The Application of Cellulose Nanocrystals Modified with Succinic Anhydride under the Microwave Irradiation for Preparation of Polylactic Acid Nanocomposites

Abstract

The aim of this work was to use cellulose nanocrystals that were obtained by hydrolysis in phosphoric acid solution and further modified with succinic anhydride in the microwave field for PLA reinforcement. A series of all-bionanocomposites containing unmodified and surface modified cellulose nanocrystals with CNC content in the range of 1–3 %w.t. were obtained by melt blending and tested by XRD, SEM, DSC and DMA to investigate the effect of surface esterification of CNCs on the structure, morphology, dynamic mechanical properties of bionanocomposites, as well as phase transitions of PLA in the presence of cellulosic nanofiller. DMA investigations showed the highest increase of storage modulus by ca. 7% (335 MPa at 25°C) in the glassy state of PLA for 2 %w.t. of unmodified CNC. Though, addition of 2 %w.t. of succinylated CNCs caused the highest increase of the onset of glass transition temperature (by 6.2°C) thus widening the temperature range of biocomposite application. The increase of glass transition temperature indicates the strongest interfacial interactions due to improved miscibility of surface modified nanocrystals and thus good dispersion of additive in PLA matrix providing high interface.