Synthesis Of Aliphatic Polyesters Research Articles

Brief Analysis on the Degradation of Sugar-Based Copolyesters.

Isosorbide can be used as a third monomer in the synthesis of aliphatic polyesters, and its V-shaped bridging ring structure can effectively improve the rigidity of the copolyester molecular chain. In this work, a series of degradable polyester materials were prepared by modifying polybutylene succinate and using isosorbide as the third monomer. The degradation tests in this paper were implemented through the hydrolysis of copolyesters in distilled water, degradation in natural water and degradation tests in simulated natural environments. The results showed that PBS and its copolyesters can degrade under natural conditions, and the introduction of isosorbide can accelerate the degradation of copolyesters, which could effectively reduce pollutants in nature.

Direct Synthesis of Aliphatic Polyesters with Pendant Hydroxyl Groups from Bio-Renewable Monomers: A Reactive Precursor for Functionalized Biomaterials.

Introducing desired functionalities into biomaterials is an effective way to obtain functionalized biomaterials. A versatile platform with the possibility of postsynthesis functionalization is highly desired but challenging in biomedical engineering. In this work, linear aliphatic polyesters with pendant hydroxyl (PEOH) groups were directly synthesized using renewable malic acid/tartaric acid as raw materials under mild conditions through the polyesterification reaction promoted by 1,1,3,3-tetramethylguanidine (TMG). The hydroxyl groups on PEOH provide an active stepping stone for the fabrication of demanded functionalized polyesters. We demonstrated the possibility of the PEOH as a reactive precursor for functional group transformation, coupling of bioactive molecules, and formation of crosslinking networks. Moreover, a theranostic nanoplatform (mPEG-b-(P7-asp&TPV)-b-mPEG NPs) was synthesized using PEOH as a reactive stepping stone by the programmable combination of the above functionalization methods. Overall, these hydroxyl-containing polyesters have great potential in biological applications.

In-reactor engineering of bioactive aliphatic polyesters via magnesium-catalyzed polycondensation for guided tissue regeneration

Aliphatic polyesters have been widely used in biomedicine owning to their combination of biodegradability, biocompatibility and controllable mechanical properties. Polycondensation is certainly one of the most versatile and robust methods for the synthesis of aliphatic polyesters in a large scale. Nevertheless, traditional catalysts for polycondensation, such as Sb2O3, GeO2 and SnCl2, have potential biotoxicity and need to be completely removed before using in biomedicine. Furthermore, pure aliphatic polyesters do not possess the required functionality and additional work is required for increasing their bioactivity in many biomedical applications. Here, a series of magnesium compounds were used as catalysts for the polycondensation of dicarboxylic acids and diols. We confirmed that the in situ formed magnesium dicarboxylate not only serves as the real catalyst but also endows the resultant polyester with bioactivity because of its osteogenic activity and anti-inflammatory property. Finally, the bioactive polyester was applied to guided tissue regeneration, in which the degree of bone regeneration after 16 weeks is higher than commercial PLA film. This work provides a strategy for the in-reactor engineering of bioactive polyesters within one step on a large scale, and shows promising applications for use in the biomaterial field.

Correction to Organocatalysis: A Paradigm Shift in the Synthesis of Aliphatic Polyesters and Polycarbonates

Correction to Organocatalysis: A Paradigm Shift in the Synthesis of Aliphatic Polyesters and Polycarbonates

Organocatalysis: A Paradigm Shift in the Synthesis of Aliphatic Polyesters and Polycarbonates

ADVERTISEMENT RETURN TO ISSUEPREVEditorialNEXTADDITION / CORRECTIONThis article has been corrected. View the notice.Organocatalysis: A Paradigm Shift in the Synthesis of Aliphatic Polyesters and PolycarbonatesKazuki Fukushima*Kazuki Fukushima*Email: [email protected]More by Kazuki Fukushimahttp://orcid.org/0000-0002-6980-9663 and Kyoko Nozaki*Kyoko Nozaki*Email: [email protected]More by Kyoko Nozakihttp://orcid.org/0000-0002-0321-5299Cite this: Macromolecules 2020, 53, 13, 5018–5022Publication Date (Web):July 14, 2020Publication History Published online14 July 2020Published inissue 14 July 2020https://doi.org/10.1021/acs.macromol.0c00582Copyright © 2020 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views2781Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (971 KB) Get e-AlertsSUBJECTS:Ring-opening polymerization,Organocatalysts,Monomers,Catalysts,Polymers Get e-Alerts

