Synthesis, 1H‐NMR characterization,and biodegradation behavior of aliphatic–aromatic random copolyester

Aliphatic‐aromatic copolyesters of poly(butylene adipate‐co‐butylene terephthalate) have been synthesized by polycondensation. Molecular weights and thermal properties have been measured. The four samples of copolyesters, with aromatic contents, varying from 40 to 60 mol %, were investigated by ¹H‐NMR spectroscopy to determine copolymers composition and microstructure. For all samples, the biodegradation experiment was carried out in compost, to study copolyesters degradation behavior. Using ¹H‐NMR, we noticed that the average sequence length and content of the aliphatic unit decrease and those of the aromatic unit increase. The molecular weights of the samples distinctly drop after composting. In all degraded samples, the trace of growing microorganisms was found on their surfaces by scanning electron microscopy. In combination with the results, the degradation behavior has been studied in the middle stage of copolyester degradation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2643–2649, 2007     

Synthesis and characterization of the biodegradable copolymers from succinic acid and adipic acid with 1,4-butanediol

Biodegradable homopolyesters such as poly(butylene succinate) (PBSU) and poly(butylene adipate) (PBAD) and copolyesters such as poly(butylene succinate-co-butylene adipate) (PBSA) were synthesized, respectively, from succinic acid (SA) and adipic acid (AA) with 1,4-butanediol through a two-step process of esterification and deglycolization. The polyester compositions and physical properties of both homopolyesters and copolyesters were investigated by ¹H– and ¹³C–NMR, DSC, GPC, WAXD, and optical polarizing microscopy. The melting point (T_m) of these copolyesters decreased gradually as the contents of butylene adipate increased and the glass-transition temperature (T_g) of these copolyesters decreased linearly as the contents of the adipoyl unit increased. PBSA copolyesters showed two types of XRD patterns of PBSU and PBAD homopolyesters. Furthermore, the biodegradation and hydrolytic degradation of the high molecular weight PBSU homopolyester, PBAD homopolyester, and PBSA copolyesters were investigated in the composting soil and NH₄Cl aqueous solutions at a pH level of 10.6. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2808–2826, 2001     

Synthesis and characteristics of biodegradable copolyesters from the transesterification of poly(butylene adipate‐co‐succinate) and poly(ethylene terephthalate)

Poly(butylene adipate‐co‐succinate) (PBAS), an aliphatic polyester, is known for its excellent biodegradability, but its physical and mechanical properties are poor. To improve the physical properties, stiff aromatic rings were added to PBAS through transesterification with poly(ethylene terephthalate) (PET). New biodegradable copolyesters were prepared by the intermolecular ester‐exchange reactions between molten PBAS and PET. The transesterification reaction was carried out at 280°C without a catalyst. The newly synthesized copolyesters were characterized with ¹H‐NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The mechanical properties were measured with a universal test machine, and the biodegradability was also investigated. By the new peaks appearing in ¹H‐NMR spectra of the copolyesters, the occurrence of the transesterification reaction between PBAS and PET was confirmed. A reduction of the melting temperature was observed for the copolyesters. The elongations at break of the new copolyesters increased for all compositions and reaction times, in comparison with PBAS. However, the tensile strength decreased with the induction of terephthalate units in the copolyesters. The biodegradability of the copolyesters also depended on the number of terephthalate units. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3266–3274, 2004     

Synthesis and thermal characterization of random poly(butylene terephthalate‐co‐2‐methyl‐ethylene terephthalate) copolyesters

Poly(butylene terephthalate‐co‐2‐methyl‐ethylene terephthalate) (PBT/MET) was synthesized by incorporating 1,2‐propandiol(1,2‐PDO) into PBT chains. The molar composition and chemical structure of PBT/MET copolyesters were confirmed by means of FT‐IR and ¹H‐NMR. To investigate the effect of 1,2‐PDO on the thermal properties of PBT/MET copolyesters, the copolymerizations were carried out by varying various contents of MET units, and the prepared materials were evaluated by differential scanning calorimetry and thermogravimetric analysis. Results suggested that with the increase of the content of 1,2‐PDO, the amount of crystallinity and the melting temperature decline, while the glass transition temperature increases and the copolyesters become more transparent and brittle with respect to PBT homopolymer. In addition, the T_g‐composition and T_m‐composition data are well subjected to the Wood equation and Flory's equation, respectively. All these copolyesters are found to consist of the general trend displayed by copolymers reported elsewhere. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Characterization and biodegradability of poly(butylene adipate‐co‐succinate)/poly(butylene terephthalate) copolyester

