Issue 11, 2017

Sustainable bisphenols from renewable softwood lignin feedstock for polycarbonates and cyanate ester resins

Abstract

The selective reductive catalytic depolymerisation of softwood lignin (e.g. pine, spruce) yields predominantly 4-n-propylguaiacol (4PG; 15–20 wt% on lignin basis), an interesting platform chemical for bio-based chemistry. This contribution specifically shows promising technical, sustainable and environmental advantages of such a bio-phenol for various polymer applications. The bisphenolic polymer precursor, 5,5′-methylenebis(4-n-propylguaiacol) (m,m′-BGF-4P), was therefore first synthesized by acid-catalysed condensation, and its synthesis and isolation are compared with shorter chain analogs, viz. 4-methyl- and 4-ethylguaiacol. A thorough GC-GPC/SEC analysis of the crude condensation mixture was developed to assess the purity of the isolated dimers. Isolation is done by a single-step crystallization, yielding 57 wt% of m,m′-BGF-4P in >99% purity. This pure m,m′-BGF-4P bisphenol displays a notably reduced potency to activate human estrogen receptor alpha (hERα; EC50 at 10−5 M) in comparison with commercial bisphenols, and is therefore useful for future polymer applications. As a proof of concept, polycarbonates and cyanate ester resins were prepared from m,m′-BGF-4P and compared to other bisphenols. The polycarbonate had Mn = 5182 g mol−1, Tg = 99 °C, Tm = 213 °C, Td,5% = 360 °C, and displayed improved processability in common solvents, as opposed to the methylated and ethylated bisguaiacols. A fully cured resin disk exhibited a Tg = 193 °C, Td,5% = 389 °C and a water uptake of only 1.18% after being immersed in 85 °C water for four days. These results underscore the potential of the intrinsic functionality of lignin-derived building blocks to transcend the scope of renewability.

Graphical abstract: Sustainable bisphenols from renewable softwood lignin feedstock for polycarbonates and cyanate ester resins

Supplementary files

Article information

Article type
Paper
Submitted
13 Mar 2017
Accepted
27 Apr 2017
First published
27 Apr 2017

Green Chem., 2017,19, 2561-2570

Sustainable bisphenols from renewable softwood lignin feedstock for polycarbonates and cyanate ester resins

S.-F. Koelewijn, S. Van den Bosch, T. Renders, W. Schutyser, B. Lagrain, M. Smet, J. Thomas, W. Dehaen, P. Van Puyvelde, H. Witters and B. F. Sels, Green Chem., 2017, 19, 2561 DOI: 10.1039/C7GC00776K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements