Functionalized blown films of plasticized polylactic acid/chitin nanocomposite: Preparation and characterization

Abstract

Bionanocomposite films prepared with melt compounding and film blowing were evaluated for packaging applications. The nanocomposite masterbatch with 75 wt.% polylactic acid (PLA), 5 wt.% chitin nanocrystals (ChNCs) and 20 wt.% glycerol triacetate plasticizer (GTA) was melt compounded and then diluted to 1 wt.% ChNCs with PLA and polybutylene adipate-co-terephthalate (PBAT) prior to film blowing. The morphological, mechanical, optical, thermal and barrier properties of the blown nanocomposite films were studied and compared with the reference material without ChNCs. The addition of 1 wt.% ChNCs increased the tear strength by 175% and the puncture strength by 300%. Additionally, the small amount of chitin nanocrystals affected the glass transition temperature (Tg), which increased 4 °C compared with the reference material and slightly enhanced the films degree of crystallinity. The chitin nanocomposite also had lower fungal activity and lower electrostatic attraction between the film surfaces; leading to easy opening of the plastic bags. The barrier and optical properties as well as the thermal degradation of the films were not significantly influenced by the addition of chitin nanocrystals. Keywords: Nanocomposite, Extrusion, Nanocrystals, Mechanical properties, Thermal properties, Film blowing