Characterization of poly(butylene adipate‐co‐succinate) (PBAS)/poly(butylene terephthalate) (PBT) copolyesters resulting from the intermolecular ester‐exchange reaction between molten PBAS and PBT have been analyzed using ¹H‐NMR spectroscopy, differential scanning calorimetry, wide‐angle X‐ray diffraction, and total organic carbon lab analyzer. Using the assignment of proton resonance due to homogeneous and heterogeneous dyads, the average block lengths were investigated over the entire range of copolymer composition. A decrease in melting temperature was observed with the increase of a terephthalate unit in the composition. The result of X‐ray diffraction curve matches well with that of average block length and thermal property. When a rich component is crystallized, the poor component is excluded completely in a crystal formation. The biodegradability in copolyesters also depended on the terephthalate unit in the composition and average block length of the aromatic unit. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 593–608, 1999     

Aliphatic–aromatic poly(butylene carbonate‐co‐terephthalate) random copolymers: Synthesis,cocrystallization, and composition‐dependent properties

A series of aliphatic–aromatic poly(carbonate‐co‐ester)s poly(butylene carbonate‐co‐terephthalate)s (PBCTs), with weight‐average molecular weight of 113,000 to 146,000 g/mol, were synthesized from dimethyl carbonate, dimethyl terephthalate, and 1,4‐butanediol via a two‐step polycondensation process using tetrabutyl titanate as the catalyst. The PBCTs, being statistically random copolymers, show a single T_g over the entire composition range. The thermal stability of PBCTs strongly depends on the molar composition. Melting temperatures vary from 113 to 213°C for copolymers with butylene terephthalate (BT) unit content higher than 40 mol %. The copolymers have a eutectic melting point when about 10 mol % BT units are included. Crystal lattice structure shifts from the poly(butylene carbonate) to the poly(butylene terephthalate) type crystal phase with increasing BT unit content. DSC and WAXD results indicate that the PBCT copolymers show isodimorphic cocrystallization. The tensile modulus and strength decrease first and then increase according to copolymer composition. The enzymatic degradation of the PBCT copolymers was also studied. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41952.     

The thermal,mechanical and viscoelastic properties of poly(butylene succinate-<Emphasis Type="Italic">co</Emphasis>-terephthalate) (PBST) copolyesters with high content of BT units

Poly(butylene succinate-co-terephthalate) (PBST) copolyesters, with rigid butylene terephthalate (BT) units varying from 50 to 70 mol%, were synthesized via direct esterification route. The chemical structure and comonomer composition were characterized by ¹H NMR. The weight-average molecular weights (M _w ) of the prepared products measured by GPC spanned a range of 1.39 × 10⁵–1.93 × 10⁵ with corresponding M _w /M _n value of 2.23–2.42. Based on the WAXD analysis, PBST copolyesters were identified to have the same crystal structure as that of poly(butylene terephthalate) (PBT). The researches on the thermal properties showed that the melting temperature and decomposed temperature of PBST copolyesters increased with the increasing content of rigid BT units through DSC and TGA measurement. Furthermore, the tensile test results presented that the copolyester with higher content of BT units had higher initial modulus, higher breaking strength but lower elongation at break. Additionally, the viscoelastic properties of the prepared PBST films were analyzed by DMA measurement. It was found that both storage modulus (E′) and loss modulus (E″) corresponding to the peak tended to heighten with the increase of BT units, indicating the copolyester with higher BT units content had the more prominent viscoelasticity. The peak of loss factor (tan δ) curve shifted to higher temperature as the content of rigid BT units increased due to the increasing of the glass transition temperature (T _g).     

