巯基化合物的合成及巯基-乙烯基光固化工艺

合成出三种不同官能度的巯基化合物,在对其表征的基础上,利用傅立叶变换红外光谱原位跟踪和紫外光差示扫描量热实时跟踪方法,研究了巯基化合物官能度、巯基与乙烯基配比和辐照强度对巯基-VL20体系光固化反应的影响规律。结果表明:高官能度的巯基化合物,反应速率较快;光聚合反应速率约与光强的0.5次方成正比。

丙烯酸酯/液晶复合体系的光聚合动力学

采用光差示扫描量热分析方法研究了以2,4,6-三甲基苯甲酰基-二苯基氧化膦(TPO)为光引发剂,丙烯酸异辛酯(EHA)和三羟甲基丙烷三甲基丙烯酸酯(TMPTA)为单体,丙烯酸酯/液晶(P0616A)复合体系在-40～80℃的光聚合动力学.研究结果表明,丙烯酸酯/液晶复合体系光聚合速度明显高于传统的自由基聚合反应体系,转化率在约50 s的时间内即达到增长平台,聚合反应速率和表观动力学常数在聚合过程中均存在最大值.随着反应温度的升高,体系的最终转化率和最大聚合反应速率(Rp,max)均明显提高;当反应温度高于20℃后,其增长均趋于平缓.随着体系中液晶含量的增加,体系的Rp,max呈下降趋势,聚合反应转化率随时间的增长速率较慢,但是最终转化率差别不大,均接近80%.随着UV光强的增加,体系的Rp,max和最终转化率均明显提高,体系的阈值光强约为4 mW/cm2.而随着体系平均官能度的增加,体系的Rp,max和最终转化率则呈下降的趋势.

巯基/乙烯基硅氮烷紫外光固化的研究

利用原位红外跟踪技术和光-示差扫描量热技术研究了不同类型多官能巯基化合物与乙烯基硅氮烷的紫外光聚合动力学过程.结果表明,巯基化合物官能度越高,聚合反应速率越高,但最终转化率越低.巯基丙酸酯类化合物比烷基硫醇类化合物更易与乙烯基硅氮烷反应.在较低温度下,反应温度对聚合反应的影响较弱,反应活化能约为2.3kJ/mol,而较高反应温度下反应速率偏离Arrhenius方程.

新型二苯乙烯类光引发剂的光引发性能分析

报道了3个新型近紫外光引发剂:4-甲氧基-4-苯甲酰基二苯乙烯,3,4-二甲氧基-4-苯甲酰基二苯乙烯,3,4,5-三甲氧基-4-苯甲酰基二苯乙烯。利用光照实验和光示差热扫描量热仪(Photo-DSC)对这些分子的光引发性能进行了系统研究,分析不同数目的甲氧基、光照时间以及光引发剂浓度对光引发性能的影响。结果表明:由Photo-DSC测得3种化合物的单体聚合速率分别为0.065 32,0.102 01,0.163 23s-1,表明随着随着甲氧基数目的增多,能有效地提高光引发剂的引发性能;随着光照时间的增长与引发剂浓度的增大,光聚合比率逐渐降低并趋于稳定。

Effect of a Novel Nucleating Agent on Isothermal Crystallization of Poly（L-lactic acid）

The effect of a novel active nucleating agent(TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy(FTIR) . The analysis on kinetics demonstrates that TBC8-eb can not only accelerate the crystallization rate but also transform most of the original spherulite crystals of PLLA into sheaf-like crystals. Furthermore,the free energy of folding(σe) of PLLA and PLLA with TBC8-eb is 0.15 and 0.06 J·m-2,respectively,which suggests that the addition of TBC8-eb favors the regular folding of molecule chains in the crystallization of PLLA,improv-ing its crystallization rate. The FTIR results show that TBC8-eb can accelerate the conformational ordering of PLLA in the isothermal crystallization. The conformational ordering of PLLA nucleated with TBC8-eb begins with the interchain interaction of CH3,and then a short helix emerges where a couple of CH3 groups interact.

