Showing papers in "Journal of Macromolecular Science, Part A in 2014"
TL;DR: In this paper, a single step approach is used to synthesize ZnO nanoparticles by using biodegradable natural biopolymer viz. Gum Tragacanth.
Abstract: ZnO nanoparticles have been synthesized by using biodegradable natural biopolymer viz. Gum Tragacanth. This single step approach is very cost effective and reproducible. The reaction time and concentration of precursor zinc acetate play a major role in the nature and growth of ZnO nanoparticles. ZnO nanoparticles were characterized by X-ray diffraction, SEM, FTIR, EDAX, UV-visible spectroscopy and TEM. ZnO nanoparticles with 20-30 nm in diameter and hexagonal morphology were found; dispersed uniformly. Raman spectrum shows the mode E2 high at 437 cm−1 that is related to the vibration of wurtzite Zn-O bond in crystal structure of ZnO. The space between adjacent lattice fringes is ∼ sharp 2.42 A. UV-visible absorption spectrum shows the sharp absorption band at 308 nm assigned to the intrinsic transition from valance band to conduction band. The ZnO nanoparticles display superior catalytic activity of conversion of aldehyde to acid as compared to bulk-ZnO material, because of high surface area of ZnO nanopa...
129 citations
TL;DR: In this paper, the results found in the last nine years pertaining to phosphorus removal through the use of adsorption and precipitation using different metal-containing compounds are reviewed and compared.
Abstract: Phosphorus removal from polluted water is a global concern considering the detrimental environmental effects that excess phosphorus has. Phosphorus can lead to poor water quality and aquatic life loss due to eutrophication when found in excess in aquatic systems. Industry and agriculture are two of the main sources that lead to the accumulation of phosphorus in wastewater. In an attempt to prevent harmful environmental effects of excess phosphorus, several techniques have been designed to remove phosphorus from wastewater. These techniques range from adsorption and precipitation to enhanced biological phosphorus removal and constructed wetlands. Adsorption and precipitation predominantly require the use of different metals in the phosphorus removal process. This article reviews the results found in the last nine years pertaining to phosphorus removal through the use of adsorption and precipitation using different metal-containing compounds. Advances concerning the parameters of enhanced biological phospho...
85 citations
TL;DR: Gelatin (Gel), sodium alginate (SA) and hyaluronic acid (HA) based various hydrogels for biomedical applications were prepared by freezing-drying method using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) as a crosslinker as discussed by the authors.
Abstract: Gelatin (Gel), sodium alginate (SA) and hyaluronic acid (HA) based various hydrogels for biomedical applications were prepared by freezing-drying method using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) as a crosslinker. The physical properties including morphology, water vapor transmission rate and hydrophilicity were investigated. The result showed the Gel/SA/HA composite hydrogels were successfully crosslinked by the crosslinking agent. All the Gel/SA/HA composite hydrogels with different compositions had highly homogeneous and interconnected pores, and the compositions had no significant effect on the surface and cross-section morphologies of the Gel/SA/HA hydrogels. The incorporation of sodium alginate enhanced the water vapor transmission capacity of the hydrogel; however, there were no significant differences between the water vapor transmission rates of all the Gel/SA/HA hydrogels. Gelatin had a low hydrophilic behavior, while sodium alginate exhibited relatively high hydrophilic behavio...
42 citations
TL;DR: In this article, reversible addition-fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) and ring-opening polymerization (ROP) of β-butyrolactone (BL) or ϵ-caprolacton (CL) using a novel difunctional macro-RAFT agent was carried out by one-step synthesis of the triblock copolymers.