Nonisothermal crystallization behavior of biodegradable poly(butylene terephthalate‐co‐butylene adipate‐co‐ethylene terephthalate‐co‐ethylene adipate) copolyester

A series of biodegradable aliphatic‐aromatic copolyester, poly(butylene terephthalate‐co‐butylene adipate‐co‐ethylene terephthalate‐co‐ethylene adipate) (PBATE), were synthesized from terephthalic acid (PTA), adipic acid (AA), 1,4‐butanediol (BG) and ethylene glycol (EG) by direct esterification and polycondensation. The nonisothermal crystallization behavior of PBATE copolyesters was studied by the means of differential scanning calorimeter, and the nonisothermal crystallization kinetics were analyzed via the Avrami equation modified by Jeziorny, Ozawa analysis and Z.S. Mo method, respectively. The results show that the crystallization peak temperature of PBATE copolyesters shifted to lower temperature at higher cooling rate. The modified Avrami equation could describe the primary stage of nonisothermal crystallization of PBATE copolyesters. The value of the crystallization half‐time (t_1/2) and the crystallization parameter (Z_c) indicates that the crystallization rate of PBATE copolyesters with more PTA content was higher than that with less PTA at a given cooling rate. Ozawa analysis was not suitable to study the nonisothermal crystallization process of PBATE copolyesters, but Z.S. Mo method was successful in treatingthis process. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Synthesis and biodegradation of aliphatic polyesters from dicarboxylic acids and diols

Poly(butylene succinate) (PBS) and its copolymers, poly(butylene succinate‐co‐adipate) (PBSA) and poly(butylene‐co‐hexylene succinate) (PBHS), were synthesized by direct polyesterification of corresponding diols and dicarboxylic acids. Dimethyl benzene was used as solvent and water‐removing agent. Several catalysts were used to study the esterification of butanediol and succinic acid. Among them, SnCl₂ demonstrated superior catalysis behavior. Kinetic behaviors of the synthesis of PBS, PBSA, and PBHS were investigated using SnCl₂ as catalyst. By using a water trap containing a 4‐Å molecular sieve, a relatively faster reaction rate was achieved and the molecular weight of some polyesters surpassed 30,000. The variation of molecular weight distribution during the polymerization was monitored by GPC and M_w/M_n demonstrated a trend of decrease with the reaction time. The melting point (T_m) and the glass‐transition temperature (T_g) were measured by DSC technique. The results show that the incorporation of a third monomer unit to PBS lowered T_g and T_m. The biodegradation test was carried out both in the laboratory and in outdoor soil burial. The copolyesters displayed a faster degradation rate than that of PBS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 982–990, 2003     

Synthesis and characterization of poly(L‐lactide‐co‐ϵ‐caprolactone)‐b‐poly(L‐lactide) biodegradable diblock copolyesters: Effect of the block lengths on their thermal properties

Poly(L ‐lactide‐co‐ε‐caprolactone)‐b‐poly(L ‐lactide) [P(LL‐co‐CL)‐b‐PLL] diblock copolyesters were synthesized in a two‐step process with 1‐dodecanol (DDC) and stannous octoate as the initiating system. In the first‐step reaction, a 50:50 mol % amorphous poly(L ‐lactide‐co‐ε‐caprolactone) [P(LL‐co‐CL)] copolyester was synthesized via the bulk copolymerization of L ‐lactide and ε‐caprolactone, which was followed by the polymerization of the PLL crystalline block at the end chain in the second‐step reaction. The yielded copolyesters were characterized with dilute‐solution viscometry, gel permeation chromatography, ¹H‐ and ¹³C‐NMR, and differential scanning calorimetry methods. The molecular weights of the P(LL‐co‐CL) copolyesters from the first‐step reaction were controlled by the DDC concentrations, whereas in the second‐step reaction, the molecular weights of the P(LL‐co‐CL)‐b‐PLL diblock copolyesters depended on the starting P(LL‐co‐CL) copolyester molecular weights and L ‐lactide/prepolymer molar ratios. The starting P(LL‐co‐CL) copolyester molecular weights and PLL block lengths seemed to be the main factors affecting specific thermal properties, including the melting temperature (T_m), heat of melting (ΔH_m), crystallizing temperature (T_c), and heat of crystallizing (ΔH_c), of the final P(LL‐co‐CL)‐b‐PLL diblock copolyester products. T_m, ΔH_m, T_c, and ΔH_c increased when the PLL block lengths increased. However, these thermal properties of the diblock copolyesters also decreased when the P(LL‐co‐CL) block lengths increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Preparation and characterization of aliphatic/aromatic copolyesters based on bisphenol-A terephthalate,hexylene terephthalate and lactide mioties