Preparation and Characterization of Magnetic Resin Made from Chitosan and Cerium

In this study, the water-based ferromagnetic fluid and magnetic resin made from chitosan and cerium complex （MRCCC） were successfully prepared by using the chemical co-precipitation technique and by the reversed-phase suspension cross-linking polymerization. MRCCC presented uniform and narrow panicle size distribution as determined by the Laser Panicles Sizer. The Inductively Coupled Plasma-Atomic Emission Spectrometry （ICP-AES）, Fourier transform infrared spectroscopy （FT-IR）, differential scanning calorimetry （DSC） and X-ray powder diffraction （XRD） study demonstrated that there were iron and cerium existing in MRCCC. The movement of MRCCC under magnetic field proved its magnetic property. The swelling kinetics in water or solutions with different pH indicated that MRCCC could be applied in solutions with pH greater than 1.0. The ferromagnetic fluid particles were stable in MRCCC soaked in solutions with pH 〉2.0. In view of these results, MRCCC can be used as material for separation, clarification, adsorption, sustained release and hydrolysis activity.

Microstructure and dielectric properties of Ca-Al-B-Si-O glass/Al_2O_3 composites with various alkali oxides contents

The effects of alkali oxides （Na2O and K2O addition on both the sintering behavior and dielectric properties of Ca-AI-B-Si-O glass/Al2O3 composites were investigated by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimeter （DSC）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of alkali oxides in the glass causes the decrease of [SiO4], which results in the decrease of the continuity of glass network, and leads to the decrease of the softening temperature Tf of the samples and the increasing trend of crystallization. And that deduces corresponding rise of densification, dielectric constant, dielectric loss of the low temperature co-fired ceramic （LTCC） materials and the decrease of its thermal conductivity. By contrast, the borosilicate glass/A1203 composites with 1.5% （mass fraction） alkali oxides sintered at 875 ℃ for 30 rain exhibit better properties of a bulk density of 2.79 g/cm3, a porosity of 0.48%, a 2 value of 2.28 W/（m.K）, a er value of 7.82 and a tand value of 9.1 × 10-4 （measured at 10 MHz）.

Low-temperature phase transitions of sodium aluminate solutions

A series of low-temperature phase transitions of sodium aluminate solutions were studied by differential scanning calorimetry (DSC) and Raman spectroscopy. The results indicate that NaOH concentration is a primary impact factor for the binary eutectic point and ice melting temperature of sodium aluminate solutions with low NaOH concentration. In addition, the phase transition process of sodium aluminate solutions with low NaOH concentration from 123.15 to 283.15 K is divided into four steps: non-crystal to crystal, ternary eutectic reaction, binary eutectic reaction and ice melt. The projection phase diagram of NaOH-Al(OH)3-H2O system at low temperature was plotted, in which the ternary eutectic temperature for sodium aluminate solutions is 183.15 K.

Characterization of calcium deposition induced by Synechocystis sp. PCC6803 in BG11 culture medium

Calcium carbonate （CaCO3） crystals in their preferred orientation were obtained in BG11 culture media inoculated with Synechocystis sp. PCC6803 （inoculated BG11）. In this study, the features of calcium carbonate deposition were investigated. Inoculated BGll in different calcium ion concentrations was used for the experimental group, while the BGll culture medium was used for the control group. The surface morphologies of the calcium carbonate deposits in the experimental and control groups were determined by scanning and transmission electron microscopy. The deposits were analyzed by electronic probe micro-analysis, Fourier transform infrared spectrum, X-ray diffraction, thermal gravimetric analysis and differential scanning calorimetry. The results show that the surfaces of the crystals in the experimental group were hexahedral in a scaly pattern. The particle sizes were micrometer-sized and larger than those in the control group. The deposits of the control group contained calcium （Ca）, carbon （C）, oxygen （O）, phosphorus （P）, iron （Fe）, copper （Cu）, zinc （Zn）, and other elements. The deposits in the experimental group contained Ca, C, and O only. The deposits of both groups contained calcite. The thermal decomposition temperature of the deposits in the control group was lower than those in the experimental group. It showed that the CaCO3 deposits of the experimental group had higher thermal stability than those of the control group. This may be due to the secondary metabolites produced by the algae cells, which affect the carbonate crystal structure and result in a close-packed structure. The algae cells that remained after thermal weight loss were heavier in higher calcium concentrations in BGll culture media. There may be more calcium- containing crystals inside and outside of these cells. These results shall be beneficial for understanding the formation mechanism of carbonate minerals.

