in the chemical structure of PLAs. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1135–1147, 2010

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

AbstractThe spherulitic growth of poly(ethylene succinate) (PES) and two PES‐rich copolyesters at constant cooling rate was monitored and recorded using a system of polarized light microscope. Individual experiment of these polyesters lasted 40, 60, and 120 min, respectively. A continuous curve of isothermal growth rates between the melting and glass transition temperatures can be obtained after curve fitting procedures. These curves fit very well with those data points determined in the isothermal experiments, which are time consuming. The continuous data of PES was analyzed with the Hoffman (Lauritzen equation. A transition of regime II → III was found at 70.7 °C, which is very close to the literature values. The maximum growth rate was formulated in the Arrhenius and WLF expressions for the molecular transport term. A master curve of crystal growth rate for PES was constructed based on the continuous data of PES. When the reduced growth rates after normalization were plotted against the reduced temperatures, a universal master curve was observed for PES and two PES‐rich copolyesters. This nonisothermal method provides an efficient and reliable way for studying the crystallization kinetics of polymer and for constructing a universal master curve of crystal growth rate of PES. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 932–939, 2010

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

AbstractPoly(ethylene succinate) (PES), poly(butylene succinate) (PBS), and PES‐rich copolyesters were synthesized using an effective catalyst, titanium tetraisopropoxide. PES was blended with minor amounts of PBS for the comparison. The compositions of the copolyesters and the blends were determined from NMR spectra. Their thermal properties were studied using a differential scanning calorimeter (DSC), a temperature modulated DSC (TMDSC), and a thermogravimetric analyzer. No significant difference exists among the thermal stabilities of these polyesters and blends. For the blends, the reversible curves of TMDSC showed a distinct glass‐rubber transition temperature (Tg), however, the variation of the Tg values with the blend compositions was small. Isothermal crystallization kinetics and the melting behavior after crystallization were examined using DSC. Wide‐angle X‐ray diffractograms (WAXD) were obtained for the isothermally crystallized specimens. The results of DSC and WAXD indicate that the blends have a higher degree of crystallinity and a higher melting temperature than those of the corresponding copolymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Miscibility enhancement and formation of interpenetrating spherulites in ternary blends of crystalline polymers

AbstractMiscible blends of three crystalline polymers, namely poly(butylene succinate) (PBS), poly(ethylene succinate) (PES), and poly(oxyethylene) (POE), exhibited interpenetrating spherulites, where a spherulite of one component grows inside the spherulites of other components. PBS and PES were immiscible above the melting points, Tm, of these substances, while ternary blends with POE showed miscibility, which depended on the molecular weight of POE. PBS and PES exhibited the same spherulitic growth process as in a miscible binary blend when they were crystallized from a homogeneous ternary melt. Spherulites of PBS, which is the highest‐Tm component, filled the whole volume first when a miscible ternary blend was quenched below Tm of POE, the lowest‐Tm component. Then, the blends showed either two types of crystallization processes. One was successive nucleation and growth of PES and POE spherulites, that is, PES nucleated and developed spherulites inside the PBS spherulites and then POE spherulites grew inside the interlocked spherulites of PBS and PES. The other was simultaneous growth and the formation of interpenetrating spherulites of PES and POE inside the PBS spherulites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 706–711, 2010

Miscibility, Crystallization, and Rheological Behavior of Solution Casting Poly(3-hydroxybutyrate)/poly(ethylene succinate) Blends Probed by Differential Scanning Calorimetry, Rheology, and Optical Microscope Techniques

The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybutyrate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.

A biodegradable copolymer from coupling poly(pdioxanone) with poly(ethylene succinate) via toluene-2,4- diisocyanate

AbstractPoly(p-dioxanone) (PPDO) and poly(ethylene succinate) (PES) prepolymers were reacted together using toluene-2,4-diisocyanate (TDI) as a chain extender to produce high molecular weight of chain-extended products of PPDO and PES (PPDOES) in a suitable reaction condition. The novel biodegradable polymers were characterized by 1H-NMR, DSC, POM and WAXD. DSC measurement shows that PPDOES has only one Tg, which means that PPDO has good compatibility with PES. Beside this, the glass transition temperatures and the melting temperatures of PPDOES increased with the increase of PES content. The crystallization rate of PPDOES was slower than that of PPDO as confirmed by DSC and POM. The diffraction peaks of PPDOES appear at the same 2θ angles as that of homopolymers, suggesting that PPDO and PES segment of the chainextended products reserve their own crystallization form. The results of thermal oxidative degradation show that chain-extended products have better thermal stability than PPDO.

