Formulation and characterization of in situ generated copper nanoparticles reinforced cellulose composite films for potential antimicrobial applications

Cellulose was dissolved in aq.(LiOH C urea) solution pre-cooled to –12.5 C and the wet films were prepared using ethyl alcohol coagulation bath. The gel cellulose films were dipped in 10 wt.% Cassia alata leaf extract solution and allowed the extract to diffuse into them. The leaf extract infused wet cellulose films were dipped in different concentrated aq. copper sulphate solutions and allowed for in situ generation of copper nanoparticles (CuNPs) inside the matrix. The morphological, structural, antibacterial, thermal, and tensile properties of dried cellulose/CuNP composite films were carried out. The presence of CuNPs was established by EDX spectra and X-ray diffraction. The composite films displayed higher thermal stability than the matrix due to the presence of CuNPs. Cellulose/CuNP composite films possessed better tensile strength than the matrix. The composite films showed good antibacterial activity against E.coli bacteria. We conclude that good antibacterial activity and better tensile properties of the cellulose/CuNP composite films make them suitable for antibacterial wrapping and medical purposes

Bio-mediated Synthesis of Nanomaterials for Packaging Applications

Change in lifestyle of humans in this present generation with huge dependence on packaging materials has encouraged several studies on development of new variety of packaging materials. Emphasis on replacement of existing non-biodegradable packaging materials with biodegradable materials paved the way for the use of biopolymers. Lack of properties, such as thermal stability and mechanical strength in biopolymers led to the development of bio-polymer nano-composites by adding metal/metal oxide nanoparticles as fillers into the biopolymers. Metal/metal oxide nano-particles improve mechanical/tensile strength, thermal stability as well as antimicrobial properties of the binding and receiving polymer matrix. Bio-mediated synthesis of metal/metal oxide nanoparticles result to development of novel packaging materials at a low cost and without releasing hazardous wastes into the environments. Novel packaging materials with metal/metal oxide nanoparticles as additives are capable of increasing the shelf life of food stuffs, in certain cases they act as indicators of quality food inside the package. Summarily, this present chapter focuses on bio-mediated synthesis of various metal/metal oxide nano-particles and their applications in food packaging.Peer reviewe

Free Vibration, Mechanical and Damping Properties of Woven Jute FRP Composites with the Effect of Stacking Arrangements

© 2023 The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/978-981-19-8979-7_12Currently, the demand for vibration damping, lightweight and environmentally friendly material is increasing in automotive and aerospace sectors. Due to this quest, the use of eco-friendly fibrous material has gained importance for its use as a reinforcement in polymeric matrix composite. Therefore, in this present investigation, woven jute fiber mats or layers were added to pure polyester resin to form various composite samples, using compression molding technique. Five different samples were fabricated: neat polyester resin plate and 2–5 woven jute/polyester composites, denoted as NPRP, 2WJPC, 3WJPC, 4WJPC and 5WJPC samples, respectively. The natural frequencies and viscoelastic behaviours of the various samples were examined by free vibration test. From the free vibration test, both natural frequencies and damping factors were obtained. From the results obtained, it was evident that 4WJPC sample exhibited the maximum natural frequencies of 32.96, 231.9 and 659.2 Hz under modes I, II and III, respectively. Also, the natural frequency of 4WJPC sample was 40% higher than that of NPRP. Therefore, it was evident that the addition of woven jute fiber mat has a significant and good influence on the composite natural frequency. Comparison between experimental and theoretical analysis was carried out and found closely related with each other. Applicably, woven jute fiber mat reinforced polyester composite can be used as a vibration absorbing material (damper), low cost and efficient engineering structure

Nanocomposite cotton gauze cloth with in situ generated silver, copper and their binary metal nanoparticles by bioreduction method

© 2022 Taylor & Francis Group, LLC. This is the accepted manuscript version of an article which has been published in final form at: https://doi.org/10.1080/24701556.2021.2025096In the present work, the authors prepared nanocomposite cotton gauze cloth (NCGC) by in situ generating the nanoparticles of silver (ANPs) and copper (CuNPs) and their binary metallic nanoparticles (BMNPs) using aqueous extraction of Azadirachta indica leaves as a reducing agent. The NCGCs had roughly spherical AgNPs, CuNPs and BMNPs in the size range of 50–120 nm. The corresponding mean size of the spherical AgNPs, CuNPs and BMNPs was 94, 89 and 87 nm respectively. The participation of the hydroxyl and amino groups of the leaf extract in the generation of the metal nanoparticles in the NCGCs was established by studying the chemical interactions. All the NCGC specimens exhibited significant antibacterial activity. However, the NCGCs with BMNPs had higher antibacterial efficiency when compared to those with homo metal nanoparticles. Hence, the NCGC with generated BMNPs can be effectively used as antibacterial wound dressing material.Peer reviewe

Bipartite entanglement via distance between the states in a one dimensional spin 1/2 dimer copper acetate monohydrate

In this paper, we used a theoretical measure known as distance between the states, $\mathcal{E}(\rho_e)$ , to determine the bipartite entanglement of a one dimensional magnetic dimer system. The calculation was compared with the well-known entanglement measure, concurrence, and found to be the same. was, then, expressed in terms of two thermodynamic quantities, namely, magnetic susceptibility and specific heat. Experimental verification of temperature variation of the bipartite entanglement measure in terms of magnetic susceptibility and specific heat was done on single crystals of copper acetate-an excellent one dimensional dimer system. The results showed the existence of bipartite entanglement till temperatures as high as room temperature! Large sized single crystals of copper acetate were grown by a new evaporation technique and characterised by thermogravimetric analysis, IR and Raman spectroscopy measurements. Density functional theory calculations were done to calculate the delocalisation index which showed much lower values of $\delta(\mathrm{Cu,Cu})$ than other bonds, implying that the probability of direct Cu–Cu exchange in copper acetate is very small. Band structure calculations revealed the presence of flat bands at the Fermi level implying very weak intermolecular interactions in copper acetate