Preparation of Renewable Epoxy-Amine Resins With Tunable Thermo-Mechanical Properties, Wettability and Degradation Abilities From Lignocellulose- and Plant Oils-Derived Components.

Louis Hollande,Patrick Balaguer,Florent Allais,Richard A Gross,Izia Do Marcolino,Sandra Domenek

doi:10.3389/fchem.2019.00159

Abstract

One-hundred percent renewable triphenol—GTF—(glycerol trihydroferulate) and novel bisphenols—GDFx–(glycerol dihydroferulate) were prepared from lignocellulose-derived ferulic acid and vegetal oil components (fatty acids and glycerol) using highly selective lipase-catalyzed transesterifications. Estrogenic activity tests revealed no endocrine disruption for GDFx bisphenols. Triethyl-benzyl-ammonium chloride (TEBAC) mediated glycidylation of all bis/triphenols, afforded innocuous bio-based epoxy precursors GDFxEPO and GTF-EPO. GDFxEPO were then cured with conventional and renewable diamines, and some of them in presence of GTF-EPO. Thermo-mechanical analyses (TGA, DSC, and DMA) and degradation studies in acidic aqueous solutions of the resulting epoxy-amine resins showed excellent thermal stabilities (Td5% = 282–310°C), glass transition temperatures (Tg) ranging from 3 to 62°C, tunable tan α, and tunable degradability, respectively. It has been shown that the thermo-mechanical properties, wettability, and degradability of these epoxy-amine resins, can be finely tailored by judiciously selecting the diamine nature, the GTF-EPO content, and the fatty acid chain length.

Highlights

Thermoset polymers are widely used in industrial applications thanks to their versatile performance, good durability, and excellent chemical resistance provided by their highly cross-linked structure (Ellis, 1993; Auvergne et al, 2014; Ramon et al, 2018)
Chemo-Enzymatic Synthesis Chemical esterification of p-hydroxycinnamic acids with alcohol is unselective and side reactions generally lead to an unwanted product that needs to be removed by purification steps, generating waste to dispose of
The lipase-mediated enzymatic synthesis offers some advantages for synthesizing esters, such as milder reaction conditions and selectivity

Summary

Introduction

Thermoset polymers are widely used in industrial applications thanks to their versatile performance, good durability, and excellent chemical resistance provided by their highly cross-linked structure (Ellis, 1993; Auvergne et al, 2014; Ramon et al, 2018). It is very common to find these polymers in a broad range of applications such as maintenance coating, adhesives for aerospace (Prolongo et al, 2009) and automobile (Holbery and Houston, 2006) industries, or binders in composites (Gojny et al, 2006). Epoxy resins are one of the most important thermoset materials and are usually synthesized by reacting (poly)phenolic compounds with epichlorohydrin under basic conditions (Bruins, 1968). Solvay or Dow Chemical have already initiated the transition with the commercialization of bio-based epichlorohydrin prepared from the chlorination of bio-based glycerol, a by-product of biodiesel production (Strebelle et al, 2001; Freddy, 2006). A number of renewable resources—including fatty acids (Biermann et al, 2000; Maisonneuve et al, 2013; Laurichesse et al, 2014), lignocellulosic biomass (Isikgor and Becer, 2015), and enzymatic products—have been reported as alternative feedstocks in polymers synthesis

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