KINETICS OF NON-ISOTHERMAL CRYSTALLIZATION OF POLY (ETHYLENE TEREPHTHALATE) MODIFIED BY POLY (ETHYLENE GLYCOL)

The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t 1/2 ( the half life of crystallization) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport, the equilibrium melting temperature (T_m~0),the nucleation parameter (ψ),themaximum crystallization temperature (T_(e, max)), and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed.     

脲醛树脂合成反应过程的FTIR研究

利用傅里叶变换红外(FTIR)光谱研究了脲醛树脂合成中不同结构形成和变化情况. 对FTIR谱图解析和分析的结果表明, 在脲醛树脂预聚物合成过程中, 随着甲醛与尿素反应的进行, 红外谱图特征峰发生有规律的变化, 酰胺II带特征峰波数逐渐低移, 有更多羟甲基、醚键和—NHCH2—结构基元形成, 固化反应使上述结构基元相应减少. 着重分析了不同甲醛与尿素摩尔比(nF/nU)下尿素与甲醛反应产物结构的变化, 随nF/nU的增加, 酰胺II带特征峰波数逐渐低移, 碱性条件下醚键和—NHCH2—结构基元明显增加, 在较强酸性条件下Uron环、亚甲基桥和羟甲基显著增加, 而—NHCH2—结构基元含量下降.     

含柔性间隔基的热致液晶性共聚酯的结晶形态

采用偏光显微镜、扫描和透射电镜从不同层次的结构水平上研究了含柔性间隔基热致液晶性共聚酯的结晶形态。在偏光显微镜下观察到典型的负光性球晶形态,透射电镜揭示了球晶是由厚度为10nm并沿着径向生长的片晶结构所组成,分子链沿晶片厚度方向取向排列。并研究了分子链的刚性程度对热致聚芳酯结晶性质的影响。结果表明,分子链刚性越大其结晶性和球晶的完善性越高。     

HNCS与C_2H(X~2Π)反应微观动力学的理论研究

用量子化学密度泛函理论的UB3LYP/6-311 G鄢鄢方法和高级电子相关的UQCISD(T)/6-311 G鄢鄢方法研究了异硫氰酸(HNCS)与乙炔基自由基(C2H(X2Π))反应的微观机理.采用双水平直接动力学方法IVTST-M,获取反应的势能面信息,应用正则变分过渡态理论并考虑小曲率隧道效应,计算了在250～2500K温度范围内反应的速率常数.研究结果表明,HNCS与C2H(X2Π)反应为多通道、多步骤的复杂反应,共存在三个可能的反应通道,主反应通道为通过分子间H原子迁移,生成主要产物NCS C2H2.反应速率常数随温度升高而增大,表现为正温度效应.速率常数计算中变分效果很小.在低温区隧道效应对反应速率的贡献较大,反应为放热反应.     

Synthesis, Crystal Structure and Electrochemistry Properties of a (N,N'-Ethylene-bis(salicylaldiminato)) Nickel(Ⅱ) Complex, [Ni2(salen)2]·NCS-NH4

A new Ni(Ⅱ) complex [Ni2(salen)2]·(NCS)·NH4 (salen = N,N'-bis(salicylidenea-mino)ethanato) has been prepared and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.8725(13), b = 19.0046(15), c = 20.0583(16) (A), Z = 8, V = 6431.8(9) (A)3, C33H32N6Ni2O4S1, Mr= 726.13, Dc = 1.500 g/cm3, F(000) = 3008, μ = 1.284 mm-1, the final R = 0.0394 and wR = 0.0767 for 4449 observed reflections with Ⅰ＞2σ(Ⅰ). The complex involves a N,N'-ethylene-bis(salicylaldiminato) Schiff base, an isothiocyanato anion and an ammonium cation. The nickle(Ⅱ) ion adopts a distorted square coordination geometry with N2O2 set of Schiff base ligand. The complexes are linked into a dimmer via intermolecular hydrogen bonds and the [Ni(salen)] moieties are connected together to form a 2-D layer structure by intermolecular N-H…O hydrogen bonds and π-π stacking. Cyclic-voltammetry method was used to characterize electrochemically the complex.     

铂-金交替修饰的铂核纳米颗粒的制备与表征

通过吸附在铂纳米颗粒表面的氢交替还原氯金酸和氯铂酸,得到了复合型纳米颗粒Pt@Au/Pt,用UV-Vis光谱、TEM和XRD对其进行了表征.     

脱氢姜黄烯及其类似物的合成

利用苯乙酮及苯乙酮衍生物,经过傅-克乙酰化反应、偶联反应、Wittig烯化反应,合成了脱氢姜黄烯及其类似物.再经选择性催化氢化反应,可分别得到α-姜黄烯、黄根醇甲醚及姜黄氢醌甲醚.     

25,26,27-三失碳-B-高-7-氧-6-酮-5α-胆甾-3α,24-二醇的合成

本文报道以3α-羟基-6-羰基-5α-胆烷酸甲酯(3)为原料经六步反应合成了油菜甾醇类似物25,26,27-三失碳-B-高-7-氧-6-酮-5α-胆甾-3α,24-二醇(9a).总产率14%.9a的促进植物生长作用是24-表油菜甾醇内酯的60%.     

Highly Efficient Pd/C-Catalyzed Suzuki Coupling Reaction of p-（un）Substituted Phenyl Halide with （p-Substituted phenyl） Boronic Acid

A highly efficient Pd/C-catalyzed ligandless, heterogeneous Suzuki reaction of p-（un）substituted phenyl halide with （p-substituted phenyl）boronic acid in DMF/H2O solvent in a short reaction time （0.5 h） at 75 ℃ was developed. The key for such a catalytic system was the addition of 1 equivalent of tetrabutylammonium bromide. A wide variety of substituents can be tolerated and high yields of cross coupling products were achieved. The palladium catalyst can be easily recovered and reused without significantly decreasing its efficiency.     

LB膜诱导Ba(NO3)2晶体取向生长

In this work, Ba(NO₃)₂ crystals with single crystal face were induced by using the the method of bio-mimetic mineralization and double LB films of behenic acid (BA) as the template. The crystals were characterized by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The crystals were observed in regular square shape with uniform size about 5～8 μm by SEM, and they were found by XRD to grow along the (111) plane. From these experiments, we can conclude that the good selection of the (111) crystal face of Ba(NO₃)₂ is due to the electrostatic interactions , the match between this crystal face and the definite lattice structure of the LB films.