The global market for polyols was US$26.2 billion in 2019 and is expected to grow up to US$34.4 billion by 2024. Polyols are most commonly employed as the main component in the synthesis of polyurethanes, which is the sixth most important polymer family produced with a global production that reached around 22 Mt in 2019. In the interest of improving the sustainability of the polyurethane industry, for more than a decade the market has undergone a shift toward biobased polyols made from renewable resources. For this reason, the demand of biobased polyols has grown rapidly and offers new opportunities to valorize biomass into technical grade polyols for the polyurethane industry. This Perspective aims to summarize current strategies to produce polyols from biomass and the problems associated with their market implementation. Different natural resources, including lignocellulose, lipids, or carbohydrates for the synthesis of biobased polyester- or polyether-based polyols and polyphenols will be reviewed. Subsequently, the gaps that are currently preventing the transition from academic laboratories to industrial plants will be commented upon, highlighting in particular the use of nonscalable chemical transformations and the lack of competitive biobased raw material suppliers. Finally, a case study of the issues associated with the scale-up process of novel biobased polyols will be discussed in detail.

Polyethers constitute a well-established class of polymers covering a wide range of applications from industrial manufacturing to nanomedicine. Nevertheless, their industrial implementation is limited to short chain aliphatic polyethers such as polyethyeleglycol (PEO or PEG), polypropyleneglycol (PPG) or polytetramethylenglycol (PTMG) produced by the ring-opening polymerization of the corresponding cyclic ethers. Herein we report a sustainable and scalable approach for the preparation of medium and long chain aliphatic polyethers by the melt self-polycondensation of aliphatic diols in the presence of non-eutectic acid base mixtures as organocatalyst. These organocatalysts were prepared by forming stoichiometric and non-stoichiometric complexes of methanesulfonic acid (MSA) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as confirmed by NMR spectroscopy and DFT calculations. The non-stoichiometric 2:1 and 3:1 MSA:TBD molar complexes showed superior thermal stability. These non-eutectic acid base mixtures were tested in the bulk-self condensation of 1,6-hexanediol leading to telechelic hydroxy-poly(oxyhexane). The optimized polymerization conditions involved the use of MSA:TBD (3:1) catalyst in a three step polycondensation process at 130 o C-180 °C and 200 °C respectively. These conditions were applied to the synthesis of a wide range of aliphatic polyethers with a number of methylene units ranging from 6 to 12 units and molecular weights between 5,000 and 22,000 g mol-1. The aliphatic polyethers were highly semicrystalline with melting temperatures ranging from 55 to 85 °C. The synthesis approach was extended to the preparation of value-added copolymers from different lenght chain diols and different functionality, giving rise to different copolymer architectures from linear copolyethers to polyether thermosets. Altogether, this straightforward polymerization strategy enables the access to medium-long chain and cross-linked aliphatic polyethers using easily prepared and recyclable organocatalysts.

Although the study of melt memory has attracted much interest, the effect of polymer chemical structure on its origin has not been fully elucidated. In this work, we study melt memory effects by Differential Scanning Calorimetry employing a selfnucleation protocol. We use homologous series of homopolymers containing different polar groups and different number of methylene groups in their repeating units: polycarbonate, polyesters, polyethers and polyamides. We show that melt memory in homopolymers is generally controlled by the strength of the intermolecular interactions. The incorporation of methylene groups reduces melt memory effects by decreasing the strength of segmental chain interactions, which is reflected by the decrease in dipolar moments and solubility parameters. This work presents for the first time a unified view of the melt memory effects in different homopolymers.