Triethylenetetramine Research Articles

Energetic Nitrate-Based Polymer-Bonded Explosives Derived from Sustainable Aza-Michael Reactions.

A novel nontoxic method for processing energetic binder, namely, polyglycidyl nitrate (PGN), using Aza-Michael reactions for deriving high-performance explosive formulations is being reported. The polyol binders used in polymer-bonded explosives (PBX) including PGN are usually cross-linked using isocyanate leading to polyurethane (PU)-based cured solid networks. These reactions require mild reaction conditions and yield good mechanical properties for the PBX but remain challenging due to extraneous reactions of isocyanate resulting in defects in the cured blocks. In addition, the presence of nitrato groups in the vicinity of terminal hydroxyl groups of PGN results in the decuring of cross-linked urethane that affects the storage life of PBX, though PGN-based binder can provide an 18% improvement in the velocity of detonation of PBX at lower solid loadings of 70%. This prevents researchers from exploiting the major performance advantage of using PGN for PBX compositions. This article herein features a green and mild aza-Michael reaction for functional modification of PGN using readily available substrates and triethylene tetramine to form a cross-linked β-aminocarbonyl network. The methodology ensures a void-free, stable, cured network and offers an effective replacement for toxic cure chemistry currently employed for processing of PBX.

INVESTIGATION OF FUNGICIDAL PROPERTIES OF HEXYL BROMIDE COMPLEX OF N'-(2,2-BITCYCLO[2.2.1]HEPT-5-EN-2-YL-4,5-DIHYDRO-1-H-IMIDAZOLIN-1- YLETHYL)ETHANE-1,2-DIAMINE AS ANTIMICROBIAL ADDITIVE TO LUBRICANTCOOLANT FLUIDS

The results of a study of the antifungal properties of an imidazoline hexyl bromide complex obtained on the basis of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid and triethylenetetraamine as an additive to cutting fluids are presented. First, imidazoline was obtained by reacting norbornene carboxylic acid with triethylene tetraamine. In the next step, imidazoline was reacted with hexyl bromide to obtain its alkyl halide complex. The physicochemical properties of the resulting complex were determined, and its composition and structure were confirmed by IR spectroscopy. The complex has been tested as an antimicrobial additive in cutting fluids. It was found that the resulting complex has a destruction zone of 1.3-1.5 cm at a concentration of 0.25% and 2.4-2.6 cm at a concentration of 0.5%. N'-(2,2-bicyclo[2.2.1]hept-5-en-2-yl-4,5-dihydro-1-Himidazolin-1-ylethyl)ethane-1,2-diamine hexyl bromide complex as an antimicrobial additive exhibiting high fungicidal properties, destroys fungi even at a concentration of 0.25% - the affected area is 1.3-1.5 cm.

3,4-dimethoxychalcone induces autophagy and reduces neointimal hyperplasia and aortic lesions in mouse models of atherosclerosis

Autophagy inducers can prevent cardiovascular aging and age-associated diseases including atherosclerosis. Therefore, we hypothesized that autophagy-inducing compounds that act on atherosclerosis-relevant cells might have a protective role in the development of atherosclerosis. Here we identified 3,4-dimethoxychalcone (3,4-DC) as an inducer of autophagy in several cell lines from endothelial, myocardial and myeloid/macrophagic origin, as demonstrated by the aggregation of the autophagosome marker GFP-LC3 in the cytoplasm of cells, as well as the downregulation of its nuclear pool indicative of autophagic flux. In this respect, 3,4-DC showed a broader autophagy-inducing activity than another chalcone (4,4- dimethoxychalcone), spermidine and triethylene tetramine. Thus, we characterized the potential antiatherogenic activity of 3,4-DC in two different mouse models, namely, (i) neointima formation with smooth muscle expansion of vein segments grafted to the carotid artery and (ii) genetically predisposed ApoE−/− mice fed an atherogenic diet. In the vein graft model, local application of 3,4-DC was able to maintain the lumen of vessels and to reduce neointima lesions. In the diet-induced model, intraperitoneal injections of 3,4-DC significantly reduced the number of atherosclerotic lesions in the aorta. In conclusion, 3,4-DC stands out as an autophagy inducer with potent antiatherogenic activity.