Ring-Opening Polymerization of L-lactide Initiated by Samarium(III) Acetate

Background: The synthesis of the aliphatic polyesters obtained by the ring opening polymerization has been achieved using as initiators a large amount of organometallic compounds derivative from: Alkali metals, alkaline earth metals, transition metals and lanthanide metals. Of all these compounds, the lanthanide derivatives have acquired great importance in the synthesis of aliphatic polyesters, since these show a greater catalytic activity and also can provide polymer with characteristics that will be very useful in the design of biomaterials. Objective: It was proposed the synthesis of poly(L-lactida) (PL-LA) through a ring opening polymerization process of L-lactide initiated with samarium(III) acetate (Sm(OAc)3) under solvent-free melt conditions. The influence of different parameters of reaction, such as temperature, time, molar ratio monomer to initiator, on typical variables of polymers, e.g., conversion, dispersity, and molar mass, were analyzed. Methods: All polymerizations were carried out under solvent-free melt conditions in ampoules-like flasks, equipped with a magnetic stirrer. The obtained polyesters were characterized by size exclusion chromatography (SEC) and 1H-NMR. Results: The Sm(OAc)3 induces the polymerization of L-LA at high conversion, and produce polyesters with number-average molecular weights of 1.00 x 103 to 30.00 x 103 Dalton. The 1H-NMR analysis indicates a typical polymerization mechanism of coordination-insertion, with a breakdown of the acyl-oxygen bond of the L-LA. Conclusion: Sm(OAc)3 was an effective initiator for the ring-opening polymerization of L-LA. SEC chromatography showed that, at high temperatures and prolonged reaction times, the molar mass of the polyester decreases, which is associated with the transesterification collateral reactions that occur during the polymerization process.

Precision Aliphatic Polyesters via Cross-Metathesis Polymerization.

Cross-metathesis (CM), a carbon-carbon bond transformation that features exceptional selectivity, reactivity and tolerance to functionalities, has been extensively investigated in organic chemistry. On the other hand, the use of CM in polymer synthesis is also growing in both scope and breadth, thus offering a wealth of opportunities for introducing a vast range of functionalities into polymer backbone so as to manipulate properties and expand applications. In this review, we propose the concept of "cross-metathesis polymerization" (CMP) referring to polymer synthesis via repetitive CM reaction and summarize emerging strategies for the precision synthesis of aliphatic polyesters via CMP based on the high CM tendency between acrylates and α- olefins. Due to the carbon-carbon bond-forming step-growth polymerization nature, CMP brings a new concept to polyester synthesis. This remarkable polymerization method possesses unique advantages such as mild condition, full conversion, fast kinetics, almost quantitative yield and extraordinary tolerance to functionalities. In particular, CMP provides the ability to regulate macromolecular architectures including linear, block, cyclic, star, graft, dendron, hyperbranched and dendrimer topologies. Ultimately, advanced polymeric materials with outstanding performances can be facially constructed based on these sophisticated macromolecular architectures.

Facile Synthesis of Aliphatic ω-Pentadecalactone Containing Diblock Copolyesters via Sequential ROP with l-Lactide, ε-Caprolactone, and δ-Valerolactone Catalyzed by Cyclic Trimeric Phosphazene Base with Inherent Tribasic Characteristics

Degradable long-chain aliphatic polyesters are promising alternatives to polyolefins. The ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) enables the synthesis of aliphatic polyesters with melting temperature close to low-density polyethylene (LDPE). However, this ROP reaction is of great challenge because of low ring strain of the PDL monomer. The occurrence of intra- and intermolecular transesterification reactions during ROP made it difficult to prepare well-defined block copolyesters for advanced properties. In this context, cyclic trimeric phosphazene base (CTPB) in combination with benzyl alcohol (BnOH) was proved to be an efficient initiator system for ROP of PDL, showing an excellent polymerization rate (TOF up to 600 h–1) at 80 °C. Well-defined diblock copolyesters, i.e., PPDL-b-PLLA, can be easily synthesized by sequential addition of PDL and l-lactide (L-LA). In contrast, sequential addition of PDL and e-caprolactone (CL) or δ-valerolactone (VL) only led to the random copolyesters...