Rapid monomerization of poly(butylene succinate)-co-(butylene adipate) by Leptothrix sp.

For rapid monomerization of biodegradable plastics, various microorganisms were screened and TB-71 was selected as the best strain. TB-71 degraded solid poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ethylene succinate), and poly(epsilon-caprolactone) but not poly(butylene succinate), poly(2-hydroxybutylate-co-valerate) or poly(lactic acid). Esterase activity was observed in the culture broth during PBSA degradation, which was specifically induced by PBSA. Analysis of the degradation products revealed that PBSA was degraded to monomers.

Incorporation of aliphatic units into aromatic water-soluble polyesters to improve the performances for warp sizing

Aliphatic units (ethylene succinate) were incorporated into aromatic water-soluble polyesters (WSP) in order to improve their environmental protection and sizing performances. The environmental performance was measured in terms of biological oxygen demand for 5 days (BOD5) and chemical oxygen demand (COD). Apparent and intrinsic viscosities, the adhesion to polyester fibers, glass transition temperature, and mechanical behavior of sizing films of WSP were evaluated for improving their sizing performance. The composition of copolymeric WSP was also investigated by 1H-NMR. A series of copolymeric WSP with a variation in molar ratio of aliphatic monomer (dimethyl succinate) to aromatic monomer (dimethyl terephthalate) from 10:90 to 40:60 was synthesized through a two-step reaction, transesterification and polycondensation. It was found that, by incorporating aliphatic units into the macromolecular chain of aromatic WSP, the environmental performance, apparent and intrinsic viscosities, and the toughness of sizing film were enhanced obviously. The adhesion to polyester fibers showed no sensitivity to the molar ratio of dimethyl succinate to dimethyl terephthalate when the ratio ranged from 10:90 to 30:70. In view of overall performance of the aliphatic-containing WSP sizes, the molar ratio should be 30:70. Based on the ratio, the WSP prepared showed better environmental and sizing performances.

Synthesis and Properties of Novel Biodegradable/Biocompatible Poly[propylene‐co‐(ethylene succinate)] Random Copolyesters

AbstractRandom biocompatible/biodegradable poly[propylene‐co‐(ethylene succinate)]s were prepared. Mechanical properties and crystallization rates decreased with propylene succinate content. Glass transition temperatures (Tg) varied between those for the homopolymers. DSC and TMDSC findings showed that multiple melting behaviour of PPESu samples is related to melting–recrystallization–remelting. WAXD observations, eutectic behaviour, and thermodynamic analysis of the equilibrium melting point depression indicated isodimorphic cocrystallization. The copolymers showed enzymatic hydrolysis rates between those of the homopolymers and cytotoxicity/biocompatibility similar to PLA.magnified image

Thermal properties of poly(ethylene succinate) nanocomposite

This article describes the thermal properties of clay-containing poly(ethylene succinate) (PES) nanocomposite. The nanocomposite of PES with organically modified montmorillonite (o-mmt) has been prepared by solution-intercalation-film-casting technique. Small-angle X-ray scattering patterns and transmission electron microscopy observations show the homogeneous dispersion of silicate layers in the PES matrix. The crystallization and melting behaviors of the PES matrix in the presence of dispersed silicate layers have been studied by differential scanning calorimeter, polarized optical microscope, and wide-angle X-ray scattering. Results show that the incorporation of o-mmt stops the super-cooling effect and accelerates the mechanism of nucleation and crystal growth of PES matrix significantly. The incorporation of o-mmt also improves the thermal stability of neat PES dramatically.

Novel Biodegradable Polyesters. Synthesis and Application as Drug Carriers for the Preparation of Raloxifene HCl Loaded Nanoparticles

Raloxifene HCl is a drug with poor bioavailability and poor water solubility. Furthermore nο pharmaceutically acceptable organic solvent has been reported before to dilute the drug. It was observed that Raloxifene HCl can be diluted in a solvent mixture of acetone/water or ethanol/water. The aim of this study was to use biodegradable polymers in order to prepare Raloxifene HCl nanoparticles. For this purpose a series of novel biodegradable poly(ethylene succinate-co-propylene adipate) P(ESu-co-PAd) polyesters were synthesized following the polycondensation method and further, poly(ethylene succinate) (PESu) and poly(propylene adipate) (PPAd) were used. The prepared polyesters were characterized by intrinsic viscosity measurements, end group analysis, enzymatic hydrolysis, Nuclear Magnetic Resonance Spectroscopy (1Η-NMR and 13C-NMR) and Wide-angle X-ray Diffractometry (WAXD). The drug nanoparticles have been prepared by a variation of the co-precipitation method and were studied by Wide-angle X-ray Diffractometry (WAXD), FTIR spectrometry, light scattering size distribution, Scanning Electron Microscopy (SEM) and release behavior measurements. The interactions between the polymers and the drug seem to be limited, so the drug occurs in crystalline form in all nanoparticles. The size of the nanoparticles seems to be in the range of 150-350 nm, depending on the polymer that was used. The drug release depends on the melting point and degree of crystallinity of the polyesters used. An initial high release rate was recorded followed by very slow rates of controlled release.

Characterization, crystallization kinetics, and melting behavior of poly(ethylene succinate) copolyester containing 7 mol % butylene succinate

AbstractThe copolyester was synthesized and characterized as having 92.7 mol % ethylene succinate units and 7.3 mol % butylene succinate (BS) units in a random sequence, as determined by the use of nuclear magnetic resonance. Isothermal crystallization kinetics of this copolyester was examined in the temperature range (Tc) from 30 to 80°C with the use of differential scanning calorimetry (DSC). The melting behavior after isothermal crystallization was studied with DSC by varying the Tc, the heating rate, and the crystallization time. The complex melting behavior involves both mechanisms of various lamellar crystals and melting–recrystallization–remelting. As the Tc increases, the contribution of recrystallization gradually decreases and finally disappears. The Hoffman–Weeks linear plot yielded an equilibrium melting temperature of 111.1°C, which is 1.6°C less than that of poly(ethylene succinate) (PES). The kinetic analysis of the spherulitic growth rates (G) indicated that a regime II→III transition occurred at ∼59°C (TII→III), which is ∼ 11°C less than that of PES. The overall crystallization rate, TII→III and G indicate that the random incorporation of only 7.3 mol % BS units into PES significantly inhibits the crystallization rate of PES. Finally, the morphology of melt‐crystallized samples was examined using polarized light microscopy and scanning electron microscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Synthesis and Properties of Poly(Ester Urethane)s Consisting of Poly(l-Lactic Acid) and Poly(Ethylene Succinate) Segments

An aliphatic polyester based poly(ester urethane) (PEU) consisting of poly(l-lactic acid) and poly(ethylene succinate) was successfully prepared via chain-extension reaction of poly(l-lactic acid)-diol (PLLA-OH) and poly(ethylene succinate)-diol (PES-OH) using 1,6-hexamethlyene diisocyanate (HDI) as a chain extender. PLLA-OH was obtained by direct polycondensation of l-lactic acid in the presence of 1,4-butanediol. PES-OH was synthesized by condensation polymerization of succinic acid with excessive ethylene glycol. The structures and molecular weights of PLLA-OH, PES-OH, and PEUs were characterized by proton nuclear magnetic resonance (1H NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). The PEUs were further studied by the means of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile testing. The data of GPC analysis indicated that high molecular weights for example more than 200 000 g·mol−1 were easily synthesized through chain-extension reaction. The PEUs synthesized with high molecular weight and excellent tensile properties could find some applications in biomaterials and environmental friendly materials.