Abstract: One-step synthesis of the triblock copolymers was carried out by reversible addition–fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) and ring-opening polymerization (ROP) of β-butyrolactone (BL) or ϵ-caprolactone (CL) using a novel difunctional macro-RAFT agent. For this purpose, primarily PEG-Br (polyethylene glycol bromine) was obtained by using 3-bromopropanoyl chloride and PEGs (polyethylene glycols) with different molecular weights. Then, macro-RAFT agent was synthesized by the reaction of potassium ethyl xanthogenate and PEG-Br. By using macro-RAFT agent, poly(MMA-b-EG-b-BL), and poly(MMA-b-EG-b-CL) triblock copolymers were synthesized by changing some polymerization conditions such as monomer/initiator concentration, polymerization time. The effect of the reaction conditions on the polydispersity and molecular weights were also investigated. The block lengths of the triblock copolymers were calculated by using 1H-nuclear magnetic resonance (1H-NMR) spectra. It was ob...
35 citations
TL;DR: A short review of recent studies done in this area, taking into account that some nano-based materials are ready to be used by the construction industry is presented in this paper, where some studies have been done in the polymer nanocomposite applications in construction basic...
Abstract: Nanotechnology is an enabling technology allowing to do new things in almost every conceivable area. Initial efforts to exploit nanoscience/nanotechnology development in the construction industry focused mainly on understanding phenomena and improving performance of existing materials. Recently, polymer nanocomposites started to be introduced in other areas like the construction industry. Polymer nanocomposite field attracts considerable attention these days due to a variety of potential practical applications. They have offered a great opportunity in sustainable construction/green building application due to their efficiency and environmental protection. Their use in the construction industry is still less known outside the research area. This paper is a short review of recent studies done in this area, taking into account that some nano based materials are ready to be used by the construction industry. This review covers some studies done in the polymer nanocomposite applications in construction basic ...
34 citations
TL;DR: GO or RGO in Pluronic F-127 solution could potentially improve the solubility of the water-insoluble anti-cancer drug camptothecin (CPT), especially with large drug-loaded CPT amount.
Abstract: Injectable hydrogels have attracted a lot of attention in drug delivery, however, their capacity to deliver water-insoluble or hydrophobic anti-cancer drugs is limited. Here, we developed injectable graphene oxide/graphene composite supramolecular hydrogels to deliver anti-cancer drugs. Pluronic F-127 was used to stabilize graphene oxide (GO) and reduced graphene oxide (RGO) in solution, which was mixed with α-cyclodextrin (α-CD) solution to form hydrogels. Native hydrogel was used as control. GO or RGO slightly shortened gelation time. The storage and loss moduli of the hydrogels were tracked by dynamic force measurement. The storage modulus of GO or RGO composite hydrogels was larger than that of the native hydrogel. Hydrogels were unstable in solution and eroded gradually. GO or RGO in Pluronic F-127 solution could potentially improve the solubility of the water-insoluble anti-cancer drug camptothecin (CPT), especially with large drug-loaded CPT amount. Drug release behaviors from solutions and hydroge...
31 citations
TL;DR: In this article, a graft copolymer was synthesized with varying concentration of xanthan gum (XG)-g-polyacrylamide (PAA) copolymers and its effect in the development of water-based drilling fluids.
Abstract: This research article consists of the synthesis of xanthan gum (XG)-g-polyacrylamide (PAA) copolymer and its effect in the development of water based drilling fluids. The graft copolymer was synthesized with varying concentration of XG to obtain shear stable and long chain graft copolymer. The obtained graft copolymer was characterized by Fourier transform infrared spectroscopy and Field emission scanning electron microscopy. The synthesized graft copolymer was then utilized as an additive for the development of water based drilling fluid system. The rheological properties of developed drilling fluids have increased significantly with the increase in graft copolymer concentration and these fluids have the capability to control fluid loss during filtration studies. The fluid loss volume was further reduced to 7 ml after the addition of bridging agent. The filtration and rheological properties of this system were compared with conventional water based drilling fluid system developed using partially hydrolyz...
25 citations
TL;DR: In this article, the chemical structure of Phenyl-Vinyl-POSS was characterized by FT-IR, 1H-NMR, mass spectrometry and elemental analysis.