Precision Aliphatic Polyesters via Segmer Assembly Polymerization.

Precise structure-property relation of a biodegradable polymer (e.g., aliphatic polyester) is anticipated only if monomer units and chiral centers are arranged in a defined primary sequence as a biomacromolecule. An emerging synthetic methodology, namely segmer assembly polymerization (SAP), is introduced in this paper to reveal the latest progress in polyester synthesis. Almost any periodic polyester envisioned can be synthesized via SAP using a programed linear or cyclic monomer. In this context, the macroscopic properties of a biodegradable polymer are fundamentally determined by microstructural information through a bottom-up approach. It can be highlighted that SAP ideally combines the precision of organic synthesis and the high efficiency of a polymerization reaction. Previously reported strategies including nucleophilic displacement, polyesterification, cross-metathesis polymerization (CMP), ring-opening polymerization (ROP), ring-opening metathesis polymerization (ROMP) and entropy-driven ring-opening metathesis polymerization (ED-ROMP) are critically reviewed in this paper to shed light on precision synthesis of aliphatic polyesters via SAP. Emerging yet challenging, SAP is a paradigm which reflects the convergence of organic and polymer chemistries and is also an efficient pathway to microstructural control. The current status, future challenges and promising trends in this realm are analyzed and discussed in this overview of the state-of-the-art.

New “old” polylactides for tissue engineering constructions

New methods for the synthesis of aliphatic polyesters were proposed and realized with highly effective and low-toxic 1,5,7-triazabicyclo[4.4.0]decene-5 and (2,6-di-tert-butyl-4-methylphenoxy)-butyl-magnesium as catalysts and ethanol as an initiator. The interaction processes between D,L-polylactides of different molecular weights, obtained through these methods, and supercritical carbon dioxide were studied to provide “soft and dry” formation (without high temperatures and toxic organic solvents) of highly porous (up to 90 vol %) bioresorbable matrices for tissue engineering constructions. The chemical structure, molecular weight characteristics, morphology, cytotoxicity, and matrix properties of the samples synthesized from D,L-polylactides were studied with nuclear magnetic resonance spectroscopy, gel permeation chromatography, scanning electron microscopy, colorimetric testing to estimate the metabolic activity of cells (MTT test), and coloration with a vital fluorescent dye of in vitro cultures of multipotent stromal cells of human adipose tissue. A comparative analysis for biocompatibility of these matrices with control samples made from “medical grade” polylactide analog produced industrially indicates that the materials developed can be recommended for tissue engineering.

Alternating Copolymerization of Propylene Oxide and Cyclohexene Oxide with Tricyclic Anhydrides: Access to Partially Renewable Aliphatic Polyesters with High Glass Transition Temperatures

Renewable, biodegradable polymers, such as aliphatic polyesters, based on sustainable sources have attracted considerable interest as alternatives to petroleum-based polymers. One limiting factor in the development of aliphatic polyesters as replacements for these materials has been their relatively low glass transition temperatures (Tg). For example, commercially available poly(lactic acid) has a Tg of approximately 60 °C. Epoxide/anhydride copolymerizations offer an alternative to the ring-opening polymerization of lactones for the synthesis of aliphatic polyesters and allow for tuning of polymer properties through two distinct monomer sets. We synthesized six partially or fully renewable tricyclic anhydrides and copolymerized them with propylene oxide (PO) and cyclohexene oxide (CHO). By varying both the epoxide and the anhydride, we were able to tune the Tg of the resulting polymers over a nearly 120 °C range from 66 °C to an exceptionally high 184 °C. Polymers produced with PO had a lower range of Tg...

