Super absorbent,light, and highly flame retardant cellulose‐based aerogel crosslinked with citric acid

Light (0.089–0.12 g cm^?3), superabsorbent (84–99 g water/1 g aerogel), and highly flame retardant non‐crosslinked cellulose aerogel (CA) and crosslinked cellulose aerogel (CL‐CA) have been successfully produced from pruning waste of blueberry tree. The prepared aerogels with three dimensional porous structure have a remarkably thermal stability and flame retardant performance, which totally burned after 136–200 s. Besides, CA and CL‐CA have an important Brunauer–Emmet–Teller surface area, which are 348 and 275 m² g^?1, respectively. The concepts of this study are simple and bio‐wastes are easily available and sustainable at low cost, and therefore, the current process is appropriate for industrial scale production and has a significant potential in the future of green materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45315.     

Degradation of Alizarin Red by electro-Fenton process using a graphite-felt cathode

The removal of the anthraquinone dye Alizarin Red S (AR) has been investigated by electro-Fenton process using a commercial graphite-felt to electrogenerate in situ hydrogen peroxide and regenerate ferrous ions as catalyst. The effect of operating conditions such as applied current, catalyst concentration, and initial dye content on AR degradation has been studied. AR decay kinetic, the evolution of its oxidation intermediates and the mineralization of the aqueous solutions were monitored during the electrolysis by UV–Vis analysis and TOC measurements. The experimental results showed that AR was completely removed by the reaction with OH radicals generated from electrochemically assisted Fenton's reaction, and the decay kinetic always follows a pseudo-first-order reaction. Applying a current of 300 mA and with catalyst concentration of 0.2 mM Fe²⁺, 95% of the initial TOC was removed in 210 min of electrolysis, meaning the almost complete mineralization of the organic content of the treated solution.     

Telechelic polymers by living and controlled/living polymerization methods

Telechelic polymers, defined as macromolecules that contain two reactive end groups, are used as cross-linkers, chain extenders, and important building blocks for various macromolecular structures, including block and graft copolymers, star, hyperbranched or dendritic polymers. This review article describes the general techniques for the preparation of telechelic polymers by living and controlled/living polymerization methods; namely atom transfer radical polymerization, nitroxide mediated radical polymerization, reversible addition-fragmentation chain transfer polymerization, iniferters, iodine transfer polymerization, cobalt mediated radical polymerization, organotellurium-, organostibine-, organobismuthine-mediated living radical polymerization, living anionic polymerization, living cationic polymerization, and ring opening metathesis polymerization. The efficient click reactions for the synthesis of telechelic polymers are also presented.     

The effect of decor paper properties and adhesive type on some properties of particleboard

In this study, the effects of décor paper grammage (weight per unit area) and adhesive type on the tearing index, breaking length, and mechanical (modulus of rupture and modulus of elasticity) of the decorative papers, and surface quality (abrasion resistance) properties of the overlaid particleboard panels were investigated. As the raw décor paperweight was increased, the properties of the paper, and mechanical properties and abrasion resistance of the overlaid panels were significantly improved. It appears that the décor paper grammage is the parameter, other than scratch resistance, which determines the end use of the particleboard surfaces with décor paper. While the adhesive type was found to influence the abrasion resistance, it did not statistically affect the mechanical properties of particleboard. In addition, melamine formaldehyde caused better abrasion resistance than did the urea formaldehyde and melamine urea formaldehyde.     

Simple, robust, and fast iterative solution of Underwood's equation for minimum reflux

This work has developed a simple, robust, and fast method for the solution of Underwood's equation f(x) for minimum reflux. The new scheme involves devising an iterative solver g by re-arranging this equation, obtaining a secondary function equal to g − x, and finally applying Ostrowski's fourth-order technique to find the roots of this function. The use of Ostrowski's method in place of Newton's popular second-order formula requires little extra calculation per iteration other than a function value at an auxiliary point. The novel method is successful where the direct applications of Newton's and Ostrowski's solvers to Underwood's equation fail. It keeps iterations within bounds and rapidly converges to the root of interest.     

