二(p-氨基苯氧基)二甲基硅烷的合成及其聚酰亚胺的制备

采用二甲基二氯硅烷和对氨基苯酚作为主要原料,一步法合成了二(p-氨基苯氧基)二甲基硅烷,使用核磁共振光谱,红外光谱及质谱对产物结构进行了表征.以新合成的二(p-氨基苯氧基)二甲基硅烷(SIDA)为原料和ODA,与PMDA反应合成有机硅氧烷聚酰胺酸,并分别采用热酰胺化与化学酰胺化制得了有机硅氧烷改性聚酰亚胺,使用FT-I...     

基于硅桥的V形有机凝胶因子的合成及性能研究

以对氯甲苯和二氯二甲基硅烷为原料,经偶联、氧化、酯化、酰肼化等系列反应,得到中间体二(4′-酰肼基苯基)-二甲基硅烷,将其与3,4,5-三辛氧基苯甲酸反应,合成了含有二甲基硅的V形二酰肼衍生物--N,N′-(4,4′-二甲基硅烷二基)双(苯甲酰基)双(3,4,5-三辛氧基苯并酰肼)。利用核磁共振氢谱仪、核磁共振碳谱仪、飞行时间质谱仪、傅里叶变换红外光谱仪对其结构进行了表征。合成的目标化合物只能在四氯化碳溶液中热可逆凝胶化,扫描电子显微镜分析表明干凝胶形貌类似火山岩结构。利用热重分析仪测定了目标化合物的热稳定性,其热分解温度为397℃,表明该化合物具有良好的热稳定性。     

双酚F环氧树脂的改性研究

合成了双酚F/间苯二酚共聚型环氧树脂、二甲基二酚羟基有机烷氧基硅烷,并考察了双酚F/间苯二酚共聚型环氧树脂的性能以及不同二甲基二酚羟基有机烷氧基硅烷用量对双酚F环氧树脂固化物性能的影响.结果发现:改性后的树脂粘度降低,其固化物的耐热性提高,力学性能得到显著改善.     

氯化锌催化合成含硅芳炔树脂

以二乙炔基苯、双(二甲氨基)二甲基硅烷为原料,乙腈为溶剂,通过氯化锌催化实现单步硅烷化合成含硅芳炔树脂。研究结果表明,乙腈做溶剂,二乙炔基苯与双(二甲氨基)二甲基硅烷投料比为9∶8(摩尔比),ZnCl_2相对于炔过量0.65倍,回流反应11h效果最佳,收率高达90%以上;制备的含硅芳炔树脂在室温下呈流动状态,加工性能良好,加工温度为40~180℃,加工窗口为140℃;固化后的含硅芳炔树脂,在N_2气氛下热分解5%时的温度(T_(d5))为587℃。     

羟基封端的有机硅低聚物的合成

采用甲基三乙氧基硅烷,二甲基二乙氧基硅烷,苯基三乙氧基硅烷为原料,通过水解-缩合反应合成一种羟基封端的有机硅低聚物,并初步研究了有机硅低聚物的合成条件。实验表明:反应温度为70℃,时间为4h,pH为3,可合成羟基封端的有机硅低聚物。红外光谱表明,合成的有机硅低聚物在Si-OC2H5及Si-O-Si处都出现吸收峰,其结构与理论基本相符。     

聚碳硅烷的合成与特性研究

研究了由聚二甲基硅烷热解制备聚碳硅烷的过程，探讨了合成条件笃产物特性的影响。提高反应温度、产物的分子量与熔点随之增高，但同时分子量的分散性增大使可纺性劣化。采用适当的制备方法已获得了具有所需特性的聚碳硅烷。     

苯基体系有机硅树脂封闭剂在镍金属板上的性能研究

以正硅酸乙酯(TEOS)、苯基三甲氧基硅烷、二甲基二甲氧基硅烷、有机硅树脂和冰醋酸为原料,通过共聚缩合的方法制备性能优良的苯基体系有机硅树脂封闭剂,研究了该体系中原料的配比关系对封闭剂的性能影响,对于涂覆于镍板上的封闭剂膜的硬度、耐腐蚀性等进行了分析,并用傅里叶变换红外光谱仪、电化学工作站(EIS、Tafel)、扫描电镜和热重分析仪对树脂膜进行相应的形貌和结构表征。结果表明,当TEOS与苯基三甲氧基硅烷的配比为1∶1.03,有机硅树脂占总体的2%(质量分数),二甲基二甲氧基硅烷含量为3%(质量分数),pH值为4.2时,于镍金属板上所成膜的硬度达到4H,盐水浸泡实验能达到88 h。     

