Preparation and characterization of fire-retardant and hydrophobic film composites based on bacterial cellulose

• Main Author: Ybañez, Manolito Gonzaga, Jr
• Format: text
• Language: English
• Published: Animo Repository 2021
• Subjects: Acetobacter; Fireproofing agents; Ultrasonics; Particulate matter; Flammability; Bacteria; Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/etdm_chem/1; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=1000&context=etdm_chem
• Institution: De La Salle University

Bacterial cellulose (BC), a pure cellulose synthesized by Acetobacter bacteria is a highly porous material with ultrafine 3D fiber network and good mechanical property. It is a promising material for new technologies, but the range of application is limited due to its inherent hydrophilicity and flammability. This work explores the development of hydrophobic and anti-flammable materials derived from BC. We surmise that ultrasonic treatment of BC increases the degree of material impregnation into the fiber network that would alter the hydrophobic and flammable properties of the BC-based composite films. The ultrasonic process afforded a transparent BC film with transparency up to 77%. The mechanical testing of the sonicated BC films achieved the highest averaged tensile strength (229.67 MPa) and Young’s Modulus (6.85 GPa) values. Materials such as boric acid (BA), magnesium hydroxide (MH), graphene oxide (GO) and stearic acid (SA) were impregnated into the BC films. Results show that ultrasound treatment influenced the water absorbing capacity (WAC) of BC up to 1.5 times higher compared to raw samples. FTIR analysis and FESEM-EDX confirmed the absorption of these molecules into the BC fibers. TGA-DTA analysis indicated that the incorporation of BA, MH, and GO improved the thermal stability of the composite films. The flammability tests showed that sonicated BC films impregnated with BA had the best flame retarding property at 1.03 mm/min linear burning rate. The water contact angle of BC films impregnated with GO, SA, and MH showed four-fold increase in hydrophobicity. The layer-by-layer (LbL) assembly of impregnated BC films improved the fire resistance as well as hydrophobic properties. This work has shown that ultrasonic treatment improved the absorption capability of BC, which is a critical factor in its functionalization. The investigations on BC film opens new possibilities in developing multifunctional materials based on renewable and eco-friendly sources.