Through a common solution and casting method, low contents of cellulose nanocrystals (CNC) reinforced biodegradable poly(hexamethylene succinate) based composites were successfully prepared for the first time. CNC homogeneously dispersed in PHS matrix at low loadings, showing no obvious aggregation. PHS/CNC composites showed high thermal stability as PHS. As a heterogeneous nucleating agent, CNC promoted the crystallization of PHS under both nonisothermal and isothermal crystallization conditions. In addition, the higher the CNC content, the faster the crystallization of PHS/CNC composites. The heterogeneous nucleating agent role of CNC was directly confirmed by the crystalline morphology study; moreover, the crystal structure of PHS remained unmodified despite the presence of CNC. As a reinforcing nanofiller, CNC also improved the mechanical property of PHS, especially the Young's modulus and yield strength. In brief, low contents of CNC may improve both the crystallization and mechanical property of PHS, providing an easy method to tune the physical property and promote the wider application of biodegradable polymers.
Keywords: cellulose nanocrystals; crystallization; poly(hexamethylene succinate).