多取代(口山)酮及其糖甙(口山)酮的1H和13C NMR研究

总结了作者所测定过的多取代(口山)酮及其糖甙类衍生物的¹H和¹³C NMR位移数据,着重就取代基与结构的关系进行了探讨,认为多取代(口山)酮1位和8位取代情况直接影响着其他位置的化学位移数值,这一现象可以直接用于该类化合物的结构鉴定.     

钼(Ⅵ)-水杨基荧光酮配合物探针定量测定尿蛋白

本文研究了金属－占吨类染料配合物与蛋白质结合物的吸收光谱行为。提出了以钼（Ⅵ）－水杨基荧光酮配合物作为光谱探针测定微量蛋白质的新方法。测得配合物与蛋白质的最大结合数ｎ＝１００,结合物的摩尔吸光系数ε５７５＝２．８６×１０６Ｌｍｏｌ－１ｃｍ－１。方法具有很高的灵敏度和选择性,可以直接用于尿蛋白的测定。     

甲基百里酚蓝-铜(Ⅱ)络合物与白蛋白的相互作用

在模拟动物体生理条件下,采用荧光光谱、紫外-可见光谱法研究了甲基百里酚蓝-铜(Ⅱ)络合物与牛血清白蛋白(BSA)的相互作用.实验表明,MTB-Cu(Ⅱ)络合物与BSA之间为一形成复合物的静态猝灭过程.根据Stern-Volmer方程和Lineweaver-Burk方程求出了其结合常数(295K:3.449×105L·mol-1;310K:2.792×105L·mol-1)和热力学参数(△H=-10.71kJ·mol-1;△S=69.69J·K-1/69.71J·K-1;△G=-31.27kJ·mol-1/-32.32kJ·mol-1).证明二者主要以静电力作用,该过程是一个熵增加、Gibbs自由能降低的自发超分子过程.依据Foerster理论求出了结合距离r=2.25nm,阐明了猝灭机制是通过能量转移产生的.     

4-苯乙炔基-4′-二甲氨基查尔酮的合成与溶剂极性敏感的发光特性

以4-溴-4′-二甲氨基查尔酮和苯乙炔为原料,通过Sonogashira钯催化偶联反应合成了4-苯乙炔基-4′-二甲氨基查尔酮,并通过红外光谱和核磁共振氢谱对其结构进行了表征。进一步研究了4-苯乙炔基-4′-二甲氨基查尔酮在不同极性的溶剂中的紫外可见吸收光谱和荧光光谱,结果表明该化合物具有极性敏感的发光特性。     

氧化石墨烯-亚甲基蓝体系荧光光度法灵敏测定铋(Ⅲ)离子

在水溶液中,氧化石墨烯(Go)对亚甲基蓝(CMB)的荧光可产生猝灭作用,加入适量Bi3+可使体系的荧光增强,且增强程度与Bi3+的加入量有关。氧化石墨烯含有大量的含氧官能团使之表面带负电荷,易于分散在水中。带正电荷的荧光染料亚甲基蓝通过静电引力和π—π堆积作用吸附在GO表面,形成了GO-MB复合物,从而产生荧光猝灭。使用改进的Hummers制备了氧化石墨烯,应用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对制备的GO进行了表征。利用紫外可见吸收光谱验证了石墨烯与亚甲基蓝的作用过程,结果表明亚甲基蓝的荧光猝灭后,其两个主要吸收峰强度明显降低,而且GO的吸收光谱与MB的发射光谱完全不同,重叠度太小,不能发生能量转移,因此,GO与MB发生的荧光猝灭属于静态猝灭过程。当向亚甲基蓝氧化石墨烯络合体系加入Bi3+后,由于Bi3+体积小,带正电荷多从而取代了亚甲基蓝致使亚甲基蓝脱离氧化石墨烯,荧光恢复,荧光恢复的程度随Bi3+量的增加而增强,据此建立了氧化石墨烯-亚甲基蓝荧光光度法测定Bi3+的新方法。考察了亚甲基蓝、氧化石墨烯浓度,酸度以及试剂加入顺序对体系荧光恢复的影响,该络合体系的激发波长为667 nm,发射波长为690 nm,在优化条件下,Bi3+的浓度在0.5～100 μmol·L-1范围内与荧光强度呈良好的线性关系,相关系数为0.995 5。方法的检出限为1.0×10-8 mol·L-1(S/N=3)。评价了该方法的选择性,结果表明当共存离子为1 000倍的K+,Ca2+,Na+,Mg2+,Cu2+;100倍的Fe3+,Be2+,SiO2-₃,Al3+,Ni2+,Sb3+,NO-₃,Cl-,F-;20倍的Pb2+,Hg2+,Cd2+不干扰Bi3+的测定,新方法具有灵敏度高、快速、成本低等优点,将提出的方法用于环境水样的分析,回收率为93.4%～105.2%。     