Abstract: 1,3,5,7,9,11,13-heptaphenyl-15-vinyl cage half siloxane (Phenyl-Vinyl-POSS) was synthesized via the corner capping reaction of incompletely condensed silsesquioxane, [(C6H5)7Si7O9(OH)3], with trichlorovinylsilane. The chemical structure of Phenyl-Vinyl-POSS was characterized by FT-IR, 1H-NMR, mass spectrometry and elemental analysis. Phenyl-Vinyl-POSS/ATC silicone rubber organic-inorganic hybrid materials were prepared by hydrosilylation between Phenyl-Vinyl-POSS and addition-type curable (ATC) silicone rubber with karstedt platinum catalyst. These hybrid materials were characterized through SEM, IR, XRD, TGA, DSC and tensile test. The results indicate that Phenyl-Vinyl-POSS is successfully incorporated into silicone rubber matrix by chemical bonding. Both mechanical properties and thermal properties of Phenyl-Vinyl-POSS/ATC silicone rubber hybrid materials have been improved compared to neat silicone rubber. The hardness of Phenyl-Vinyl-POSS/ATC silicone rubber hybrid materials increases from 18A to 28A,...
24 citations
TL;DR: In this article, a novel inorganic-organic siloxane hybrid material with self-adhesion ability and high refractive index for high-power light emitting diodes (LEDs) encapsulation is introduced.
Abstract: A novel inorganic-organic siloxane hybrid material with self-adhesion ability and high refractive index for high-power light emitting diodes (LEDs) encapsulation is introduced. Under the catalysis of an anion exchange resin, the hybrid material was synthesized by a sol-gel condensation process from methacryloxy propyl trimethoxyl silane (MPTS), γ-(2, 3-epoxypropoxy)propytrimethoxysilane (EPTS) and diphenylsilanediol (DPSD). This hybrid material was characterized by Fourier-transform infrared spectroscopy and 1H-NMR. The resin-type encapsulation material was then prepared by hydrosilylation of the newly synthesized inorganic-organic siloxane hybrid material and methylphenyl hydrogen-containing silicone resin. The cured silicone resin-type encapsulation material can be used as a LEDs encapsulant, owing to high refractive index (n = 1.544), high transparency, appropriate hardness, and excellent thermal stability, as well as good adhesive strength between the encapsulating material and the substrate of LED le...
22 citations
TL;DR: A series blend films based on FK and polyvinyl alcohol (PVA) was prepared by solution casting, and dialdehyde starch (DAS) was introduced to achieve better physicochemical properties for the blend films as discussed by the authors.
Abstract: Feathers, as a by-product of the poultry industry, have long been treated as solid waste disposal which causes a series of environmental and economic problems. Feather keratin (FK) can be extracted from feathers and have very strong stretching resistance. A series blend films based on FK and poly (vinyl alcohol) (PVA) was prepared by solution casting, and dialdehyde starch (DAS) were introduced to achieve better physicochemical properties for the blend films. According to DSC analysis, the single glass transition temperature and single melting temperature of the blend films indicated the good compatibility among FK, PVA and DAS. With increasing PVA content, the tensile strength (σb), elongation at break (ϵb), and decomposition temperature increased, indicated that hydrogen bonds were formed between FK and PVA. With certain PVA content, the increase of DAS caused σb to increase and ϵb, decomposition rates, solubility and water vapor permeability (WVP) to decrease, suggesting the formation of crosslink netw...
22 citations
TL;DR: In this paper, the authors studied the process of grafting acrylic acid on the surface of polypropylene nonwoven using oxygen plasma treatment and optimized it using the response surface methodology (RSM) involving D-optimal criterion.
Abstract: In this paper, the process of grafting of acrylic acid on the surface of polypropylene nonwoven using oxygen plasma treatment is studied and optimized. The response surface methodology (RSM) involving D-optimal criterion was used for the modeling and optimization of the process. The effect of plasma treatment time, plasma power, acrylic acid concentration, grafting time and grafting temperature on grafting yield was investigated. According to analysis of variance (ANOVA) results, the proposed model can be used to navigate the design space very well. The results showed good agreement between experimental and model predictions with high correlation coefficients. The optimum operation condition for obtaining the highest amount of accessible functional sites was predicted. The results showed that the grafting yield is affected by all the parameters studied but it is mostly sensitive to plasma treatment and grafting times and grafting temperature.
