Starch/Polyethylene Nanocomposites

Cellulose nanofibers were isolated from wheat straw by a chemical-mechanical treatment. Initially, wheat straw fibers were subjected to a chemical process to eliminate lignin, hemicelluloses, and pectin. After cutting, wheat straw fibers were soaked in An alkali solution to swell the cell walls to enable chemical molecules to penetrate through the crystalline region of cellulose and dewaxing. Then, hemicellulose and pectin removed from pulp in acid hydrolysis stage.  Soluble lignin removed in alkali treatment and klasson lignin removed in bleaching stage. Obtained chemical-purified cellulose microfibers were then mechanically separated into nanofibers by sonication. The chemical composition of fibers at different stages were analyzed according to the NREL standards and showed increase in α-cellulose content and decrease in lignin, hemicelluloses, and pectin. Structural analysis of untreated & acid hydrolyzed fibers and final nanofibers was carried out by ATR-FTIR that indicated this chemical treatment led to partial removal of hemicellulose and lignin from the structure of the fibers. The nanofibers morphology and size were characterized using a scanning electron microscope (SEM) that indicate average diameter less than 100nm and average length about 1µm for obtained nanofibers. These nanofibers are suitable for manufacturing nanocomposites. In the next stage of the project, a process for manufacturing starch/polyethylene nanocomposites is developed and optimized. Moreover, the final  properties of the composite will be investigated.

Key words: nanofiber, acid hydrolysis, nanocomposite