Preparation of Composite Phase Change Material Based on Sol-Gel Method and Its Temperature-Adjustable Textile

In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.

Thermal behavior and mass spectrometry analysis of N-methyl-N-nitroso-p-toluenesulfonamide

The effect of temperature on the functional groups transition of N-methyl-N-nitroso-p-toluenesulfonamide （Diazald） and thermal decomposition were investigated by Fourier Transform Infrared Spectroscopy （FT-IR） and Differential Scanning Calorimeter （DSC）. The results showed that the functional groups transition of Diazald was temperature dependent, and thermal decomposition of Diazald was accelerated above 47.7℃. The HPLC-ESI-MS method was used for Diazald analysis, which indicated the strong hydrogen bonding between Diazald and water and instability of the NO group.

Investigation on specific heat capacity and thermal behavior of sodium hydroxyethyl sulfonate

The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the second and third stages may be about the groups of CH_3CH_2OH, CH_3CHO and SO_2 volatilized, respectively. The decomposition residuum of three stages was analyzed by FT-IR, and the results of FT-IR agreed with the decomposition process predicted by theoretical weight loss. The specific heat capacity of sodium hydroxyethyl sulfonate was determined by differential scanning calorimetry(DSC). The melting temperature and melting enthalpy were obtained to be 465.41 K and 25.69 kJ·mol^(-1), respectively. The molar specific heat capacity of sodium hydroxyethyl sulfonate was determinated from 310.15 K to 365.15 K and expressed as a function of temperature.

Physicochemical Characterization and Solubility Enhancement Studies of Mebendazole Solid Dispersions in Solvent Mixtures

Abstract： The objective was to obtain solid dispersion to improve the dissolution rate, solubility and oral absorption of MB （mebendazole）, poor water-soluble drugs. The new formulation was characterized by DSC （differential scanning calorimetry）, PXRD （powder X-ray diffraction）, FT-1R （fourier transform infrared spectroscopy） and STEM （scanning transmission electron microscopy） methods. Solid dispersions of MB with polyvinylpyrrolidone K-30 （PVP K30） were prepared by solvent evaporation method. The solubility of MB （original powder） and that of the solid dispersions was measured at 25℃ in ethanol-water. The aqueous solubility of MB was favoured by the presence of the polymer in solvent mixtures. Combination of solid dispersions with co-solvents increased the water solubility of MB in a larger extent that each method separately. Solubility parameter （o） was used to relate to solubility profiles. MB and the solid dispersions show a solubility curve with a single peak at 51 = 30.78 MPav2. Solid state characterizations indicated that the solid dispersion exist an amorphous material entrapped in polymer matrix getting highest improvement in wettability and solubility.

Effects of High Hydrostatic Pressure Treatment on Physicochemical Characteristics of Sea Cucumber

The effects of high hydrostatic pressure （HHP） treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen （TVB-N）, mucopolysaccha ride and protein, were investigated experimentally. The shelf-life of sea cucumber was greatly prolonged by HHP treatment. High pressure treatment of sea cucumber significantly reduced the activity of autoenzyme at 550 MPa. The TVB-N content was 8.4 mg/100 g in the HHP-treated samples after 38 days＇ storage at 4 ~C, while it had already reached 11.2 mg/100 g in the untreated ones after 5 days＇ storage under the same condition. The relative mucopolysaccharide content of the HHP-treated samples was 94.3%, while that of the heat-treated ones was only 35.5%. The sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）, Differential scanning calorimetric （DSC）, ANS fluorescence probe method and fourier-transform infrared （FTIR） spectroscopy results indicated some changes in protein subunits, denaturation, surface hydrophobicity and secondary structure of sea cucumber protein. This study has provided complementary information of pressure-induced structural changes on both the molecular and the sub-molecular level of sea cucumber protein.

