Infrared spectra of chlorinated petroleum fractions

The infrared spectra of several chlorinated petroleum fractions are reported. Although the spectra of chlorinated branched and linear fractions are different in the 600–800 cm^?1 region, it is very difficult to detect less than 15% of the toxic chlorinated kerosene in mixtures with chlorinated n-paraffin waxes.     

Photocrosslinkable modified vegetable oil based resin for wood surface coating application

An acrylated epoxidized linseed oil (AELO) was synthesized from epoxidized linseed oil through ring opening of the oxirane group using acrylic acid as ring opening agent. The occurrence of the acrylate group and the ring opening of oxirane group was monitored using FT-IR spectroscopy. The AELO was mixed with three different photoinitiators at two different concentrations. Wood surfaces were coated with the mixtures, subsequently cured under UV light and the resulting surface properties of the coated samples gloss, scratch resistance, solvent resistance, and coating adhesion were characterized. The efficiency of the photoinitiators and the influence of their concentration on the rate and the extent of the curing were studied by curing the AELO mixtures under a monochromatic wavelength of 365 nm and measuring absorption spectra during the cure by real time FT-IR spectroscopy. The decrease of absorption in the measured spectra at 1406 cm⁻¹ was used to calculate the conversion of acrylic double bonds with increasing time of UV light exposure to obtain information on the cure kinetics for each photoinitiator and concentration.     

Synthesis,Structural Characterization,Spectroscopic Properties,and Theoretical Investigations of Aminoacridine Derivatives

Synthesis of four N-(heterocyclic)-9-aminoacridine derivatives was investigated. The synthesized compounds, N-thiazolyl-9-aminoacridine (AC1), N-(1,3,4-thiadiazolyl)-9-aminoacridine (AC2), N-(5-methyl-1,3,4-thiadiazolyl)-9-aminoacridine (AC3), and N-(5-phenyl-1,3,4-thiadiazolyl)-9-aminoacridine (AC4) were characterized by FT-IR, ¹H NMR, mass-spectral, and elemental analysis. Amine-imine tautomerism was suggested by density functional theory (DFT) calculations. The optimized structures were obtained using B3LYP/6–311++G(d,p) level of theory. The UV–Vis absorption spectra were measured in various organic solvents. The synthesized compounds AC1–AC4 exhibit absorption spectra characteristic of typical donor–acceptor compounds. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) analysis have been used to explain the internal charge transfer (ICT) phenomena within the molecules. Also, simulated UV spectra were calculated using TD-DFT (B3LYP/6–311++G(d,p) and the results were compared with the experimental values.     

Helical polyurethane-imide with optical activity based on binaphthyl units: preparation, characterization, and study of interchain hydrogen bonds

Helical polyurethane-imide with optical activity based on R-1,1′-binaphthyl-2′,2-diol (R-BINOL) and racemic polyurethane-imide (racemic-PUI) based on racemic 1,1′-binaphthyl-2′,2-diol (racemic-BINOL) were synthesized by hydrogen transfer addition polymerization procedure and characterized by ¹H NMR spectra, Fourier Transform Infrared Spectroscopy (FT-IR), thermal Fourier transform infrared spectroscopy (thermal FT-IR), X-ray diffraction (XRD), circular dichroism (CD) spectroscopy and thermogravimetric analysis (TGA). R-PUI exhibits the single-handed helical conformation and optical activity via CD spectra analysis. The optical rotation of R-PUI is +55.0°, which is larger than that of R-BINOL. The thermal stability of R-PUI is higher than that of racemic-PUI by TG analysis. According to the FT-IR and thermal FT-IR analysis, R-PUI with single-handed conformation possesses prominently interchain hydrogen bonds interactions, which plays an important role in thermal stability and optical activity.     

同位素标记法用于植物纤维中LCC蒸煮过程中结构变化的研究

为了研究植物纤维原料中的木素-碳水化合物复合体(lignin-carbohydrate complexes,LCCs)在硫酸盐法蒸煮过程中的结构变化,向天然植物稻秆中投入带¹³C同位素标记的松柏醇葡萄糖苷,用Björkman的方法将木素-碳水化合物复合体从稻秆粉末中分离出来,结合红外光谱和高分辨率的液态¹³C NMR检测分析发现木素与糖类主要是通过苯甲醚键、酯键和缩醛键连接。其中,在LCC中木素的主要结构为β-O-4结构。将分离出来的带标记的LCC模拟硫酸盐法蒸煮,分离得到木素-碳水化合物复合体的硫酸盐木素。通过对天然稻秆LCC硫酸盐木素和稻秆LCC硫酸盐木素-[α-¹³C]的红外光谱和高分辨率¹³C NMR分析,证实了在稻秆LCC硫酸盐蒸煮后,产物中还存在少量以苯甲醚键和缩醛键连接的LC结构。另外,所得硫酸盐木素主要以β-O-4结构为主,含有少量的β-β、β-5和β-1结构。     