TL;DR: In this paper, a hydrophobic polyurethane foam was prepared using hy-drosilicone oil-grafted polybutadiene as soft segment via foaming technology.
Abstract: In this work, hydrophobic polyurethane foam was prepared using hy-drosilicone oil-grafted polybutadiene as soft segment via foaming technology. It was found that the hydrophobic polyurethane foams exhibited good hydrophobic capability and were regenerated easily. Of great interest, the hydrophobic polyurethane foams expand in contact with the oils. This indicates that the process of sorption by the hydrophobic polyurethane foams involves both the filling of the pores with oils and the absorption of oils by the polymer regions (polyurethane elastomer skeleton), and the adsorption capacity of the hydrophobic polyurethane foams can be enhanced by the swelling of the polyurethane elastomer skeleton. We can use this finding to improve the adsorption capacity of the hydrophobic polyurethane foams without merely changing the porosity. The effect of the swelling property of the hydrophobic polyurethane foams on the sorption capacity was further investigated. The results suggest that the hydrophobic polyurethane f...
TL;DR: The Gel-HA/NBG scaffolds showed no acute systemic toxicity and the liver, heart, lung, and kidney samples also showed no remarkable change in the morphology, which makes them a suitable candidate of biomedical materials for tissue engineering.
Abstract: To evaluate the biological safety of the composite materials based on gelatin (Gel), hyaluronic acid (HA), and nano-bioactive glass (NBG), which has a potential application in tissue engineering, the in-vivo biological properties were investigated by hemolysis behavior, micronucleus, skin irritation and acute toxicity test. Scanning electron microscopy (SEM) morphology demonstrated that the Gel-HA/NBG composite scaffolds had interconnected pores with mean diameters of 50–500 μm. The hemolysis test suggested that the Gel-HA/NBG composite scaffold, with a hemolysis ratio of 1.11%, showed no obvious hemolysis reaction. The micronucleus frequency of the Gel-HA/NBG was (3.1 ± 0.52) %; this indicated that it shows no genotoxic effect. The skin irritation result showed no systemic signs of toxicity in the integrity skin of the animals. The Gel-HA/NBG scaffolds showed no acute systemic toxicity and the liver, heart, lung, and kidney samples also showed no remarkable change in the morphology. Therefore, Gel-HA/NBG...
TL;DR: In this paper, a green and facile method has been developed to prepare gold nanoparticles (Au NPs) coated by chitosan in aqueous solutions, which acted as reducing and stabilizing agents.
Abstract: A green and facile method has been developed to prepare gold nanoparticles (Au NPs) coated by chitosan in aqueous solutions. Herein, Au NPs capped with chitosan which acted as both the reducing and stabilizing agents were prepared through a two-step route at low temperature. HAuCl4 and chitosan initially reacted for 6 h at room temperature, and subsequently the mixture reacted for another 1 hour at 35°C. Ultraviolet visible spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy results confirmed the presence of Au NPs. Transmission electron microscopy indicated that the nanoparticles were dispersed individually. The analysis of thermogravimetric analysis and Fourier transform infrared spectroscopy showed that chitosan was capped on the surface of Au NPs.
TL;DR: Recent progress on the preparation of CPs with AIE or AEE characteristics, where AIE-active luminogens are located at polymer backbones or pendants are summarized and their potential applications including fluorescent sensors, biological probes, and active layers for the fabrication of light-emitting diodes are described.
