Synthesis and dielectric properties of polyarylene ether nitriles with high thermal stability and high mechanical strength

A series of polyarylene ether nitriles were synthesized by the nucleophilic aromatic substitution polymerization of 2, 6-dichlorobenzonitrile with various bisphenol monomers. Owing to the different structural units, the derived copolymers showed different glass transition temperatures in the range of 166–260 °C. Moreover, they all showed good film-forming properties and high mechanical strength ranging from 75 MPa to 117 MPa, and also exhibited high thermal stability with the 5% weight loss temperatures ranging from 373 °C to 498 °C. Furthermore, both the dielectric constant and dielectric loss were found to be relatively stable with respect to temperature before the turning point temperature, which is very near to the glass transition temperature.     

Microstructure and mechanical properties of novel Al-Y-Sc alloys with high thermal stability and electrical conductivity

The microstructure and mechanical properties of novel Al-Y-Sc alloys with high thermal stability and electrical conductivity were investigated.Eutectic Al3 Y-phase particles of size 100-200 nm were detected in the as-cast microstructure of the alloys.Al3 Y-phase particles provided a higher hardness to as cast alloys than homogenized alloys in the temperature range of 370-440℃.L12 precipitates of the Al3(ScxYy) phase were nucleated homogenously within the aluminium matrix and heterogeneously on the dislocations during annealing at 400℃.The average size of the L12 precipitates was 11±2 nm after annealing for 1 h,and 25-30 nm after annealing for 5 h,which led to a decrease in the hardness of the Al-0.2 Y-0.2 Sc alloy to15 HV.The recrystallization temperature exceeded 350℃and 450℃for the Al-0.2 Y-0.05 Sc and Al-0.2 Y-0.2 Sc alloys,respectively.The investigated alloys demonstrated good thermal stability of the hardness and tensile properties after annealing the rolled alloys at 200 and 300℃,due to fixing of the dislocations and grain boundaries by L12 precipitates and eutectic Al3 Y-phase particles.The good combination of strength,plasticity,and electrical conductivity of the investigated Al-0.2 Y-0.2 Sc alloys make it a promising candidate for electrical conductors.The alloys exhibited a yield stress of 177-183 MPa,ultimate tensile stress of 199-202 MPa,elongation of 15.2-15.8%,and electrical conductivity of 60.8%-61.5% IACS.     

Side radical influence on the nonlinear optical properties and thermal stability of poled polymer films

Films of polyetherketone doped with the chromophores Disperse Red 1 (DR1) and Disperse Red 13 (DR13) were prepared by spin-coating method. By the in situ Second-harmonic Generation (SHG) signal intensity measurement, the optimal poling temperatures were obtained. For the investigated polyetherketone polymer doped with DR1 (DR1/PEK-c) and polyetherketone polymer doped with DR13 (DR13/PEK-c) films, the optimal poling temperatures were 150°C and 140°C, respectively. Under the optimal poling conditions, the high second-order nonlinear optical coefficient ₃₃ ⁽²⁾ = 11.02 pm/V has been obtained for the DR1/PEK-c; and for DR13/PEK-c at the same conditions the coefficient is 17.9 pm/V. The SHG signal intensity DR1/PEK-c could maintain more than 80% of its initial value when the temperature was under 100°C, and the SHG signal intensity of the DR13/PEK-c could maintain more than 80% of its initial value when the temperature was under 135°C.     

Nonlinear optical materials: Synthesis,characterizations, thermal stability and electro-optical properties

Two series of thermal stable polyimides and polyimide/silica hybrid materials have been synthesized. The silica content in the hybrid materials was varied from 0 to 22.5 wt.% and SiO₂ phase was well dispersed in the polymer matrix. The glass transition temperature (T_g) and the decomposition temperature (T_d) were in the range 226–382 °C and 345–499 °C, respectively, for materials. The polymer solutions could be spin coated on the indium–tin–oxide (ITO) glass or other substrates to form optical quality thin films. The electro-optic coefficients (γ₃₃) at the wavelength of 832 nm for polymer thin films poled were in the range of 12–25 pm/V and the values remained well (retained > 85% for more than 100 h). The heat capacities of some materials were in the range of 0.9755–1.1821 J K^− 1 g^− 1 for the temperature 273 and 363 K. No thermal anomaly was found in this temperature range. Most of them showed high thermal stability.     