Activation of inert triethylene tetramine-cured epoxy by sub-critical water decomposition

Cured epoxy is stable and difficult to be recycled. To make the inert cured epoxy and its derivatives or composites reactive is still a challenge. In this study, sub-critical water was used to decompose the solid diglycidyl ether-based epoxy resin (bisphenol A and bisphenol F) cured with triethylene tetramine (TETA) to reactive species. First of all, the thermally most unstable bonds in the epoxy resin underwent homogeneous cleavage reaction. Next, the generated free radicals were saturated by extracting hydrogen from the sub-critical water. The decomposition rate was improved with increasing the temperature and reaction time. During the reaction, breakage occurs preferentially in the epoxy resin main chain because of the existence of ether groups. The compounds evolved and the decomposition was analyzed. The experimental outcomes revealed that the decomposition mechanism of diglycidylether of bisphenol A (DGEBA)/TETA and diglycidylether of bisphenol F (DGEBF)/TETA resin regimes in sub-critical water may include side group elimination, random fracture and unzipping. Moreover, a segmented second-order kinetic analysis of the decomposition process was performed. The decomposition processes of two resins in sub-critical water were divided into two stages. Both stages were second-order reaction, the activation energy of DGEBA/TETA was 175 kJ/mol (Ea1(15-45min)), and 612 kJ/mol (Ea2(52.5-75min)). The activation energy of DGEBF/TETA was 258 kJ/mol (Ea1(15-45min)), and 686 kJ/mol (Ea2(52.5-75min)), respectively. This study provides a way for recycling inert epoxy wastes from different industrial fields and generating reactive and functional polymers.

Surface modification of thin film composite nanofiltration membrane with graphene oxide by varying amine linkers: Synthesis, characterization, and applications

We report surface modifications of thin film composite nanofiltration (TFC NF) membrane with amine and the characterization of the resulting membrane for anti-biofouling properties. Graphene oxide (GO) was grafted on the surface of the TFC NF membrane using three linkers, ethylene diamine, diethylene triamine and triethylene tetraamine. Grafting of GO on the surface was successfully validated through Raman Spectroscopy and XPS. Ring-like structures were observed on the surface of the dense polyamide layer of TFC NF membranes under SEM after modification with GO. A slight increase in the roughness, and hydrophilicity was noticed in the membranes modified with GO. GO-grafted membranes demonstrated enhanced chlorine stability, lower biofouling tendency, lower flux decline during filtration of seawater and improved hexavalent chromium rejection in the basic pH. The improved chlorine stability is attributed to intermolecular hydrogen bonding between GO and polyamide structure, while the enhanced biofouling resistance and lower flux decline is ascribed to hydrophilic GO. The membranes were further evaluated for rejection of heavy metal ions, in particular hexavalent chromium, which showed about 97% rejection in basic pH attributed to the rise in negative character of the membrane surface due to the grafting of GO. Na2SO4 rejection for control TFC was reduced by 9.6%, while a reduction between 1 and 5.5% was found in fGO grafted membranes after 1 h exposure to 1000 ppm NaOCl.

Heteroatom doped carbon dots from green sources as metal ion sensor and as fluorescent ink

In this study, novel eco-friendly nitrogen-doped carbon dots (NCDs) were prepared via a green, efficient, and one-pot synthesis method from Sida cordifolia root as the carbon source and triethylene tetraamine as the nitrogen source for the detection of metal ions. The amorphous, nanosized carbon dots with 17.8 % quantum yield exhibited exceptional stability towards different experimental conditions. These NCDs acted as a nanoprobe for the sensing of Co(II) and Cu(II) via fluorescence and electrochemical techniques, respectively. These blue fluorescent carbon dots detects Co(II) with a detection limit as low as 0.11 μM and Cu(II) with 0.03 nM. The inner filter effect (IFE) acted as the primary fluorescence quenching mechanism. Also, the developed sensor could detect metal ions in different water samples. Moreover, NCDs were used as fluorescent security ink for writing and drawing. The findings of this study open up a new platform for the effective and reliable sensing of metal ions.

