C. Uma Maheswari

Mechanical Properties and Chemical Resistance of Short Tamarind Fiber/Unsaturated Polyester Composites: Influence of Fiber Modification and Fiber Content

In the present work, tamarind fibers were extracted from ripened fruits by the water retting process. Using these fibers as reinforcement and unsaturated polyester as matrix, composite samples were prepared by the hand lay-up technique. The effect of chemical surface treatments (alkali and silane) of tamarind fibers on the mechanical properties, chemical resistance, and interfacial bonding was studied. The mechanical properties of the composites with surface modified fibers were found to be higher than those with unmodified fibers. Morphological studies indicated improvement of interfacial bonding by alkali and silane coupling agent treatments of the fibers. The composites were found to be resistant to many chemicals.

Preparation and Properties of Biodegradable Spent Tea Leaf Powder/Poly(Propylene Carbonate) Composite Films

The aim of the present work is to develop novel bio-based lightweight material with improved tensile and thermal properties. Spent tea leaf powder (STLP) was used as a filler to improve the tensile and thermal properties of polypropylene carbonate (PPC). Tea is an important material used in hotels and households, and spent tea leaf is a resulting solid waste. Composite films with STLP were obtained by the solution casting method. These films were characterized by optical and scanning electron microscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis, and tensile testing to examine the effect of filler content on the properties of the composites. The results showed that composite films have increased tensile strength due to enhanced interfacial adhesion between the filler and the matrix. In addition, the composite films also exhibited higher thermal degradation temperatures than pure polypropylene carbonate. The morphology results indicate that there is a good interface interaction between STLP and PPC. Results of the study reveal STLP to be a promising green filler for polymer plastics.

TENSILE AND THERMAL PROPERTIES OF POLYCARBONATE-COATED TAMARIND FRUIT FIBERS

In this work agro-based waste natural tamarind fibers were extracted from ripened fruit, and alkali treatment and polycarbonate coating were used to improve the properties of the chemically modified fibers. The tensile properties of these chemically modified fibers were found to be improved by polymer coating. Scanning electron micrographs indicated better interfacial bonding between the fiber and matrix. Thermogravimetric analysis showed that the thermal stability of the coated fibers was lower than that of polycarbonate but higher than that of uncoated fibers. The moisture absorption of the polycarbonate-coated fibers was lower than that of uncoated fibers.

Effect of Chemical Treatment and Fiber Loading on Mechanical Properties of Borassus (Toddy Palm) Fiber/Epoxy Composites

The aim of the present study was to investigate and compare the mechanical properties of untreated and chemically modified Borassus fiber–reinforced epoxy composites. Composites were prepared by the hand lay-up process by reinforcing Borassus fibers with epoxy matrix. To improve the fiber-matrix adhesion properties, alkali (NaOH) and alkali combined with silane (3-aminopropyltriethoxysilane) treatment of the fiber surface was carried out. Examinations through Fourier transform-infrared spectroscopy and scanning electron microscopy (SEM) were conducted to investigate the structural and physical properties of the Borassus fibers. Tensile properties such as modulus and strength of the composites made with chemically modified and untreated Borassus fibers were studied using a universal testing machine. Based on the experimental results, it was found that the tensile properties of the Borassus-reinforced epoxy composites were significantly improved as compared with the neat epoxy. It was also found that the fiber treated with a combination of alkali and silane exhibited superior mechanical properties to alkali-treated and untreated fiber composites. The nature of the fiber/matrix interface was examined through SEM of cryo-fractured samples. Chemical resistance of composites was also found to be improved with chemically modified fiber composites.

Extraction and Characterization of Cellulose from Pretreated Ficus (Peepal Tree) Leaf Fibers

In this work, we carried the physicochemical characterization of the cellulose extracted from the forestry residue of ficus leaves using chemical method. Detailed chemical composition of the ficus leaf fibers (both untreated and pretreated) and extracted cellulose was carried out. The chemical analysis confirmed the sequential removal of the lignin and hemicellulose components from the ficus leaves fibers. The morphology of the ficus leaf fibers and extracted cellulose was investigated using scanning electron microscopy. Structural analysis was carried out by Fourier transform infrared and nuclear magnetic resonance spectroscopy. The studies indicated that on chemical treatments the lignin and hemicellulose were removed extensively from the ficus leaf fibers. X-ray diffraction studies reveal that extracted cellulose was more crystalline than the ficus leaf fibers. The thermal stability of ficus leaf fibers and extracted cellulose was investigated by thermogravimetric analysis and the extracted cellulose had good thermal stability.