Change of chemical composition and hydrogen bonding behavior due to chlorination of crosslinked polyamide membranes

The effect of membrane exposure to hypochlorite oxidant on property changes (chemical composition and hydrogen bonding behavior) of four FilmTec© thin film composite crosslinked polyamide membranes has been investigated. Crosslinking densities of the membranes were about 25–35%, with about 3–4 chlorines bound to the repeating unit of the polyamide membranes. This was equivalent to ～ 39% of all nitrogens being chlorinated in the polyamide membranes assuming the amide nitrogen is the dominant reaction site with chlorine. FTIR spectra showed the amide I band (C?O stretching peak at 1663 cm^?1) of polyamide membranes shifted to higher wave‐numbers and the peak intensity of the amide II band (N? H bending peak at 1541 cm^?1) decreased after chlorination. The peak shift and decrease of peak intensity resulted from breakage of hydrogen bonds between C?O and N? H groups within the polymers. The XPS and FTIR analytical analysis showed that there is no difference in the chlorine attack of polyamide membranes of higher or lower crosslinking density, and that the chlorination breaks and weakens hydrogen bonding. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The method for surface functionalization of single-walled carbon nanotubes with fuming nitric acid

Surface functionalization of single-walled carbon nanotubes (SWCNTs) was carried out using fuming nitric acid as a NO₂ radical source. The surface double bonds of the SWCNTs reacted with the NO₂ radicals at 10–90 °C under sonication, and following treatment with aqueous NaOH yielded modified carbon nanotubes with high affinity for polar solvents such as dimethylformamide. The structure of the product was characterized using Fourier transform-infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis, and atomic force microscopy. FT-IR and XPS spectra revealed the product has OH groups (3400, 1200 cm⁻¹), which was expected due to the addition of NO₂ radicals to the surface double bonds and subsequent substitution with OH groups. C_1s curve fitting analysis of the XPS spectra was used to quantitatively determine the different functional groups on the surface, and the amount of COOH groups was found to be increased from 2.8% to 9.3% due to progressive oxidation by increasing the reaction temperature from 10 to 90 °C.     

Copolymers of aniline and o‐methoxyaniline: Synthesis and characterization

High‐conversion (HC) copolymers of aniline and o‐methoxyaniline (o‐anizidine) were synthesized for the first time by chemical oxidative copolymerization by using various polymerization techniques (simultaneous or consecutive introduction of comonomers into the polymerizing system). Low‐conversion (LC) copolymers have also been synthesized for comparison. The polymers obtained were characterized by using ¹H‐NMR, infrared, and electronic absorption spectroscopy; differential scanning calorimetry; and electrical conductivity measurements. Solubility characteristics and composition of different fractions of the copolymers were also determined. It was shown that, in contrast to the LC copolymers, HC copolymers reveal relatively poor solubility. Electrical conductivity of copolymers and also of o‐methoxyaniline homopolymer is lower as compared to polyaniline, which correlates with notable hypsochromic (blue) shift of the bands in electronic absorption spectra. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1822–1828, 2005     

Interface,thermal, and Fourier transform—infrared spectroscopy investigation on polylactic acid/polyhydroxyalkanoate composites with silane-treated aluminum particles and intercalated montmorillonite inclusions for semiconductor devices

