Publications by authors named "Duan-Fu Xu"

Article Synopsis
  • Researchers synthesized comb-like polymers called N-hexadecylated polycaprolactam (PA6C16) through N-alkylation, varying the degree of alkylation.
  • Thermal analysis using differential scanning calorimetry (DSC) showed that while hexadecyl side chains can crystallize, higher degrees of alkylation resulted in lower melting points.
  • Fourier transform infrared spectroscopy (FTIR) indicated different crystallization forms for the side chains based on alkylation degree, with PA6C16-H showing a conformational transition in its backbone during melting, unlike PA6C16-L.
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Article Synopsis
  • - The study focuses on N-hexadecylated poly(p-phenylene terephthamide) (PPTAC16), which is a comb-like polymer made from a PPTA backbone with hexadecyl side chains, synthesized through N-alkylation reactions.
  • - Characterization techniques such as differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the molecular structure and thermal behavior of PPTAC16, revealing that the crystallization of the hexadecyl side chains is less organized compared to n-hexadecane.
  • - The temperature-dependent IR spectroscopic results indicated significant changes in the characteristics of the methylene groups' vibrations, suggesting that the side chains melt
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The degradation behavior of polypropylene and polypropylene/stabilizer composites, caused by gamma radiation, was studied in the present work The stabilizers used were hindered phenol antioxidant and hindered amine light stabilizer. FTIR spectroscopy and DSC analysis were used to determine the structural variation induced by gamma radiation. It can be seen that the evolution of PP and composites PP/stabilizers on gamma irradiation is an increase in absorbance in the hydroxyl and carbonyl absorption regions.

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The J-aggregates and the photosensitive properties of two kinds of mixed cyanine dye and the corresponding independent cyanine dyes absorbed on AgBr cubic microcrystal were investigated. The reflection spectra of the J-aggregates of the mixed cyanine dyes and the corresponding independent cyanine dyes were measured by the use of UV-Vis spectroscopy. The results showed that the absorption band of the mixed J-aggregates absorbed on AgBr cubic microcrystal had two-peak wavelengths and accorded with the independent cyanine dyes, respectively.

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Photooxidation degradation of polypropylene (PP)/organomontmorillonite (OMMT) nanocomposites was studied under UV irradiation at wavelength 365 nm. The OMMT was dispersed homogeneously in the PP matrix. The structural variation induced by photooxidation was detected by FTIR spectroscopy.

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In order to investigate the relationship between the aggregation structure and fluorescence properties of composites of rare earth fluorescent complexes and polymers, the fluorescent complexes of Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2 were synthesized by the reaction of TTA (2-thenoyltrifluoroacetone), TPPO (triphenylphosphine oxide) and EuCl3, and their composites with polyvinylpyrrolidone (PVP K30) were prepared. The fluorescence spectroscopy, FTIR spectroscopy and TEM were used to characterize these composites. Fluorescence spectroscopy results indicated that the fluorescence intensity of the PVP/Eu(TTA)3 x 2H2O composites is obviously improved compared with that of the Eu(TTA)3 x 2H2O complexes.

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Temperature-dependent FT IR, DSC and POM were used to investigate the interaction between PVPK90 and nylon 6 molecules and its effect on the thermal behavior and morphology of nylon 6. DSC results suggest that the melting and crystallization behavior of nylon 6 are obviously influenced by the introduction of PVP. With the PVP content increasing, the crystallization temperature, melting temperature and the crystallinity of nylon 6 decreased, and eventually, both the exothermal and endothermic peaks could not be observed when the PVP content reached 80%, implying that the aggregation structure of nylon 6 changes from the crystalline state to the amorphous state.

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In the present paper, the fluorescence spectral curves of J-aggregates of two kinds of anionic-cationic cyanine dyes adsorbed on AgIBr cubic microcrystals were measured by using fluorescence spectroscopy, and compared with the sensitivity characteristic of anionic-cationic cyanine dyes. The results show that the peaks of fluorescence spectral curves of anionic-cationic cyanine dyes were lower than that of anionic and cationic cyanine dyes, and the higher sensitivity efficiency was due to the fact that more electrons transfer to the surface of AgIBr microcrystal.

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Two-dimensional (2D) correlation spectroscopy is a powerful method to study the intermolecular interactions between different molecules/functional groups. In the present paper, variable concentrations were selected to construct 2D synchronous spectrum for studying the weak intermolecular interactions in solutions. Mathematical analysis performed on 2D synchronous spectra using variable concentration as an external perturbation shows that the "Orthogonal Sample Design Scheme" is necessary for eliminating the interfering cross peaks in 2D synchronous spectra.

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A new fluorescent staining method to distinguish normal and malignant rectum tissues using terbium(III)-Ciprofloxacin complex was investigated. The terbium (III) complex exhibits strong fluorescence and the staining process with the complex is very fast. It needs 3-5 minutes.

