Cyclic oligo(butylene 2,5-furandicarboxylate) and e-caprolactone were copolymerized in bulk at 130-150 °C by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the e-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible e-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably degraded by lipases in an extend that increased with the content in CL units.
Morales, J.; Martinez de Ilarduya, A.; Muñoz, S. Journal of polymer science. Part A, polymer chemistry Vol. 56, num. 3, p. 290-299 DOI: 10.1002/pola.28895 Data de publicació: 2018-02-01 Article en revista
Cyclic oligo(butylene 2,5-furandicarboxylate) and e-caprolactone were copolymerized in bulk at 130-150 ºC by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the e-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible e-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably
Two series of aliphatic-aromatic copolyesters derived from succinic and 2,5-furandicarboxylic acids, and di-O-2-(hydroxyethyl) resorcinol as diol substituent of either 1,4-butanediol or ethylene glycol, respectively, were obtained by ring opening polymerization(ROP) performed in bulk and catalyzed by Sn(Oct)2. Cyclic oligomers of furandicarboxylate of di-O-2-(hydroxyethyl) resorcinol were successfully synthesized by high-dilution condensation, and then copolymerized with cyclic oligomers of either butylene or ethylene succinate. The synthesized resorcinol-containing succinate-furanoatecopolyesters had Mw oscillating between 50,000 and 30,000 g·mol-1 depending on composition, and they all displayed a nearly random microstructure. They showed an excellent thermal stability with onset decomposition temperatures near 300 °C. They are amorphous with Tg increasing monotonically with the content in resorcinol in both series with values ranging from -30 or -13 °C for butylene and ethylene-based copolyesters, respectively, up to around 45 °C. The resorcinol-containing succinate-furanoate copolyesters showed appreciable hydrolytic degradation when incubated for a few weeks in water under physiological conditions, a behavior that was notably enhanced in the presence of lipases
Batista, C.; Safari, M.; Martinez de Ilarduya, A.; Morales, J.; Iturrospe, A.; Arbe, A.; Müller, A.; Muñoz, S. European polymer journal Vol. 95, p. 795-808 DOI: 10.1016/j.eurpolymj.2017.05.002 Data de publicació: 2017-10-01 Article en revista
In this paper, the preparation of PBS-ran-PCL copolyesters by enzymatic ring opening polymerization is presented for the first time. The copolyesters were produced in a wide composition range and free of metallic contaminants, so they may be regarded as potential biomaterials. The copolymers have been characterized by proton and carbon nuclear magnetic resonance (1H and 13C NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM) and wide angle X-ray scattering (WAXS). The PBS-ran-PCL copolyesters were able to crystallize in the entire composition range and displayed a pseudo-eutectic region. Most copolymers away from the pseudo-eutectic region exhibited a single crystalline phase (PBS-rich or PCL-rich crystalline phase), while within the pseudo-eutectic region the copolymers were double crystalline. Observations by PLOM, during isothermal crystallization showed that both nucleation density and spherulitic growth rate of the copolyesters are determined by the component that constitutes the majority phase. WAXS studies revealed that d spacings of selected crystallographic planes depend on composition. Therefore, both DSC and WAXS results suggest that the copolymers are probably isodimorphic, as the PBS-rich crystalline phase may contain small inclusions of PCL co-units, while the PCL-rich crystalline domains may also contain a minor quantity of PBS co-units inside.
Poly(ethylene succinate) (PES) with weight-average molecular weight above 60,000 g mol-1 was efficiently obtained by enzymatic ring opening polymerization of cyclic oligo(ethylene succinate)s c(ES)n, which in turn were prepared by lipase-catalysed cyclocondensation in solution of dimethyl succinate and ethylene glycol. The methodology was demonstrated to be also applicable to the synthesis of high molecular weight PES-copolyesters containing butylene succinate, e-hydroxycaproate or L-lactate units with a random distribution.
