A. Varada Rajulu

Chemical Resistance and Tensile Properties of Short Bamboo Fiber Reinforced Epoxy Composites

Short bamboo fiber reinforced epoxy composites have been developed with varying fiber length. The chemical resistance tests indicate that the composite materials are resistant to acetic acid, hydrochloric acid, nitric acid, sodium hydroxide, sodium carbonate, ammonia, benzene, carbon tetrachloride and toluene. The variation of tensile load at break with fiber length has been studied and the tensile load is found to be maximum for the fiber length of 30 mm.

Physico-chemical, Tensile, and Thermal Characterization of Napier Grass (Native African) Fiber Strands

This article presents the extraction and effect of alkali treatment on the physical, chemical, tensile, and thermal characteristics of fiber strands obtained from Napier grass, a renewable biomass. In order to improve these properties, the Napier grass fiber strands were treated with sodium hydroxide. The alkali treatment was carried out using NaOH solution at three different concentrations (5, 10, and 15%) for 2 h. Characterization of untreated and alkali-treated Napier grass fiber strands was carried out by studying the chemical composition, surface morphology, functional group variation, crystallinity, and tensile and thermal behavior. It was found that untreated fiber strands have lower cellulose content, crystallinity, tensile properties, and thermal stability than alkali-treated fiber strands. Napier grass fiber strands treated with 10% NaOH showed optimum tensile strength, modulus, and percentage elongation with an improvement of 51.9, 47.3, and 12.1% respectively. Based on the properties determined for alkali-treated Napier grass fiber strands, we expect that these fibers will be suitable for use as a reinforcement in natural fiber composites.

Ultrasonic studies of water/poly(ethylene glycol) mixtures

Abstract The ultrasonic velocity and density of liquid mixtures of water and poly(ethylene glycol)-200 have been measured at 30 °C. The variation of sound velocity and adiabatic compressibility with concentration shows a change in the slope at a mole ratio of four indicating the formation of tetrahydrate.

Miscibility of PVC/PMMA blend by the ultrasonic and refractive index method

The ultrasonic velocity and refractive index of polyvinyl chloride (PVC)/polymethyl methacrylate (PMMA) blend solutions in cyclohexanone have been measured at 30°C. The variation of these parameters with blend composition has been found to be linear, indicating the miscibility of PVC with PMMA. The results obtained have been compared with those obtained by the viscosity method.

Extraction and Characterization of Novel Lignocellulosic Fibers From Thespesia Lampas Plant

In this work, the lignocellulosic fibers from the plant Thespesia lampas were extracted and investigated in detail. The prime objective of this work was to study the effect of alkali treatment on the chemical composition, tensile properties, morphological and structural changes, and thermal degradation of Thespesia lampas fibers. Chemical analysis, FT-IR, and 13C CP-MAS NMR spectroscopic studies indicated lowering of amorphous hemicellulose content on alkali treatment. Wide-angle X-ray diffraction studies indicated increase in crystallinity of the fibers on alkali treatment. The tensile strength and modulus of the fibers and thermal stability increased on alkali treatment. Scanning electron micrographs revealed roughening of the surface of the fibers due to the removal of the hemicellulose layer on alkali treatment. Tensile properties of Thespesia fibers were compared to those of other important natural fibers, and it was indicated as an alternative suitable source for composite construction.

Mechanical properties of short, natural fiber Hildegardia populifolia-reinforced styrenated polyester composites

Short, natural fibers belonging to the species Hildegardia populifolia were reinforced in styrenated polyester matrix. The mechanical properties of these polymer composites such as tensile modulus, compression strength at first deformation, flexural modulus, and izod impact strength were determined. The effect of alkaline treatment of the natural fiber on the mechanical properties of the composites has been reported. The fractured surfaces of these composites were investigated by scanning electron microscopic technique (SEM) to investigate the interfacial bonding between matrix and the reinforcement. The present work has been carried out in order to make partially biodegradable and eco-friendly composites.

Chemical resistance and tensile properties of epoxy/polycarbonate blend coated bamboo fibres

The bamboo fibres belonging to the family of Dendrocalamus strictus were coated with a blend of epoxy/polycarbonate with varying polycarbonate content. The chemical resistance of these fibres to some acids, alkalis and solvents was studied. The tensile load at break for these fibres was determined. The coated fibres showed higher tensile load at break, and were resistant to acids and alkalis. However, the solvent resistance of the coated fibres was found to be minimal.

Ultrasonic, refractometric, and viscosity studies of some polymer blends in solution

The polymer blend solutions of polyvinyl chloride/polystyrene and polyvinyl chloride/cellulose acetate in common solvent have been prepared in different percent of the components. The ultrasonic velocity, viscosity and refractive index have been measured at 30 degrees C The interaction parameters have been computed using the viscosity data to probe the miscibility. The obtained revelations have been confirmed by the ultrasonic velocity and refractive index data.

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.

Effect of Alkali Treatment on the Properties of Century Fiber

Century natural fibers (Agave americana L.) have superior mechanical properties. For their usage as an effective reinforcement in biocomposites, they require surface modification. In the present study, these fibers were treated with 5% aq. NaOH solution for optimized 1-h period. The effect of alkali treatment on the mechanical, thermal, and morphological properties was been studied. The results indicated thinning and surface roughening of the fibers and removal of hemicellulose on alkali treatment. The tensile strength and elongation at break improved on alkali treatment. X-ray studies indicated increase of crystallinity for alkali-treated fibers.