Nanocelluloses are prepared by downsizing plant cellulose fibers, which are efficiently produced at the industrial level as paper and dissolving pulps from renewable wood biomass resources. The number of scientific publications and patents concerning nanocelluloses has been increasing every year, because nanocelluloses are expected to contribute to creation of a sustainable society partly in place of petroleumbased materials. Nanocelluloses are categorized as cellulose nanonetworks (CNNeWs), cellulose nanofibrils or nanofibers (CNFs), and cellulose nanocrystals (CNCs) depending on their morphologies, originating from crystalline cellulose microfibrils abundantly present in each plant cellulose fiber. When no chemical pretreatment is applied to plant cellulose fibers, only CNNeW-type nanocelluloses with heterogeneous morphologies are obtained even after harsh mechanical disintegration in water. In contrast, when positionselective chemical pretreatment is applied to plant cellulose fibers for introduction of a large amount of charged groups on the cellulose microfibril surfaces, CNFs and CNCs with homogeneous ~3 nm widths can be prepared from the chemically pretreated plant cellulose fibers by gentle mechanical disintegration in water. These charged groups are used as scaffolds to add diverse functionalities to nanocelluloses by simple ion exchange in water. Chemical modifications of nanocellulose surfaces, hydrogels, preparation of nanocellulosecontaining composites with various organic and inorganic compounds, the fabrication processes from nanocellulose/water dispersions to dried films, fibers, and porous materials, as well as their versatile applications, have been extensively reported in the last few years. In this review, some research topics are selected from nanocellulose-related publications and briefly overviewed.
The separation of protein plays a critical role in the protein production process. A functionalized nanofiber fabric was prepared by immobilizing Cibacron Blue (CB) on a polyvinyl alcohol (PVA) nanofiber fabric produced by an electrospinning method. To evaluate its separation performance, the adsorption test of bovine serum albumin (BSA), a kind of protein, was conducted using this fabric. The CB molecules were immobilized by the covalent bonding of hydroxyl group of PVA and chlorinated triazine ring of CB under alkaline condition. The adsorption test of CB-enhanced affinity PVA nanofiber fabric was conducted by soaking it into the BSA solution as an adsorbate. As a result, after enhancing affinity by CB, the BSA adsorption amount of the PVA nanofiber fabric indicates a significant increase due to functionalization. Moreover, the adsorption characteristics were heavily dependent on the solution environment.
Colored yarns interweaving in accordance with specific weave structure provides the opportunity for textile designers to create an enormous number of mixing color effects on fabric surface. The key point of this idea is to search an appropriate model to match the optical mixing color of a fabric with the targeted or desired color. Based on the present prediction models such as K/S, Log (K/S), S-N and Friele model for colored yarn mixing, this study proposes a new color mixing model with a variable parameter to predict optical mixing color values of yarn-dyed fabrics. In order to optimize the model and improve the adaptive capacity for different kinds of yarn materials, a constant σ is introduced. Using a fitting approximation algorithm, the optimal value of constant σof the model can be found per different yarns and interweave density of fabrics. Compared with previous models, the new model has much lower color differences.
Fibre Reinforced Polymer is a new type of reinforced material that can be produced by using fibres and resins. It is an effective and economical material used for repair of new and existing structures in construction. This type of composite materials also have good mechanical properties such as impact resistance,strength, stiffness, flexibility and load carrying ability. Use of FRP for confinement has proved to be effective which is classified into two types retrofitting and strengthening. This study is determining the potential of aramid FRP composites in strengthening of RC beams. Mechanical characteristics of Aramid Fibre Reinforced Polymer (AFRP) confined concrete specimens can be analysed by conducting compression, split tension and flexural tests. Shear strength of AFRP wrapped RC beam was also taken into account. From the experimental results it is evidenced that the beams wrapped with AFRP possess better strength than the unconfined beams in both wrapping of single and double plies.