Glass and sub-glass relaxation changes induced by thermal ageing of epoxy-amine polymer networks – A DMA study

Four epoxy-amine networks were characterized by Dynamical Mechanical Analysis (DMA) and by Dielectric Relaxation Spectroscopy (DRS). The epoxy-amine networks were cured with DGEBA and four aliphatic amine hardeners: three ethylamine hardeners of increasing complexity: ethylene diamine (EDA), diethylene triamine (DETA), triethylene tetramine (TETA), and 4,7,10-Trioxa-1,13-tridecanediamine (TTDA). DGEBA-DETA was aged at 160 °C. Its α relaxation temperature was shown to decrease with time, implying a predominant chain scissions mechanism through the thermal oxidation. DGEBA-DETA and DGEBA-TETA were also shown to display a sub-glassy relaxation made of two components. After ageing at 160 °C, the lowest one around −50 °C, associated to the local motions of hydroxypropyl ether segments, increases in intensity. The second one around 30 °C, with unknown origin but probably from motions in more densely crosslinked areas within the network, disappears with ageing. Those results are discussed regarding the molecular aspects of oxidation.

Effect of concentration on the properties of nitrogen-doped zinc oxide thin films grown by electrodeposition

Zinc oxide is one of the most researched semiconductors owing to the outstanding properties that make it useful in various industrial applications, such as solar cells and other optoelectronics. In this work, ZnO thin films were prepared in five different concentrations and doped with four nitrogen atoms from triethylene tetramine (TETA) to fabricate a ZnO for optoelectronic applications using an electrodeposition technique. The doped ZnO thin films were synthesized and deposited on ITO glass substrates. The deposited thin films were annealed at 400°Cfor 60min in a furnace under the same conditions. The thin films' optical, electrical, and surface morphological properties were characterized using UV–Vis Spectrophotometer, Four Point Probe (FPP), and Scanning Electron Microscope (SEM), respectively. The optical properties confirmed the film's suitability for various transparent device applications with a high optical transmittance of about 90% at the wavelength between 250 and 950 nm. The optical band gaps of 3.25 eV to 3.50 eV were obtained at ZnO concentrations from 0.2 M to 1.0 M. The SEM images depicted a polycrystalline nature of the films with irregular nanoparticle shapes across the substrates. Electrical results established the high conductivity of nitrogen-doped ZnO thin films, thereby making the thin films suitable as transparent conducting oxides for devices such as solar cells and optoelectronics.

AKT-driven epithelial-mesenchymal transition is affected by copper bioavailability in HER2 negative breast cancer cells via a LOXL2-independent mechanism

