Natural fiber composites (NFCs) are gaining importance in various fields of engineering due to their ecofriendly nature and low cost. The present work is aimed in studying the mechanical properties such as tensile strength, flexural strength, impact strength, and hardness for natural fiber/epoxy resin composites reinforced with sisal and jute. The composites are prepared by hand lay-up method by varying the proportion of jute fiber. One set of fibers is surface treated with NAOH solution and its impact on mechanical strength was studied. From the results obtained, it was observed that the tensile strength increases by 20%, flexural strength by 25%, impact strength increases by 27.27%, and hardness by 5% for surface treated composites. Scanning electron microscope was used to study the morphology of prepared specimen and fractured specimen. The results indicate that surface-treated composites perform better than the untreated fiber composites. [ABSTRACT FROM AUTHOR]
DIAMMONIUM phosphate, MECHANICAL behavior of materials, and FIBROUS composites
In this study, the properties of molded ramie fibers reinforced with polylactic acid (PLA) biocomposites were investigated. Before preparation of composites, diammonium phosphate (DAP) was applied to the surface of ramie fibers with and without pretreatments to analyze the interfacial adhesion of ramie-PLA composite. Wettability and adhesion behavior of ramie fibers in the PLA resin were characterized by contact angle (CA) measurements. The surface chemical analysis was performed by Fourier transform infrared spectroscopy (FTIR). The thermal properties were recorded using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The wetting analysis results showed that the introduction of DAP treatment to ramie fibers significantly improved the wetting behavior of ramie in the PLA resin. Similarly, the results of TGA indicated that DAP treatment substantially decreased the degradation temperature of the composites. The result of FTIR was also consistent with the results of wettability, TGA, and DSC for the observed changes of peaks in the transmission spectrum. [ABSTRACT FROM AUTHOR]
Sugarcane bagasse fibers were pre-treated with sulfuric acid solution to improve the mechanical properties of polypropylene (PP) composites for automotive parts. It was used maleic anhydride grafted polypropylene (PPg-MA) as coupling agent. Fibers were characterized by the techniques of scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. The chemical composition of fibers was also evaluated. PP was mixed to fibers, in proportions of 5 to 10% (wt/wt) using a thermokinetic mixer model MH-50H. Furthermore tensile specimens were prepared for evaluation of mechanical properties by tensile test. Pre-treatment fibers permitted the removal of other components from sugarcane bagasse. The chemical treatment reduced some of the fibers amorphous components, causing changes in their surface. The addition of pre-treated and compatibilizedfibers to PP matrix caused an increase in the elastic modulus in tensile. It was possible to obtain a more rigid and less deformable material with up to 10% fiber content. However, the use of the coupling agent showed results superior to other composites. [ABSTRACT FROM AUTHOR]
BIODEGRADATION, CASHEW nut, and ANTI-infective agents
Experimental investigations are conducted to study the effectiveness of protective coating with cashew nut shell liquid (CNSL) on coir. CNSL solution has been applied on suitably pretreated coir yarns and coating concentrations are optimized to reduce moisture absorption and microbial growth. Two common cellulose and lignin degrading fungi (Aspergillus nigerandRhizopus stolonifer) have been taken as test organisms. Qualitative and quantitative analyses are carried out to measure fungal growth on untreated and treated fibers. The study shows that treated fibers inhibit the development of fugal growth on fiber surface by 95%. The reduced moisture absorption and improved hydrophobicity of the treated yarns are also reported. Increase in tensile strength up to 17% is noticed. The better properties achieved are explained on the basis of selection of the coating methodology and also the interfacial features of the coatings with the coir fiber. The results indicate the possibility of future application of such treated fibers in geotextiles having better performance compared to the untreated counterparts. [ABSTRACT FROM AUTHOR]
In this study, effect of various surface treatment processes on waste jute fibers, which can be used for composite material production, was considered. For this purpose, jutes (J) were treated with NaOH as a pretreatment process before the other surface treatments. Then, alkali treated jutes (AJ) were modified with silane coupling agent (ASJ), fluorocarbon-based agent (AFJ), and also argon plasma (APJ). To investigate effects of the treatments on surface characteristics and physical properties of jutes; Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy, thermogravimetric analysis, x-ray diffraction, and scanning electron microscopy (SEM) were used. The effects of treatments were also revealed by determination of moisture content and density of the jute particles. It is determined that alkali treatment increase hydrophilicity of jute particles with providing reactive hydroxyl groups by partially removal of surface impurities as supported by FTIR analysis. This surface cleaning is also confirmed by SEM which shows surface fibrillation of AJ particles. The crystallinity index of the jute particles increased with the surface treatments by improving the crystallite packing order. Thermal stability of the jute particles changed after all of the surface treatments. According to the findings obtained from surface characterizations and physical tests, the most hydrophobic surface was achieved after fluorocarbon treatment (with alkali pretreatment) by providing the highest C/O ratio on the surface of the jute particles and reduced moisture content, which can be benefits in short fiber or particulate reinforced composite manufacturing by preventing agglomeration of fillers. [ABSTRACT FROM AUTHOR]
MANILAL, V. B., AJAYAN, M. S., and SREELEKSHMI, S. V.
Journal of Natural Fibers. 2010, Vol. 7 Issue 4, p324-333. 10p. 7 Black and White Photographs, 3 Charts.
COIR, PLANT fibers, COIR industry, BIOMASS chemicals, and HYDROGEN peroxide
This study presents an ecofriendly color improvement method for clean bioextracted coir fiber with biogas recovery. The fiber samples were subjected to treatment with hydrogen peroxide (H2O2)and were optimized at 0.08% with 1:10 fiber to water ratio for 24 h. Combination treatments with (nitric acid) HNO3 and H2O2 were also studied, and matching color of H2O2 treatment at 0.08% was resulted by the treatment of the fiber with 0.016 N HNO3 and 0.03% H2O2, respectively. There was no significant difference in mechanical properties of the samples. The scanning electron microscopic studies of the samples could show significant improvement of surface finish by the treatments. [ABSTRACT FROM AUTHOR]
MEDEIROS NEIRA, DORIVALDA SANTOS and MARINHO, GEORGE SANTOS
Journal of Natural Fibers. 2009, Vol. 6 Issue 2, p115-126. 12p. 3 Black and White Photographs, 3 Charts, 4 Graphs.
NONWOVEN textiles, THERMAL insulation, SODIUM hydroxide, ELECTRIC resistance, THERMOGRAVIMETRY, and THERMAL conductivity
The present study describes experiments carried out to analyze the effects of superficial treatment on the thermal performance of needlepunched nonwoven sisal fiber used as thermal insulation material. Nonwovens with gramature 1300-1400 g/m2 “in natura” and treated (2% w/w sodium hydroxide) were used to the thermal insulation of a tube of steel internally heated by electric resistance. The samples were submitted to three heating levels: 22.5 W, 40 W, and 62.5 W, corresponding respectively to 77°C, 112°C, and 155°C. Thermogravimetric analysis was carried out and the thermal conductivity was determined. [ABSTRACT FROM AUTHOR]