Open Access

ARTICLE

Chemoenzymatic Route to Renewable Thermosets Based on a Suberin Monomer

by

1 Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, Stockholm, Sweden
2 Department of Coating Materials and Polymers at the University of Paderborn, Paderborn, Germany
3 Department of Biochemistry, KTH Royal Institute of Technology, Stockholm, Sweden
4 Wallenberg Wood Science Centre (WWSC), KTH Royal Institute of Technology, Stockholm, Sweden
5 SP Trätek, SP Technical Research Institute of Sweden, Stockholm, Sweden

* Corresponding Author:

Journal of Renewable Materials 2013, 1(2), 124-140. https://doi.org/10.7569/JRM.2012.634109

Received 01 November 2012; Accepted 10 January 2013;

Abstract

The present study describes the use of an epoxy functional fatty acid, 9,10-epoxy-18-hydroxyoctadecanoic acid (EFA), extracted from birch (Betula pendula) outer bark to produce thermosets. The purifi ed epoxy fatty acid was polymerized by enzyme-catalyzed polycondensation utilizing Candida antarctica lipase B (CalB) to form oligomers with targeted degrees of polymerization (DP) of 3, 6, and 9 and obtained DPs of 2.3, 5.9 and 7.3, respectively. It was determined that it is possible to fi rst enzymatically polymerize and aliphatically endcap the epoxy functional fatty acid resulting in controlled oligomer lengths while also maintaining the epoxy functionality for further reaction by main-chain homo-epoxy cationic photopolymerization. The enzymatic polymerized oligomers were characterized in terms of conversion of the residual epoxy groups (FT-IR), the thermal properties (DSC, TGA) and the purity by MALDI-TOF and ¹ H-NMR. The amorphous thermoset fi lms with varying degrees of crosslinking resulting from the cationically photopolymerized oligomers, were characterized in terms of their thermal properties and residual epoxy content (FT-IR ATR). The crosslinked polyesters formed insoluble, amorphous, and transparent fi lms. This work demonstrates that thermoset fi lms with designed properties can be effectively made with the use of forest products to reduce the petroleumbased plastics market.

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Keywords

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