FTIR spectra of plasticized grafted natural rubber-LiCF3SO3 electrolytes

Reduction of sulfur in fuel oil using Fe2O3 hybrid nanoadsorbent by solvent deasphalting and optimization of operational parameters with CCD

The present study investigated and tested the effect of adding three types of nanoadsorbents (multi-walled carbon nanotubes (MWCNT)) in pure form, multi-walled carbon nanotubes with Fe2O3 particles (MWCNT-Fe2O3) hybrid, and Silanated-Fe2O3 hybrid to heavy fuel oil to reduce sulfur using a deasphalting process with solvent. First, all three types of nanoadsorbents were synthesized. Then, the Central Composite Design (CCD) method was used to identify the parameters effective in deasphalting, such as the type of nanoadsorbent, the weight percentage of nanoadsorbent, and the solvent-to-fuel ratio, and to obtain their optimal values. Based on the optimization result, under laboratory temperature and pressure conditions, the highest percentage of sulfur reduction in deasphalted fuel (DAO) was obtained by adding 2.5% by weight of silanated-Fe2O3 nano-adsorbent and with a solvent-to-fuel ratio of 7.7 (The weight percentage of sulfur in DAO decreased from 3.5% by weight to 2.46%, indicating a decrease of 30%). Additionally, by increasing the temperature to 70 °C, in optimal conditions, the results revealed that the remaining sulfur percentage in DAO decreased to 2.13% by weight, indicating a decrease of 40%. Synthesized nanoadsorbents and asphaltene particles adsorbed on the surfaces of nanoadsorbents were evaluated by XRD, FTIR, FESEM, and TEM techniques.

Novel synthesized attapulgite nanoparticles-based hydrophobic monolithic column for in-tube solid-phase microextraction of thiosildenafil, pseudovardenafil, and norneosildenafil in functional foods

In this study, a novel method which involved in-tube solid-phase microextraction (SPME) using an attapulgite (ATP) nanoparticles-based hydrophobic monolithic column was successfully developed. It was coupled with high-performance liquid chromatography-ultraviolet detection for the determination of three phosphodiesterase-5 (PDE-5) inhibitors, including thiosildenafil, pseudovardenafil, and norneosildenafil, in functional foods. The monolithic column was prepared by one-step polymerization, using 3-trimethoxysilylpropyl methacrylate-modified ATP nanoparticles and 1-butyl-3-vinylimidazolium bromide (VBIMBr) as the functional monomers, and ethylene glycol dimethacrylate (EDMA) as the cross-linker. The obtained poly(ATP-VBIMBr-EDMA) monolith was characterized by scanning electron microscopy equipped with energy-dispersive analysis of X-ray, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. The adsorption capacity, up to 2.00 μg/cm calculated by the Langmuir isotherm model, was about six times that of the poly(VBIMBr-EDMA) monolith. Crucial factors affecting the extraction efficiency, including sample solvent, elution solvent, flow rates of sampling loading and elution, sample loading volume, and elution volume, were investigated in details. Under the optimal in-tube SPME conditions, the proposed method showed good reproducibility with run-to-run, column-to-column, and batch-to-batch relative standard deviations less than 7.2%, and low limits of detection of 0.5-0.9 ng/mL in real samples. Thiosildenafil was detected in four types of functional foods with the contents of 1.30-4.78 μg/g. This newly proposed in-tube SPME method based on poly(ATP-VBIMBr-EDMA) monolith may provide a simple, efficient, and promising alternative to daily monitoring of PDE-5 inhibitors in functional foods.