Evaluation of mechanical behavior of chemically modified Borassus fruit short fiber/unsaturated polyester composites

Natural fine fibers were extracted from Borassus fruits belonging to the Arecaceae family. To improve the surface, these fibers were treated with aq NaOH solution. Composites were prepared by the hand lay up process using both the untreated and alkali-treated Borassus fine fibers as reinforcement and unsaturated polyester resin as matrix. The effect of a coupling agent and alkali treatment of fibers on tensile, flexural and impact properties of the composites was studied. The mechanical properties and interfacial bonding were found to improve when surface modified fibers were employed in the composites. This is due to the improvement of chemical bonding between the treated fibres and polyester matrix as also supported by Fourier transform infrared results. Water absorption by the different composite types was also found to be negligible.

Tensile Properties and Thermal Degradation Parameters of Tamarind Fruit Fibers

Tamarind has the scientific name Tamarindus Indica and belongs to the Fabaceae family. The fibers from tamarind fruit were treated with 5% aqueous NaoH solution. The primary thermograms of both untreated and the alkali treated fibers were recorded in an inert atmosphere at a heating rate of 10°C/min. Using these thermograms, the initial and final degradation temperatures and inflections points were calculated. Employing the Doyle method, the integral procedural degradation temperature and refractoriness were also determined. The thermal stability was found to increase on alkali treatment. The morphology of the fiber before and after alkali treated was studied. The tensile parameters — maximum stress, Youngs modulus and %elongation at break were also determind for both untreated and the alkali treated tamarind fibers.

A Comparative Study of Modified and Unmodified High-Density Polyethylene/Borassus Fiber Composites

In this work, composite samples were prepared using Borassus fibers and a high-density polyethylene matrix. Alternatively, a chemically modified matrix (maleic anhydride grafted HDPE) was also used to improve fiber-matrix compatibility. The effect of fiber loading on the mechanical properties was investigated. Borassus fiber/modified HDPE composites exhibited improved mechanical performance as compared to pure HDPE composites. SEM studies on the fractured specimens of unmodified HDPE fiber composites reveal the poor fiber-matrix interaction, whereas the interaction is strong with enhanced mechanical properties for modified HDPE fiber composites. This is due to an improvement of the chemical bonding between the modified HDPE matrix and the Borassus fiber as also supported by Fourier transform infrared spectroscopy results. Thermal stability was also found to be enhanced slightly for modified HDPE composites.

Preparation and characterization of regenerated cellulose films using borassus fruit fibers and an ionic liquid

In this study, we successfully extracted cellulose from borassus fruit fibers by chemical process. The extracted cellulose was dissolved in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). Using this solution, regenerated cellulose films were prepared with water as the non solvent. The raw fruit fibers and extracted cellulose were characterized by chemical analysis. The results indicated that the content of the components other than cellulose was significantly decreased during the cellulose extraction process. Further, FTIR, 13CP-MAS NMR, wide-angle X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to provide structural characterization of raw fibers, extracted cellulose and regenerated cellulose films. The average tensile strength, modulus and elongation at break of the regenerated cellulose films were found to be 111±19MPa, 6149±603MPa and 3.1±0.8%, respectively. The notable properties of regenerated cellulose films advocate their effectiveness for various industrial applications.

Preparation, Chemical Composition, Characterization, and Properties of Napier Grass Paper Sheets

In this study, perennial fast growth Napier grass fibers were used for pulp and papermaking. Chlorination and alkaline processes were carried out using sodium chlorite and sodium hydroxide respectively, for pulp extraction from Napier grass. Detailed chemical composition analysis of the Napier grass fibers and the extracted pulp was carried out and a comparison with other perennial grasses was made. The extracted fibers and pulp obtained from Napier grass were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. The physical, optical, and mechanical properties of Napier grass pulp handmade paper sheets produced in the laboratory were investigated by finding the opacity, brightness, tensile index, breaking length, and burst index. Handmade paper sheets made from Napier grass pulp were compared to paper made from other perennial grasses. The superior properties of paper produced from Napier grass pulp indicate the suitability of Napier grass as an alternative non-wood source for papermaking.