Cellulose nanofiber for eco-friendly polymer nanocomposites

Abstract

Nanocomposite is the reinforced composite material consists of nanoscale reinforcing fillers and matrix polymer. Fillers are dispersed within nanoscale and require just less amount than conventional reinforcing fillers, but the properties of composites are greatly improved. There would be only insignificant deterioration of properties in case of recycling; therefore, it is able to be an eco-friendly composite material. Recent studies show that interests in cellulose nanocomposites consists of nanocellulose fiber and matrix polymer are enhanced more and more in recent years. Especially, cellulose nanocomposites are best representative eco-friendly material as compared with nanocomposites reinforced with inorganic nanoscale fillers such as nanoclay, montmorillonite, mica, and silica. Natural filler such as cellulose nanofiber from palm empty fruit bunch (OPEFB) has drawn bigger attention as it promotes eco-friendly character. In current study, cellulose nanofiber (CNF) was prepared through pretreatment to remove noncellulosic content and then undergoes acid hydrolysis process. Starch-based nanocomposite film was formed by incorporation of 2–10 % CNF per weight of starch into the film matrix. The nanocomposite film that formed appears translucent and easy to handle. However, the film becomes more opaque as percentage of CNF incorporation increased. It was observed that films with the addition of up to 2 % CNF showed higher tensile strength and thermal stability, better barrier properties to water vapor than control films. Further study on the effect of CNF was carried out on Starch/Chitosan composite packaging film to determine the influence of CNF toward antimicrobial properties of the composite film as applied packaging for perishable food. The effects of CNF contents on the tensile, dynamic mechanical and thermal properties as well as the barrier properties of the Starch/Chitosan nanocomposite were also investigated. It also embarks a potential of cellulose nanofiber as filler for antimicrobial packaging as it enhances the results on antimicrobial efficacy toward food shelf life.