Enzymatically catalyzed poly(butylene succinate)(PBS) copolymers as building blocks for degradable scaffolds

Event Abstract Back to Event Enzymatically catalyzed poly(butylene succinate)(PBS) copolymers as building blocks for degradable scaffolds Miroslawa El Fray1, Monika Malesa1 and Aleksandra Kaczmarek1 1 West Pomeranian University of Technology Szczecin, Biomaterials and Microbiological Technologies, Poland Introduction: An increasing exploitation of regenerative potential of living tissues is observed from last two decades since temporary, biodegradable polymeric templates (scaffolds) are being developed for tissue engineering[1]. Biodegradable polymers are synthesized from non-toxic monomers, but toxic catalysts are frequently used like in case of biodegradable aliphatic polyesters where highly toxic tin compounds are used[2]. Therefore, stiff but biodegradable polymers are needed for tissue engineering and other biomedical applications. In our work we focus on much safer enzymatic biocatalysts which are proposed for the synthesis of aliphatic polyester, poly(butylene succinate)(PBS) and its copolymers. Materials and Methods: Poly(butylene succinate)(PBS) and its copolymers containing ethylene glycol sequences (PBS-EG) and dilinoleic acid sequences (PBS-DLA) were prepared by enzymatic polymerization of succinic acid ester (diethyl succinate)(DES), 1,4-butanediol (1,4-BD) and poly(ethylene glycol) (PEG_3000) or dilinoleic acid (DLA) in organic solvent (diphenyl ether). Lipase B derived from Candida antarctica strain, trade name Novozym 435th (N435), was used as a catalyst. The hard segments (PBS) to soft segments (EG or DLA) ratio based on stoichiometric calculations was 50:50 wt%. The reaction mixture was dissolved in chloroform to remove the unreacted monomers and impurities and then the microspheres in which the enzyme catalyst was immobilized were separated. Samples chemical structure were assessed by using ATR-FTIR and NMR analysis, degradation and contact angle measurement. Sample mechanical characterization was performed by tensile test. Preliminary cell viability tests have been performed by using fibroblasts. Results and Discussion: The PBS-EG and PBS-DLA copolymers were synthesized using Candida Antarctica from lipase B. Analysis of chemical structure with 1H NMR and ATR FT-IR spectroscopy confirmed the presence of specific bonds and groups, characteristic for ester and ether groups. The contact angle measurements on both materials revealed differences in hydrophilicity thus indicating that depending from the nature of copolymer building block, degradation profile can be adjusted. This can be achieved along with mechanical properties changes since PBS-DLA copolymer showed to be more flexible as compared to PBS-EG. Positive results from the preliminary cell viability tests have been also obtained. Conclusions: Enzymatically catalyzed copolymers of poly(butylene succinate), namely PBS-EG and PBS-DLA has been obtained. Results showed that these materials have different surface and mechanical properties depending from the chemical structure of soft segment building block. Their degradation profile and mechanical properties can also be adjusted thus making them an interesting candidate for degradable scaffolds, specifically for heart tissue engineering. This work was supported by the National Science Centre under the HARMONIA scheme (UMO-2014/14/M/ST8/00610).

Synthesis of Aliphatic Polyesters via Ring‐Opening Polymerization of Macrocyclic Oligoesters

SummaryTo synthesize high molecular weight aliphatic polyesters, ring‐opening polymerization (ROP) of macrocyclic oligoesters made from several dicarboxylic acids and diols was investigated. Macrocyclic oligoesters used for the ROP were synthesized in ca. 50% yield via polycondensation of dicarboxylic acids (small excess) and diols under dilute condition in toluene, followed by washing with aq. NaHCO3 to remove linear oligomers. The obtained products were the mixtures of macrocyclic oligoesters with various ring size (dimer to heptamer). The polymerization of the macrocyclic oligoesters made from succinic acid and 1,4‐butanediol using rare earth catalysts such as Nd(BH3)(thf)3 and Nd(OiPr)3 was found to give high molecular weight polymers in good yields. Cyclic dimer of butylene succinate ((BS)2) was isolated from the mixture of the cyclic oligomers by column chromatography, and was similarly polymerized by the rare earth catalysts. Bulk polymerization of (BS)2 by Nd(BH3)(thf)3 yielded poly(butylene succinate) with Mn up to 38 000. Cyclic oligomers of trimethylene oxalate were not polymerized under the similar conditions applied in this study.

Organocatalyzed Synthesis of Aliphatic Polyesters from Ethylene Brassylate: A Cheap and Renewable Macrolactone.