BackgroundThe main mechanism underlying cancer dissemination is the epithelial to mesenchymal transition (EMT). This process is orchestrated by cytokines like TGFβ, involving “non-canonical” AKT- or STAT3-driven pathways. Recently, the alteration of copper homeostasis seems involved in the onset and progression of cancer.MethodsWe expose different breast cancer cell lines, including two triple negative (TNBC) ones, an HER2 enriched and one cell line representative of the Luminal A molecular subtype, to short- or long-term copper-chelation by triethylenetetramine (TRIEN). We analyse changes in the expression of EMT markers (E-cadherin, fibronectin, vimentin and αSMA), in the levels and activity of extracellular matrix components (LOXL2, fibronectin and MMP2/9) and of copper homeostasis markers by Western blot analyses, immunofluorescence, enzyme activity assays and RT-qPCR. Boyden Chamber and wound healing assays revealed the impact of copper chelation on cell migration. Additionally, we explored whether perturbation of copper homeostasis affects EMT prompted by TGFβ. Metabolomic and lipidomic analyses were applied to search the effects of copper chelation on the metabolism of breast cancer cells. Finally, bioinformatics analysis of data on breast cancer patients obtained from different databases was employed to correlate changes in kinases and copper markers with patients’ survival.ResultsRemarkably, only HER2 negative breast cancer cells differently responded to short- or long-term exposure to TRIEN, initially becoming more aggressive but, upon prolonged exposure, retrieving epithelial features, reducing their invasiveness. This phenomenon may be related to the different impact of the short and prolonged activation of the AKT kinase and to the repression of STAT3 signalling. Bioinformatics analyses confirmed the positive correlation of breast cancer patients’ survival with AKT activation and up-regulation of CCS. Eventually, metabolomics studies demonstrate a prevalence of glycolysis over mitochondrial energetic metabolism and of lipidome changes in TNBC cells upon TRIEN treatment.ConclusionsWe provide evidence of a pivotal role of copper in AKT-driven EMT activation, acting independently of HER2 in TNBC cells and via a profound change in their metabolism. Our results support the use of copper-chelators as an adjuvant therapeutic strategy for TNBC.

Preparation and Characterization of Water-borne Polyurethane Based on Benzotriazole as Pendant Group with Different N-Alkylated Chain Extenders and Its Application in Anticorrosion.

A series of novel anti-corrosive coatings were synthesized successfully. Water-borne polyurethane (WPU) was synthesized using polyethylene glycol and modified by grafting benzotriazole (BTA) as a pendant group (WPU-g-BTA) and N-alkylated amines (ethylene diamine (A), diethylene triamine (B), triethylene tetramine (C)) as side-chain extenders. Fourier-transform infrared spectroscopy, thermogravimetry, and dynamic mechanical analyses were used to characterize the structural and thermomechanical properties of the samples. A gas permeability analyzer (GPA) was used to evaluate molecular barrier properties. The corrosion inhibition performance of WPU-g-BTA-A, WPU-g-BTA-B, and WPU-g-BTA-C coatings in 3.5 wt% NaCl solution was determined by electrochemical measurements. WPU-g-BTA-C coating synthesized with a high cross-linking density showed superior anticorrosive performance. The as-prepared coatings exhibited a very low icorr value of 0.02 µA.cm-2, a high Ecorr value of -0.02 V, as well as excellent inhibition efficiency (99.972%) and impedance (6.33 Ω) after 30 min of exposure.

Experimental and theoretical insights on the thermal oxidation of epoxy-amine networks

This paper reports an investigation of the oxidation of three epoxy-amine networks obtained from DGEBA cured with three sorts of aliphatic hardeners ethylene diamine (EDA), diethylene triamine (DETA), and triethylene tetraamine (TETA). Oxidation was monitored by FTIR with an innovative discussion of CH2 consumption. Methylene groups held by hardeners groups were shown to be more sensitive to oxidation, which was confirmed by a discussion of Bond Dissociation Energies (BDE) computed by a machine-learning approach.

Polymeric micelle/nano hydrogel composite matrix as a novel multi-drug carrier

According to the World Health Organization (WHO), fatality of cancer is 9.6 million in 2018. Of these, 1.8 million deaths are due to colorectal cancer. However, it doesn't seem that proper medications are unavailable. Instead, the medications should reach the site of action without causing any further side effects. With the advent of smart biomaterials this target is on its verge to be achieved. Previous reports prove that the side effects induced by Cisplatin (CIS) could be greatly decreased by curcumin (CUR). Hence, if these two drugs are used in unison, greater efficacy with lesser toxicity could be achieved. However, to incorporate two drugs and to release them simultaneously without any premature leakage can be achieved by polymeric micelles. To increase the core and hydrophobicity, monomers with large alkyl chains like triethylene tetraamine (TETA) and oleic acid (OA) were grafted to the backbone of heparin (HEP) skeleton. To target these drugs, folic acid was entrapped within hydroxyl appetite (HAP) based hydrogel and was dispersed onto polymeric micelle (PM). This coating could further act as a potential barrier to sustain the drug release as evident from similar previous studies. All the reaction steps were monitored using FTIR, XRD, H1 NMR, DLS and SEM studies. The in vitro swelling and release studies proved promising with folic acid showing burst release followed by the sustained release of chemotherapeutic drugs. The efficacy was further ascertained by MTT assay on normal and HCT 116 colon cancer cell lines. This was further proved by fluorescence studies. Thus, the present material could act as a promising candidate for the treatment of colorectal cancer with high efficacy and minimal toxicity.