Poly(butylene 2,5-furandicarboxylate-co-succinate) copolyesters (coPBFxSy) have been synthesized by
ring opening polymerization (ROP). Cyclic butylene 2,5-furandicarboxylate and butylene succinate
oligomer mixtures, to be used as monomers for ROP, were prepared by high dilution condensation
and enzymatic cyclization reactions, respectively. Two different catalytic systems, tin dioctanoate and
supported Candida antarctica lipase B (CALB), were used for polymerization. Thus two series of copolyesters
covering the whole range of compositions were prepared and their properties comparatively
examined. In both cases, random copolyesters with compositions close to those used in their respective
feeds were obtained. The influence of composition on reaction kinetics with respect to time and
temperature was evaluated for the two series. Chemically catalyzed ROP rendered copolyesters with Mw
in the ~50 000–65 000 g mol-1 range, whereas values between 15 000 and 45 000 g mol-1 were attained
when the ROP reaction was assisted by CALB. The thermal behavior of coPBFxSy obtained by ROP was
similar to that reported for such copolymers prepared by melt polycondensation. They all start to decompose
above 300 °C and display melting enthalpy and temperatures that decrease with copolymerization,
attaining minimum values when the comonomer contents are approximate to balance. On the
contrary, the glass-transition temperature increased almost linearly with the content of butylene furandicarboxylate
units, covering the whole range of values between those of the two parent homopolyesters.
Small deviations in thermal properties observed between the two series could be attributed to their differences
in molecular weights. Hydrolytic and enzymatic degradation studies revealed that coPBFxSy
became more degradable with increasing content of succinic units, whereas the homopolyester PBF
remained practically unaffected when incubated under similar conditions.
In this work, the synthesis of both c(BF)n and c(BT)n has been performed using the high dilution cyclization technique and these cycles have been then used for the preparation of the homopolyesters PBF and PBT, as well as of a series of poly(butylene 2,5-furandicarboxylate-co-terephthalate) (coPBFxTy) with a wide range of compositions (Fig. 1). Results are compared with those obtained from similar copolyesters prepared by melt polycondensation, which have been recently reported
In this communication we wish to report on the synthesis of PBFxSy copolyesters by ring opening polymerization (ROP) using either organometallic catalysts or enzymes. The ROP of macrocyclic oligomers (MCOs) has been demonstrated to offer significant advantages over the traditional polycondensation method. The synthesis of MCOs of butylene succinate c(BS)n is known from long whereas MCOs of butylene 2,5-furandicarboxylate (c(BF)n) have not been reported until very recently. In this work, the synthesis of c(BF)n and c(BS)n has been performed using high dilution condensation (HDC) and enzymatic cyclization, respectively. Mixtures of dimer to tetramer and dimer to nonamer were obtained for c(BF)n and c(BS)n respectively.
Morales, J.; Martinez de Ilarduya, A.; Muñoz, S. ACS sustainable chemistry & engineering Vol. 4, num. 9, p. 4965-4973 DOI: 10.1021/acssuschemeng.6b01302 Data de publicació: 2016-09-01 Article en revista
A series of poly(butylene 2,5-furandicarboxylate-co-terephthalate) copolyesters coPBFxTy covering the whole range of compositions has been prepared via ring opening polymerization (ROP). Cyclic oligomers of butylene 2,5-furandicarboxylate c(BF)n and butylene terephthalate c(BT)n, both mainly consisting of a mixture of dimer, trimer, and tetramer species, were synthesized by the high dilution condensation method. Random copolyesters with the targeted compositions and weight-average molecular weights within the 55¿000–80¿000 g·mol–1 range were obtained by ROP of c(BF)n/c(BT)n mixtures in periods of time much shorter than those required by melt polycondensation. The thermal properties of these copolyesters were consistent with their compositions and comparable to their isocompositional analogs obtained by polycondensation. A comparative kinetics study of the isothermal crystallization of the homopolyesters and copolyesters differing in composition revealed that the presence of the 2,5-furandicarboxylate units decreased the crystallization rate of PBT. Nevertheless, coPBFxTy copolyesters with moderate contents in BF units were still able to crystallized rapidly from the melt
The preparation of cyclic ethylene and butylene 2,5-furandicarboxylate oligoesters and their conversion to furan-based polyesters poly(ethylene furanoate) (PEF) and poly(butylene furanoate) (PBF) by ring-opening polymerization (ROP) are described. The cyclic oligoesters were obtained in high yields by both high dilution condensation and thermal cyclodepolymerization methods, and they consisted of mixtures of small size species. Cyclic dimer, trimer and tetramer oligoesters were isolated by semipreparative chromatography and found to be crystalline compounds melting within the 140–200 °C range. ROP catalyzed by Sn(Oct)2 of both mixtures and individual species afforded PEF and PBF with weight-average molecular weights between 50,000 and 60,000 g mol-1. Polymerization rate was found to be higher for butylene than for ethylene cyclic oligofuranoates, and also to increase slightly as cycle size decreased. The thermal properties of PEF and PBF prepared by ROP were in full agreement with those reported for these polyesters obtained by melt polycondensation.