Self-assembly and crystallization of double crystalline aliphatic thermoplastic biopolyurethane and its nucleation with cellulose nanocrystals

Abstract

[EN] An aliphatic segmented thermoplastic biopolyurethane (STPU), based on aliphatic hexamethylene diisocyanate (HDI) and 1,3 propanediol (1,3PD) as urethane rich phase and a poly(sebacate) as a macrodiol phase, with ~50 wt% of renewable carbon content, was synthetized and mixed with cellulose nanocrystals (CNC) to develop new bionanocomposites. The phase behaviour of the STPU and derived bionanocomposites was analysed with a variety of techniques which include differential scanning calorimetry (DSC), isothermal crystallization, X-ray scattering and atomic force microscopy (AFM). The Isothermal crystallization of the STPU matrix allowed fitting to the Lauritzen-Hofmann model and calculation of the overall crystallization constant, Kg. Further dynamic thermal analysis by X-ray scattering and DSC allowed the determination of the impact of CNC on the morphology and nucleation of the urethane rich phase. Self-nucleation experiments with the STPU matrix allowed quantification of the nucleation effect of the CNC.