多价抗衡离子诱导聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA)刷构象转变的UCST行为

本文应用分子场理论,研究pH、[Fe(CN)_6]~(3-)诱导聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA)刷的上临界溶解温度(UCST)构象转变与结构特性.理论模型考虑p H和[Fe(CN)_6]~(3-)对PDMAEMA刷体系的静电调控作用.研究发现,在不同[Fe(CN)_6]~(3-)浓度、不同p H条件下,PDMAEMA刷呈现了UCST构象转变行为.由于p H调节PDMAEMA单体质子化,[Fe(CN)_6]~(3-)通过与PDMAEMA带正电荷的单体结合,形成了在PDMAEMA链内以[Fe(CN)_6]~(3-)为中介的带电单体间的静电吸引结合.随着温度升高,[Fe(CN)_6]~(3-)与PDMAEMA带正电荷的单体结合被破坏,[Fe(CN)_6]~(3-)在链内凝聚导致的静电屏蔽效应减弱,PDMAEMA链内带电单体间的静电排斥增强,PDMAEMA刷的构象呈现了从塌缩到溶胀的UCST转变行为,并且在较高[Fe(CN)_6]~(3-)浓度条件下,PDMAEMA刷构象转变的UCST增高.在较低p H值条件下,较多的PDMAEMA单体被质子化,[Fe(CN)_6]~(3-)与PDMAEMA带正电单体的结合增强,PDMAEMA刷构象转变的UCST增大.基于pH和[Fe(CN)_6]~(3-)对PDMAEMA刷体系中的静电调控效应,可以预言,在较小p H和较大[Fe(CN)_6]~(3-)浓度条件下,PDMAEMA链在垂直培基表面沿着链方向形成结节状结构.这是由于以[Fe(CN)_6]~(3-)为中介的链内带电单体间的静电吸引作用增强,导致临近单体间汇聚结节.我们的理论结果符合实验观测,由此表明,pH调节PDMAEMA单体的带电状态,以及[Fe(CN)_6]~(3-)在PDMAEMA链内凝聚导致的静电屏蔽效应,决定着PDMAEMA刷的UCST构象转变和结构特性.     

用于质子交换膜材料的侧链型磺化聚芳醚酮砜的光谱分析

采用直接缩聚的方法,通过调整氨基单体用量,合成出了系列带有不同氨基含量的聚芳醚酮砜(Am-PAEKS)聚合物,在聚合物侧链上进行后磺化接枝制备出了系列不同磺化度的侧链型磺化聚芳醚酮砜(S-SPAEKS),并且通过调整磺酸基团含量来控制聚合物的磺化度。通过红外光谱(FTIR)和氢核磁谱(1HNMR),对所合成的单体及其聚合物的结构进行了表征,S-SPAEKS红外光谱在1 239和1 060 cm-1处出现了磺酸基团中OSO的特征吸收峰,氢核磁谱中1.64 ppm处出现了处于烷基链中间位置的两个氢(—CH₂—CH₂—)化学位移,证明得到了S-SPAEKS聚合物。经热失重分析发现,聚合物中磺酸基团的脱落温度都高于240 ℃,聚合物主链降解温度都高于450 ℃。研究表明,该系列聚合物具有良好的热性能,可以用作质子交换膜材料。     