Adsorption of CO2 by amine-modified novel nanomaterials

The greenhouse effect has a serious impact on our living environment. The development of novel amine-modified porous organic polymer materials is of great significance to achieve the capture of greenhouse gas CO2. In this study, hexadecyltrimethyl ammonium bromide (CTAB) was used as template, resorcinol formaldehyde resin adhesive was synthesized by polycondensation reaction between 1,3 resorcinol and formaldehyde, and ethyl orthosilicate (TEOS) was used as inorganic precursor (prepared by reaction of silicon tetrachloride and ethanol). Choline, tetramethylammonium hydroxide, plant growth regulators, herbicides, strong base anionic and cationic resins, dye levelling agents, and a range of basic colours all are manufactured from trimethylamine. Trimethylamine is recognized by gas sensors used it to check for seafood freshness. One-step sol-gel method was used. A novel nanoporous carbon silicon material (NNCMR) was synthesized. Using the composite porous material as a carrier, the isomers triethylene tetraamine (TETA) and tri (2-aminoethyl) amine (TAEA) as modifiers, respectively. New amine-modified porous carbon-silicon materials (NNCMR-TETA-X and NNCMR-TAEA-X) were prepared by impregnation method. Triethylenetatramine (TETA) is an orphaned medication that treats copper excess in tissues. It is a selective divalent Cu(II) chelator. Trientine, a salt form of D-penicillamine, was released in 1969 as a substitute for D-penicillamine. The results show that this kind of material has rich microporous structure and ordered mesoporous structure, and realizes the framework fusion of carbon and silicon oxide, and uniformly loads the amine material. NNCMR-TETA-50 showed the best adsorption performance among the new nanoporous carbon and silicon materials, with a maximum adsorption capacity of 4.21 mmol/g. The composite porous materials with different amine structures as modifiers have different effects on CO2 capture performance. In the presence of water vapor, NNCMR-TAEA-50 showed the best adsorption performance, with a maximum adsorption capacity of 4.96 mmol/g, since the tertiary amine group could not effectively capture CO2 in the absence of water vapor, but could work well in the presence of water vapor. This can help us design suitable adsorbent materials for CO2 capture in different practical applications. At the same time, the new nanoporous carbon silicon material has good thermal stability and recycling.

Facile Preparation of Loose P84 Copolyimide/GO Composite Membrane with Excellent Selectivity and Solvent Resistance.

In this study, multilayer graphene oxide (GO) was used to prepare the functional layer of polyimide/GO composite membrane with polyimide (P84) used as the supporting layer. Chitosan added in the functional layer was utilized to adjust the selectivity of the composite membrane. The effects of GO and chitosan contents on membrane morphology and separation performance were investigated in detail. The composite membrane showed high rejection to Congo red and Methyl orange with high flux but low rejection to Na2SO4 and MgCl2 at 0.2 MPa and ambient temperature. The membrane exhibited excellent solvent resistance in N,N-dimethylacetamide (DMAc) after being crosslinked with 0.5 wt.% triethylene tetramine. The result means that a highly selective and solvent-resistant P84/GO composite membrane was prepared with the facile filtration preparation method.

