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Modulating the thermal properties of poly(hydroxybutyrate) by the copolymerization of rac-beta-butyrolactone with lactide
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-1922-128X
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. University of Sannio, Italy.ORCID iD: 0000-0001-9699-9151
2016 (English)In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 40, no 9, 7671-7679 p.Article in journal (Refereed) Published
Abstract [en]

Biobased poly(hydroxybutyrate) is produced by microorganisms under controlled conditions. It is a linear, high molecular weight, fully isotactic and highly crystalline polymer. However, it has poor mechanical and thermal properties. We have modulated the thermal properties of this material by ring-opening co-polymerization of rac-beta-butyrolactone (BL) with lactide (LA) in the presence of salan-based yttrium and aluminum catalysts. The prepared poly(hydroxybutyrate-co-lactide) copolymers were characterized by proton and carbon nuclear magnetic resonance (H-1 and C-13 NMR), size exclusion chromatography (SEC) and differential scanning calorimetry (DSC) analyses. The salan-yttrium compound was a more effective catalyst compared to the aluminum compound, affording high molecular weight copolymers with higher monomer conversion and a monomodal distribution of the molecular weights. The kinetic experiments showed a higher rate of polymerization for the LA with respect to the BL. The copolymers were amorphous and DSC showed unique transition temperatures for all of the samples. The formation of a gradient copolymer is proposed.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2016. Vol. 40, no 9, 7671-7679 p.
National Category
Polymer Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-193865DOI: 10.1039/c6nj00298fISI: 000382820000054Scopus ID: 2-s2.0-84985041093OAI: oai:DiVA.org:kth-193865DiVA: diva2:1034492
Funder
VINNOVA, 291795Swedish Research Council, 621-2013-3764
Note

QC 20161012

Available from: 2016-10-12 Created: 2016-10-11 Last updated: 2017-12-11Bibliographically approved
In thesis
1. Synthesis of degradable aliphatic polyesters: strategies to tailor the polymer microstructure
Open this publication in new window or tab >>Synthesis of degradable aliphatic polyesters: strategies to tailor the polymer microstructure
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Key factors for successful tissue engineering are the synthesis and design of the scaffold materials. Aliphatic polyesters have been studied and often used as scaffold materials for tissue engineering. However, their lack of biological cues and degradation under high-temperature processing (e.g., 3D printing) are a limitation. In this thesis, different synthesis strategies are presented which has the potential to improve the performance of aliphatic polyesters as scaffolds for tissue regeneration.

To stimulate interactions between exogenous materials and the surrounding tissue, two different strategies were applied. Either, by designing a two component system in which the different degradation profiles of the polymers allow for sequential release of growth factors. Or, by peptide functionalization of an aliphatic polyester chain using template-assisted chemo-enzymatic synthesis. The results from the studies were successful. A hierarchical system was obtained in which the poly(L-lactide-co-glycolide)-graft-poly(ethylene glycol) methyl ether (PLGA-g-MPEG), hydroxyapatite solution formed a gel around and within the pores of the poly(L-lactide-co-ε-caprolactone) scaffold at 37 ºC, within 1 min, that was stable for 3 weeks. The peptide functionalization was also successful where an aliphatic polyester of L-lactide was functionalized with different oligopeptides using a grafter (ethyl hept-6-enoylalaninate) and chemo-enzymatic synthesis.

The thermal properties of poly(L-lactide-co-hydroxybutyrate) were tailored (by modification of the microstructure) to potentially improve the processability of the aliphatic polyester.  The results showed that the yttrium salan catalyst was the most successful, yielding high molecular weight copolymers in shorter time. They also showed that the Tg could be tailored by varying the amount of rac-β-butyrolactone in the copolymer to better suit thermal processing techniques, such as 3D printing.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2018. 78 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2017:35
Keyword
Polymer synthesis, enzymatic synthesis, degradable polyesters, peptides, scaffolds
National Category
Polymer Technologies
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-219550 (URN)978-91-7729-615-7 (ISBN)
Public defence
2018-01-15, F3, Lindstedtsvägen 26, Stockholm, 09:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 2013-3764
Note

QC 20171207

Available from: 2017-12-07 Created: 2017-12-07 Last updated: 2017-12-07Bibliographically approved

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