In this investigation, the dielectric properties of silane-influenced aluminum conductive particles in polylactic acid, polyhydroxyalkanoates, and intercalated montmorillonite (MMT) composite were assessed for enhancing the dielectric constant, dielectric loss, and AC conductivities. Eight different sets of samples were fabricated with untreated and silane-treated batches of biopolymer composites where the highest recorded dielectric constant was 3.98 at relaxation frequency of 10 kHz. One of the notable observations in the dielectric loss was with PLA/PHA/iMMT/Al (10 wt%) (silane-treated) composites exhibited the lowest losses past relaxation frequencies. Furthermore, FT-IR spectra were conducted on the samples to identify stretching and bonds created by silane and aluminum particles. The IR spectra confirm the formation of the Si O Al bond when treated with 3-glycidyloxypropyl-trimethoxysilane (GPTMS) solution and confirm the bond of Al OH hydroxyl bonds in the untreated composite samples. Other IR spectra information that was gathered would include carbonyl group stretching at 1750 cm⁻¹ and absorption bands of hydroxy acids, between 3511 and 3640 cm⁻¹, respectively. Scanning electron microscopy was performed on the sample to observe the formation of matrix cracks and exfoliation. A rough surface can be seen on PLA/PHA blends and the crystallization of these polymer blends regions can be vividly seen from the micrographs. Lastly, thermogravimetry analysis on the composite samples shows a predominant mass loss at 300°C before complete degradation and the notable composite with the lowest mass loss would be PLA/PHA/iMMT/Al (10 wt%) (ST) composite samples and with the inclusion of a constant 5 wt% organoclay MMT fillers imposed a high-onset degradation temperature, which was remarkable for composites that were fabricated through standard hot-press compression molding and cooling procedures.     

Electronic properties and atomic structure of graphene oxide membranes

We have performed a near-edge X-ray absorption fine-structure (NEXAFS) and a transmission electron microscopy (TEM) investigation of freely suspended graphene oxide (GO) sheets. We utilized a photoemission electron microscope to identify GO membranes and to acquire C K and O K absorption spectra. The overall line shape of C K-edge spectra demonstrates that the honeycomb carbon network of graphene is the scaffold of GO. However, the intensity ratio of π^∗ and σ^∗ resonances, and a broad feature at about 20 eV from the edge, indicate the presence of new carbon bonds. The O K-edge spectra show that oxidized regions are made of carbonyl, epoxide, and hydroxyl groups attached to the plane of graphene, while carboxyl groups might also be present at the edges. Further, our study indicates the presence of ordered arrangements of oxygen atoms in GO sheets. Our investigation provides a new and efficient route to study the electronic structure of suspended membranes.     

The ultra-wideband near-infrared luminescence properties and applications of K2SrGe8O18:Cr3+ phosphor

The near-infrared (NIR) light sources are fascinating in real-time nondestructive examination applications. Given that chemical bonds in organic substances (such as C–H, O–H and N–H) have extensive absorption and reflection of light in the NIR region, the emission spectrum of the NIR light sources should be as broad as possible. In this work, ultra-wideband K₂SrGe₈O₁₈ (KSGO):Cr³⁺ NIR-emitting phosphors with a 650–1200 nm emission span are developed. Structural analysis combined with electron paramagnetic resonance (EPR), photoluminescence (PL) spectra, time-resolved spectrum (TRES) and temperature-dependent PL spectra confirm that the super broadband emission with full width at half-maximum (FWHM) of 214 nm originates from the double Cr³⁺ luminescence centers occupying different [GeO₆] octahedra. Li⁺ ion as charge compensator is introduced to balance the negative charge induced by the un-equivalent replacement of Cr³⁺ for Ge⁴⁺, and the PL intensity and thermal stability are greatly enhanced. The NIR phosphor-converted luminescent diodes (pc-LEDs) prepared by combining optimized KSGO:0.10Cr³⁺, 0.07Li⁺ samples with 460 nm LED chips demonstrate their application in night vision. The measured absorption spectra of hemoglobin, water, ethyl alcohol and peanut oil illuminated by the as-prepared KSGO:0.10Cr³⁺, 0.07Li⁺ phosphors indicate nondestructive analysis in the areas of food safety.     

Surface structural features and optical analysis of nanostructured Cu-oxide thin film coatings coated via the sol-gel dip coating method

Nanostructured thin film coatings of copper oxide (Cu-oxide) were investigated to determine their physical structure, surface morphology, surface electronic bonding states, and optical properties. The Cu-oxide had been coated onto reflective aluminum substrates via a facile one-step sol–gel dip-coating route using a copper nitrate precursor. Characterizations were conducted using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and ultra-violet visible (UV–Vis) spectroscopic methods, and representative sol-gel reactions using copper nitrate precursor were proposed. The XPS spectra confirmed the presence of copper oxide elements. Further exploration of the Cu2p3/2 peak in XPS spectra revealed that the electronic structure of the copper component consisted of tetrahedral Cu(I) and octahedral Cu(II) with the presence of octahedral Cu(II) enabling coatings to have high absorption levels across the solar spectrum. The deconvolution of the O1s spectra exhibited three curve-fitting components: the lattice O²⁻, surface oxygen, and subsurface O⁻ species. FESEM results showed that the coating surface was an agglomerated copper oxide nanoparticles structure forming a porous structure. The optical band-gap of Cu-oxide thin film coatings, via the Tauc plot, was 2.7 eV.     

