https://pubs.rsc.org/en/Content/ArticlePDF/2016/GC/C6GC00605A

Itaconic acid – a versatile building block for renewable polyesters with enhanced functionality

Advances in sustainable thermosetting resins: From renewable feedstock to high performance and recyclability

Utilisation of bio-derived platform molecules in polymer synthesis has advantages which are, broadly, twofold; to digress from crude oil dependence of the polymer industry and secondly to reduce the environmental impact of the polymer synthesis through the inherent functionality of the bio-derived platform molecules. Bulk polymerisation of bio-derived unsaturated di-acids has been employed to produce unsaturated polyester (UPEs) which have been analysed by GPC, TGA, DSC and NMR spectroscopy, advancing on the analysis previously reported. UPEs from the diesters of itaconic, succinic, and fumaric acids were successfully synthesised with various diols and polyols to afford resins of MN 480–477,000 and Tg of −30.1 to −16.6 °C with solubilities differing based on starting monomers. This range of properties allows for many applications and importantly due to the surviving Michael acceptor moieties, solubility and cross-linking can be specifically tailored, post polymerisation, to the desired function. An improved synthesis of itaconate and succinate co-polymers, via the initial formation of an itaconate bis-diol, is also demonstrated for the first time, resulting in significantly improved itaconate incorporation.

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Synthesis of Unsaturated Polyester Resins from Various Bio-Derived Platform Molecules

The esterification of triethylene glycol (TEG) with methacrylic acid (MAA) was carried out over various solid acid catalysts and the results were compared with conventional acid catalysts. Among the catalysts studied, heteropolyacids showed higher activities than the conventional acids. These were attributed to the acidity of the catalysts. A systematic investigation was carried out for the esterification of triethylene glycol with methacrylic acid over phosphotungstic acid without any free radical inhibitor. The effects of catalyst concentration, alcohol/acid molar ratio and temperature were also studied. Parameters such as activation energy, reaction enthalpy and reaction entropy were derived for the above reaction over phosphotungstic acid in the temperature range of 353–383 K. The obtained results were also compared with silicotungstic acid.

Esterification by solid acid catalysts—a comparison

Biomass residues are a potential renewable source for the sustainable production of chemicals, materials, fuels, and energy embodying the so-called biorefinery concept. In this context, agro-forestry and agro-food industry by-products have attracted considerable interest of researchers in academia and industry as a renewable source of polymeric materials. The research developed to date on the valorization of biomass residues by converting them into polyols through oxypropylation is the subject of this review. These bio-based polyols exhibit properties similar to their petrochemical counterparts and, as such, can be used with economical advantage in the production of polyurethanes. The operating conditions of the oxypropylation reaction depend on the biomass and on the desired polyol properties. The discussion of their influence and the economic viability of the process are also presented.

Biomass‐Based Polyols through Oxypropylation Reaction

Determination of acid value, hydroxyl value and water content in reactions between dicarboxylic acids and diols using near-infrared spectroscopy and non-linear partial least squares regression

A generally applicable stoichiometric and kinetic model was developed for the polyesterification of unsaturated dicarboxylic acid with diols in the presence of a homogeneous acid catalyst. The model also incorporates, besides the esterification, the cis-trans isomerization and the double-bond saturation reactions. Rate equations based on plausible mechanistic reaction steps were derived, and the parameters of the rate equations were determined with nonlinear regression analysis using the polyesterification of maleic acid with propylene glycol at 150-190 °C as a demonstration system. Comparisons of the model predictions with the experimental data showed that the approach is useful in predicting the polyesterification kinetics and the product distribution.

Kirsi Immonen

Papers

Determination of acid value, hydroxyl value and water content in reactions between dicarboxylic acids and diols using near-infrared spectroscopy and non-linear partial least squares regression

Kinetic model for the homogeneously catalyzed polyesterification of dicarboxylic acids with diols

Kinetic model for main and side reactions in the polyesterification of dicarboxylic acids with diols

Polyesterification kinetics of complex mixtures in semibatch reactors

Kinetic analysis of the reaction network in the catalyzed polyesterification of unsaturated carboxylic acids