非线性光学晶体4-(4-二甲基氨基苯乙烯基)甲基吡啶对甲基苯磺酸盐的制备与性能研究

采用籽晶法制备了大体积高质量的4-(4-二甲基氨基苯乙烯基)甲基吡啶对甲基苯磺酸盐(DAST)晶体，对制备条件进行了优化，对DAST晶体X射线衍射谱图中的主要峰进行了指标化.另外，还对所制备的DAST晶体的透光性、热稳定性进行了研究， 并对265℃的焙烧产物进行了X射线衍射 (XRD)和傅里叶变换红外光谱(FT-IR)测试，证明了260℃是DAST晶体的熔化相变温度， 说明采用熔融法制备DAST晶体是可行的；同时还对DAST晶体的热失重过程进行了初步探讨. 关键词： 4-(4-二甲基氨基苯乙烯基)甲基吡啶对甲基苯磺酸盐 晶体生长 X射线衍射 热稳定性     

三链核酸poly(U)·poly(A)·poly(U)主链的振动位移

基于三链核酸 poly(U)· poly(A)·poly(U)的螺旋对称性 ,利用晶格动力学方法 ,计算了三链核酸分子 poly(U)·poly(A)·poly(U)主链振动的本征矢 ,探讨了振动位移矢量和线二色光谱的关系。结果表明 ,对应着磷酸双氧的反对称振动谱线可以用于直接确定磷酸根的取向 ,精度大约为 1°。其他谱线必须通过对分子的简正分析来帮助确定分子的结构。     

Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料的上转换发光及其温度传感特性EI北大核心CSCD

采用CO_(2)激光区熔法制备了Lu_(2)O_(3)∶0.5%Er^(3+)/x%Yb^(3+)(x=1,3,5)上转换荧光材料。X射线衍射结果表明,所制备的Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料具有纯Lu_(2)O_(3)晶相。在980 nm激光激发下,样品发出明亮的上转换荧光。光谱测试结果表明,样品上转换荧光强度和荧光中绿光与红光比例随Yb^(3+)离子浓度改变,当Er^(3+)和Yb^(3+)离子浓度分别为0.5%和3%时,样品上转换荧光强度最强。通过荧光强度比(FIR)技术研究了样品Lu_(2)O_(3)∶0.5%Er^(3+)/3%Yb^(3+)在298~873 K温度范围内上转换荧光温度传感特性,在532.8 K时最大绝对灵敏度为0.0060 K^(-1),在298 K时最大相对灵敏度为0.0090 K^(-1)。结果表明,Lu_(2)O_(3)∶Er^(3+)/Yb^(3+)荧光材料非常适合用于宽温度范围荧光温度传感。     

Improving the Barrier Properties of Poly(Lactic Acid) by Blending with Poly(Ethylene-Co-Vinyl Alcohol)

Poly(lactic acid) (PLA)/poly(ethylene-co-vinyl alcohol) (EVOH) blends were prepared via melt blending to improve the barrier properties of PLA. The phase morphologies and final properties (rheological behavior, thermal and dynamical-mechanical features, barrier properties, and mechanical behaviors) of the blends were investigated as a function of the EVOH content. The results indicated that hydroxyl groups of EVOH promoted the degradation of PLA, and thus affected the viscosities and morphologies of the resulting blends. The intrinsic viscosities of PLA in the blends decreased with the content of EVOH. The PLA and EVOH presented typical phase-separated morphologies, with a relatively small domain size of the EVOH phase. The EVOH enhanced the cold-crystallization behavior of PLA. The barrier properties to water vapor and oxygen increased linearly with increasing EVOH content.     

Toughening of Poly (Butylene Terephthalate) with Epoxy-Filled Poly (Ethylene–Octene) Copolymer

Toughened poly (butylene terephthalate) (PBT) with triglycidyl isocyanurate (TGIC)-filled poly (ethylene–octene) (POE) was prepared by melt reaction extrusion. For retarding the reaction extent between PBT and the epoxy component, the TGIC was first blended with POE to enwrap its reactive epoxy groups. Then, the TGIC-filled POE was used to melt blend with PBT. The Fourier transform infrared (FTIR) spectra showed that no other peaks appeared in the POE/TGIC specimens except for those originally existing in pure POE and TGIC. The rheological results further confirmed that no reaction occurred between the epoxy and the POE matrix. When the POE/TGIC was blended with PBT, a distinct increase of the viscosity suggested that the migration of the TGIC from POE to PBT during the melt processing induced chain extension reactions of PBT. The results obtained from DSC and DMA revealed that the chain extension of PBT induced by the reaction with TGIC restricted the mobility of PBT chains leading to a limitation of the recrystallization-remelting process and an increase of the glass transition temperature of PBT. The mechanical tests showed that the presence of TGIC in the POE phase distinctly improved the toughness of PBT. Compared to the case of a PBT/POE (80/20, wt%/wt%) blend, the elongation at break and impact strength of the system filled with 5 phr TGIC were increased more than three and six times, respectively.     