The use of organocatalysts for the polymerization of ethylene brassylate, a commercially available, cheap, and renewable macro(di)lactone is reported for the first time. Ethylene brassylate was polymerized by ring-opening polymerization under bulk and solution conditions at 80 °C. Polymerizations were carried out in the presence of several organic catalysts, such as dodecylbenzenesulfonic acid (DBSA), diphenyl phosphate (DPP), p-toluenesulfonic acid (PTSA) and bases, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,2,3-tricyclohexylguanidine (TCHG), and 1,2,3-triisopropylguanidine (TIPG), using benzyl alcohol as initiator. Results agreed with a ring opening polymerization process in which the rate of polymerization was accelerated by the catalysts presence in the order of TBD > PTSA > DBSA > DPP > TIPG > TCHG. Complementary computational studies supported the experimental results. The obtained poly(ethylene brassylate) aliphatic polyesters were characterized by NMR, SEC, MALDI-TOF, DSC, and TGA. They showed molecular weights ranging from 2 to 13 kg mol-1 and polydispersity index between 1.5 and 2. Poly(ethylene brassylate) is a semicrystalline polyester similar to poly(ε-caprolactone) with slightly higher melting and glass transition temperatures (Tm = 69 °C, Tg = -33 °C) and good thermal stability.

Production of biodegradable polyesters via enzymatic polymerization and solid state finishing

ABSTRACTThe synthesis of aliphatic polyesters (PEs) derived from diols (1,4‐butanediol and 1,8‐octanediol) and diacids or their derivatives (diethyl succinate, sebacic acid, 1,12‐dodecanedioic acid, and 1,14‐tetradecanedioic acid) was achieved in order to produce poly(butylene succinate) (PE 4.4), poly(octylene sebacate) (PE 8.10), poly(octylene dodecanate) (PE 8.12), and poly(octylene tetradecanate) (PE 8.14). The herein suggested procedure involved two stages, both sustainable and in accordance with the principles of “green” polymerization. The first comprised an enzymatic prepolymerization under vacuum, in the presence of diphenylether as solvent using Candida antarctica lipase B as biocatalyst, whereas a low‐temperature postpolymerization step [solid state polymerization (SSP)] followed in order to upgrade the PEs quality. In the enzymatically synthesized prepolymers, the range of number–average molecular weight attained was from 3700 to 8000 g/mol with yields reaching even 97%. Subsequently, SSP of PE 4.4 and 8.12 took place under vacuum or flowing nitrogen and lasted 10–48 h, at temperatures close to the prepolymer melting point (Tm − TSSP varied between 4°C and 14°C). The solid state finishing led to increase in the molecular weight depending on the prepolymer type, and it also contributed to improvement of the physical characteristics and the thermal properties of the enzymatically synthesized PEs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40820.

Lipase-catalyzed synthesis of aliphatic polyesters via copolymerization of lactide with diesters and diols

Aliphatic lactate-bearing copolyesters were successfully synthesized via copolymerization of L-lactide (LLA) with diesters and diols using Candida antarctica lipase B (CALB) as the catalyst. The resultant copolymers had a Mw up to 38,000 Da with Mw/Mn between 1.5 and 2.0, and contained L-lactate units (up to 53 mol%), C6–C12 diester units, and C4–C6 alkylene units in the polymer chains. The lactate repeat units were present primarily as lactate–lactate diads in the polymers. The LLA-diester-diol copolymers were purified in good yield (70–85%) and all purified copolymers were optically active. Hydrolytic degradation study shows that LLA-diethyl adipate-1,6-hexanediol (LLA-DEA-HD) copolymers are degradable polymers as the molecular weight (Mw) of the copolymer with 53% lactate units decreased by ∼70% upon incubation in PBS solution under physiological conditions (37 °C, pH of 7.4) for 80 days. The LLA-diester-diol copolymers are thermally stable up to at least 300 °C with the temperature of maximum degradation rate ranging from 380 to 410 °C. The copolymers exhibit a wide range of physical properties (e.g., from white solid to wax and liquid) depending on their structure and composition. In particular, the LLA-DEA-HD and LLA-DEA-1,4-butanediol copolymers with ∼50 mol% lactate units are colorless, viscous liquids at ambient temperature. Biodegradable liquid polymers are potentially useful biomaterials for drug delivery to treat ocular ailments because of their good compatibility with sensitive soft tissues.