Effective regulation of second-order nonlinear optical properties of macrocyclic thiophene-based derivatives with dipole structure

The static second-order nonlinear optical susceptibilities (β₀) of a series of macrocyclic thiophene-based derivatives with strong donor/acceptor (D/A) substituents were studied in detail on the basis of the stability of the equilibrium geometries calculated at density functional theory (DFT) level. The research results show that the type of substituent, the pair number and the position of D/A group all have important influence on the value of β₀. The molecule 4A_1–4D_5–8 with four pairs of electron donor (NH₂) and acceptor (CN) located at contraposition has larger value of β₀ (−338.88 × 10⁻³⁰/esu), which is close to 50 times larger than that of SII. And the absolute value of β₀ enlarges as increasing the ring size or the pair number. Moreover, the effects of BLA and charge transfer are analyzed to explain the significant enlargement of β₀ for the molecules with stronger D/A group, besides the influence factors of ƒ, Δμ and W in the two-level approximation formula. In addition, it indicates an approximately proportional relationship between the values of β₀ and δ_max for most studied molecules.     

一种非线性光学偶氮分子的合成及跃迁偶极矩的测定

以对甲氧基苯胺、苯酚、溴丙炔等为原料，通过重氮化-偶合反应、醚化反应等合成了一种非线性光学偶氮分子；用红外光谱、核磁共振、紫外可见光谱对其结构进行了表征，测定了分子的跃迁偶极矩为5．12D。     

新型聚丙烯酸酯的制备与非线性光学性能

设计合成了一种含偶氮苯和取代苯乙炔基长共轭生色团的丙烯酸酯,并采用溶液聚合法合成了功能化的聚丙烯酸酯,利用FTIR、NMR等对化合物的结构进行了表征,证实得到了指定结构的化合物.利用z-scan技术对合成的聚丙烯酸酯的非线性光学性能进行了表征,对聚合物的非线性吸收进行拟合,计算得到非线性吸收系数β和三阶非线性系数x(3).     

Synthesis of MCM-48 with a high thermal and hydro-thermal stability

High thermal and hydro-thermal stable MCM-48 was synthesized by a mixed nonionic-cationic surfactant templating pathway. The sample retains its cubic structure when at 1000 °C for 2 h and when calcined in air with 100% water vapor at 600 °C for 2 h.     

Synthesis,mechanical, thermal and chemical properties of polyurethanes based on cardanol

Cardanol, an excellent monomer for polymer production, has been isolated from CNSL and allowed to react with formaldehyde in a particular mole ratio in the presence of glutaric acid catalyst to give high-ortho novolac resin. Such characterized polyol has been condensed with diphenylmethane diisocyanate to produce rigid polyurethane. A commercially available polyol, polypropylene glycol-2000 (PPG-2000), has also been condensed with diphenylmethane diisocyanate and polyol to produce tough polyurethane. These polyurethanes were characterized with respect to their resistance to chemical reagents and mechanical properties such as tensile strength, percentage elongation, tear strength and hardness. Differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) were undertaken for thermal characterization.     

Synthesis and nonlinear optical properties of a side-chain polyurethane

Abstracts are not published in this journal     

Synthesis and nonlinear optical properties of Lead Telluride nanorods

Lead Telluride (PbTe) nanorods have been uniformly grown on silicon substrates, using the thermal evaporation technique under high vacuum conditions. The structural and morphological studies are done using X-ray diffraction and scanning electron microscopy. Optical nonlinearity studies using the open aperture z-scan employing 5 ns and 100 fs laser pulses reveal a three-photon type absorption. For nanosecond excitation the nonlinear absorption coefficients (γ) are in the order of 10⁻²² m³ W⁻² and for femtosecond excitation it is in the order of 10⁻²⁹ m³ W⁻². The role of free carriers and excitons in causing the nonlinearity in both excitation time domains is discussed. Results indicate that PbTe nanorods are good optical limiters with potential device applications.     

