Preparation And Characterization Of Bacterial Cellulose-Polyethylene Glycol Composites And Acetylated BC/BC-PEG Films

Bacterial cellulose(BC)A natural polymer produced by the fermentation of Acetobacter xylinus and having a network structure composed of nanometer-sized micro fibrils.It has excellent mechanical properties and can achieve a dry film tensile strength of 120 MPa.Meanwhile,the bacterial cellulose good compatibility with biological cells between the organization and can be degraded under natural conditions.Polyethylene glycol has good water solubility with no toxicity.Polyethylene glycol molecules and bacterial cellulose microfiber Ties intertwine to form a denser and more uniform network structure by adding PEG into media.In recent years,there are literature shows that acetylation of bacterial cellulose can make BC more excellent properties with hydrophobicity and liquid crystalline property,the composite membrane is expected to be applied in biomedical materials,liquid crystal optical materials.In this paper,BC-PEG composites were prepared by In-situ and impregnated methods,Then BC/BC-PEG films ware acetylated by Acetic anhydride/acetic acid system with Citric acid catalysis.The BC/BC-PEG and acetylated films were characterized by SEM,IR,XRD,TG and other methods for the micro-surface morphology,compositional structure,crystallization properties,thermal properties,mechanical property and so on.The SEM images of the BC/BC-PEG showed that the bacterial cellulose microfibrils could effectively entangle with the polyethylene glycol molecules to form a more compact and regular nanofiber network structure.Compared with the pure BC membrane,the BC-PEG films with PEG 3.0 compound can increase the tensile strength by 44%and the light transmittance by 61%to 88%.Adding PEG into the BC media has no significant effect on the high crystallinity of bacterial cellulose.After acetylation modified BC/BC-PEG dry film,the transmittance can reach 90%(480-780nm,in Visible light area),at the same time in a short reaction time(1h),the Tensile strength has greatly improved by more than 50%,After acetylation reaction of BC/BC-PEG films surface,BC/BC-PEG membrane can retain the good crystalline core of the membrane material,at the same time give the surface a certain degree of hydrophobic ity,and increase its application potential in biomedical materials,liquid crystal optical materials and other fields.