Synthesis and Antibacterial Performance of Quaternary Phosphonium Salts with Reactive Hydroxyl Group

Quaternary phosphonium salts （QPS） with reactive groups used as antibacterial agents are promising which could be covalently linked to inert polymer surfaces by in situ polymerization. In this work, two kinds of quaternary phosphonium salts with hydroxyl groups were synthesized successfully. Characterization of these two quaternary phosphonium salts was performed by the Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance （NMR） spectrometry. The thermal stability and antibacterial activity of antibacterial agents were also investigated by using thermo-gravimetric analysis, differential scanning calorimetry （TG-DSC） and agar diffusion method. The test results showed that these two QPS exhibited good thermal stability and excellent antibacterial activity against both bacteria： Staphylococcus aureus and Escherichia coll.

Synthesis and Characterization of Novel Copolymers Based on 3(S)-Methyl-Morpholine-2,5-Dione

A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- nous octoate as catalyst. The copolymers were characterized by means of ~H-NMR and FT-IR spectroscopy. Gel permeation chromatography （GPC） test shows that the average-number relative molecular mass and average-weight rela- tive molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry （DSC） demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.

Chelating agents role on phase formation and surface morphology of single orthorhombic YMn_2O_5 nanorods via modified polyacrylamide gel route

YMn2O5nanorods were synthesized through a modified polyacrylamide gel route.The synthesis strategy in this work is based on a sol-gel process using a polyacrylamide gel method in which oxalic acid,citric acid or tartaric acid is employed as the chelating agent.In the gel routes,oxalic acid was used as a carboxyl chelating agent,while citric acid or tartaric acid was a carboxyl and hydroxyl chelating agent.The as-prepared samples were characterized by means of techniques such as X-ray powder diffraction(XRD)measurement,thermogravimetric analysis(TG),differential scanning calorimetry analysis(DSC),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),thermal expansion measurement and field-emission scanning electron microscopy(SEM)investigations.It was found that oxalic acid is the best chelating agent with Y(NO3)3·6H2O and Mn(CH3COO)2·4H2O as precursors to prepare a single orthorhombic YMn2O5nanorods at 1000°C.Scanning electron microscope observation shows that the morphology of YMn2O5powders is significantly dependent on the chelating agent.The peaks(single orthorhombic YMn2O5nanorods)at 642,600,573,546,521,493,486,468,448 and 400cm?1were observed from FTIR spectra.The phase,surface morphology and chelation mechanisms of YMn2O5samples have been discussed on the basis of the experimental results.

Cementing mechanism of bio-phosphate cement

Cementing mechanism of bio-phosphate cement was investigated by Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), thermogravimetric-differential scanning calorimetry(TG-DSC) analysis and scanning electron microscopy(SEM). The results of FTIR and XPS show that Si-O bond and Si(2p) electron binding energy in sandstone cemented via chemical and microbiological methods are changed by the binding effects of barium hydrogen phosphate with quartz sand. Compared with barium hydrogen phosphate precipitated in solution, there were higher decomposition temperatures or melting points in sandstone. The FTIR, XPS, and TG-DSC results indicate that the microbial-induced and chemical precipitation of barium hydrogen phosphate can interact with quartz sand to generate van der Waals bond, which plays a role in the binding function between loose sand particles and barium hydrogen phosphate. SEM results show that barium hydrogen phosphate after chemical precipitation in sandstone has better dispersion than microbiological deposition. Therefore, barium hydrogen phosphate via chemical precipitation did not bind loose sand particles into sandstone.