Synthesis of nano-ceria powder of high thermal stability

A new method is studied for preparing nano-ceria by acid leaching MgO from CeO₂−MgO mixed powder made by calcining a gel. The MgO in the mixed powder can be leached completely with acetic acid solution at room temperature, but the CeO₂ remains unaffected. The surface area (Sg) of the resulting CeO₂ increases with Mg/Ce ratio, but approaches constant after the ratio is larger than a given value which is higher for the higher gel calcining temperature. When Mg/Ce is 8 (molar ratio) and the calcining temperature is 1253 K, the Sg of the resulting ceria remains 25.1 m²/g even after annealed at 1253 K for 4 h. In comparison with the conventional methods, CeO₂ from the new method shows higher surface area and higher thermal stability.     

Isosorbide based chiral polyurethanes: optical and thermal studies

A new class of chiral polyurethanes containing amido linkages in the polymer backbone have been synthesized by reacting toluene diisocyanate with isosorbide (IS) chiral moiety and the chromophores [N,N′-ethane-1,2-diyl bis(6-hydroxy hexanamide), N,N′-butane-1,4-diyl bis(6-hydroxy hexanamide) and N,N′-hexane-1,6-diyl bis(6-hydroxy hexanamide)]. The corresponding chromophores were obtained by the aminolysis of ε-caprolactone by using the diamines, diaminoethane, diaminobutane and diaminohexane, respectively. All the polymers were synthesized according to the symmetry conditions so as to obtain the non-centrosymmetric environment. A series of polyurethanes were synthesized by varying the chiral–chromophore composition. The polyurethanes developed were characterized by optical and thermal methods.     

Synthesis of novel two-dimensional spindle-type fluorinated nonlinear optical chromophores

Two novel two-dimensional spindle-type fluorinated chromophores with fluorinated phenyl as side groups connecting to the π conjugated bridge were prepared for second-order nonlinear optical applications. The detailed synthetic procedure was reported. Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed that the spindle-type fluorinated chromophores have excellent thermal stability. Host-guest doped materials had been used to prepare the second-order nonlinear optical films. The nonlinear electro-optic (EO) coefficient of the poled films was measured by Teng-Man technique at the fundamental wavelength of 1310 nm, and the r₃₃ up to 28 pm/V was achieved.     

新型多羟基树枝化线形聚氨酯的合成

聚氨酯侧链接枝末端舍有大量羟基且具有良好生物相容性的脂肪族聚酯树枝状分子,在引入大量反应官能团的同时增加分子间空间间隔,为生物活性分子的接枝提供一种性能优异的中间材料.通过1H-NMR、DSC、接触角及表面分析等测试方法表征聚氨酯树枝化前后结构及性能的改变.结果显示,多羟基树枝化线形聚氨酯的氢键化程度大大提高,结晶性能降低,亲水性及表面粗糙度增加.细胞培养试验证明,该材料具有很好的细胞相容性,为其在生物医学上的应用奠定了良好的基础.     

Synthesis and nonlinear optical properties of Lif films containing gold nanoparticles

We have studied the structure and optical properties of a thin lithium fluoride (LiF) film containing nanosized gold particles, which has been obtained by the thermal evaporation of LiF and Au followed by deposition onto the surface of a glass substrate heated to 590 K. Data of scanning electron microscopy and X-ray diffraction (XRD) showed that the composite film possesses a polycrystalline structure with an average LiF grain size of about 170 nm. The formation of gold nanoparticles in the film was confirmed both by XRD data and the presence of plasmon resonances in the optical absorption spectrum, which is close to the spectra obtained by model calculations for a LiF matrix with 20- to 40-nm-sized gold particles. Using the Z-scan technique, it is shown that the composite film exhibits nonlinear absorption of pulsed laser radiation with a wavelength of 780 nm and pulse duration of 150 fs at a power exceeding 100 mW. The magnitude of this effect is comparable to that observed previously for various single-crystalline matrices containing gold nanoparticles.     

