Influence of chitin nanofibrils ultrasonic treatment on structure and properties of chitosan-based composite materials

The influence of ultrasonic treatment parameters of chitin nanofibrils aqueous suspension on structure, strength and deformation properties of chitosan-based composite films and fibers was investigated. Model calculations of ultrasound-induced cavitation parameters in the aqueous suspension of the chitin nanofibrils showed that an increase in the field power up to 630 W led to destruction of the cavity, to an increase in the temperature in the vicinity of cavitation area (up to 507 degrees C) and, as a consequence, to destruction of chitin glycoside ring (which is confirmed by the IR data). The results of light scattering, IR spectroscopy, and electron microscopy investigations indicated that the optimal duration of ultrasonic treatment of the chitin nanofibrils aqueous solution was 4-10 min (depending on oriented state of the scaffold). Tensile strength of the composites was 130 +/- 11 MPa (films), 226 +/- 4.8 MPa (fibers); deformation at break was 43 +/- 7.5% (films), 10 +/- 0.6% (fibers).