Effect of the atmospheric plasma treatment parameters on jute fabric: The effect on mechanical properties of jute fabric/polyester composites

The effect of atmospheric air plasma treatment of jute fabrics on the mechanical properties of jute fabric reinforced polyester composites was investigated. The jute fabrics were subjected to different plasma powers (60, 90, and 120 W) for the exposure times of 1, 3, and 6 min. The effects of plasma powers and exposure times on interlaminar shear strength, tensile strength, and flexural strength of polyester based composites were evaluated. The greatest ILSS increase was about 171% at plasma power of 120 W and exposure time of 6 min. It is inferred that atmospheric air plasma treatment improves the interfacial adhesion between the jute fiber and polyester. This result was also confirmed by scanning electron microscopy observations of the fractured surfaces of the composites. The greatest tensile strength and flexural strength values were determined at 120 W for 1 min and at 60 W for 3 min, respectively. Moreover, it can be said that atmospheric air plasma treatment of jute fibers at longer exposure times (6 min) made a detrimental effect on tensile and flexural properties of jute‐reinforced polyester composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Porous magnetic chelator support for albumin adsorption by immobilized metal affinity separation

Magnetic poly(2‐hydroxyethylmethacrylate) (mPHEMA) beads are modified by iminodiacetic acid (IDA) to implify the reactive groups and subsequent binding of Cu²⁺ ions to form metal chelate. mPHEMA beads, in the size range of 80–120 μm, were produced by a modified suspension polymerization technique. mPHEMA beads were characterized by swelling tests, electron spin resonance (ESR), FTIR, and scanning electron microscopy (SEM). Important results obtained in this study are as follows. The swelling ratio of mPHEMA beads was 34%. The presence of magnetite particles in the polymeric structure was confirmed by ESR. FTIR data confirmed that the magnetic polymer beads were modified with functional groups IDA. The mPHEMA beads have a spherical shape and porous structure. The effect of pH and concentration of human serum albumin (HSA), on the adsorption of HSA to the metal‐chelated magnetic beads, were examined in a batch reactor. Most importantly, the magnetic beads had little nonspecific adsorption for HSA (0.5 mg/g) before introducing IDA groups. Cu²⁺ chelation increased the HSA adsorption up to 28.4 mg/g. Adsorption behavior can be described at least approximately with the Langmuir equation. Regeneration of the metal‐chelated magnetic beads was easily performed with 1.0M NaSCN, pH 8.0, followed by washing with distilled water and reloading with Cu²⁺. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2501–2510, 2004     

Transition Metal Nanoparticles in Catalysis for the Hydrogen Generation from the Hydrolysis of Ammonia-Borane

Over the last decade, transition metal nanoparticles have attracted much attention owing to their unique properties, different to their bulk counterparts, which facilitate their application in different fields from materials science to engineering. Of particular interest, the use of transition metal nanoparticles in catalysis has brought transcendent efficiency in terms of activity, selectivity and lifetime to heterogeneous catalysis. In this account, we summarize the recent developments in the synthesis routes and the catalytic performance of transition metal nanoparticles tested in the hydrogen generation from the hydrolysis of ammonia-borane, which has been considered as one of the attractive materials for the efficient storage of hydrogen that is still one of the key issues in the “Hydrogen Economy”.     

A polymeric nanocomposite system for potential adhesive applications in restorative dentistry

This article presents and discusses the preliminary results obtained as a continuation of a work aiming to contribute to the effort of exploring the potential of certain types of polymer nanocomposites to be successful candidates in new fields such as dental restoration. An epoxy-functional silicate-/Zr-based polymeric nanocomposite material system containing phosphorus was obtained via a sol–gel method, and applied to bring about a bonding between bovine teeth and feldspathic ceramic discs with or without the use of visible light (VL)-curing process. Infrared spectroscopy was employed to show the presence of phosphorus within the structure. Mechanical tests were performed to determine the shear-bond strength of the nanocomposite adhesive system developed. An approximate shear-bond strength value of 0.4 MPa was obtained for both VL-cured and uncured systems. Though this value was lower than that of commercially available material systems, it was promisingly comparable to them. Another significant finding was that the material system developed within the study might potentially eliminate the use of curing process. Also, it was demonstrated that the general problem of ‘shrinkage-upon-polymerization’ could be overcome by use of a polymeric nanocomposite adhesive material system of this type. Overall results indicated that this polymeric nanocomposite system could indeed be potentially considered as an adhesive alternative in prospective dental restoration applications.     

Stress wave propagation in a through-thickness functionally graded adhesive layer

In this study, an improved mathematical model is presented to investigate the stress wave propagation in two circular cylinders bonded with a functionally graded adhesive layer. In the proposed model, the spatial derivatives of mechanical properties are included in the governing equations of the wave propagation. Also, the finite-difference method was used for the solution of the governing equations and boundary conditions. The Mori-Tanaka homogenization scheme was employed to evaluate the through-thickness mechanical properties of the adhesive layer. The effects of the spatial derivatives of the local mechanical properties and the through-thickness material composition variation in the adhesive layer were examined in detail. The presence of the material spatial derivatives in the governing equations mitigated the stress and displacement levels as well as axial and radial wave speeds.