A Method to Improve the Characteristics of EPDM Rubber Based Eco-Composites with Electron Beam

A natural fiber reinforced composite, belonging to the class of eco composites, based on ethylene-propylene-terpolymer rubber (EPDM) and wood wastes were obtained by electron beam irradiation at 75, 150, 300, and 600 kGy in atmospheric conditions and at room temperature using a linear accelerator of 5.5 MeV. The sawdust (S), in amounts of 5 and 15 phr, respectively, was used to act as a natural filler for the improvement of physical and chemical characteristics. The cross-linking effects were evaluated through sol-gel analysis, mechanical tests, and Fourier Transform Infrared FTIR spectroscopy comparatively with the classic method with dibenzoyl peroxide (P) applied on the same types of samples at high temperature. Gel fraction exhibits values over 98% but, in the case of P cross-linking, is necessary to add more sawdust (15 phr) to obtain the same results as in the case of electron beam (EB) cross-linking (5 phr/300 kGy). Even if the EB cross-linking and sawdust addition have a reinforcement effect on EPDM rubber, the medium irradiation dose of 300 kGy looks to be a limit to which or from which the properties of the composite are improved or deteriorated. The absorption behavior of the eco-composites was studied through water uptake tests.

Study of PVAc-PMMA-LiCl polymer blend electrolyte and the effect of plasticizer ethylene carbonate and nanofiller titania on PVAc-PMMA-LiCl polymer blend electrolyte

lithium ion conducting polymer electrolyte is one of the essential components of modern rechargeable lithium batteries because of its good interfacial contact with electrodes and effective mechanical properties. A solid lithium ion conducting polymer blend electrolyte is prepared using poly (vinyl acetate) (PVAc) and poly (methyl methacrylate) (PMMA) polymers with different molecular weight percentages (wt%) of lithium chloride (LiCl) by the solution casting technique with tetrahydrofuran as a solvent. The polymer electrolytes were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), Thermogravimetry (TG), AC impedance spectroscopy and ionic transport measurements. XRD and FTIR studies confirm the amorphous nature of the polymer electrolyte and the complexation of salt with polymer. The thermal behavior of polymer electrolytes has been studied from DSC and TG. The highest conductivity obtained using AC impedance spectroscopy is 1.03×10−5 Scm−1 at 303 K for 70 wt%PVAc:30 wt%PMMA:0.8 wt% of LiCl polymer-salt complex. The plasticizer ethylene carbonate (EC) and nanofiller titania (TiO2) were added to the optimized high conducting blend polymer electrolyte. An enhancement in conductivity by one order of magnitude was observed for the plasticized 70 wt%PVAc-30 wt%PMMA-0.8 wt% LiCl polymer electrolyte at ambient temperature. The ionic conductivity value obtained using AC impedance spectroscopy for the plasticized 70 wt%PVAc-30 wt%PMMA-0.8 wt% LiCl polymer electrolyte was 1.03×10−4 Scm−1. The highest conductivity obtained for 70 wt%PVAc-30 wt%PMMA-0.8% LiCl-6 mg TiO2 was 4.45×10−4 Scm−1. Dielectric properties of polymer films are studied and discussed. The electrochemical stability of 1.69 V and 2.69 V was obtained for 70 wt%PVAc-30 wt%PMMA-0.8% LiCl and 70 wt%PVAc-30 wt%PMMA-0.8% LiCl-6 mg TiO2 polymer electrolytes, respectively, using linear sweep voltammetry. The value of Li+ ion transference number was estimated by the DC polarization method and was found to be 0.99 for the highest conducting 70 wt%PVAc-30 wt%PMMA-0.8 wt% LiCl-6 mg TiO2 nanocomposite polymer electrolyte.

Vibrational studies of flexible solid polymer electrolyte based on PCL-EC incorporated with proton conducting NH4SCN

