Synthesis And Melt-Spinning Of Partly Bio-Based Thermoplastic Poly(Cycloacetal-Urethane)S Toward Sustainable Textiles

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 potentially bio-based flexible polytetrahydrofuran and diisocyanates to prepare thermoplastic poly(cycloacetal-urethane)s. A modified one-step solution polymerization protocol resulted in relatively high molecular weights (M-n similar to 41.5-98.9 kDa). All the obtained poly(cycloacetal-urethane)s were amorphous with tuneable glass transition temperatures up to 104 degrees C. Thermogravimetric analysis indicated that these polymers were thermally stable up to 253 degrees C and had a relatively high pyrolysis char residue, which may indicate potential inherent flame resistance. Melt rheology measurements were performed to determine a suitable processing window between 165-186 degrees C, after which the polymer was successfully melt-spun into similar to 150 meters of homogeneous fibres at 185 degrees C. The resulting fibres could be readily hydrolysed under acidic conditions, resulting in partial recovery of the original chemical building blocks.