To obtain higher molecular weight processable polyesters which are of potential interest for tissue engineering, a series of biodegradable aliphatic/aromatic copolyesters, poly(4,4′-isopropylidenediphenyl terephthalate)-co-poly(hexylene terephthalate)-co-polylactide (PBHTL), were synthesized via direct polycondensation from terephthaloyl dichloride, bisphenol-A, 1,6-hexanediol, and oligolactide. The resulting copolyesters, PBHTL, were characterized by proton nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetry (TG) and wide-angle X-ray scattering (WAXS), and their glass transition temperature (T_g), and thermal decomposition temperature (T_d) were obtained. The PBHTL shows two-step thermal decomposition, which is corresponding to segment of 4,4′-isopropylidenediphenyl terephthalate (BAT) and segments of hexylene terephthalate (HT) and lactide (LA), respectively. Due to the incorporation of flexible aliphatic unit into the main chains of copolyesters, PBHTL has lower T_g, and shows enhanced hydrolytic degradability under a physiological conditions with increasing lactide and hexylene moieties. Initial experiments indicated excellent biocompatibility based on cell seeding experiments and microscopic evidence.     

Syntheses and properties of the PET‐co‐PEA copolyester

An aliphatic‐aromatic random‐block copolyester of poly(ethylene terephthalate) (PET), and poly(enthylene adipate) (PEA), PET‐co‐PEA, was synthesized via melt polycondensation. The chemical structure of the products were characterized by two kinds of spectroscopic techniques (Fourier transform infrared and ¹H‐NMR). The thermal properties of the copolyester were characterized by thermogravimetry analysis, differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy. It was found that the crystallization ability, melting point, glass transition temperature of the random‐block coplyester decreased apparently. Meanwhile, the tensile strength and hydrolysis performance were measured as well. The result showed that the random‐block copolyesters PET‐co‐PEA displayed excellent properties in elasticity and strength. In addition, the potential degradability was found in hydrolysis measurement. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44967.     

Synthesis,characterization, and properties of biodegradable poly(butylene succinate) modified with imide dihydric alcohol

A series of high molecular weight poly (butylene succinate) and its copolyester containing rigid imide units were synthesized in this article. The chemical structure and composition of the copolyesters were determined by ¹H NMR spectroscopy and Fourier transform infrared spectroscope (FT‐IR). The thermal properties, crystallization behavior and mechanical properties of polymers were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide‐angle X‐ray diffraction (WAXD) and mechanical testing. The enzymatic degradation was investigated using pancreatic lipase solution. The results showed that the melting temperature (T_m) of the copolyester decreased with the increment in pyromellitic imide unit content. However, the thermal degradation temperature (5% decomposition temperature) changed little. Meanwhile, the enzymatic degradation rate of poly (butylene succinate) was enhanced. The mechanical properties showed that the tensile strength had a trend of decrease, but the elongation at break was improved with the increment in imide units. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40807.     

Synthesis and characterization of poly(L‐lactic acid)‐b‐poly(ethylene terephthalate‐co‐sebacate)‐b‐poly(L‐lactic acid) copolyesters