新型双光子聚合引发剂的合成和非线性光学性质的研究

合成了两种新的双光子聚合引发剂反式-二苯基-{{4-[2-(4-吡咯基-1-苯基)-乙烯基]-苯基}胺(简称DPVPA)和反式-9-{4-[2-(4-吡咯基-1-苯基)-乙烯基]-苯基]-9-氢咔唑(简称PPVPA).用1H NMR谱和元素分析进行了表征.测试了紫外吸收光谱、单光子荧光光谱、单光子荧光寿命和双光子荧光光谱.在760 nm的飞秒脉冲激光激发下,DPVPA和PPVPA均发出较强的上转换荧光,荧光峰分别位于468和452 nm.以DPVPA做引发剂,加入丙烯酸酯型齐聚物(CN120C80),用DATACHROOM-5000纳秒激光器辐射出600nm的激光做光源,实现了双光子聚合反应,并定性地解释了其聚合机理.     

Synthesis and nonlinear optical properties of nanometer-size silver-coated polydiacetylene composite vesicles

Two kinds of nanometer-size silver-coated polydiacetylene (PDA) composite vesicles were prepared by simple and effective approaches. Silver nanoparticles were coated onto the outer and inner surface (I) or only on the outer surface of PDA vesicles (II), respectively. UV-vis spectra and transmission electron microscopy (TEM) were used to confirm the formation of PDA/Ag nanocomposite vesicles. Nonlinear optical (NLO) properties of these PDA/Ag nanocomposite vesicles had been measured by the Z-scan technique. The value of n(2) for pure PDA vesicles was 1.2 × 10(-14)?cm(2)?W(-1). However, for PDA/Ag nanocomposite vesicles (on the outer surface) it was 7.3 × 10(-14)?cm(2)?W(-1). Nearly seven times enhancement was observed as a result of local field enhancement under the surface plasmon resonance of silver nanoparticles at the interface. NLO?properties of these PDA/Ag nanocomposite vesicles can be modulated by varying the size, shape and coverage of Ag nanoparticles and these PDA/Ag nanocomposite vesicles are expected to be good candidates for new optical and nonlinear devices.     

有机功能色素类化合物的合成与三阶非线性光学性能

设计并合成了苯并二呋喃酮、双偶氮-9,10-蒽二酮、苯并噻蒽以及偶氮-1,3,4-噻二唑4个系列的有机色素类化合物,并用UV,IR,1H NMR和元素分析表征了结构.采用飞秒激光,运用简并四波混频法,研究了化合物的三阶非线性光学性能.它们的三阶非线性光学极化率χ(3)为2.64～3.95×10-13esu,非线性折射n2为4.85～7.27×10-12esu,分子二阶超极化率γ为2.85～3.72×10-31esu.探索了化合物的分子结构对三阶非线性光学性能的影响.长的共轭链、吸供取代基和杂环的引入、取代基强的供电子或吸电子能力等因素有利于获得较大的三阶非线性光学性能.     

Synthesis and nonlinear optical properties of some donor–acceptor oxadiazoles

Heterocyclic 1,3,4-oxadiazole moiety has been used as a new π-conjugation relay to prepare a number of donor–acceptor molecules carrying a π-electron-rich aromatic ring as a donor and either a p-nitrophenyl or a pyridine/pyridinium ring as an acceptor. Several of these oxadiazoles display significant second-order molecular nonlinearity, β (14–124 × 10⁻³⁰ esu) and provide the basis for future design of efficient nonlinear optical materials having the oxadiazole core.