Abstract: Conjugated polymers (CPs) have long been recognized as an important class of materials. The highly conjugated backbone of the CPs will facilitate the rapid exciton migration and result in amplification of fluorescence signals. However, CPs are likely to aggregate and form excimers in solid states, directly leading to the fluorescence quenching, namely aggregation-caused quenching (ACQ), hence inhibiting their prospective utilizations in a large degree. Since the effect of aggregation-induced emission (AIE) is opposite to that of notorious ACQ, the AIE has raised great attention from scientists. CPs with AIE or aggregation-enhanced emission (AEE) features may help to solve the ACQ problem and meanwhile impart polymers with new properties and practical applications. In this review, we summarize the recent progress on the preparation of CPs with AIE or AEE characteristics, where AIE-active luminogens are located at polymer backbones or pendants. Their potential applications including fluorescent sensors, bio...
TL;DR: The viscosity of HPC solution with or without an additive has been measured continuously as a function of temperature with the help of a vibro-viscometer as discussed by the authors.
Abstract: The viscosity of hydroxypropyl cellulose (HPC) solution with or without an additive has been measured continuously as a function of temperature with the help of a vibro-viscometer. The viscosity of...
TL;DR: In this paper, the impact of the synthesis parameters on the productivity and conductivity of polyaniline was studied and the result showed that the oxidant-anilines molar ratio is the most prominent factor influencing the comprehensive index.
Abstract: Polyaniline has attracted increasing attention due to its various excellent properties; however, polyaniline doped by the acids with small molecules has poor solubility and thus impeded its widespread application. In this paper, soluble and conductive polyaniline doped by itaconic acid was prepared and orthogonal experiment design was conducted to study the impact of the synthesis parameters on the productivity and conductivity of polyaniline. The result showed that the oxidant-aniline molar ratio is the most prominent factor influencing the comprehensive index. The optimum oxidant-aniline molar ratio, oxidant concentration, itaconic acid-aniline molar ratio and itaconic acid concentration values were found to be 1.5, 0.5 mol/L, 0.5 and 0.5 mol/L, respectively. The chemical structures of the products based on the FT-IR spectra confirmed that the different oxidant states and molecular connection modes of polyaniline backbones brought about the conductivity diversity. The UV-Vis spectra showed that the prot...
Abstract: The transport of Zn(II) and Cd(II) ions from aqueous nitrate donor phase solution (1×10−3M) by polymer inclusion membranes (PIMs) has been investigated using 2,8,14,20-tetrahekxyl-4,6,10,12,16,18,22,24-oktahydroxycalix[4]resorcinarenes as the carrier. The Zn(II) and Cd(II) ions were transported through PIM of cellulose triacetate (CTA) as a polymeric support material and 2-NPOE as a plasticizer. The prepared PIM was characterized by Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy(SEM), and Atomic Force Microscopy (AFM) techniques. The efficiency of the transport of Zn(II) and Cd(II) ions through the PIM was investigated in terms of the effects of carrier concentration, the pH in the acceptor phase, the amount of plasticizer in the membrane and the thickness of the membranes. The kinetic parameters which have been calculated as the constant rate (k), permeability coefficient (P), flux (J) and diffusion coefficient (D). This study has demonstrated the driving force of pH throug...
TL;DR: In this article, three new low band gap Schiff bases were prepared by using 3-etoxy-4-hydroxybenzaldehyde and different o-phylene diamines, and their photophysical, electrochemical, thermal, mechanical and morphological properties were investigated.
Abstract: In this paper, three new low band gap Schiff bases were prepared by using 3-etoxy-4-hydroxybenzaldehyde and different o-phylene diamines. Then, these Schiff bases were converted to low band gap polyurethane derivatives, and their photophysical, electrochemical, thermal, mechanical and morphological properties were investigated. Photophysical properties of the compounds were investigated by using UV-Vis and photoluminescence (PL) spectroscopy. Electrochemical properties of Schiff bases and polyurethanes containing azomethine were investigated by using cyclic voltammetry (CV). Thermal decomposition and transitions were determined by using TG-DTA, DMA and DSC techniques, respectively. Morphological properties of the compounds were also determined by using scanning electron microscopy (SEM). SEM images showed that polyurethanes containing azomethine consist of semi-crystalline particles.