Toughened Poly(Trimethylene Terephthalate) by Blending with a Functionalized Metallocenic Poly(Ethylene-Octene) Copolymer

New toughened poly(trimethylene terephthalate) (PTT) materials were obtained by melt blending with maleic anhydride grafted poly(ethylene-octene) (POEg). Rheological properties, mechanical properties, and morphological characteristics of PTT/POEg blends at four different compositions—95/5, 90/10, 80/20, and 70/30—were studied. The melt viscosity of the blends shows a linear decrease on increasing the POEg content. The addition of rubbery POEg to the PTT matrix increases the impact strength, while tensile properties decrease. Scanning electron microscopy (SEM) displayed a very good dispersion of POEg particles in the PTT matrix. Differential scanning colorimetry (DSC) experiments showed that for all samples the melting point was almost constant and the crystallinity did not show obvious differences. SEM results showed shear yielding of the PTT matrix was the major toughening mechanism.     

各种烷氧基取代聚对苯乙炔的合成和发光性能研究

利用脱氯缩合聚合法合成了聚（2－甲氧基－5－丁氧基）对苯乙炔（PMOBOPV），聚（2－甲氧基－5－辛氧基）对苯乙炔（PMOCOPV）和聚（2－丁氧基－5－丁氧基）对苯乙炔（PDBOPV），聚（2－辛氧基－5－辛氧基）对苯乙炔（PD－COPV）4种发光材料。对反应体系的浓度，酸碱度，反应温度及时间等工艺条件和路线进行了细致的研究。结果表明：反应物的纯度，含量对合成产物的产率和性能有较大的影响；碱性是影响脱氯缩合反应的关键因素，而反应温度和时间对缩合反应影响则相对较小，在一定温度下当反应时间达到一定阶段后其转化率基本不变，对合成材料的化学结构，物理性能和发光特性进行了表征和检测。结果显示：非对称烷氧基取代PPV具有良好的溶解性，成膜性和稳定性；而对称性烷氧基取代PPV的溶解性和成膜性相对较差。以PMOBOPV为发光材料，采用旋涂工艺制作出单层和双层发光器件，并对器件的电致和光致发光性能进行了研究。     

Effect of Alkyl Side Chain Length on Relaxation Behaviors in Poly(n-alkyl Acrylates) and Poly(n-alkyl Methacrylates)

Dynamic mechanical analysis (DMA) is used to investigate the effect of alkyl side chain length on the relaxation behavior of poly(n-alkyl acrylates) (PnAA) and poly(n-alkyl methacrylates) (PnAMA) above the glass transition temperature (T_g). Master curves and shift factors (log a_T) were obtained using the time–temperature superposition (TTS) principle. The log a_T curves of PnAA and PnAMA exhibit a dynamic crossover from one Vogel–Fulcher–Tammann–Hesse (VFTH) equation to another above T_g. The corresponding temperature was designated as the dynamic crossover temperature (T_c). It is found that T_c/T_g and the apparent activation energy (E_g) increases, e whereas the fragility index (m) decreases with increasing alkyl side chain length. Further analysis shows that m ∝ T_g, E_g∝ , and E_g∝ m² for both PnAA and PnAMA.     

