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Enzymatic Synthesis of Functional Polyesters
KTH, School of Biotechnology (BIO), Biochemistry.
2008 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

Enzymes are successfully employed in the synthesis of different types of polymers. Candida antarctica lipase B is a highly efficient catalyst for the synthesis of polyesters by ring opening polymerization. ω-Pentadecalactone is an interesting lactone due to the unique proprieties of its polymer (poly-pentadecalactone). These polymers have not been applied in any industrial application due to the difficulties to reach them by chemical polymerization. Enzymatically, poly-pentadecalactone macromonomers can be obtained to high conversion.

In this investigation we synthesized difunctionalized poly-pentadecalactone with different functional groups. Taking advantage of the selectivity of Candida antarctica lipase B, we introduced different functional end groups. α,ω-Difunctionalized poly-pentadecalactone macromonomers with two thiol ends, two (meth)acrylate ends or with one thiol and one acrylate end were obtained with a high degree of functional ends. We have improved the difunctionalization procedure to a single-step route for the synthesis of α,ω-functionalized poly-pentadecalactones. This procedure has a great potential for industrial applications due to the simplicity of the process and the clean products afforded. Macromonomers with functionalized ends can be used to obtain new polymer architectures with novel proprieties.

We also show how the use of enzymes could have some limitations when using an initiator with a cleavable ester bond. 2-Hydroxyethyl methacrylate (HEMA) was used as initiator for the ring opening polymerization (eROP) of ε-caprolactone and ω-pentadecalactone aiming for methacrylate functional polyester. However, the lipase catalyzed not only the ring opening polymerization but also the cleavage of the HEMA moiety resulting in a mixture of polymer products with various end groups. A kinetics study of the eROP and the transesterification processes when using HEMA showed that the transesterification processes occurs at moderate frequency at low monomer concentration, it becomes dominant at longer reaction times. We showed that fully difunctionalized polymers can be obtained when using HEMA as initiator for the eROP of lactones by adding a proper end capper.

Place, publisher, year, edition, pages
Stockholm: KTH , 2008. , viii, 25 p.
National Category
Biochemistry and Molecular Biology
Identifiers
URN: urn:nbn:se:kth:diva-4641ISBN: 978-91-7178-881-8 (print)OAI: oai:DiVA.org:kth-4641DiVA: diva2:13209
Presentation
2008-03-07, FB54, AlbaNova, Roslagstullsbacken 21, Stockholm, 14:00
Opponent
Supervisors
Note
QC 20101124Available from: 2008-02-20 Created: 2008-02-20 Last updated: 2010-11-24Bibliographically approved
List of papers
1. One-Pot Difunctionalization of Poly-(ω-pentadecalactone) with Thiol-Thiol or Thiol-Acrylate Groups, Catalyzed by Candida antarctica Lipase B
Open this publication in new window or tab >>One-Pot Difunctionalization of Poly-(ω-pentadecalactone) with Thiol-Thiol or Thiol-Acrylate Groups, Catalyzed by Candida antarctica Lipase B
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2006 (English)In: Macromolecular rapid communications, ISSN 1022-1336, E-ISSN 1521-3927, Vol. 27, no 22, 1932-1936 p.Article in journal (Refereed) Published
Abstract [en]

An enzymatic one-pot procedure has been developed for the synthesis of difunetional polyesters containing terminal thiols and acrylates. Candida antarctica lipase B was used as a catalyst for the ring-opening polymerization of ω-pentadecalactone. The polymerization was initiated with 6-mercaptohexanol, then terminated with γ-thiobutyrolactone or vinyl acrylate to create two types of difunetional polyesters with a very high content of thiol-thiol or thiolacrylate end-groups.