Random copolyester namely, poly(ethylene terephthalate‐co‐sebacate) (PETS), with relatively lower molecular weight was first synthesized, and then it was used as a macromonomer to initiate ring‐opening polymerization of l ‐lactide. ¹H NMR quantified composition and structure of triblock copolyesters [poly(l ‐lactic acid)‐b‐poly(ethylene terephthalate‐co‐sebacate)‐b‐poly(l ‐lactic acid)] (PLLA‐PETS‐PLLA). Molecular weights of copolyesters were also estimated from NMR spectra, and confirmed by GPC. Copolyesters exhibited different solubilities according to the actual content of PLLA units in the main chain. Copolymerization effected melting behaviors significantly because of the incorporation of PETS and PLLA blocks. Crystalline morphology showed a special pattern for specimen with certain composition. It was obvious that copolyesters with more content of aromatic units of PET exhibited increased values in both of stress and modulus in tensile test. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of biodegradable poly(butylene succinate‐co‐propylene succinate)s

Biodegradable polyesters such as poly(butylene succinate) (PBS), poly(propylene succinate) (PPS), and poly(butylene succinate‐co‐propylene succinate)s (PBSPSs) were synthesized respectively, from 1,4‐succinic acid with 1,4‐butanediol and 1,3‐propanediol through a two‐step process of esterification and polycondensation in this article. The composition and physical properties of both homopolyesters and copolyesters were investigated via ¹H NMR, DSC, TGA, POM, AFM, and WAXD. The copolymer composition was in good agreement with that expected from the feed composition of the reactants. The melting temperature (T_m), crystallization temperature (T_c), crystallinity (X), and thermal decomposition temperature (T_d) of these polyesters decreased gradually as the content of propylene succinate unit increased. PBSPS copolyesters showed the same crystal structure as the PBS homopolyester. Besides the normal extinction crosses under the polarizing optical microscope, the double‐banded extinction patterns with periodic distance along the radial direction were also observed in the spherulites of PBS and PBSPS. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and properties of poly(alkylene p,p′-bibenzoate-co-adipate)s

Various poly(alkylene p,p′-bibenzoate-co-adipate)s were prepared by melt polycondensation of dimethyl-p,p′-bibenzoate, adipic acid, and an alkylene glycol. The copolyesters were characterized by inherent viscosity, FTIR, proton NMR, DSC, polarized microscopy, and X-ray diffraction. The polymer composition and sequence distribution of the copolyesters can be seen from NMR spectra. The copolyesters exhibit a degree of randomness of about 1, indicating that they are random copolymers. From the DSC data, the glass transition temperature (T_g) and melting point (T_m) of the copolyesters can be detected. When the content of the flexible adipate unit increases, the T_g of copolyesters decreases significantly. The type of alkylene glycol used also affects the T_g to some extent. The copolymerization effect decreases crystallinity and the T_m of the copolyesters. The DSC, polarized microscopy, and X-ray diffraction data show that some copolyesters derived from 1,6-hexanediol exhibit a monotropic smectic phase. As the molar fraction of adipate unit in diacid units, x, is more than 0.4, the liquid crystallinity is completely destroyed. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:893–900, 1997     

Preparation of random poly(butylene alkylate-co-terephthalate)s with different methylene group contents: crystallization and degradation kinetics

Random copolyesters having 1,4-butanediol units were synthesized from a transesterification process between homopolymers constituted by aliphatic dicarboxylates (i.e. succinate, adipate or sebacate) and the aromatic therephthalate derivative, as verified by NMR spectroscopy. Biodegradability of resulting copolyesters was studied via enzymatic hydrolysis using Pseudomonas cepacia lipase at pH = 7.2 and 37 °C. Kinetics of degradation showed that in all cases the degradation rate decreased after 19 days of exposure. The observed glass transition temperatures, T _g, of the random copolyesters showed a non-linear dependence on composition, a feature that was explained in terms of the internal stiffening effect of butylene terephthalate units. Copolymers with higher aliphatic (i.e. 50 and 70 mol-%) and methylene (i.e. adipate and sebacate units) contents showed double melting peaks in DSC thermograms. These copolyesters resulted in two different crystalline rich phases after melt-crystallization and subsequent cooling. The ratio between these phases logically depended on the predominant aliphatic or aromatic dicarboxylate content. The copolymers initially crystallized via the aromatic units through a heterogeneous nucleation and a spherulitic growth. The presence of aliphatic dicarboxylate units hindered the beginning of the crystallization process, but the overall growth kinetic constant was similar for all samples. The secondary nucleation constants were determined and showed higher values for samples with higher adipate and sebacate contents.     

