二聚酸聚酯二醇基可紫外光固化水性聚氨酯的合成与性能

以异佛尔酮二异氰酸酯、二聚酸聚酯二醇（PDFA）、2,2-二羟甲基丙酸、1,4-丁二醇等为主要原料,采用季戊四醇二丙烯酸酯和丙烯酸羟乙酯分别在分子链的侧基和末端引入可UV固化的双键,制备出具有不同双键含量的可UV固化的水性聚氨酯PDFA-PU。红外光谱（FT-IR）分析证实了PDFA-PU的结构以及UV固化后双键的交联...     

新型可紫外光固化水性聚氨酯的制备与表征

以异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇Pol-1256、二羟甲基丙酸(DMPA)为主要原料,采用预聚体法制备了水性聚氨酯预聚体,然后用自制的扩链剂对该预聚体进行扩链,并用丙烯酸羟乙酯(HEA)对扩链后的预聚体进行封端,最后中和乳化,制备了高紫外光(UV)固化基团含量的可UV固化水性聚氨酯乳液。采用FTIR对产物的结构进行了鉴定,利用旋转流变仪对分散体的流变性能进行了表征,通过TGA分析了UV固化膜的耐热性能,并对其拉伸性能进行了测试。研究结果表明:所制扩链剂符合预期结构特征,所得产物符合可UV固化的水性聚氨酯结构特征;乳液呈现出剪切变稀的特征,属于假塑性流体;UV固化膜具有良好的耐热性能,同时具有较高的断裂伸长率和良好的拉伸强度。     

UV固化超支化聚磷酸酯的制备与性能研究

以三(2-羟乙基)异氰脲酸酯和三氯氧磷制备第一代超支化聚磷酸酯,再以异佛尔酮二异氰酸酯(IPDI)及丙烯酸羟乙酯(HEA)的加成产物(IPDI-HEA)对超支化聚磷酸酯的羟基进行改性,通过控制改性程度,制备了—CC—双键含量不同的可UV固化超支化聚磷酸酯HPUA-1,研究了影响UV固化膜力学性能的影响因素。结果表明:固化后的HPUA附着力为0级,冲击强度50kg·cm,柔韧性为1mm,固化膜硬度和玻璃化转变温度随—CC—双键改性程度的增加而增加。     

可UV固化脲-异丁醛-甲醛树脂的合成与表征

以异佛尔酮二异氰酸酯(IPDI)、丙烯酸羟乙酯(HEA)改性脲-异丁醛-甲醛树脂(UIFR),通过两步法合成了一种含碳碳双键可紫外光(UV)固化的脲-异丁醛-甲醛树脂(UVUIF)。研究了反应温度和催化剂用量对反应的影响。适宜的反应条件为:第一步反应温度70℃,催化剂用量0.10wt%;第二步反应温度60℃。通过红外光谱分析,证明了合成的UVUIF结构中已引入了光敏性的碳碳双键。经UV辐射固化后,固化膜仍具有较好的热稳定性、硬度和附着力。     

高性能UV固化聚氨酯的制备及性能研究

选用二羟甲基丙酸(DMPA)、六亚甲基二异氰酸酯(HDI)三聚体、异佛尔酮二异氰酸酯(IPDI)、季戊四醇三丙烯酸酯(PETA)、三乙胺等为主要原料合成了高性能UV固化水性聚氨酯乳液,并在添加光引发剂1173后,UV固化制备涂层。采用FT-IR、1H NMR、TGA和DSC等对合成树脂的结构和性能进行表征。与市售水性UV固化聚氨酯乳液对比,本乳液具有更小的粒径、更高的活性,所制备的涂层具有更高的硬度、更优异的耐磨和耐水等性能。     

多官能度聚氨酯丙烯酸酯水性UV树脂的合成与性能表征

采用异佛尔酮二异氰酸酯(IPDI)、聚乙二醇600(PEG600)、2,2-二羟甲基丙酸(DMPA)为主要原料合成水性聚氨酯分散体,然后分别通过甲基丙烯酸-2-羟乙酯(HEMA)、二甲基丙烯酸甘油酯(GMDA)和季戊四醇三丙烯酸酯(PETA)引入碳碳双键,制备了2,4,6官能度的3种聚氨酯丙烯酸酯(PUA)水性UV树脂(UV-WPUA)。利用二正丁胺法测定合成过程中异氰酸根(-NCO)含量的变化,通过红外光谱(FT-IR)表征了合成产物的结构,树脂的紫外光固化结果表明4官能度的树脂具有最高的转化率(80%);随着官能度的提高,吸水率降低而光泽度逐步提高,其中4官能度的树脂力学性能更为优良。     