Curcuma amada derived nitrogen-doped carbon dots as a dual sensor for tetracycline and mercury ions

The hydrothermal approach was used to make nitrogen-doped carbon dots (NCDs) employing ginger mango and triethylene tetraamine as precursors. The as-synthesized NCDs with a size of 7 nm exhibited good aqueous dispersibility, photostability and green fluorescence under UV light. Various optical, morphological and electrochemical properties of NCDs were examined. It was used as a dual-mode probe for tetracycline and mercuric ion detection. It detected tetracycline selectively and sensitively using an inner filter-based fluorescence quenching mechanism with a detection limit of 32 nM. The NCD modified glassy carbon electrode detected mercuric ions electrochemically with a detection limit of 0.2 nM. Moreover, NCDs were utilized to sense tetracyclines and mercuric ions in tap and river water samples.

Study on the compounding of a new type of trimer epoxy resin curing agent

AbstractIn this paper, bisphenol A (BPA), epichlorohydrin (ECH), and isocyanate trimer (TDI‐T) are used as raw materials to synthesize a high toughness/trimer epoxy resin by graft copolymerization. It was cured at room temperature with low molecular weight polyamide 650 (PA650)/isophorone diamine (IPDA) and low molecular weight polyamide 650/triethylene tetramine (TETA) composite curing system respectively. The cured products of the two compound systems were studied by Fourier transform infrared spectroscopy (FT‐IR), differential scanning calorimetry (DSC), thermogravimetry (TG), and mechanical property testing. The results show that with the increase of TETA and IPDA curing agents, the heat released during the curing process of the two systems also greatly increases, and the temperature rises from the initial 33.9–69.7°C and 52.8°C. The curing time is shortened from a few days to a few hours, and the controllability of the curing time is effectively realized. When the ratio of triethylene tetramine to low molecular weight polyamide 650 is 2.86:100, the compressive strength is the best, reaching 112.7 MPa, 12% higher than pure polyamide as curing agent, and the specimen can be completely restored to its original shape in a few minutes. When the ratio of TETA to PA650 is 2.86:100, the elongation at break reaches 21.4%.

Application of amino-functionalized cellulose-poly(glycidyl methacrylate) graft copolymer (AM-Cell-g-PGMA)adsorbent for dyes removal from wastewater

In this work three amino-functionalized cellulose-poly(glycidyl methacrylate) graft copolymers (AM-Cell-g-PGMA) were tested as ion exchange resins for the adsorption of dyes, from aqueous solutions using batch techniques. The three adsorbents were prepared earlier based on the aminization of grafted copolymer with tri-ethylamine hydrochloride (TEAC), di-ethylene tri-amine (DETA) and tri-ethylene tetra-amine (TETA) which represented as R1, R2 and R3 respectively. Adsorption time and solution pH were varied. The maximum adsorption capacities of R1 were 147.5 and 150 (mg/g), while the maximum adsorption capacities of R2 were 117.7 and 133 (mg/g), and finally, the maximum adsorption capacities of R3 were124 and 138 (mg/g) for Acid black 194 and C.I. Reactive black 5 dyestuffs respectively. It was found that the maximum adsorption capacities for the three resins decreased in the order R1> R2> R3 for the sorption of the two dyes. With respect to these results, the R1 resin was then selected for further adsorption investigations regarding isotherm and kinetic studies. The isotherm data were well described by the Langmuir equation over the concentration range studied. Kinetic parameters of sorption were determined enlightening the obeying of the pseudo-second order kinetic model for the investigated system.

A novel solid–liquid ‘phase controllable’ biphasic amine absorbent for CO2 capture

The main issues in the application of biphasic amine absorbent include the inconvenient separation of the liquid–liquid biphase and the clogging that is associated with the solid–liquid mixture. A novel solid–liquid ‘phase controllable’ biphasic amine absorbent was therefore developed, in which the phase separation occurred only when the absorbent was near saturation. The absorbent, composed of triethylene tetramine (TETA), 2-amino-2-methyl-1-propanol (AMP), and N-methylformamide (NMF), turned into solid–liquid biphase under CO2 loading of 0.85 mol mol−1, which is close to saturation (0.92 mol mol−1). The solid phase comprised white powder that accounted for only 42 % of the total volume while absorbing 91 % of the total load. Turbidity and particle size tests showed that the phase separation was self-aggregating. The mechanisms of absorption and regulation were obtained using 13C NMR and molecular simulation. During the absorption, CO2 first combined with TETA to generate TETAH+CO2–/TETACO2– through the zwitterion mechanism, and then combined with AMP to generate AMPCO2– because of the lower reaction activity between CO2 and AMP. The TETA-carbamate was found to greatly weakened the strength of the hydrogen bonds and the van der Waals forces between AMPH+ and AMPCO2–, increasing the solubility of the intermediate products, and therefore achieved the purpose of controlling the phases separation inherent in the reaction.

