Multimode IR Analysis of Nylon 11

1992 ◽

Vol 50 (2) ◽

pp. 1528-1529

Author(s):

Edward G. Bartick ◽

John A. Reffner

Keyword(s):

Specular Reflection ◽

Forensic Analysis ◽

Attenuated Total Reflection ◽

Internal Reflection ◽

Standard Size ◽

Ir Microscopy ◽

Ir Analysis ◽

Plastic Explosives ◽

Internal Reflection Spectroscopy ◽

Reflectance Measurements

Since the introduction of commercial Fourier transform infrared (FTIR) microscopic systems in 1983, IR microscopy has developed as an important analytical tool in research, industry and forensic analysis. Because of the frequent encounter of small quantities of physical evidence found at crime scenes, spectroscopic IR microscopes have proven particularly valuable for forensic applications. Transmittance and reflectance measurements have proven very useful. Reflection-absorption, specular reflection, and diffuse reflection have all been applied. However, it has been only very recently that an internal reflection (IRS) objective has been commercially introduced.The IRS method, also known as attenuated total reflection (ATR), has proven very useful for IR analysis of standard size samples. The method has been applied to adhesive tapes, plastic explosives, and general applications in the analysis of opaque materials found as evidence. The small quantities or uncontaminated areas of specimens frequently found requiring forensic analysis will often be directly applicable to microscopic IRS analysis.

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Polarized microbeam FT-IR analysis of single fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163496 ◽

1996 ◽

Vol 54 ◽

pp. 206-207

Author(s):

Liling Cho ◽

David L. Wetzel

Keyword(s):

Molecular Orientation ◽

Transition Point ◽

Polymer Fibers ◽

Single Fiber ◽

Wire Grid ◽

Polyester Fibers ◽

Ft Ir ◽

Ir Analysis ◽

The Relationship ◽

Wire Grid Polarizer

Polarized infrared microscopy has been used for forensic purposes to differentiate among polymer fibers. Dichroism can be used to compare and discriminate between different polyester fibers, including those composed of polyethylene terephthalate that are frequently encountered during criminal casework. In the fiber manufacturering process, fibers are drawn to develop molecular orientation and crystallinity. Macromolecular chains are oriented with respect to the long axis of the fiber. It is desirable to determine the relationship between the molecular orientation and stretching properties. This is particularly useful on a single fiber basis. Polarized spectroscopic differences observed from a single fiber are proposed to reveal the extent of molecular orientation within that single fiber. In the work presented, we compared the dichroic ratio between unstretched and stretched polyester fibers, and the transition point between the two forms of the same fiber. These techniques were applied to different polyester fibers. A fiber stretching device was fabricated for use on the instrument (IRμs, Spectra-Tech) stage. Tension was applied with a micrometer screw until a “neck” was produced in the stretched fiber. Spectra were obtained from an area of 24×48 μm. A wire-grid polarizer was used between the source and the sample.

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Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

Revista de Chimie ◽

10.37358/rc.20.8.8275 ◽

2020 ◽

Vol 71 (8) ◽

pp. 21-26

Author(s):

Elena-Emilia Oprescu ◽

Cristina-Emanuela Enascuta ◽

Elena Radu ◽

Vasile Lavric

Keyword(s):

Maximum Yield ◽

Strength Distribution ◽

Point Of View ◽

Reaction Parameters ◽

X Ray ◽

Ethyl Levulinate ◽

Ft Ir ◽

Ir Analysis ◽

Biodiesel Blend ◽

Acid Strength Distribution

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

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Formulation, Optimization,and Ex-Vivo Evaluation of Novel Lipid Carriers for Enhanced Transdermal Delivery of Hydroquinone

Micro and Nanosystems ◽

10.2174/1876402912999200831105145 ◽

2020 ◽

Vol 12 ◽

Author(s):

Shivani Verma ◽

Sukhjinder Kaur ◽

Lalit Kumar

Keyword(s):

Ex Vivo ◽

Skin Permeation ◽

Topical Delivery ◽

Gelling Agent ◽

Minimum Size ◽

Prolonged Release ◽

Freeze Dried ◽

Ft Ir ◽

Ir Analysis ◽

Skin Retention

Background: HQ is used for hyper-pigmentation treatment using conventional creams and gels. These formulations show various disadvantages like poor skin permeation, allergic reactions, and repeated use decreasing patient compliance. Objectives: The present work involved formulation, statistical optimization, and characterization of nanostructured lipid carriers (NLCs) for efficient topical delivery of hydroquinone (HQ) for hyperpigmentation treatment. Methods: The NLCs were optimized exploring Box–Behnken design (BBD) using three independent variables and two dependent variables. Formulation having the minimum size and maximum drug entrapment was considered as optimized formulation. Optimized formulation was evaluated for drug release followed by its freeze-drying. The freeze-dried formulation was subjected to differential scanning calorimetry (DSC) analysis, X-raydiffraction (XRD) analysis, and Fourier transform-infrared spectroscopy (FT-IR) analysis. Furthermore, NLCs based gel was prepared by using Carbopol 934 as a gelling agent. NLCs based gel was evaluated for skin permeation, skin retention, and skin distribution (through confocal microscopic analysis) using pig ear skin. Results: Optimized NLCs showed smaller particle size [(271.9 ± 9) nm], high drug entrapment [(66.4 ± 1.2) %], tolerable polydispersity index (PDI) (0.221 ± 0.012), and zeta potential [(-25.9± 1.2) mV]. The FT-IR analysis revealed excellent compatibility between HQ and other excipients. The Carbopol 934 gel containing NLCs showed high transdermal flux [(163 ± 16.2) μg/cm2/h], permeability coefficient (0.0326 ± 0.0016), and skin permeation enhancement ratio (3.7 ± 0.4) compared to marketed cream of HQ. The results of confocal microscopic (CLSM) analysis revealed the accumulation of optimized NLCs in the lower epidermal layers of skin. Conclusion: NLCs based gel was considered effective in the topical delivery of HQ to treat hyper-pigmentation due high skin permeation, skin retention, and prolonged release of HQ.