Yttrium catalysts for syndioselective β-butyrolactone polymerization: on the origin of ligand-induced stereoselectivity

Synthesis of aliphatic polyesters has been studied intensively due to their biocompatible and biodegradable properties and their applications in medical and agricultural fields. Among them, polyhydroxybutyrate (PHB), which is a naturally occurring polymer, is synthesized by a variety of bacteria and algae. However, this polymer has poor mechanical properties due to its brittleness. Herein is presented a practical route to a highly syndiotactic PHB by way of a one-pot reaction. We report the results of a comprehensive investigation of the newly discovered stereoselective and controlled polymerization of racemic β-butyrolactone (rac-BBL) using an initiator prepared in situ from yttrium(III) isopropoxide Y(OiPr)3, and a bisphenoxide ligand. DFT studies on the alkoxide catalyst reveal that the R and S monomers are almost equivalent for the first ring-opening reaction. The selectivity of the next insertion was scrutinized, demonstrating that the polymerization process is predicted to be stationary (back-side insertion).

Polymerization of cyclic esters using N-heterocyclic carbene carboxylate catalysts

The ring-opening polymerization of β-butyrolactone and lactide in solvent-free conditions and using NHC carboxylates as a (pre)catalyst is described. This class of catalysts enables the synthesis of aliphatic polyesters. These organocatalysts, which are easily synthesized, are remarkably robust, thus allowing the use of a bench-top reaction setup. In addition, NHC carboxylates are highly active in bulk conditions without the use of additives. Also, we have demonstrated for the first time that decarboxylation of NHC carboxylates depends on the nature of solvents under polymerization conditions.

Scope and limitations of the nitroxide-mediated radical ring-opening polymerization of cyclic ketene acetals

The ring-opening polymerization of cyclic ketene acetals (CKAs) by controlled radical mechanisms represents an alternative route for the synthesis of aliphatic polyesters. For the first time, 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) and 2-methylene-4-phenyl-1,3-dioxolane (MPDL) were homopolymerized by nitroxide mediated polymerization (NMP), from the commercially available SG1-based BlocBuilder MA alkoxyamine. Various experimental conditions (i.e., reaction temperature, nature of solvent, and nature of the alkyl initiating radical) were varied to determine the optimized conditions in terms of polymerization kinetics and living character of the final polymer. Chain-end extensions from either PS-SG1 or PBMDO-SG1 were also performed in order to furnish PS-b-PBMDO and PBMDO-b-PS, respectively, thus demonstrating the synthesis of block copolymers comprising a CKA block. In order to have a better insight into the polymerization mechanism, the occurrence of side reactions was analyzed by 31P NMR spectroscopy and ESI-MS. It was supposed that the ketal-based macroradical could be irreversibly trapped by nitroxide and thus the corresponding macroalkoxyamine decomposed by CO–N bond dissociation. DFT calculations as well as PREDICI modeling were also undertaken in order to support this hypothesis.

Polycondensation of Sebacic Acid with Primary and Secondary Hydroxyl Groups Containing Diols Catalyzed by Candida antarctica Lipase B

The aliphatic polyesters are normally synthesized by ester interchange reactions or direct esterification of hydroxyacids or diacid/diol combinations. Biotransformation, utilizing the enzymes as catalysts, was accepted as an alternative route for the synthesis of aliphatic polyesters and offers various advantages compared with the conventional, metal-catalyzed polymerization reactions. Previous studies indicated that lipase-catalyzed polycondensation reactions between diols and diacids occurred preferentially at primary hydroxyl groups of diols, when diols contained both primary and secondary hydroxyl groups. In this work, we investigated lipase-catalyzed polycondensation of diacids and secondary hydroxyl group–containing diols, and successfully synthesized polyesters by polycondensation with secondary hydroxyl groups as well as primary hydroxyl groups. Various diols, glycerol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, and 2,4-pentanediol were tested for the polycondensation. The polymerization was achieved by heating a mixture of lipase B, sebacic acid, and the diols in anhydrous toluene at 100 °C for 72 h. The resulting polymers were characterized by 1H and 13C NMR spectroscopy, Fourier transform–infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography.