[Investigation of N-hexadecylated poly (p-phenylene terephthamide) by infrared spectroscopy].

N-hexadecylated poly(p-phenylene terephthamide) (PPTA) comb-like polymers (PPTAC16), which are composed of PPTA backbone and hexadecyl side chains, were prepared by method of N-alkylation reaction. The molecular structure and thermal transition behavior of PPTAC16 were characterized by a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) technique. DSC results indicated that the crystallization of hexadecyl side chains, and the side chain crystallization is less perfect than that of n-hexadecane crystal. IR results showed that the ordered degree of the packing of CH2 group in the side chain crystallization is lower than that of n-hexadecane crystal. Variable temperature IR spectroscopic results revealed that the stretching vibration and bending vibration bands of methylene group experience an abrupt change with increasing of temperature which indicate the melting of the side chain crystallization, furthermore the main chain of PPTAC16 was found to undergo an irreversible change accompanying the melting of the alkyl side chain crystallization. And the molten state of CH2 group in the hexadecyl of PPTAC16 is different from that of liquid n-hexadecane.

[Investigation of N-hexadecylated polycaprolactam by infrared spectroscopy].

N-hexadecylated polycaprolactam (PA6) comb-like polymers (PA6C16) with different alkylation degree, were synthesized using the method of N-alkylation reaction. The thermal transition behavior of these polymers were characterized by a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). DSC results indicated that the hexadecyl side chain can crystallize. Furthermore, the melting point of the hexadecyl side chain crystallization of the sample with high alkylation degree(PA6C16-H) is lower than that of sample with lower alkylation degree(PA6C16-L). FT-IR spectroscopic results showed that the methylene groups of the hexadecyl side chain of PA6C16-L tend to crystallize in orthorhombic form, while the methylene groups of the hexadecyl side chain of PA6C16-H tend to be packed into hexagonal form. Variable temperature IR spectroscopic results revealed that accompanying the melting of the side chain crystallization, the backbones of PA6C16-H undergo a conformation transition, while the conformation of backbones of PA6C16-L shows no obvious transition.

[Investigation on degradation of polypropylene/stabilizers composites irradiated by gamma rays].

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. Carbonyl index calculated from FTIR spectra was used to characterize the rate of degradation. When the irradiation dose was small (<50 kGy), the degradation of pure polypropylene and polypropylene/stabilizers composites was not obvious; while the irradiation dose increased (> or =50 kGy), the carbonyl indexes of all the samples increased obviously, and the degradation degree of polypropylene/stabilizer composites was bigger than pure polypropylene. This result might be partially attributed to the molecular chain scission of hindered phenol and hindered amine under larger irradiation dose. The chain scission of stabilizers forms hydroperoxides and peroxide radicals, catalyzing the degradation of polypropylene. As the irradiation dose was small (<50 kGy), the crystallization temperatures of pure polypropylene and polypropylene/stabilizer composites all showed no remarkable changes; as the irradiation dose exceeded 50 kGy, the crystallization temperatures of pure polypropylene and polypropylene/stabilizer composites all decreased obviously. Correspondingly, the melting peaks of both pure polypropylene and polypropylene/stabilizer composites moved to lower temperature and split into two peaks with increasing the irradiation dose. The decrease of crystallization and melting temperatures might be attributed to the destruction of chemical structure and stereo-regularity of the molecular chain, due to the increasing of carbonyl and hydroxyl groups brought by the oxidation of polypropylene molecular chain. At the same irradiation dose (> or = 50 kGy), the crystallization and melting temperatures of polypropylene/stabilizer composites were lower than that of pure polypropylene. It indicates that the stabilizers accelerate the degradation of polypropylene. The results were accordant with the IR results.

[Study of spectral properties of J-aggregates of mixed cyanine dyes].

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. The sensitive performance of the mixed cyanine dyes was much enhanced compared to the corresponding cyanine dyes.

[Investigation on photooxidative degradation of polypropylene/organomontmorillonite nanocomposites].

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. It can be seen that the evolution of PP and nanocomposites PP/OMMT on irradiation is an increase in absorbance in the hydroxyl and carbonyl absorption regions. Carbonyl index was used to characterize the rate of photooxidative degradation. At the early stage of irradiation (shorter than 11 hours), the rate of photooxidative degradation of PP/OMMT nanocomposites was much faster than that of pure PP. With the increase in the irradiation time, the rate of photooxidative degradation of PP/OMMT nanocomposites became slower than that of pure PP. On the other hand, the OMMT content can also influence the photooxidative degradation rate. The variation in the photooxidative degradation rate is proposed to originate from the competition between the light shielding effect and accelerating photo-oxidative degradation effect of organomontmorillonite. These two effects play roles in the photooxidation process of PP simultaneously. At the early stage of irradiation, the accelerating photooxidative degradation effect dominates. With the increase in the irradiation time, the active sites such as SiOH, --OH etc and transition metal ions (Fe2+, Fe3+ etc) in the OMMT which can accelerate photooxidation are gradually consumed, and then the light shielding effect may play the main role. The method of curve-fitting was used to characterize the influence of organomontmorillonite on the photooxidative degradation products. Compared with pure PP, the content of products of carboxylic acid and anhydride were found to increase, whereas that of ester decreases in PP/OMMT nanocomposites.

[Investigation on effect of PVP on morphological changes and crystallization behavior of nylon 6 in PVP/nylon 6 blends by FTIR spectroscopy].

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. FTIR provided the evidence of the interaction between PVP and nylon 6 molecules. With the increase in PVP content, the peak position of nu N-H of nylon 6 gradually shifts from 3311 to 3300 cm(-1) with 90% content of PVP, and the half height peak width is broadened correspondingly. Three peaks were obtained in the carbonyl group absorption band for PVPK90/Nylon 6(50/50) and PVPK90/Nylon 6(80/20) blends from the curve-fitting results. With the addition of PVP molecules, the nu C=O of nylon 6 shifts to higher wave number and a new peak located at about 1620 cm(-1) appears and its peak area increases with the content of PVP. The above spectral variation of nu C=O and nu N-H in the PVPK90/Nylon 6 blend indicates that the carbonyl group of PVP could form H-bonding with N-H group of nylon 6 molecule, and partially destroy the hydrogen bonding between the nylon 6 molecules. POM results showed that the spherulitic size of nylon 6 decreases with the increment of the PVP and becomes more imperfect, and when the PVP content reaches 80%, no spherulites could be observed. This phenomenon is attributed to the molecular interactions between the PVP and the nylon 6 molecules, which weakens the free mobility of nylon 6 chains to form regular packing and eventually induces the change in the spherulitic morphology of nylon 6. In summary, the molecular interactions between the carbonyl group of PVP molecules and N-H group of nylon 6 molecules account for the above changes in the crystalline structure and the morphology of nylon 6 in the blends.

[Investigation on composites of europium fluorescent complexes and polyvinylpyrrolidone].

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. For the composites with the molar ratio of the complexes to the repeat unit of PVP being 1:35, the intensity of 612 nm emission peak of the composites is 5.5 times for PVP/Eu(TTA)3 x 2H2O and 0.3 times for PVP/Eu(TTA)3 x (TPPO)2 higher than that of the corresponding pure rare earth fluorescent complexes. And the emission intensity ratio of 612 to 590 nm peak is 14.7 in PVP/Eu (TTA)3 x 2H2O composite, larger than that of Eu(TTA)3 x 2H2O complexes. These results suggested that the luminescent properties of the europium fluorescent complexes were obviously enhanced in the presence of PVP matrix and there are interactions between the fluorescence complexes and PVP molecules. In the presence of PVPK30, the FTIR spectra of the Eu(TTA)3 x 2H2O complexes were obviously influenced as well. Based on the curve-fitting results of IR spectra of PVP/Eu(TTA)3 2H2O composites with the molar ratio of repeat unit of PVP to Eu(TTA)3 x 2H2O being 7:1 and 2:1, multiple absorption peaks of nu C=O are observed. The IR spectral variations indicated that there are coordination interactions between Eu3+ ions and the carbonyl groups of PVP, and multiple coordination fashion exists. TEM results showed that there are microphase separation structures in PVP/Eu(TTA)3 x 2H2O and PVP/Eu(TTA)3 x (TPPO)2 composites. The microphase separation phenomenon in composite of PVP/Eu(TTA)3 x (TPPO)2 is more obvious than that of the PVP/Eu(TTA)3 x 2H2O. And the Europium complexes are in amorphous state, which further proved the interactions between PVP molecules and the rare earth fluorescence complexes Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2.

[Fluorescence spectra of J-aggregates of anionic-cationic cyanine dyes].

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.

[Studies on coordination and hydrogen bond intermolecular interaction using 1D & 2D FTIR spectroscopy].

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. The authors prepared four mixed-solutes-solutions whose concentration series satisfy the "Orthogonal Sample Design Scheme" for each chemical system and the consequent 2D synchronous spectrum was calculated from the corresponding four 1D spectra. Thus, by 1D & 2D FTIR spectra together with solid grinding reaction, the intermolecular interactions in two chemical systems (Sodium 2-Aminobenzoate/NdCl3 in aqueous solution, and 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (PC88A)/Naphthenic Acid (NA) in heptane solution) were studied, where the intermolecular interactions only induce subtle spectral variations in conventional 1D spectra. First, the cross peaks between f-f transition bands of Nd3+ ion at 521, 574, 741, 795 and 865 nm and pi-pi transition band of Sodium 2-Aminobenzoate at 308 nm in 2D synchronous spectrum confirm the coordination interaction between Sodium 2-Aminobenzoate and Nd3+. Solid grinding reaction between Sodium 2-Aminobenzoate and NdCl3 and FTIR spectra of the product indicate that the vibration bands of amino, carboxyl groups from sodium 2-aminobenzoate show considerable changes. Based on the spectral result above, a conclusion is drawn that Nd3+ can coordinate with Sodium 2-Aminobenzoate by amino and carboxyl groups. Second, the cross peaks between POH stretching band of PC88A at 983 cm(-1) and COOH stretching band of NA at 1 710 cm(-1) in 2D spectra confirm the interaction between PC88A and NA. Subtraction spectrum demonstrates that when PC88A is mixed with NA in heptane solution, and P=O stretching band of PC88A shifts from 1 199 to 1161 cm(-1), and POH stretching band shifts from 983 to 965 cm(-1). Based on the spectral result above, a conclusion was made that PC88A and NA can interact with each other by forming new assemblies with POH and COOH groups.

[Investigation on the fluorescence spectroscopy of normal and malignant rectum tissues].

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.

[New fluorescent staining method to distinguish normal and malignant rectum tissues using terbium (III)-ciprofloxacin complex].

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. The results showed that the fluorescence microscope images were similar to the images stained using traditional hematoxylin and eosin (H&E) methodology. The fluorescence spectra and FTIR spectra of normal and malignant rectum tissues were collected and the detection criterions for the malignant rectum tissues were the same as the staining results. In summary, the fluorescence staining may be developed as a simple and convenient method.

[FTIR spectroscopic studies of hydration effect on the molecular structure of polyether urethane].

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. These results suggest that the FTIR and subtraction spectroscopy technique could be a useful tool to investigate the hydration mechanism of polymer materials.

[Structural study on the transparency of cross-linked polyester polyurethane].

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. The increase in the amount and size of these heterogeneous particles, distributed in the medium of transparent polyurethane, is the main cause that brings on an opaque appearance of polyurethane.

[Characterization of the orientation of polymer material by non-polarized raman laser light spectroscopy].

The non-polarized Raman laser light was used to investigate the anisotropic polymers including polypropylene fiber, nylon 6 flat fiber, and polyethylene pipe. The Raman spectra of the same samples with different location relative to the incident direction of laser beam show obvious differences. The present result extends the application of Raman spectroscopy to the characterization of oriented polymers samples.

[The study on the growth process of ZnO nanorods].

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 (0.5, 3, 12, 24 h) and the corresponding products were measured by TEM, HR-TEM (high-resolution transmission electron microscopic), SAED (selected-area electron diffraction pattern) and XRD. The result showed that there were ZnO crystallites in the precursor of PVP and Zn(CH3COO)2.2H2O, which was dried at 110 degrees C. When the precursor was calcined at 300 degrees C for 0.5 h, ZnO nanorods could be observed with diameter of 50 nm and the nanorods consisted of two parts. One was compact nanorod with diameter of about 30 nm and the other part was ZnO crystallites attaching around the nanorod. This phenomenon indicated that there might be a transverse growth direction of ZnO nanorods at early time of crystal growth. When the precursor was calcined for 3 h, the products were direct and smooth single crystal ZnO nanorods. Further increasing the calcining time at 300 degrees C could improve the length of the ZnO nanorods in a certain extent while the diameter changed a little. The HR-TEM results showed that the growth direction of ZnO nanorods was along c axis.

[The synthesis and characteristic of Co3O4 nanocrystals].

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. Then, the solution was vaporized in water bath at 60 degrees C till the solution became viscid. The viscid solution was transferred into a ceramic boat and was dried in a oven at 110 degrees C for 12 hours. Finally, the dried sample was calcined in tube-like stove at 400 degrees C for 2 hours in air to produce the Co3O4 nanocrystals. To prepare the precursor composed of PVP and Co (CH3COO)2 x 4H2O, the authors employed two different solvent (ethanol and H2O). It was found that different appearance of Co3O4 nanocrystals was achieved by using different solvent. When ethanol is used as solvent, the prepared spherical particles with diameter of about 1 microm were consisted of Co3O4 nanocrystals with diameter of 20-50 nm. However, only Co3O4 nanocrystals with diameter of 20 nm were synthesized when H2O is used as solvent. This indicated that the solvent played a big role for the final appearance of Co3O4 nanocrystals.

[Novel infrared spectroscopy methods for clinical diagnosis of tumor].

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. The authors have investigated the malignant and normal tissues including parotid, esophagus, stomach, colon, liver, gallbladder, breast, thyroid etc. and compared with the pathological results. The accuracy of this novel IR detection method is more than 90%.

[The studies on YCl3/PEU system by rheology analysis and FTIR].

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.A new band appears at 1650 cm(-1) in the infrared spectra of the YCl3/PEU system, which corresponds to the new carbonyl structure formed through the coordination with yttrium cations. The dynamic rheological behaviors of the solutions demonstrate the interaction furthermore. A higher molecular weight formed with the higher concentration of the lanthanide ions in this DMF solution. And this could be an effective method to characterize the structure of the polymer solutions.

[Investigation of PP/PE blend with FTIR mapping].

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. Based on the above results, FTIR mapping technique was applied to characterize the samples prepared by embedding PP fiber into molten PE film, and the distribution of PP and PE in the blends can be obtained from the ratio of the characteristic peak areas of PP to PE. Good agreements have been observed between the IR mapping image and the image obtained using polarized optical microscope. These results indicated that FTIR mapping technique is an effective tool to investigate the phase separation behavior of polymer blends based on the ratio of the characteristic peak areas of different polymers.

[A comparative study of malignant tissue diagnosis using ATR and microscopy FTIR spectroscopy].

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. The area for microscopy measurement is approximately 250 microm2, it reflects the heterogeneity of the tissue. However, the ATR measurement provides more information of malignant tissue for the measured area is 1.9 x 10(5) times than microscopy. Therefore, ATR exhibit the high accuracy in cancer detection for clinical application.