水性UV固化涂料用多羟甲基苯酚丙烯酸酯的合成

以多羟甲基苯酚钠和丙烯酰氯为原料,合成了适用于水性UV固化涂料的多羟甲基苯酚丙烯酸酯,通过红外光谱表征了产物的化学结构。探讨了物料比、反应温度、反应时间和催化剂用量等因素对产物产率的影响,结果表明:当n(多羟甲基苯酚钠)∶n(丙烯酰氯)=1∶2、反应温度为0～-5℃、反应时间为2.5h、催化剂四丁基溴化铵用量为0.04%(占物料质量比)时,最有利于产物的合成;多羟甲基苯酚丙烯酸酯的水溶性及涂膜性能,也能较好地满足水性UV固化涂料的应用。     

膨胀单体改性液态光学胶的制备及性能

以三羟甲基丙烷单烯丙基醚和原碳酸四乙酯为原料制备了一种透明且含有双键的膨胀单体3,9-二乙基-3,9丙烯氧甲基-1,5,7,11-四氧杂螺[5,5]十一烷(SOC),使用傅里叶变换红外光谱、核磁共振氢谱对产物结构进行了表征。通过热稳定性、附着力、凝胶率和体积收缩率测试等分析方法,探讨了SOC加入量对液态光学胶性能的影响。结果表明,胶粘剂UV固化后的附着力和凝胶率随膨胀单体的加入先增加后减少,但热稳定性持续降低。当膨胀单体加入量为10%~15%时,胶粘剂体系无体积收缩且胶粘剂具有优异的综合性能。     

含氟丙烯酸酯单体的合成及固化膜的性能

以六氟环氧丙烷低聚物和(甲基)丙烯酸-β-羟乙酯为起始原料,合成了(甲基)丙烯酸-β-(全氟烷氧基酰基)乙酯四种新型含氟单体,其结构经红外光谱(FT-IR)、核磁共振(1H-NMR和19F-NMR)确证。初步考察了上述单体对丙烯酸酯类紫外光固化涂料的改性作用,结果表明,提高含氟组分比例对固化膜的初始水接触角影响较小,但经过加热后处理可显著增强固化膜的疏水性。由此推断,热处理能有效促进含氟侧基向表面迁移,且含氟侧链越长,这种向空气界面富集的倾向尤为明显。当含氟组分占涂料配方的4%～6%(质量分数,下同)时,固化膜的最大水接触角可达到120°。     

基于PEDA的UV固化水性聚氨酯乳液及涂膜性能研究

目的研究双键含量可调的紫外光固化水性聚氨酯乳液及其涂膜性能。方法通过直接酯化法制备季戊四醇二丙烯酸酯(PEDA),并以其为功能性扩链剂与甲苯二异氰酸酯(TDI)、聚酯二元醇(POL-756T)、二羟甲基丙酸(DMPA)等原料制备一系列从侧基引入C=C双键的水性聚氨酯乳液。分别研究不同含量的PEDA及DMPA对乳液及涂膜性能的影响。结果 PEDA含量的增加会使其涂膜拉伸强度增加,断裂伸长率降低,热稳定性随之增强;DMPA含量的增加会使乳液的稳定性增强,颜色更加透明,粒径变小,但耐水性会降低。结论当PEDA质量分数为6.1%,DMPA为8.3%时,UV固化水性聚氨酯乳液具有良好的外观、稳定的性能,且涂膜的耐水性和力学性能优异。     

Saturated and unsaturated aliphatic side chain-appended naphthalenediimide derivatives: synthesis and structure property relationship

Previous studies have shown influence of aliphatic side chain length and type on the transport properties of naphthalenediimide (NDI) materials by affecting molecular arrangement. There is lack of comparative study on the presence or absence of unsaturation in side chain and its effect on optical and electronic properties of NDI. The present work focuses on the structure–property relationship of four NDI derivatives bearing octyl (C8, OctA-NDI), hexadecyl (C16, HD-NDI), octadecyl (C18, ODA-NDI) and oleyl (C18-un, unsaturated, OLA-NDI) chain on imide-nitrogen. The self-assembling behaviour of the molecules is studied in concentrated solutions as fresh and aged samples in four different solvents by absorbance and emission spectroscopy. With increase in alkyl chain length, the aggregation behaviour is observed to increase. Very interestingly introduction of unsaturation in side chain reduces aggregation and restores the monomeric properties. Self-assembled microstructures formation was studied by scanning electron microscopy where all the four materials show different types of self-assembly formation. Finally, we compared the thermally activated electron conductivity and electron mobility of NDI derivatives, where also the side chain structure clearly influences the electron transport. Electron mobility decreases on increasing chain length from C8 to C18 and again increases in C18-un. A rationale for the structure–property relationship has been given based on the molecular packing and intermolecular π–π interactions. This study contributes significantly towards designing new NDI derivatives bearing long side chains with hampered aggregation for niche applications.