TL;DR: In this paper, a series of comb-like methoxy polyethylene glycol (MPEG) functionalized polyurethanes (PUs) were successfully prepared via click chemistry and polyaddition reaction.
Abstract: In this study, a series of comb-like methoxy polyethylene glycol (MPEG) functionalized polyurethanes (PUs) (PU–g–MPEG) were successfully prepared via ‘click’ chemistry and polyaddition reaction. The copper catalyzed Huisgen 1,3-dipolar cycloaddition was firstly carried out between 3,5-bis(hydroxymethyl)-1-propargyloxybenzene (PBM) and methoxy polyethylene glycol azide (MPEG–N3) to obtain MPEGylated diol PBM (MPEG–PBM). Then, the comb-like PUs having MPEG located on the backbones (PU–g–MPEG) were synthesized through the polyaddition of MPEGylated diol PBM and hexamethylene diisocyanate (HDI). Fourier transform infrared (FTIR), 1H NMR spectroscopy, size exclusion chromatography (SEC), and thermo gravimetric analyses (TGA) were used to characterize these synthesized MPEG-functionalized comb-like PUs (PU–g–MPEG). Compared with PU without MPEG grafts, PU–g–MPEG show a better wettability.
TL;DR: In this paper, photoirradiated Fe-mediated AGET (activators generated by electron transfer) atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was investigated at ambient temperature in N,N-dimethylformamide (DMF) using carbon tetrachloride as initiator, FeCl3·6H2O/bipyridine (Bpy) as catalyst complex, and alcohol as reducing agent.
Abstract: In this study, photoirradiated Fe-mediated AGET (activators generated by electron transfer) atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was investigated at ambient temperature in N,N-dimethylformamide (DMF) using carbon tetrachloride as initiator, FeCl3·6H2O/bipyridine (Bpy) as catalyst complex, and alcohol as reducing agent. Linear semi-logarithmic plot of conversion vs. time was obtained from the kinetic experiments, and the number-average molecular weight increased linearly with monomer conversion and corresponded to the theoretic values with molecular weight distributions (Mw/Mn) as low as 1.25, which agreed with the character of controlled/living polymerization. The kinds of alcohol played an important role in photoirradiated Fe-mediated AGET ATRP of MMA. The living characteristics were demonstrated through chain extension experiment. The obtained polymer was characterized by proton nuclear magnetic resonance (NMR) and gel permeation chromatography.
TL;DR: In this article, a Fe3+ ion selective N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine (RH6GAC) monomer was synthesized.
Abstract: In this study, Fe3+ ion selective N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine (RH6GAC) monomer was synthesized. Then, p(Acrylamide-co-N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine) (p(AAm-co-RH6GAC)) and p(2-hydroxyethyl- methacrylate-co- N-(Rhodamine-6G)lactam-N'-acryloyl-ethylenediamine) (p(HEMA-co-RH6GAC)) colorimetric hydrogels were synthesized by using acrylamide (AAm) and 2-hydroxyethylmethacrylate (HEMA) as primary monomers. FT-IR, SEM, polymerization yield and swelling characterizations were conducted for the resulting hydrogels. Then, these hydrogels were used in selective absorption of Fe3+ ions from aqueous media. The hydrogels, which could absorb Fe3+ ions selectively from a mixture of metal ions, were used as column packing material. The solutions containing Fe2+ and Fe3+ ions at different concentrations were separated at a rate of 97.7 ± 0.7%.
TL;DR: In this paper, a thorough investigation on the potential correlation between environmental stress cracking resistance (ESCR) and crystalline structure characteristics, namely, crystallinity, mean lamella thickness and its distribution, and lamella surface area (LSA), was conducted.