A flexible solid polymer electrolyte (SPE) system based on poly(ε-caprolactone) (PCL), a FDA approved non-toxic and biodegradable material in the effort to lower environmental impact was prepared. Ammonium thiocyanate (NH4SCN) and ethylene carbonate (EC) were incorporated as the source of charge carriers and plasticizing agent, respectively. When 50 wt.% of ethylene carbonate (EC) was added to PCL-NH4SCN system, the conductivity increased by two orders from of 3.94 × 10(-7) Scm(-1) to 3.82 × 10(-5) Scm(-1). Molecular vibrational analysis via infrared spectroscopy had been carried out to study the interaction between EC, PCL and NH4SCN. The relative percentage of free ions, ion pairs and ion aggregates was calculated quantitatively by deconvoluting the SCN(-) stretching mode (2030-2090 cm(-1)). This study provides fundamental insight on how EC influences the free ion dissociation rate and ion mobility. The findings are also in good agreement to conductivity, differential scanning calorimetry and X-ray diffraction results. High dielectric constant value (89.8) of EC had made it an effective ion dissociation agent to dissociate both ion pairs and ion aggregates, thus contributing to higher number density of free ions. The incorporation of EC had made the polymer chains more flexible in expanding amorphous domain. This will facilitate the coupling synergy between ionic motion and polymer segmental motion. Possible new pathway through EC-NH4(+) complex sites for ions to migrate with shorter distance has been anticipated. This implies an easier ion migration route from one complex site to another.

Effect of LiBF4 Salt Concentration on the Properties of Plasticized MG49-TiO2 Based Nanocomposite Polymer Electrolyte

A nanocomposite polymer electrolyte (NCPE) comprising of 49% poly(methyl methacrylate) grafted natural rubber (MG49) as polymer host, titanium dioxide (TiO2) as a ceramic filler, lithium tetrafluoroborate (LiBF4) as dopant salt, and ethylene carbonate (EC) as plasticizer was prepared by solution casting technique. The ceramic filler, TiO2, was synthesized in situ by a sol-gel process. The ionic conductivity, chemical interaction, structure, and surface morphology of nanocomposite polymer electrolyte have been investigated as a function of wt% LiBF4. The interaction between lithium ions and oxygen atoms occurred at carbonyl and ether groups. The crystalline phase of polymer host slightly decreases with the addition of salt. TGA and DTG analysis suggested that the thermal stability of the electrolyte decreases with the salt content. The ionic conductivity of the electrolyte was found to increase with the increase of salt concentration and then decreased after an optimum value. The highest conductivity achieved was  S cm−1 at 25 wt% of LiBF4.

Cross-Linking and Degradation Properties of Plasma Enhanced Chemical Vapor Deposited Poly(2-hydroxyethyl methacrylate)

Plasma Enhanced Chemical Vapor Deposition (PECVD) of poly-2-hydroxyethyl methacrylate (pHEMA) biocompatible, biodegradable polymer films were produced alone and cross-linked with ethylene glycol diacrylate (EGDA). Degree of cross-linking was controlled via manipulation of the EGDA flow rate, which influenced the amount of swelling and the extent of degradation of the films in an aqueous solution over time. Noncross-linked pHEMA films swelled 10% more than cross-linked films after 24 h of incubation in an aqueous environment. Increasing degree of film cross-linking decreased degradation over time. Thus, PECVD pHEMA films with variable cross-linking properties enable tuning of gel formation and degradation properties, making these films useful in a variety of biologically significant applications.

FTIR spectra and mechanical strength analysis of some selected rubber derivatives

Rubber materials have wide range of commercial applications such as, infant diapers, famine hygiene products, drug delivery devices and incontinency products such as rubber tubes, tyres, etc. In the present work, studies on mechanical properties of some selected rubber materials viz., natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) have been carried out in three states viz., raw, vulcanized and reinforced. To enhance the quality of rubber elastomers, an attempt is made to prepare new elastomers called polyblends. In the present study an attempt is made to blend NR with NBR and with EPDM. We here report, a novel approach for the evaluation of various physico-mechanical properties such as mechanical strength, tensile strength, elongation and hardness. The method is simple, direct and fast and involves infrared spectral measurements for the evaluation of these properties. With the applications of modern infrared spectroscopy, the mechanical strength of these rubber materials have been analyzed by calculating the internal standards among the methyl and methylene group vibrational frequencies obtained from FTIR spectroscopy. Also the tensile strength measurements carried out by universal testing machine. The results pertaining physico-mechanical properties of the rubber derivatives undertaken in the present study obtained by IR-based method are in good agreement with data resulted from the standard methods.