聚酯薄膜用高韧性无底涂耐磨硅树脂的制备

以正硅酸乙酯(TEOS)、苯基三甲氧基硅烷(PTMOS)、γ-(2,3-环氧丙氧)丙基三甲氧基硅烷(KH-560)和二甲基二甲氧基硅烷为原料,通过水解共缩聚的方法制备了高韧性无底涂耐磨有机硅树脂,并涂覆于聚酯(PET)薄膜表面,于120℃下固化。研究了各原料比例对树脂性能的影响,对树脂膜涂层的柔韧性、硬度、耐磨性及附着力进行了分析,并对树脂膜进行了红外光谱、扫描电镜和热重性能表征。结果表明:当合成树脂中TEOS与PTMOS摩尔比为0.9、KH-560占2.24%(wt,质量分数,下同)、二甲基二甲氧基硅烷用量为1.3%,硅树脂涂膜拥有较好的性能,涂膜的附着力能够达到1级、硬度到达5H、耐磨等级达到优、水接触角达到89.6°,耐80℃水煮能力较好。     

高苯基含量硅树脂阻燃剂的合成

以苯基三乙氧基硅烷(PTES)、二苯基二甲氧基硅烷(DPDS)和二甲基二乙氧基硅烷(DMDS)为单体,在0.1mol/L的稀盐酸催化下水解缩聚成具有阻燃性能的高苯基含量的硅树脂,采用TGA和DSC对PTES/DPDS/DMDS投料摩尔比为75.0/18.8/6.2的高阻燃性产物的热力学性能进行了表征.讨论了其结构和组成对聚碳酸酯阻燃性能的影响,实验结果表明:当硅树脂中的苯基含量为80.0%～90.0%(mol),二官能度的单体含量为20.0%～40.0%(mol)时,阻燃效果较好.     

以四烯丙基(二甲基)硅烷为核的超支化聚硅碳烷的合成与表征

以四烯丙基(二甲基)硅烷(B4)为核、甲基氢二烯丙基硅烷(AB2)为单体,通过硅氢加成反应,采用无核一步法、核一步法、核多步法合成了超支化聚有机硅碳烷。用FT-IR1、H-NMR、MALLS-GPC对该聚合物的结构进行了表征。研究了核多步法对超支化聚合物分子量及其分布的控制,结果表明,用核多步法合成超支化聚有机硅碳烷可有效地控制产物的分子量及其分布。     

Photostriction of CH3NH3PbBr3 Perovskite Crystals

Organic–inorganic hybrid perovskite materials exhibit a variety of physical properties. Pronounced coupling between phonon, organic cations, and the inorganic framework suggest that these materials exhibit strong light–matter interactions. The photoinduced strain of CH₃NH₃PbBr₃ is investigated using high‐resolution and contactless in situ Raman spectroscopy. Under illumination, the material exhibits large blue shifts in its Raman spectra that indicate significant structural deformations (i.e., photostriction). From these shifts, the photostrictive coefficient of CH₃NH₃PbBr₃ is calculated as 2.08 × 10^?8 m² W^?1 at room temperature under visible light illumination. The significant photostriction of CH₃NH₃PbBr₃ is attributed to a combination of the photovoltaic effect and translational symmetry loss of the molecular configuration via strong translation–rotation coupling. Unlike CH₃NH₃PbI₃, it is noted that the photostriction of CH₃NH₃PbBr₃ is extremely stable, demonstrating no signs of optical decay for at least 30 d. These results suggest the potential of CH₃NH₃PbBr₃ for applications in next‐generation optical micro‐electromechanical devices.     

(La2/3Ca1/3)(Mn(3-x)/3)Fex/3)O3体系磁电阻行为的研究

通过系统地测量（La_2/3Ca_1/3）（Mn_{（3-x）／3}Fe_x／3）O₃（x＝0、0.1、0．2、0．3的体系样品的电阻率-温度关系以及一定温度下磁电阻率与磁场的关系,发现随x的变化其磁电阻率峰和电阻率峰均发生位移,磁电阻率峰值增大,并伴生磁电阻率峰展宽效应．作者认为由于Fe的替代,引起体系中Mn³⁺／Mn⁴⁺比率及磁矩的变化,加之外场对磁有序结构的调制作用,从而影响了Mn³⁺－O^－Mn⁴⁺的双交换作用,最终导致磁电阻行为发生变化．     

