Cellulose hybrid nanocomposites using Napier grass fibers with in situ generated silver nanoparticles as fillers for antibacterial applications.

Initially silver nanoparticles (AgNPs) were in situ generated in Napier grass fibers (NGFs) and these nanocomposite NGFs were used as fillers (by 1 wt% to 5 wt%) in cellulose matrix to make hybrid nanocomposite films. The formation of in situ generated AgNPs on the surface of the NGFs was studied using scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), Energy dispersive X-ray spectroscope (EDX) and X-ray photoelectron spectroscope (XPS). The HR-TEM analysis indicated the presence of spherical AgNPs on the surface of the fillers with a size ranging from 10 to 100 nm but majority of them in the 11 to 20 nm range. The POM images indicated the randomly oriented fillers in the hybrid composite films. Though the inflection temperatures of the hybrid composites were lower than for the matrix (due to catalytic activity of the AgNPs), the residual weight for them was higher than that of the matrix. The tensile strength of the hybrid nanocomposites varied between 73 MPa and 40 MPa while their tensile modulus between 4350 MPa and 2580 MPa for various filler contents. The hybrid nanocomposite films showed good antibacterial activity against Gram negative (E. coli) and Gram positive (S. aureus) bacteria.

All-cellulose composite films with cellulose matrix and Napier grass cellulose fibril fillers.

Diverse move has been attempted to use biomass as a filler for the production of biodegradable all-cellulose composites. In this study, cellulose fibrils (CFs) extracted from native African Napier grass (NG) fibres were used as fillers in cellulose matrix and made all-cellulose composites. Napier Grass Cellulose fibrils (NGCFs) loading was varied from 5 to 25 wt% in cellulose matrix in random orientation and the all cellulose composites were made by regeneration process. These composites were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, thermogravimetric analysis, optical microscopy, and tensile testing. The FTIR spectra indicated not only the presence of minute amounts of hemicelluloses and lignin in the filler but also the possible interaction between the matrix and NGCFs. The crystallinity of the all-cellulose composites was found to be lower than that of the cellulose matrix. The thermal stability of the all-cellulose composites was found to be higher than that of the cellulose matrix and increased with NGCFs filler content. The tensile strength of the all-cellulose composites though was lower than that of the cellulose matrix but still was higher than for commodity polymers. The all-cellulose composites can be considered for wrapping and mulching applications.

Preparation of cellulose composites with in situ generated copper nanoparticles using leaf extract and their properties.

In the present work, copper nanoparticles (CuNPs) were in situ generated in cellulose matrix using Ocimum sanctum leaf extract as a reducing agent and aq. CuSO4 solution by diffusion process. Some CuNPs were also formed outside the film in the solution which were separated and viewed by Transmission electron microscope and Scanning electron microscope (SEM). The composite films showed good antibacterial activity against Escherichia coli bacteria when the CuNPs were generated using higher concentrated aq. CuSO4 solutions. The cellulose, matrix and the composite films were characterized by Fourier transform infrared spectroscopic, X-ray diffraction, thermogravimetric analysis and SEM techniques. The tensile strength of the composite films was lower than that of the matrix but still higher than the conventional polymers like polyethylene and polypropylene used for packaging applications. These biodegradable composite films can be considered for packaging and medical applications.

Preparation and properties of biodegradable films from Sterculia urens short fiber/cellulose green composites.

The development of commercially viable "green products", based on natural resources for the matrices and reinforcements, in a wide range of applications, is on the rise. The present paper focuses on Sterculia urens short fiber reinforced pure cellulose matrix composite films. The morphologies of the untreated and 5% NaOH (alkali) treated S. urens fibers were observed by SEM. The effect of 5% NaOH treated S. urens fiber (5, 10, 15 and 20% loading) on the mechanical properties and thermal stability of the composites films is discussed. This paper presents the developments made in the area of biodegradable S. urens short fiber/cellulose (SUSF/cellulose) composite films, buried in the soil and later investigated by the (POM), before and after biodegradation has taken place. SUSF/cellulose composite films have great potential in food packaging and for medical applications.