A family of lignin-based polyols (LBPs) has been prepared and characterized by a novel and unprecedented synthetic approach consisting of a cationic ring opening polymerization reaction of oxiranes in the...

Isosorbide is a biobased compound which could become in the near future an advantageous competitor of petroleum-derived components in the synthesis of polymers of different nature. When the reactivity of isosorbide is not enough, it can be successfully transformed into secondary building blocks, such as isosorbide bis(methyl carbonate), which provides extra functionalities for polymerization reactions with diols or diamines. The present review summarizes the possibilities for isosorbide as a green raw material to be used in the synthesis of polycarbonates and polyurethanes to obtain products of similar or enhanced properties to the commercial equivalents.

The chemical fixation of carbon dioxide by cycloaddition to biobased epoxides, e.g., vegetable oils, fatty acids, etc., is an efficient, sustainable, and clean strategy to obtain biobased cyclic carbonates. These can be used as feedstocks for the synthesis of environmentally friendly biobased polymers as an alternative to polymers used in daily life such as polyurethanes (PUs) and/or polycarbonates (PCs). Nevertheless, this reaction is not trivial at all due to both the low reactivity of the CO 2 molecule and the nature of the needed substrates (biobased epoxides) where the epoxide groups are internal and sterically hindered, hampering the CO 2 cycloaddition reaction. Therefore, the design of efficient catalytic systems to overcome these hurdles is mandatory. Most of the catalytic systems developed for this transformation aim to facilitate the rate-determining step in the CO 2 cycloaddition catalytic cycle. They comprise an ionic liquid or an ionic compound with a nucleophilic anion alone or in the presence of a cocatalyst to assist the epoxide ring-opening. The most commonly used catalyst is tetrabutylammonium bromide [TBA][Br] ionic liquid, but other ammonium-, phosphonium-, and sulfonium-based ionic liquids in combination or not with a cocatalyst have also been disclosed in the literature. This Review presents a structured overview of the reported catalytic systems, both homogeneous and heterogeneous catalysts, employed in the transformation of any epoxidized vegetable oil or derivates into biobased carbonated materials. The different catalytic systems have been discussed and compared in terms of catalytic performance, employed substrates, and reaction conditions.

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Lignin-based polyols (LBPs) with controlled microstructure were obtained by cationic ring opening polymerization (CROP) of oxiranes in an organosolv lignin (OL) tetrahydrofuran (THF) solution. The control on the microstructure and consequently on the properties of the LBPs such as hydroxyl number, average molecular weight, melting, crystallization and decomposition temperatures, are crucial to determine the performance and application of the derived-products. The influence of key parameters, for example, molar ratio between the oxirane and the hydroxyl groups content in OLO, initial OL concentration in THF, temperature, specific flow rate and oxirane nature has been investigated. LBPs with hydroxyl numbers from 35 to 217 mg KOH/g, apparent average Mw between 5517 and 52,900 g/mol and melting temperatures from −8.4 to 18.4 °C were obtained. The CROP procedure allows obtaining of tailor-made LBPs for specific applications in a very simple way, opening the way to introduce LBPs as a solid alternative to substitute currently used fossil-based polyols.

Six lignin-based polyols (LBPs) have been prepared by cationic ring opening polymerization of an oxirane in the presence of an organosolv lignin in tetrahydrofuran (THF) as reaction media and co-monomer. The prepared LBPs have been characterized and tested for the first time as phase change materials (PCMs) for thermal energy storage (TES) at low temperature. It was found a strong influence of the LBPs composition on their performance to storage thermal energy. Thus, LBPs with higher THF wt% content and lower oxirane/THF mass ratio exhibit the highest latent heats. Furthermore, a clear inversely proportional trend between the oxirane/THF mass ratio and the melting temperatures of the prepared LBPs was noticed. Among the prepared LBPs, the highest obtained latent heat was 53.7 J/g demonstrating the potential application of lignin as feedstock for PCMs preparation. To the best of our knowledge, this is the first time that a biomass derived PCM based on lignin has been studied and considered for TES applications at low temperature. LBPs show energetic solid-liquid transitions that point out their promising potential as bio-PCMs. This work paves the way to introduce new bio-based PCMs from lignin in TES systems, for example, in a more sustainable construction sector. K E Y W O R D S bio-based phase change materials, lignin-based phase change materials, lignin upgrading, thermal energy storage, thermodynamic properties

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