The changes in the structure and some physical properties of mesocarbon microbeads by heat treatment

The carbonization process of type C mesocarbon microbeads was studied using X-ray diffraction (XD), XPS and FT-IR. The intensity of absorption continued from the visible to the IR region observed by FT-IR spectroscopy and increased with the heat treatment. A theory of amorphous semiconductors was applied to simulate the absorption edge, and it was found that a factor relating to the absorption A correlated well with the diameter of graphite-like crystallite (L_a) obtained from XD for the specimens heat-treated above 700°C. Also, A was found to have good correlation with a valence band peak in XPS spectra, and this was interpreted by the increase in the density of electronic states, which could be excited by the infrared ray.     

Chelation of chitosan derivatives with zinc ions. II. Association complexes of Zn2+ onto O,N‐carboxymethyl chitosan

The chelation of zinc ions onto O,N‐carboxymethyl chitosan (ONCMCh) was characterized using a Fourier transform infrared (FTIR) spectrophotometer and a scanning electron microscope (SEM). From the FTIR spectra, little change in the absorption intensities and frequencies at 3300–3600 cm⁻¹ of Zn²⁺ ONCMCh chelated specimens suggested that  OH and  NH₂ groups were not participating in the chelation reaction. The absence of absorption bands at 1755–1700 cm⁻¹ suggested that the carboxyl group CO was not ionized, and the ionized CO bands were observed at 1400–1600 cm⁻¹ for chelated specimens. Thus, the chelation sites took place at the carboxyl group rather than at the  OH and NH₂ groups. It also confirmed that water‐insoluble chelates, which were formed through the Zn O and Zn N bonds, presented a tetrahedral structure. The water‐soluble complexes where zinc ions connected with oxygen of CO and water molecules were only due to electron attraction. Formation of different microstructures on the surfaces, as revealed by SEM, provided evidence to distinguish different chelating mechanisms between water‐soluble and water‐insoluble complexes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1476–1485, 2001     

Development of Siloxane Based Tetraglycidyl Epoxy Nanocomposites for High Performance Applications—Study of the Mechanical,Thermal, Water Absorption and Flame Retardant Behaviour

A study was made in the present investigation on siloxane containing tetraglycidyl epoxy nanocomposites in order to determine their suitability for use in high performance applications. The synthesis of the siloxane tetraglycidyl epoxy resin denoted as ‘E’ was done and it was characterized by Fourier Transform Infrared (FT-IR) spectra and ¹H, ¹³C Nuclear Magnetic Resonance (NMR) spectra. Nanoclay and polyhedral oligomeric silsesquioxanes (POSS)-amine nanoreinforcements denoted as N1 and N2 were incorporated into the synthesized epoxy resin. Curing was done with diaminodiphenylmethane (DDM) and bis (3-aminophenyl) phenylphosphine oxide (BAPPO) curing agents denoted as X and Y respectively. The mechanical, thermal, flame retardant and water absorption behaviour of the epoxy nanocomposites were studied and the results are discussed.     

Effect of Field Strength and Electronegativity of CaO and MgO on Structural and Optical Properties of SiO<Subscript>2</Subscript>–K<Subscript>2</Subscript>O-CaO-MgO Glasses

The glass composition 55 SiO₂-10 K₂O-(35-x) CaO-(x) MgO (0 ≤ x ≤ 30) is prepared by the melt quenched technique. The as prepared samples are characterized by X-ray diffraction, Fourier Transform-Infrared Spectroscopy (FT-IR) and UV-Visible reflectance spectroscopy. The MgO containing glasses show better polymerization (cross-linking) and have a compact glass network as compared to CaO containing glass. Interestingly, some weak bonds are observed around 1393, 1461 and 1530 cm^-1 in FT-IR spectra related to Ca/Mg-O-H. The optical band gap of the series varies from 3.42 eV to 3.72 eV, indicating wide-band gap materials that could be used in non-linear optical applications.     

