Macro and nano dimensional plant fiber reinforcements for Cementitious Composites

uncorrected proofNowadays, the use of plant fibers in the civil construction industry is growing rapidly due to their low cost, light weight and good specific mechanical properties, lower health hazard, and environmental benefits. Nanodimensional fibers derived from plants such as nanocellulose are also getting considerable attention due to their excellent mechanical properties. This chapter discusses these different types of plant fibers and their derivatives which have huge application potential in the civil construction sector. The influence of plant fibers on microstructure as well as on physical–mechanical properties of cementitious composites are discussed in detail. The challenges regarding plant fiber processing and dispersion, the fiber/matrix interface, and the durability of plant fiber-cement composites are also addressed. The application of nanocellulose in polymer composites has been included in this chapter just to provide the readers sufficient background information and techniques to inspire engineered cement-based composites. Finally, the chapter concludes with the current application of plant fibers in civil construction and the future trends(undefined)info:eu-repo/semantics/publishedVersio

Adsorption of Hydrogen Sulfide on Reduced Graphene Oxide-Wrapped Titanium Dioxide Nanofibers

This work presents a fabrication of room-temperature gas sensor for hydrogen sulfide (H2S) adsorption. Pristine titanium dioxide (TiO2) nanofibers, reduced graphene oxide (rGO) sheets, and reduced graphene oxide-wrapped titanium dioxide (rGO-wrapped TiO2) nanofibers were presented in the form of integrated suspension used for a gas-sensing layer. The TiO2 nanofibers were firstly synthesized by using an electrospinning method with a polyvinylpyrrolidone (PVP) polymer. The rGO sheets were then wrapped around TiO2 nanofibers by a hydrothermal method. Scanning electron microscope, transmission electron microscope, X-ray diffractometer, and Raman spectrometer confirmed the presence of rGO sheets onto the surface of TiO2 nanofibers. Ultraviolet-visible spectrophotometer was also considered and displayed to calculate the band gap of TiO2 and rGO-wrapped TiO2 nanofibers. After preparing the gas-sensing suspensions, they were dropped onto the polyethylene terephthalate substrates with silver-interdigitated electrodes. The gas-sensing properties of sensors were evaluated for H2S adsorption at room temperature. Based on the results, the rGO-wrapped TiO2 nanofiber gas sensor exhibited higher H2S sensitivity and selectivity than pristine TiO2 nanofiber and pure rGO gas sensors. The H2S-sensing mechanism of rGO-wrapped TiO2 nanofiber gas sensor was discussed based on a formation of p-n heterojunctions between p-type rGO sheets and n-type TiO2 nanofibers. Furthermore, a direct charge-transfer process by physisorption was also highlighted as a second H2S-sensing mechanism

Multifunctional silk fabrics by means of the plasma induced graft polymerization (PIGP) process

International audienc

Mechanical Strength and Hydrophobicity of Cotton Fabric after SF6 Plasma Treatment

Surface treatments to tailor fabric properties are in high demand by the modern garment industry. We studied the effect of radio-frequency inductively coupled SF 6 plasma on the surface characteristics of cotton fabric. The duration of the treatment and the SF 6 pressure were varied systematically. We measured the hydrophobicity of treated cotton as a function of storage time and washing cycles. We used the weight loss (%) along with the etching rate, the tensile strength, the morphology changes and the hydrophobicity of the fabric as observables after treatments with different plasma conditions. The weight loss remains below 1% but it significantly increases when the treatment time is longer than 5 min. Substantial changes in the surface morphology of the fiber are concomitant with the increased etching rate and increased weight loss with measurable consequences in their mechanical characteristics. The measured water absorption time reaches the maximum of 210 min when the SF 6 pressure is higher than 0.3 Torr. The water contact angle (149 °) and the absorption time (210 min) of cotton treated with extreme conditions appear to be durable as long as the fabric is not washed. X-ray photoelectron spectroscopy analysis reveals that the water absorption time of the fabric follows the same increasing trend as the fluorine/carbon ratio at the fabric surface and atom density of fluorine measured by Ar actinometer. © 2010 Elsevier B.V. All rights reserved.Fil: Kamlangkla, K.. Chulalongkorn University; TailandiaFil: Paosawatyanyong, B.. Chulalongkorn University; TailandiaFil: Pavarajarn, V.. Chulalongkorn University; TailandiaFil: Hodak, Jose Hector. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Mahidol University; TailandiaFil: Hodak, Satreerat K.. Chulalongkorn University; Tailandi