Graphene oxide-coated amino-modified polyacrylonitrile to fabricate highly conductive fabrics

Graphene conductive polyacrylonitrile (PAN) substrate is an important material, owing to its high strength, flexibility, and comfort. In this work, a PAN fabric was cationized with triethylene tetramine (TETA) for increased adsorption of anionic graphene oxide (GO), which mainly forms ionic bonds. The TETA-modified PAN (Amino-PAN) fabric was then treated with GO using a dipping method followed by in situ reduction of GO to obtain reduced graphene oxide (RGO). The electric conductivity of Amino-PAN fabrics was increased with the increasing of TETA modification temperature from 90°C to 110°C. A surface electric resistance of 0.61 kΩ cm−1 was obtained for 2 g L−1 GO and TETA modification performed at 110°C for 2 h. This resistance was considerably lower than that of the original PAN fabric for one cycle of the dipping–reduction GO treatment (1RGO-PAN, 42.69 kΩ cm−1) and six cycles of the dipping–reduction GO treatment (6RGO-PAN, 1.52 kΩ cm−1). The results revealed that the anionic GO was more easily adsorbed on the surface of the Amino-PAN fabrics than on the original PAN fabrics. The surface electric resistance of the 1RGO-Amino-PAN fabrics slightly increased from 0.61 to 0.79 kΩ cm−1 after 30 washing cycles. The results showed that the RGO-coated Amino-PAN fabric had excellent washability. Furthermore, the TETA modification process reduced the dipping–reduction times of the GO finishing PAN fabrics, and can be easily used in the production of RGO-based flexible conductive material.

Triethylene tetramine-modified crosslinked acrylonitrile as Cu(II) ion adsorbent by photo-induced precipitation polymerization

Heavy metal pollution is a serious environmental problem, and adsorption is regarded as an effective technology for metal ions removal. A new absorbent triethylene tetramine (TETA)-modified crosslinked polyacrylonitrile (TETA-modified XL-PAN) was prepared by photo-induced precipitation polymerization of acrylonitrile in water at room temperature using FeC2O4 as photoinitiator and N,N′-methylenebisacrylamide as crosslinking agent. The TETA provided amidogens, to bond Cu(II) ions and the crosslinking agent was used to improve the stability of adsorbent. FTIR, SEM, BET, and TG were used to characterize the TETA-modified XL-PAN. The FTIR results demonstrate that the XL-PAN was successfully modified by TETA. The SEM images show that TETA-modified XL-PAN powders were agglomerated from 100 to 200 nm spherical particles. TETA-modified XL-PAN was used as an adsorbent to remove Cu(II) ion from wastewater. The effects of contact time, pH, Cu(II) concentration, temperature, and reuse cycles on adsorption were investigated, respectively. Experimental results showed that the adsorption isotherms agreed well with the Langmuir model and a chemical adsorption between TETA-modified XL-PAN and Cu(II) was inferred. After optimizing the experimental conditions, the maximum adsorption capacity of TETA-modified XL-PAN for Cu(II) was 46.6 mg/g with an adsorption time of 8 h. Furthermore, the TETA-modified XL-PAN adsorbent can be well regenerated by acid solutions. After eight regeneration and adsorption processes, the adsorption capacity still reached more than 90% of the first adsorption capacity. These results demonstrated the potential use of TETA-modified XL-PAN as an effective adsorbent for Cu(II) ions removal from wastewater.