Keyword
Biocatalysis, Enzymes, Polyesters, Ring-opening polymerization
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-8003 (URN)10.1002/marc.200600527 (DOI)000242616900008 ()2-s2.0-33845199474 (Scopus ID)
Note
QC 20100924Available from: 2008-02-20 Created: 2008-02-20 Last updated: 2017-12-14Bibliographically approved
2. Single-step, solvent-free enzymatic route to alpha,omega-functionalized polypentadecalactone macromonomers
Open this publication in new window or tab >>Single-step, solvent-free enzymatic route to alpha,omega-functionalized polypentadecalactone macromonomers
2008 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 41, no 14, 5230-5236 p.Article in journal (Refereed) Published
Abstract [en]

A straightforward enzymatic single-step route toward the synthesis of alpha,omega-functionalized polypentadecalactone (PPDL) macromonomers containing dithiol, thiol-acrylate, diacrylate, or dimethacrylate end groups has been developed. Two solvent-free approaches, mixing all components at start, using Candida antarctica lipase B (CALB) as an efficient catalyst were demonstrated. In the first approach difunctionalized polymers (with dithiol or thiol-acrylate end groups) were synthesized by mixing lipase, lactone, and equimolar amounts of functional initiator (6-mercapto-1-hexanol) and terminator (11-mercapto-1-undecanoic acid or vinyl acrylate). Polymers with a high fraction (95%) of dithiol end groups or polymers with thiol-acrylate end groups (86% and 96%, respectively) were obtained. In the second approach, a functional diester (ethylene glycol diacrylate or ethylene glycol dimethacrylate) was mixed with lactone and lipase without predrying, using water as an initial initiator. Reduced pressure was applied after 2 h of incubation to evaporate water and push the equilibrium toward high functionalization. Polymers with >96% diacrylated or dimethacrylated end groups were achieved.

Keyword
Acrylic monomers, Alcohols, Ethylene, Ethylene glycol, Glycols, Mixing, Monomers, Polymers, Solvents
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-8004 (URN)10.1021/ma800074a (DOI)000257665900022 ()2-s2.0-48949100426 (Scopus ID)
Note
QC 20100929. Uppdaterad från Submitted till Published (20100929). Tidigare titel:"One-Step, Solvent Free Enzymatic Route to α,ω-Functionalized Poly-pentadecalactone Macromonomers". Available from: 2008-02-20 Created: 2008-02-20 Last updated: 2017-12-14Bibliographically approved
3. Lipase Catalyzed HEMA Initiated Ring-Opening Polymerization: In Situ Formation of Mixed Polyester Methacrylates by Transesterification
Open this publication in new window or tab >>Lipase Catalyzed HEMA Initiated Ring-Opening Polymerization: In Situ Formation of Mixed Polyester Methacrylates by Transesterification
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2008 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 9, no 2, 704-710 p.Article in journal (Refereed) Published
Abstract [en]

2-Hydroxyethyl methacrylate (HEMA) was used as initiator for the enzymatic ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) and ∈-caprolactone (CL). The lipase B from Candida antarctica was found to catalyze the cleavage of the ester bond in the HEMA end group of the formed polyesters, resulting in two major transesterification processes, methacrylate transfer and polyester transfer. This resulted in a number of different polyester methacrylate structures, such as polymers without, with one, and with two methacrylate end groups. Furthermore, the 1,2-ethanediol moiety (from HEMA) was found in the polyester products as an integral part of HEMA, as an end group (with one hydroxyl group) and incorporated within the polyester (polyester chains acylated on both hydroxyl groups). After 72 h, as a result of the methacrylate transfer, 79% (48%) of the initial amount of the methacrylate moiety (from HEMA) was situated (acylated) on the end hydroxyl group of the PPDL (PCL) polyester. In order to prepare materials for polymer networks, fully dimethacrylated polymers were synthesized in a one-pot procedure by combining HEMA-initiated ROP with end-capping using vinyl methacrylate. The novel PPDL dimethacrylate (>95% incorporated methacrylate end groups) is currently in use for polymer network formation. Our results show that initiators with cleavable ester groups are of limited use to obtain well-defined monomethacrylated macromonomers due to the enzyme-based transesterification processes. On the other hand, when combined with end-capping, well-defined dimethacrylated polymers (PPDL, PCL) were prepared.

Keyword
Catalysis, Lipases, Monomers, Polyesters, Transesterification
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-8005 (URN)10.1021/bm7010449 (DOI)000253102100040 ()2-s2.0-39749139410 (Scopus ID)
Note
QC 20100921. Uppdaterad från In press till Published (20100921).Available from: 2008-02-20 Created: 2008-02-20 Last updated: 2017-12-14Bibliographically approved

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