聚对苯撑乙炔咔唑薄膜对TNT挥发物的检测

以3, 6-二溴-9-辛基咔唑和2, 5-二戊烷氧基-1, 4-二乙炔基苯为单体,通过Pd催化的Sonogashira偶联反应合成了聚对苯撑乙炔咔唑衍生物PPECz。PPECz的溶液和固体薄膜都具有较好的发光性能,并且均对2, 4, 6-三硝基甲苯(TNT)有明显的响应。在常温常压条件下,微量(40 μg)的TNT挥发物在60 s内就能使聚合物PPECz薄膜的荧光强度被猝灭56%,可作为一种潜在的硝基苯类爆炸物的荧光检测材料。     

Microstructures and Mechanical Properties of Poly(Trimethylene Terephthalate)/Maleic Anhydride Grafted Poly(Ethylene-octene)/Polypropylene Blends

A range of blends based on 70 wt% of poly(trimethylene terephthalate) PTT with 30 wt% dispersed phase were produced via melt blending. The dispersed phase composition was varied from pure maleic anhydride grafted poly(ethylene-octene) (POE-g-MA) over a range of POE-g-MA:polypropylene (PP) ratios. The micromorphology and mechanical properties of the ternary blends were investigated. The results indicated that the domains of the POE-g-MA are dispersed in the PTT matrix, and at the same time the POE-g-MA encapsulate the PP domains. The interfacial reaction between the hydroxyl-end group of PTT and maleic anhydride (MA) during melt blending changes the formation from “isolated formation” to “capsule formation,” where the PP domains are encapsulated by POE-g-MA. Compared to the PTT/POE-g-MA blends, mechanical properties of ternary blends, such as tensile strength and Young's modulus, were improved significantly.     

Discrimination of Poly(butylenes adipate-co-terephthalate) and Poly(ethylene terephthalate) with Fourier Transform Infrared Microscope and Raman Spectroscope

ABSTRACT

The analysis of plastics and fibers is of importance to forensic scientists, especially in the investigation of trace evidence. In this study, we use Fourier transform infrared microscope and confocal Raman spectroscope to investigate two kinds of polymers: poly(butylenes adipate-co-terephthalate) and poly(ethylene terephthalate), which are very similar in structure and cannot be discriminated easily with other instruments. Infrared and Raman spectra were tentatively interpreted. The indicative peaks (937 cm^?1, 1121 cm^?1 in Infrared spectra; 996 cm^?1, 1396 cm^?1 in Raman spectra) to distinguish the two polymers were also summarized. The data in this study can help forensic scientists identify these two polymers accurately and avoid wrong certificate of authenticity. The data also offer the producer and researchers an effective and fast method to characterize and identify the poly(butylenes adipate-co-terephthalate).     

Polarized Fluorescence of Diphenylhexatriene-Incorporated Poly(Styrene) Film at Room Temperature

Poly(styrene) is a highly viscous, and cross-linked polymer at room temperature. This makes it ideal to use as a molecular fixer. The polarized fluorescence of a diphenylhexatriene (DPH)-incorporated poly(styrene) film has been studied. The excitation and emission wavelength dependence of the anisotropy of fluorescence of a luminophore-incorporated poly(styrene) film reveals that with decreasing excitation wavelength the anisotropy changes remarkably but is independent of emission wavelength. The investigation estimates an angle of no more than 7.4° between the absorption and the emission transition dipole moment for DPH, suggesting poly(styrene) as a suitable medium to evaluate the mutual orientation of absorption and the emission transition dipole moments at room temperature.     

Isothermal Melt Crystallization Kinetics for Poly(Trimethylene Terephthalate)/Poly(Butylene Terephthalate) Blends

The kinetics of isothermal melt crystallization of poly(trimethylene terephthalate) (PTT)/poly(butylene terephthalate) (PBT) blends were investigated using differential scanning calorimetry (DSC) over the crystallization temperature range of 184–192°C. Analysis of the data was carried out based on the Avrami equation. The values of the exponent found for all samples were between 2.0 and 3.0. The results indicated that the crystallization process tends to be two‐dimensional growth, which was consistent with the result of polarizing light microscopy (PLM). The activation energies were also determined by the Arrhenius equation for isothermal crystallization. The values of ΔE of PTT/PBT blends were greater than those for PTT and PBT. Lastly, using values of transport parameters common to many polymers (U*=6280 J/mol, T _∞=T _g – 30), together with experimentally determined values of T _m ⁰ and T _g, the nucleation parameter, K _g, for PTT, PBT, and PTT/PBT blends was estimated based on the Lauritzen–Hoffman theory.