Fructose based rigid diol with a spirocyclic structure and low GHG emission profile toward high performance biopolymers.

Bio-based rigid diols are key building blocks in the development and preparation of high-performance bioplastics with improved thermal and dimensional stabilities. Here, we report on the straightforward two-step synthesis of a diol with a spirocyclic acetal structure, starting from bio-based vanillin and pentaerythritol. According to a preliminary life cycle assessment (LCA), the greenhouse gas emissions of this bio-based diol are significantly lower than those of bio-based 1,3-propanediol. Copolymerization of the rigid spiro-diol with 1,6-hexanediol and dimethyl terephthalate by melt polymerization yielded a series of copolyesters, which showed improved glass transition temperature and thermal stability upon the incorporation of the spiroacetal units. The crystallinity and melting point of copolyesters decreased with increasing content of the spirocyclic backbone structures. The copolyester containing 10% of the new diol was semicrystalline, while those with 20 and 30% spiro-diol incorporated were completely amorphous. Moreover, dynamic mechanical analysis indicated that the copolyesters showed storage moduli comparable to Akestra, a commercial fossil-based high-performance polyester.

Levulinic acid derived from lignocellulose is an important biobased building block chemical. Here, we report on the synthesis and polymerization of a rigid spirocyclic diester monomer to produce polyesters and...

A rigid diol with a cyclic acetal structure was synthesized by facile acetalation of fructose-based 5-hydroxymethyl furfural (HMF) and partly bio-based di-trimethylolpropane (di-TMP). This diol (Monomer T) was copolymerized with...

Spirocyclic acetal structures have recently received growing attention in polymer science due to their dual potential to raise the glass transition temperature (T g ) and enable chemical recycling of biobased polymers. In the present work, a vanillinbased diol with a spirocyclic acetal structure was incorporated in a series of rigid amorphous polyesters based on neopentyl glycol and dimethyl terephthalate (DMT). Up to 50 mol % of spirocyclic diol (with respect to DMT) could be incorporated in the copolyesters, but a reasonably high molecular weight was only achieved when ≤30 mol % of the spirocyclic diol was used. The presence of the spiroacetal units in the polyesters not only enhanced the T g (up to 103 °C) and thermal stability (T 5 ≥ 300 °C) but also the oxygen barrier of solution-cast films. We found that the acetal units in the copolyesters could be selectively hydrolyzed under acidic conditions while virtually retaining all of the ester bonds in the polymer backbone. After acidic hydrolysis, telechelic polymers exclusively terminated by two aldehyde end groups were obtained. In this work, we have demonstrated that these telechelic polyesters can be conveniently converted back into poly(acetal-ester)s via cycloacetalization reactions with pentaerythritol.