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In the present article the fluorescence characteristics of normal and malignant rectum organ tissues of 12 samples were investigated in vitro using UV (200-400 nm) fluorescence spectroscopy and compared with the results of the infrared spectra of normal and malignant rectum organ tissues. The results showed that the fluorescence intensity of normal rectal tissue was higher than that of rectal malignant tissue. The difference in fluorescence intensity at 492 and 544 nm between normal rectal tissue and malignant tissue may be considered as a detection criterion.

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The polyurethane material with cross-linked structure was synthesized using half pre-polymerization method. IR, UV-Vis, TEM and XRD methods, and physical properties measurements indicate that different moulding temperatures influence the apparent transparence of polyurethane and abrasive performance, and the nature of these changes is related to the conditions of processand chemical reaction which lead to gradual micro-phase separation of the polyurethane molecules with different compositions, resulting in the domain-forming with the size of sub-micro-, micro- and even more than ten micro-meters. Such domains aggregate one another to form particles with different shapes and complicated structures.

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The interaction between water molecules and the polar groups in linear polyether urethane was studied by FTIR and subtraction spectroscopy technique. Direct proofs of the combining of water molecule and carbonyl group were obtained. The reorganizations of the ether linkage, carbamate, and carbon-hydrogen chain after hydration were also observed.

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FTIR spectroscopy and rheology analysis were applied to study the YCl3/PEU system. It is apparent that modification with lanthanide complexes such as yttrium leads to a slight increase in viscosity of the polyether urethane solution. The authors conclude that this may be due to the interaction between the lanthanide ions and the polar group in urethane.

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In this paper, the authors have reviewed their investigation on the clinical detection of tumor tissues by infrared spectroscopy in recent ten years. Based on the comparison of different IR spectroscopic methods such as IR transmission spectroscopy, micro-IR spectroscopy etc, the authors found the good consistency of the results of ATR (attenuated total reglection) IR spectroscopic method with those of pathological biopsy. The authors have directly measured the IR spectra of frozen tissues stored in liquid nitrogen and freshly resected tissues, and have realized the measurement of tumor tissues in vito during the operation process using a specially designed IR spectrometer connected with a mid-IR fiberoptic with an ATR probe.

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Article Synopsis
  • The study utilized non-polarized Raman laser light to analyze various anisotropic polymers like polypropylene, nylon 6, and polyethylene.
  • Results showed distinct differences in Raman spectra based on the sample's orientation relative to the laser beam direction.
  • This research enhances the use of Raman spectroscopy for studying and characterizing oriented polymer materials.
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Albstract The authors synthesized ZnO nanorods by calcining the precursor composed of PVP and Zn(CH3COO)2.2H2O at 300 degrees C. In order to investigate the growth process of ZnO nanorods, the precursor was calcined for different time (0.

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The authors found a new method to synthesize Co3O4 nanocrystals, which were synthesized using Co(CH3COO)2 x4H2O and PVP as precursor. The as-prepared products were measured by SEM, TEM and XRD. Co(CH3COO)2 x 4H2O and PVP were dissolved together in a kind of solvent.

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A series of polyether polyurethane (PU)-LaCl3 composites with different lanthanum contents were prepared. DSC results indicate that LaCl3 promotes phase transition behavior of the LaCl3/PU composites, which causes the endothermic peak at 11.58 degrees C to disappear.

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A total of 184 specimens from gastroscopy were studied using Fourier transform infrared (FTIR) spectroscopy. The spectra of small-sized gastric endoscope samples with high quality were measured using the modified FTIR spectrometer with a MCT detector. The results show that the spectra of chronic superficial gastritis are similar to those of the normal block tissue in our previous study.

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A comparative FTIR study was undertaken between ATR (attenuated total reflection) and infrared microscopy on their application to measuring the same tissue for cancer diagnosis. The measurements showed that the coincidence of pathological diagnosis with ATR is higher than that of microscopy FTIR method. The result indicated that the measured area of tumor tissue is critical.

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The polypropylene/polyethylene (PP/PE) blends with different weight ratio were studied by FTIR spectroscopy. The characteristic absorption bands of PP and PE in different blends were compared. It was found that the ratio of the characteristic absorption peak areas of PP to those of PE is correlated with the weight ratio of PP to PE in the blends.

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X-ray diffraction and FTIR spectroscopic method have been used to investigate the interaction between the amide group of nylon 6 and zinc chloride. The nylon sample obtained by adding formic acid solution of nylon into aqueous solution saturated by zinc chloride is significantly different from the nylon precipitated after mixing formic acid solution of nylon and water. X-ray diffraction results demonstrate that nylon precipitated from water has crystallization while the sample acquired from saturated solution of ZnCl2 remains amorphous.

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