Constitution of the Ni3Cr-Ni3Al-Ni3W system

Isothermal sections of the Ni-Cr-Al-W system have been investigated at 75 at % Ni and temperatures of 1523 and 1273 K, by means of phase compositional analysis, X-ray diffraction and microscopical examination. The alloys studied lay in the range 2.5 to 10 at % Cr, 12.5 to 20 at% Al, 2.5 to 6.25 at % W, The phases formed were, and the bcc solid solution based on tungsten (designated ₂). The maximum extent of the region was found to be 3 at % each of chromium and tungsten. Preferential partitioning of tungsten to occurred. Study of an Ni-10Cr-12.5Al-2.5W alloy aged at 1273 and 1073 K, after quenching from 1573 K, showed that changes in and compositions and lattice parameters occur as a function of ageing time.     

PbZrO3-CdTiO3 solid solutions

The structural, nonlinear optical, and dielectric properties of (1-x)PbZrO₃ ·xtCdTiO₃ solid solutions were studied. The phase relations in the composition rangesx = 0–0.3 and 0.85-1.0 were established. The results suggest that the ferrielectric ordering in CdTiO₃ persists up to 730 K.     

3 Cr3 Mo3 VNb 在热冲孔中的应用研究

高合金钢热冲孔冲头寿命关系到模具与产品成本、生产效率、自动化设备的使用,因此,应注重冲头的选材、材料制备与冲头制造工艺。 用 3 Cr3Mo3 VNb 作为高合金钢热冲孔冲头,为提高模具寿命,在材料制备上,优化了成分,采用电渣重熔冶炼,减少杂质,毛坯锻造两次,用大锻造比锻造,冲头热处理用真空炉,三次回火,热处理硬度取 HRC42 ~ 46 ,冲头表面处理采用镀铬工艺,开展了热冲孔工艺试验。 结果表明,用3 Cr3Mo3 VNb 可使冲孔冲头寿命平均达到 800 件以上。     

Phase equilibria in the system LaMnO3 + δ-SrMnO3-LaFeO3-SrFeO3 − d

We have revealed the formation of a continuous series of orthorhombic LaMn_{1 ? y} Fe_yO₃ solid solutions (0<y<1); La_{1 ? x} Sr_xFeO₃ solid solutions in the composition range 0 < x ≤ 0.8, with an orthorhombic structure at 0 < x ≤ 0.6 and a cubic structure at 0.6 < x ≤ 0.8; and a tetragonal SrMn_{1 ? y} Fe_yO₃ phase in the range 0.6 ≤ y ≤ 1. The composition stability limits of the perovskite phase La_{1 ? x} Sr_xMn_{1 ? y} Fe_yO₃ have been determined, and the 1100°C isotherm of the La₂O₃-SrO-Mn₃O₄-Fe₂O₃ system in air has been constructed.     

Multicolor up-conversion emissions of Tm3+/Er3+/Yb3+ tri-doped YF3 phosphors

Tm3+/Er3+/Yb3+ tri-doped yttrium fluoride (YF3) phosphors were prepared by a facile hydrothermal method. X-ray topographic analysis found that the phosphors were crystallized products. Their sizes and morphologies were characterized by scanning electron microscopy (SEM, Hitachi S-4800), which indicated that most of the YF3 phosphors were hundreds of nanometers in size. Up-conversion (UC) spectra were recorded under 980-nm diode laser excitation at room temperature with a fluorescence spectrometer (Hitachi F-4500). Plenty of UC emissions of Tm3+ and Er3+ were observed from ultraviolet to red. For Tm3+ ions, a five-photon process (approximately 291 nm and approximately 347 nm), a four-photon process (approximately 362 nm and approximately 452 nm), and a three-photon process (approximately 475 nm) were identified in the UC spectra. The UC emissions from the Er3+ were: approximately 380 nm, approximately 408 nm, approximately 521 nm, approximately 537 nm, and approximately 652 nm. Therefore, cyan-white light can be observed by the naked eye at 980-nm excitation, even under low excitation power density. By comparing the UC spectra of the phosphors annealed at different temperatures, we found that the intensity of the UC luminescence increased as annealing temperature increased. Furthermore, the spectral dependencies on Tm3+ doped concentrations were studied. The energy transfer processes and fluorescence dynamics in the tri-doped system are currently being investigated.