New polymer syntheses. IX. Synthesis and properties of new conducting polyazomethine polymers containing main chain cycloalkanone and pyridine moieties

Novel polyazomethines containing cycloalkanones or pyridine moieties were synthesized by the polycondensation of 2,5‐bis(m‐aminobenzylidene)cyclopentanone (BMAP, IV), 2,6‐bis(m‐aminobenzylidene)cyclohexanone (BMAH, V), 2,6‐bis(p‐aminobenzylidene)cyclohexanone (BPAH, VI), and 2,6‐bis(m‐aminostyryl)pyridine (BMAS, VIII) diamines with terephthalaldehyde in EtOH at 25°C. These polymers were yellow to orange in color, had reduced viscosities up to 1.42 dL/g, and had electric conductivities as high as 10⁻¹¹–10⁻¹² S cm⁻¹. All the polyazomethines were insoluble in common organic solvents but dissolved completely in concentrated sulfuric acid. However, they were readily hydrolyzed in concentrated H₂SO₄. X‐ray diffraction diagrams showed that the crystallinities of the polyazomethines were low. These azomethine polymers showed high thermal and thermooxidative stability and exhibited no appreciable decomposition up to 400°C in air. The electronic spectra of the polymers indicated a large bathochromic shift of the π–π* absorption band (∼360 nm) that was due to the presence of CN bonds in the polymer main chain. Doping with iodine dramatically raised the conductivity and produced dark brown to black colored semiconductive polymers with a maximum conductivity on the order of 10⁻⁷ S cm⁻¹. Furthermore, the morphology of selected examples of the four polyazomethines was examined by scanning electron microscopy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1218–1229, 2000     

Copolymers of aniline and o‐methoxyaniline: Synthesis and characterization

High‐conversion (HC) copolymers of aniline and o‐methoxyaniline (o‐anizidine) were synthesized for the first time by chemical oxidative copolymerization using various polymerization techniques (simultaneous or consecutive introduction of comonomers into the polymerizing system). Low‐conversion (LC) copolymers have also been synthesized for comparison. The polymers obtained were characterized using ¹H‐NMR, infrared, and electronic absorption spectroscopy, differential scanning calorimetry, and electrical conductivity measurements. Solubility characteristics and composition of different fractions of the copolymers were also determined. It was shown that in contrast to the LC copolymers, HC copolymers reveal relatively poor solubility. Electrical conductivity of copolymers and also of o‐methoxyaniline homopolymer is lower compared to polyaniline, which correlates with notable hypsochromic (blue) shift of the bands in electronic absorption spectra. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 75–81, 2006     

Infrared Spectroscopic Investigation of Hydrogen Bonding in EVOH Containing PVA Fibers

Fibers of poly(vinyl alcohol) (PVA) containing ethylene‐vinyl alcohol copolymer (EVOH) are made by gel spinning. By using IR spectroscopy, the hydrogen bonds of the PVA/EVOH fibers with different EVOH content and different draw ratio are discussed. The peaks in the neighborhood of 3 400 cm^–1 and the peaks near 3 600 cm^–1 are used to analyze the hydroxyl absorption engaged in hydrogen bonds and the free hydroxyl absorption, respectively. As for PVA/EVOH films, with increasing EVOH content the H‐bond is gradually weakened. As for fibers, however, with increasing EVOH content the strength of the H‐bond increases, while the number of H‐bonds is decreased. Similarly, with increasing draw ratio of the PVA/EVOH fibers, the strength of H‐bond increases, while the number of H‐bonds seems decreased. Higher EVOH content in the PVA/EVOH fibers causes a higher maximum draw ratio because of weakening of the H‐bond. However, higher draw ratio does not always cause better mechanical properties of PVA/EVOH fibers.     

Compositional analysis and infrared spectra of styrene–methyl methacrylate random copolymers

Compositional analysis of styrene–methyl methacrylate random copolymers by UV spectrophotometry at 260 nm, proton-NMR, and IR at 1730 cm^?1 have been accomplished and agreement between these three independent methods was excellent. IR spectra of the copolymers in the region of 1100 and 1300 cm^?1 are mainly characteristic absorption bands for the methyl methacrylate (MMA) component, but not the same for those of MMA homopolymer, that is, the IR spectra of the copolymers were not additive with those of polystyrene and PMMA. Information about the sequence distribution of copolymers of the same composition can be obtained by comparing the wavenumbers and absorption coefficients of the IR spectra in the region of 1100–1300 cm^?1