Abstract: Studies were conducted on the crystalline properties of different polyethylene resins to identify their influence on phase interconnectivity between amorphous and crystalline regions. This work offers a thorough investigation on the potential correlation between environmental stress cracking resistance (ESCR) and crystalline structure characteristics, namely, crystallinity, mean lamella thickness and its distribution, and lamella surface area (LSA). The initial objective of this work was to investigate an existing ambiguity in the literature with respect to the effect of the crystalline phase on ESCR. In addition, research was conducted to evaluate the degree of variability in the lamella surface area, as a measure of phase interconnectivity and ESCR, with processing temperature and post-process annealing. Annealing at various conditions, along with cooling at different rates, were employed to investigate the effect of temperature on LSA. It was observed that a clear correlation exists between crystalline...
TL;DR: In this article, the authors investigated the gel properties using swelling measurements and microscopic techniques, and they proposed that the deviation point of the results of dilatometric technique from those of the gravimetric one can be a new criterion for gel point.
Abstract: The simultaneous gravimetric and dilatometric techniques have been used to study the kinetics of aqueous free radical crosslinking copolymerization of acrylamide (AAm) and N,N'-methylenebisacrylamide (MBA) at different crosslinker ratios, and reaction temperatures. In this study, the gel properties were investigated using swelling measurements and microscopic techniques. Based on the data, it was proposed that the deviation point of the results of dilatometric technique from those of the gravimetric one can be a new criterion for gel point. The monomer conversion and the equilibrium swelling ratio of the hydrogels were measured as a function of the reaction time. Experimental data showed an inverse dependence of the critical gel point on crosslinker concentration. As the MBA/AAm ratio was decreased to 0.1 wt%, the product appearance changed. In addition, the effects of temperature on the reaction rate and critical gel point were studied. At higher temperatures, the equilibrium swelling ratio reached to it...
TL;DR: In this article, a semi-continuous heterophase polymerization (SHP) under monomer-starved conditions of methyl methacrylate and hexyl methacylate is reported, at various monomer addition rates to elucidate the effect of monomer solubility on the mechanism of particle nucleation and growth.
Abstract: The semi-continuous heterophase polymerization (SHP) under monomer-starved conditions of methyl methacrylate and hexyl methacrylate is reported, at various monomer addition rates to elucidate the effect of monomer solubility on the mechanism of particle nucleation and growth. Polymer particles in the nanometer range from both monomers were obtained, which decreased in size as monomer addition rate was decreased. Molar masses of both polymers also diminished as monomer addition rate was slowed down. The propagation rate constant dictates how fast the starved condition is achieved rather than the monomer solubility in the aqueous phase. A slow particle rate of growth helps to obtain a narrower PSD.
TL;DR: In this paper, the preparation and thermal, morphological, electrochemical and proton conducting properties analysis of azolic copolymers based on 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and 5-(methacryloyl chloride with 5-aminotetrazole) (MTet) were performed throughout this work.
Abstract: The preparation and thermal, morphological, electrochemical and proton conducting properties analysis of new azolic copolymers based on 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and 5-(methacrylamido)tetrazole) (MTet) were performed throughout this work. MTet monomer, prepared by the reaction of methacryloyl chloride with 5-aminotetrazole, was copolymerized with AMPS via conventional free radical copolymerization at different monomer feed ratios to achieve poly(MTet-co-AMPS) copolymer membranes. The obtained copolymer membranes were analyzed by FTIR, 1H-NMR, thermogravimetric analysis (TGA), differantial scanning calorimetry (DSC), Elemental Analysis (EA), Cyclic Voltammetry (CV), and Impedance Spectroscopy. The composition of copolymers was determined via elemental analysis (EA). TGA demonstrated that the copolymer electrolyte membranes are thermally stable up to approximately 250°C. The appearance of a single Tg in the DSC curves verified the homogeneity of the membranes. CV curves demonstrate...
TL;DR: In this article, the results of the research on a new polymer-membrane and gel electrolytes for electrochromic devices were presented, which indicated good reversibility, low power consumption of ± 3 V in colored state, high variation of transmittance changing of 64% in gel electrolyte, and lower 7% in membrane electrolyte and good memory effect under opencircuit conditions.