     

C60的高分子修饰和功能材料化研究

综述Ｃ６０的高分子化与材料化研究的最新进展。Ｃ６０作为一种特殊的功能基因可以 链、侧链及与其它功能性高分子进行共混，同时还可以形成有机金属高分子。Ｃ６０的高分子化与材料化研究展示了一个广阔的新领域。     

Comparative study of the fracture behavior of flow-molded GMT-PP with random and chopped-fiber mats

The fracture toughness, K_Q, of hot-flow compression-molded glass-mat-reinforced thermoplastic polypropylene (GMT-PP) with random (R) and chopped (C) fiber mats was determined on single-edge-notched specimens loaded in tension (SEN-T) at ambient temperature. The development of damage was assessed by location of the acoustic emission (AE) activity in specimens cut from the side and central parts of the molded plaques and loaded along (L) and transverse (T) to the flow direction. The molding-induced anisotropy was clearly reflected in the K_Q values, which were considerably higher in the L than in the T orientation, especially for specimens cut from the side of the plaque. The toughness response of GMT-PPs with R and C mats was similar however. It was found that the fracture toughness calculated by considering non-linearity in the force vs. displacement curve according to ASTM E 399 is the best estimate for the initiation value. The damage zone and its development was estimated by considering the located AE events. AE served also to trace the differences in the failure mode as a function of mat type and loading ranges.     

Powder X-ray diffraction, infrared and conductivity studies of AgSbMP3O12 (M = Al, Ga, Fe and Cr)

New Nasicon type of compounds of composition AgSbMP₃O₁₂ (M = Al, Ga, Fe and Cr) are synthesized by solid-state method. All the compounds crystallize in the hexagonal lattice with space group . The infrared spectra of these compounds show characteristic bands due to PO₄ group. The frequency independent conductivity of these compounds shows Arrhenius type behavior and the activation energy for conduction is in the range 0.40–0.55 eV. Frequency independent conductivity (σ_dc) studies and frequency dependent (σ_ac) impedance measurements correlate well. The Cole–Cole plots do not show any spikes on the lower frequency side indicating negligible electrode effects. The activation energies obtained from the plots of log σ_dcT versus 1/T, log σ_ac(0) versus 1/T and log τ versus 1/T are approximately the same. The peak width at half height for electric modulus (M″) plot is 1.24 decades for all samples, which is close to 1.14 decades observed for Debye solid. The height of electric modulus (M″) obtained from the experimental plots are close to that of M″ (max) = C₀/2C indicating the Debye nature of the samples.     

采用BNi-7的Ti（C，N）基金属陶瓷与17-4PH沉淀硬化不锈钢的真空钎焊研究

采用镍基共晶钎料BNi-7对Ti（C,N）基金属陶瓷与17—4PH沉淀硬化不锈钢行了真空钎焊连接。研究了钎焊温度和焊缝厚度对焊接接头力学性能和微观结构的影响。结果表明,BNi-7对金属陶瓷粘结相具有较强的溶解能力,这是熔降元素（磷）能够在金属陶瓷侧大范围分布、钎焊接头获得良好界面结合的主要原因。随钎焊温度升高,磷在金属...     

On the behavior of indole-containing species sequestered within reverse micelles at sub-zero temperatures

We report on the effects of temperature (+30 to -100 degrees C) on the fluorescence from N-acetyl tryptophanamide (NATA) and human serum albumin (HSA) sequestered within Aerosol-OT (AOT) reversed micelles. NATA reports simultaneously from the polar and non-polar side of the reverse micelle interface. As the sample temperature decreases, the relative fraction of NATA molecules associated with the polar side increases. This redistribution process is characterized by DeltaH = -14.8 +/- 0.6 kJ/mol and DeltaS = -54 +/- 2 J/(K mol). The activation energy for thermal quenching (E(a,TQ)) associated with the polar side NATA molecules is 6.7 kJ/mol before the micelles have shed water and 1.0 kJ/mol after water shedding (below approximately -20 degrees C). The time-resolved fluorescence intensity decay for tryptophan-214 in HSA is triple exponential. We suggest that these lifetimes arise from three indole residue conformations in equilibrium. Cooling the sample causes a freezing-in of the least quenched conformer; the other conformers are frozen out. The E(a,TQ) value for the shortest lifetime component is 6 kJ/mol. The E(a,TQ) for the long and intermediate lifetime components are equivalent (approximately 1.5 kJ/mol).     