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Electrogeneration of Conducting Poly(α-tetrathiophene). Effect of Solution Stirring and Detection of Linear Oligomers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20031326 ◽

2003 ◽

Vol 68 (7) ◽

pp. 1326-1344 ◽

Cited By ~ 9

Author(s):

Francesc Estrany ◽

Ramon Oliver ◽

Esther García ◽

Esther Gualba ◽

Pere-Lluís Cabot ◽

...

Keyword(s):

Ion Pairs ◽

Polymer Chains ◽

Polymerization Process ◽

Anodic Process ◽

Cathodic Peak ◽

Linear Chains ◽

Monomer Solution ◽

Ir Analysis ◽

Microscopy Images ◽

Tof Ms

The anodic oxidation of α-tetrathiophene on Pt was studied in a 1.0 mM monomer solution in 0.1 M LiClO4 in 45:35:20 acetonitrile/ethanol/DMF. Three consecutive oxidation peaks were detected by cyclic voltammetry, along with a cathodic peak related to the reduction of electroactive polarons formed during the first anodic process. Uniform, adherent, insoluble and black polymer films were obtained by chronoamperometry at 1.000 V vs Ag|AgCl corresponding to the first oxidation-polymerization process. Stirring of monomer solution promotes the production of polymer, favoring the oxidation of polymer chains with the incorporation of more doping ClO4- ions and ion pairs of Li+ClO4- in their monomeric units. The conductivity of the polymer obtained under stirring was three orders of magnitude higher than that synthesized from a quiescent solution. The scanning electron microscopy images also showed much more uniform films under stirring. This behavior points to the existence of less crosslinking in the polymer and the production of longer linear chains when the solution is stirred. IR analysis of these materials confirmed the formation of crosslinked chains with predominance of β-β linkages. Short linear oligomers such as the dimer, trimer and tetramer were detected in all polymers by MALDI-TOF-MS, thus showing a radical polycondensation as initial electropolymerization mechanism. A larger proportion of linear oligomers is formed under solution stirring.

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Phytotoxic effects of invasive Ageratina adenophora on two native subtropical shrubs in Nepal

Scientific Reports ◽

10.1038/s41598-021-92791-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tej Bahadur Darji ◽

Barsha Adhikari ◽

Seeta Pathak ◽

Shristi Neupane ◽

Lal B. Thapa ◽

...

Keyword(s):

Low Ph ◽

Potential Mechanism ◽

Phytotoxic Effects ◽

Seedling Length ◽

Ageratina Adenophora ◽

Ir Analysis ◽

Allelopathic Interference ◽

Phosphorus And Potassium ◽

Native Shrubs ◽

Nitrogen Phosphorus

AbstractThe response of native plants to allelopathic interference of invasive species may differ from species to species. In this study, the phytotoxic effects of Ageratina adenophora were tested on two native shrubs (Osbeckia stellata and Elsholtzia blanda) of Nepal. Both the shrubs were grown in pots under treatments of A. adenophora fresh leaves and root leachates, and litter. Then, the seedling length and biomass were compared among the treatments. The results show that A. adenophora litter has stimulatory effects but the leachates from fresh leaves and root are phytotoxic to the growth and development of native shrubs. Infrared Spectroscopy (IR) analysis confirmed the presence of O–H (Hydroxyl), N–H (Amines), C≡C (Alkynes), and C–H stretching (Aromatic) or C–O–C stretching (Ethers) in the leachates representing harmful allelochemicals. The invaded soil by A. adenophora had low pH and a high amount of organic matter, total nitrogen, phosphorus, and potassium than the uninvaded soil. The results indicate that the native O. stellata and E. blanda are harmed by A. adenophora in nature by leaching of allelochemicals and probably by reducing the soil pH. Overall, this study has provided valuable insights regarding the effects of A. adenophora invasion on native shrubs and revealing the potential mechanism of its invasiveness.

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Properties and biodegradability of chitosan/nylon 11 blending films

Polymer Degradation and Stability ◽

10.1016/j.polymdegradstab.2006.07.025 ◽

2006 ◽

Vol 91 (12) ◽

pp. 3097-3102 ◽

Cited By ~ 21

Author(s):

Ping-Chung Kuo ◽

Diptiranjan Sahu ◽

Hsin Her Yu

Keyword(s):

Nylon 11

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Impact of Chemical Modification on the Physical and Mechanical Properties of Tropical Wood Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.576.314 ◽

2012 ◽

Vol 576 ◽

pp. 314-317

Author(s):

Sinin Hamdan ◽

M. Saiful Islam

Keyword(s):

Mechanical Properties ◽

Diazonium Salt ◽

Treated Wood ◽

Coupling Reaction ◽

Physical And Mechanical Properties ◽

Modulus Of Rupture ◽

Ft Ir ◽

Ir Analysis ◽

D Values ◽

Benzene Diazonium

Five types of selected tropical light hardwoods were chemically modified with benzene diazonium salt to improve their physical and mechanical properties. Benzene diazonium salt underwent a coupling reaction with wood which was confirmed through FT-IR analysis. The compressive modulus of the treated wood increased, whereas modulus of rupture was shown to decrease on treatment. The modified wood samples had higher hardness (Shore D) values compared to that of the control ones.

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