Abstract: The paper presents the results of the research on a new polymer-membrane and gel electrolytes for electrochromic devices. A complementary solid-state electrochromic device consisting of cathodically coloring working electrode of WO3 and anodically coloring counter electrode of NiO films is prepared to compare the effects of gel or membrane forms of carboxymethyl cellulose (CMC) polymer electrolyte on the electrochromic properties of devices. The performance evaluations of the complementary solid-state electrochromic devices indicate good reversibility, low power consumption of ±3 V in colored state, high variation of transmittance changing of 64% in gel electrolyte, and lower 7% in membrane electrolyte and good memory effect under open-circuit conditions. CMC based electrolytes can be used as an ion-conducting medium and be a good candidate for complementary electrochromic devices owing to, the improved properties as well as its cheapness.
TL;DR: In this paper, itaconic acid doped polyaniline nanorods were successfully synthesized via chemical oxidation polymerization under the optimal polymerization condition obtained by the previous orthogonal experiment design and characterized by various measurements.
Abstract: Nanostructured polyaniline has attracted more attention due to its interesting properties and potential applications. In this paper, itaconic acid doped polyaniline nanorods were successfully synthesized via chemical oxidation polymerization under the optimal polymerization condition obtained by the previous orthogonal experiment design and characterized by various measurements. The itaconic acid doped polyaniline has high productivity up to 94.5%, the conductivity of 2.11×10−2 S/cm and good solubility in organic solvents. Its particle size distribution is mono-dispersed and the morphology is the interconnected nanorods with the diameter of 67 nm. The crystallinity of itaconic acid doped polyaniline is 39.36%, but that of undoped polyaniline is 14.92%, as indicates that the existence of the dopant intensifies the order of the polyaniline crystal structure. There is a classic and specific absorption peak at 1243 cm−1 for doped polyaniline. The weight loss of itaconic acid doped polyaniline is mainly caused...
TL;DR: In this article, the dispersion degree of carbon nanotubes in polyvinyl butyral composites was characterized by scanning electron microscopy (SEM) and mechanical properties were measured with tensile testing.
Abstract: In this research, poly(vinyl butyral) (PVB)/single wall carbon nanotubes (SWCNT) composites were prepared via solution blending method. Dispersion degree of SWCNT in the composites was characterized by Scanning Electron Microscopy (SEM) and mechanical properties were measured with tensile testing. Thermal degradation of composites was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). SEM analysis confirmed good dispersion of the nanotubes in the PVB. The tensile tests showed significant increases in mechanical properties such as exceptional improvement in tensile strength, Young's modulus and flexibility for the composites compared to PVB at low SWCNT content.The TGA curves indicated that adding SWCNT improved the thermal stability of the PVB significantly and the degradation of the polymer matrix shifted to the higher temperatures. For the sample containing 0.6 wt%, an increase of 171% in modulus and a 258.4% enhancement of tensile strength were achieved. Al...
TL;DR: In this paper, the effect of crosslink density, water phase to oil phase ratio, and the hydrophilic-lipophilic balance (HLB) value on polymerization rate, particle size, and swelling ratio were investigated.
Abstract: Nanosized hydrogel particles prepared through inverse microemulsion polymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid, using the combination of an oil soluble emulsifier (SPAN80) with a water soluble emulsifier (TWEEN 80), and precise determination of HLB range related to the formation of stable single phase microemulsions. The effect of crosslink density, water phase to oil phase ratio, and the hydrophilic-lipophilic balance (HLB) value on polymerization rate, particle size, and swelling ratio were investigated. It found that polymerization rate and particle size are strongly dependent on the water phase to oil phase ratio. Hydrogel samples prepared using oil soluble and water soluble initiators and the results showed that the initiator type had a great influence on monomer conversion and particle size. Effect of pH on equilibrium swelling of hydrogels was studied by dynamic light scattering and hydrogels showed pH-independent swelling behavior in a broad range of pH values. We also reported...