Preparation and properties of cellulose / tamarind nut powder green composites

Using biopolymer cellulose as the matrix and tamarind nut powder (TNP) obtained from agricultural waste of tamarind nuts as the filler, the green composites were made. Cellulose was dissolved in environmental friendly solvent of aq. 8 wt. % Lithium hydroxide and 15 wt. % urea which was precooled to −12 ° C. To the cellulose solutions, TNP was added in 5 wt. % to 25 wt. % of cellulose separately. Each solution was evenly spread on glass plates and the wet composites were prepared by regeneration method using ethyl alcohol coagulation bath. The wet films were dried in air at room temperature. The dried composite films were characterized by FTIR spectroscopy, X-ray diffraction, thermogravimetric analysis and also tested for their tensile properties. The tensile strength and the % elongation at break of the composites were higher than those of the matrix and increased with TNP content. While the matrix had a tensile strength of 111.8 MPa, the cellulose/TNP composite loaded with 25 wt.% TNP possessed a tensile strength of 125.4 MPa (12% increase). Though the thermal stability of the composites was lower than cellulose matrix, all the composites were stable up to a temperature of 350 °C

Experimental studies on the absorption, swelling and erosion performance of hybrid woven Kevlar/hemp reinforced epoxy composites

Hybridization of natural and synthetic fibers in a single composite material can be made by several means, and one of the best methods is the intra-ply in which both fibers are woven within a single layer. Through hybridization, the advantages of one type of fiber can improve the limitations of the other. Further the blending of natural and synthetic fibers leads to the fabrication of composites with higher mechanical performance. Hence, this work focuses on the fabrication of intra-ply Kevlar and hemp fiber reinforced epoxy hybrid composites with different weaving patterns such as plain weave, basket weave, and twill weave type. Yarns were woven by handloom technique to make intra-ply Kevlar and hemp fiber mats, and the composites were fabricated by compression molding. The water absorption, thickness swelling, and solid particle erosion characteristics of the composites were examined. The results of the experiments showed that the hemp fiber composites exhibited the least resistance (8.45% change in absorption and 4.34% change in thickness) towards the absorption and swelling, whereas pure epoxy (0.67% change in absorption and 0.31% change in thickness) and Kevlar (2.67% change in absorption and 1.67% change in thickness) composites possessed higher resistance. The absorption and swelling performance of all other hybrids was found to be in between the hemp and Kevlar composites hence proving the effectiveness of the hybridization. Further, Taguchi’s experimental design results indicated that the basket weave type hybrid composites had a minimal erosion rate for 2 minutes of exposure duration and an impact angle of 90°. The morphological analysis of the eroded surfaces of composites revealed the presence of micro cavities, broken fibers, crater formation, and microcracks

Fabrication and Characterization of an Active Nanocomposite Film based on Polystyrene/Thyme/Nano ZnO for Food Packaging

The main objective of this research is to develop an active antifungal packaging material utilizing polystyrene as the matrix material with active agents. The uniqueness of this study lies in the use of thyme extract as a reducing agent in the green synthesis of zinc oxide nanoparticles. The nanocomposite film was fabricated by impregnating zinc oxide nanoparticles in polystyrene. The nanocomposite films were characterized using XRD, FTIR, SEM and antifungal testing. The crystallite size of the synthesized ZnO NPs was observed to be in the 20–30 nm range. The FTIR spectra revealed the presence of ZnO NPs at the peak of 1000 cm–1. The morphological analysis showed the nanoparticles having a spherical shape. The results indicated that nanocomposite films exhibited excellent resistance against the fungus viz., Pencillum sp, Nigrospora oryzae and Chaetomium oryzae. The development of such active packaging materials with nanoparticles to preserve food grains will pave the way for a new technological path in food packaging applications

A practical green synthesis method of Ag NPs using rosy periwinkle plant leaves for solar panel coating

Coated silver nanoparticles (Ag NPs) are currently receiving interest because of their numerous uses in various fields of electronics, antimicrobials, manufacturing sectors, optical science, and pharmaceuticals. Among others, it gained significant attention in the power electronic system. The goal of the proposed study is to use a cost-effective coating material for solar panels; to accomplish this, silver nanoparticles were synthesized from the leaves of the Rosy Periwinkle plants. Green synthesis and characterization, such as Ultraviolet Visible Spectrometer (UV–Vis) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and Fourier Transform Infrared Spectroscopy (FTIR), were carried out after the silver nanoparticles have been collected prior coating. As a consequence, the effectiveness is determined based on the conductivity test, and the resulting Ag NPs are then applied to the c-si layer of the solar panel. Additionally, a modelling and experimental analysis are performed in this study to ascertain the suggested framework's ability to measure energy before and after coating panels with Ag NPs. Specifically, the Voltage Current (VI) and Power Voltage (PV) characteristics were validated in this study for analyzing the effectiveness and the obtained results revealed that the coating of green synthesized Ag NPs generated 2 % more power than the reference solar panel under the same conditions. Further, hardware testing and simulation were both used to confirm the outcomes and effectiveness of the suggested method. The open circuit voltage (Voc), short circuit current (Isc), maximum peak voltage (Vmp), maximum peak current (Imp), and efficiency are taken into account when assessing how well the suggested system performs at tracking. Moreover, the current density characteristics were evaluated with respect to various irradiation conditions for both the typical solar as well as Ag NPs coated panels. From the observation, it is noted that the efficiency level of coated panel was improved up to 19.20 %, 18 %, and 17.20 % for the irradiations of 200 W/m2, 500 W/m2, and 1000 W/m2 respectively

Mechanical, Absorption and Swelling Properties of Vinyl Ester Based Natural Fibre Hybrid Composites

Natural fibres such as Banana (B), Jute (J) and Kenaf (K) were hybridized in different stacking sequences in vinyl ester. The composites with hybridized fibres were tested to evaluate their tensile, flexural and impact properties. Further, they were also tested for their water absorption and thickness swelling behavior. The hybridization of the fibre mats had an encouraging outcome on the mechanical behavior. The JKBKBJ hybrid composite possessed the maximum tensile strength (34.12 MPa) while maximum stiffness of 1.667 GPa was observed for the KBJJBK hybrid composites. The observations from the flexural testing indicated that the hybrid composites resisted the flexural load for higher displacement. All the hybrid configurations presented better impact strength over the composites reinforced with kenaf and jute fibres. Among the hybrid composites investigated, the KJBBJK hybrid composite displayed highest impact strength (12.32 kJ/m2). The improved strength, stiffness and lower moisture absorption properties make the composites with hybridized fibres a potential candidate for the light weight structural applications