Crystallization of polylactide and its stereocomplex investigated by two-dimensional fourier transform infrared correlation spectroscopy employing carbonyl overtones

The band origins and transitions of weak vibrational modes developed in the 3500 cm(-1) region of polylactide (PLA) spectra during crystallization are investigated. The band assignment to the OH stretching mode of terminal hydroxyls is unlikely because the trace amount of chain-ends is negligible considering the long chain of high molecular weight polymer. The band intensity can be enhanced for quantitative study by increasing the sample film thickness. The results show that the transition patterns of these bands mimic those of C=O stretching modes. Therefore, these are assigned to C=O overtones. Two bands associated with crystalline and amorphous characteristics are revealed during cold crystallization. The crystalline C=O bands of PDLA and its stereocomplex counterpart are located at 3510 cm(-1) and 3482 cm(-1), respectively, indicating a weaker C=O bond in the latter crystal structure. Two-dimensional Fourier transform infrared (2D-FT-IR) correlation spectroscopy is then applied to study the correlation between C=O overtones and the crystalline characteristic band located near 900 cm(-1). The transitions of the two vibrational modes observed in crystallization of the stereocomplex are in-phase with each other. This reflects an involvement of short-range hydrogen bonding in the stereocomplex crystal structure. In contrast, crystallization of PDLA shows that the C=O overtone varies prior to that of the C-H character, indicating that dipole-dipole force is a crystal-induced interaction.     

Determination of Aqueous Solubilities of a Series of 5-Ethyl-5-Alkylbarbituric Acids and Their Correlation with Log P and Melting Points

A rapid potentiometric method has been used to determine the aqueous solubilities of an homologues series of 5-ethyl-5-alkyl (n=0-9) barbituric acids. A plot of the logarithm of solubility against the number of carbon atoms in the side chain revealed two distinct linear regions with a definite break about the butyl compound. The solubilities of all the members of this series (except 5-ethyl barbituric acid) can be predicted from log P values and melting points by the semiempirical solubility equation of Yalkowsky.     

M - C dipole formation in fcc (face centred cubic) Fe1-yMyCx solid solution (M=Ti,Nb)

Abstract

Available equilibrium carbon solubility data for fcc (face centred cubic) Fe_{1 - y}M_yC_x solid solution (M = Ti,Nb) reported as functions of temperature T and carbon activity a (C) were analysed taking into account the atomic interaction parameters derived through statistical thermodynamic analysis of related systems. In the fcc Fe_1-yM_yC_x under consideration, the affinity between C atom and M atom (M = Ti,Nb) is very much more attractive than that between C and Fe. Correspondingly, the atom configuration model in which M atoms are distributed randomly over the metal sub-lattice Fe_{1 - y}M_y and all the M atoms in the Fe_{1 - y}M_yC_x are bonded to C to form M - C dipoles was concluded to be the most realistic one reproducing the experimentally determined a (C) - T - x relationships at respective y.     

gamma-Ray-mediated oxidative labeling for detecting protein conformational changes by electrospray mass spectrometry

Exposure of proteins to hydroxyl radicals induces the incorporation of oxygen atoms into solvent-exposed side chains. Earlier studies have employed this approach for mapping protein-protein interactions in mass spectrometry-based footprinting experiments. This work explores whether the overall level of gamma-ray mediated oxidative labeling can be used for monitoring large-scale conformational changes. According to a recently developed kinetic model (Tong, X.; Wren, J. C.; Konermann, L. Anal. Chem. 2007, 79, 6376-6382), the apparent first-order rate constant for oxidative labeling can be approximated as k(app) = k(RAD)/([P](tot) + C/k(u)), where k(RAD) is the primary rate of *OH formation, [P](tot) is the protein concentration, C reflects the presence of competing radical deactivation channels, and ku is the rate constant at which hydroxyl radicals react with the protein. The current study introduces conformational effects into this model by proposing that k(u) = [see text for formula] , where N is the number of amino acids, alphai is a measure for the solvent exposure of residue i, and k(ch)(i) is the oxidation rate constant that would apply for a completely solvent-exposed side chain. Using myoglobin and cytochrome c as model systems, it is demonstrated that unfolding by addition of H(3)PO(4) increases k(app) by up to 30% and 70%, respectively. Unfolding by other commonly used denaturants such as organic acids or urea results in dramatically lower oxidation levels than for the native state, a behavior that is due to the radical scavenging activity of these substances (corresponding to an increased value of C). Control experiments on model peptides are suitable for identifying such "secondary" effects, i.e., factors that modify oxidation levels without being related to conformational changes. In conclusion, the overall *OH labeling level represents a viable probe of large-scale protein conformational changes only under conditions where secondary effects are known to be minimal and where [P](tot) is constant.