Preparation and thermal behavior of random poly(butylene terephthalate/azelate) copolyesters

Poly(butylene terephthalate), poly(butylene azelate), and poly(butylene terephthalate/butylene azelate) random copolymers of various compositions were synthesized in bulk using the well‐known two‐stage polycondensation procedure, and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. As far as the thermal stability is concerned, it was found to be rather similar for all copolymers and homopolymers investigated. All the copolymers were found to be partially crystalline, and the main effect of copolymerization was a lowering in the amount of crystallinity and a decrease of melting temperature with respect to pure homopolymers. Flory's equation was found to describe the T_m–composition data and permitted to calculate the melting temperatures (T^°_m ) and the heats of fusion (ΔH_u) of both the completely crystalline homopolymers. Owing to the high crystallization rate, the glass transition was observable only for the copolymers containing from 30 to 70 mol % of the terephthalate units; even though the samples cannot be frozen in a completely amorphous state, the data obtained confirmed that the introduction of the aromatic units gave rise to an increase of T_g, due to a chain stiffening. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2694–2702, 1999     

Synthesis and characterization of copolymeric aliphatic–aromatic esters derived from terephthalic acid, 1,4‐butanediol,and ε‐caprolactone by physical,thermal, and mechanical properties and NMR measurements

In this study, a series of aliphatic–aromatic poly(butylene terephthalate‐co‐ε‐caprolactone) (PBTCL) copolyesters were synthesized from various monomeric compositions of terephthalic acid (TPA), 1,4‐butanediol (BDO), and ε‐caprolactone (CL) in the presence of tetrabutyl titanate (Ti(Obu)₄) and stannous octoate (Sn(Oct)₂) as catalysts through a combination of polycondensation and ring opening polymerization. A significant increase in the melting temperature (T_m) of copolyesters was observed by increasing the TPA/(CL+TPA) molar ratio, starting from the low end (T_m 66.2°C) of pure poly‐ε‐caprolactone PCL upward. We found that PBTCL‐50, which has a TPA/(CL+TPA) 50% molar ratio and polycondensation at 260°C for 1.5 h, resulted in a proper T_m of 139.2°C that facilitates thermal extrusion from biomass or other biodegradable polymers of similar T_m. The number–average molecular weight (M_n) of 7.4 × 10⁴ for PBTCL‐50 was determined from the intrinsic viscosity [η] by using the Berkowitz model of M_n = 1.66 × 10⁵[η]^0.9. Good mechanical properties of PBTCL‐50 have been shown by tensile stretching experiment that indicates tensile strength, elongation, and Young's modulus are 11.9 MPa, 132%, and 257 MPa, respectively. Polymers with aforementioned properties are suitable for manufacturing biodegradable plastic films for downstream agricultural applications or merely for trash bag. This article reveals that the PBTCL‐50 contains all five monomers with different molar ratios and characteristical linkages between each other. The novel structure was furthermore analyzed by ¹H‐ and ¹³C‐NMR spectroscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of novel biodegradable poly(butylene succinate) copolyesters composing of isosorbide and poly(ethylene glycol)

A series of biodegradable isosorbide‐based copolyesters poly(butylene succinate‐co‐isosorbide succinate‐co‐polyethyleneoxide succinate) (PB_xI_yE_zS) were synthesized via bulk polycondensation in the presence of dimethyl succinate (DMS), 1,4‐butanediol (BDO), poly(ethylene glycol) (PEG) and isosorbide (ISO). The crystallization behaviors, crystal structure and spherulite morphology of the copolyesters were analyzed by differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXD) and polarizing optical microscopy (POM), respectively. The results indicate that the crystallization behavior of the copolyesters was influenced by the content of isosorbide succinate (IS) and polyethyleneoxide succinate (PEOS) units, which further tuned the mechanical and biodegradable properties of the copolyesters. The PB_xI_yE_zS copolyesters, compared to pure poly(butylene succinate), showed lower crystallization temperature, melting temperature, degree of crystallinity and degradation rate while a significant increase in glass transition temperature with increasing isosorbide content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011