Small range 文档类型:"1"

Totally found 7 items.

  • [会议] 阻燃型对二甲苯基氰酸酯的合成、表征与性能
    本文合成了两种含对二甲苯结构氰酸酯单体.通过苯酚和2,6-甲基苯酚分别与对苯二甲基二甲醚(BMBZ)反应分别制得含酚单体1,4-二(4一羟基一苄基)苯(BHBZ)和1,4-二(3,5-甲基-4-羟基-苄基)苯(BBZ),进一步与氯化氰反应合成相应对苯二甲基型氰酸酯单体.通过红外光谱(FTIR)、电喷雾质谱(ESI-MS)、氢核磁共振谱(IH-NMR)对酚中间体和氰酸酯单体结构进行表征.研究树脂浇注体的热性能、介电性能、吸湿性和阻燃性等并与双酚A型氰酸酯(BADCy)进行比较.结果表明,BHBZCy和BBZCy800℃残留率分别达到55.2%和40.5%;介电常数分别为3.03和2.8I(IMHz); 80h吸水率分别为0.87%和1.0%;阻燃等级达到UL-94Ⅴ-O级.
    关键词: 阻燃型对二甲苯基氰酸酯树脂;合成工艺;结构表征;性能评价
  • [会议] Importance of microstructural features in mechanical response of cast-cured HMX formulations
    Cast-cure formulations of plastic-bonded explosives (PBX) present some advantages in manufacturing and application compared to traditional pressed slurry formulated materials. For example, these formulations can be cast to specific shapes and then cured in place, avoiding the need for machining precision parts. However, the microstructure of these materials can be greatly affected by the specific manufacturing process. Here, we evaluate the effect of minor changes to the formulation and manufacturing process on several cyclotetramethylene-tetranitramine (HMX) PBXs. The binders were based on hydroxyl-terminated polybutadiene (HTPB) and cast-cured using diphenylmethane diisocyanate (isonate) as a curing agent. We examined the materials using X-ray computed tomography (CT) imaging and uniaxial compression testing. The isonate content was found to significantly affect the modulus and strength of the binder. The presence of significant void content could be controlled by adding a centrifuging step during the curing process, but the resulting effect on mechanical properties was relatively minor. Mesoscale simulations showed that differences in the mechanical strength of the binder were not sufficient to describe the differences observed in mechanical testing, indicating that the HMX-binder adhesion was also being changed by the manufacturing process.
    关键词: -
  • [会议] Facile One-Pot Palladium-Catalyzed Sequential Coupling to Diarylmethanes by Using Aryl Methyl Ketones as the Methylene Donors
    Diphenylmethane is an important substructure unit that is found not only in a number of natural products[1], but also in many synthetic compounds of biological and pharmaceutical importance[2]. Significant efforts are devoted to the construction of this motif and its derivatives, and diverse synthetic methods, roughly classified as conventional[3] and catalytic ones[4], have been reported so far. In this article, we described a first example for the synthesis of symmetrical diarylmethanes by facile, one-pot, two-step, palladium-catalyzed sequential coupling(Scheme 1). In the facile one-pot reaction, aryl methyl ketone acts in formal as the methylene donor. The experimental facts, including TLC monitoring, speculated intermediates as the raw materials, ex situ IR spectroscopy analysis of the co-product cesium benzoate, as well as the cross-coupling reactions of two different aryl halides, indicate a mechanism involving a palladium-catalyzed sequential two-step coupling process. The reaction is applicable for a broad spectrum of substrates(up to 21 examples) in good to excellent yields. The access to unsymmetrical diarylmethanes with this method is also explored and various factors are discussed.
    关键词: homogeneous catalysis;palladium;cross-coupling;reaction mechanism
  • [会议] Effect of Catalysts on the Properties of Fluorinated Polyurethanes
    Fluorinated polyurethanes(FPU) was prepared using fluorinated polyether polyol(FPO) as the soft segment, 4,4`-diphenylmethane diisocyanate(MDI) as the hard segment, 1,4-butanodiol(BDO) as the chain extender and catalysts. Tin metal catalysts were used to catalyze the polyurethane reaction of polyether polyols and isocyanate. The effect of different catalysts including stannous octoate(T-9) and dibutyltindalautrate(DBTDL) on the structure, surface properties and thermal properties of FPU was studied. The structural elucidation of the synthesized FPU was performed by Fourier transform infrared(FT-IR) and discovered that with decreasing catalyst efficiency or without catalyst, the strength of hydrogen bounds were enhanced. The FPU films surface was characterized by contact angle(CA) and atomic force microscopy(AFM) and it was found that the phase separation was increasing with increasing catalyst efficiency. The thermal property was exhibited by Thermo gravimetric(TG) and showed that joining catalyst improved stability significantly.
    关键词: FPU;Different Catalysts;Properties
  • [会议] Micro-Phase Separation Structure of Nonionic Polyether-Polyester Polyurethane Based On MDI
    Segmented polyether-polyester polyurethanes with an amorphous hydrophilic soft segment phase were prepared from 4,4'-diphenylmethane diisocyanate(MDI),polybutylene adipate glycol 2000(PBA2000) and polyethylene glycol 1000(PEG1000) with 1,4-butanediol(BDO) as the chain extender.Furthermore,the micro phase separation structure of the polyurethanes was studied.The studies show,the micro-structure of nonionic polyurethane has been remarkable influenced by the structure,molecule and concentration of its soft segments.
    关键词: polyurethane;micro-structure;polyether;polyester
  • [会议] Host-guest Interaction of Cucurbit[7, 8]uril and Auramine O Dye
    Auramine O(AuO)is a derivative of diphenylmethane cationic fluorescent dye,which is used to study the complexation properties of the host molecules,such as cyclodextrins1 and calix[6]arene sulfonates.2 The host-guest interaction between Auramine O and Cucurbit[n]uril3 has been investigated in aqueous solutions.The studies suggest simultaneous formation of 1:1
    关键词: Cucurbit[n]uril;Auramine O;Fluorescence
  • [会议] 亚胺键连接的二茂铁基纳米多孔有机高分子
    纳米多孔有机高分子材料因具有良好的化学稳定性、热稳定性、高孔隙率和低密度等优点,在气体吸附与存贮等领域具有巨大的应用潜力。本文以立体结构的四(4-氨基苯)甲烷为中心单体,以双层夹心结构的二茂铁二甲醛为构筑单元,通过席夫碱反应制备了二茂铁基纳米多孔有机高分子(Ferrocenyl Nanoporous Organic Polymers,FNOPs)。分别用TGA、SEM、SSNMR、氮气吸脱附等手段对FNOPs的热稳定性、表面形貌、化学结构和孔结构进行了分析与表征;研究了FNOPs对H2、CO_2和CH4的吸附能力。制备的FNOPs是尺寸约为1μm的无定形颗粒,且在240℃时会发生明显的分解和失重。FNOPs的比表面积和孔体积分别为856.5 m~2/g、1.30 cm3/g。在1.0MPa/77.3K的条件下,FNOPs对H_2的吸脱附值为1.18 wt%;在1.0MPa/273K的条件下,FNOPs对CO_2和CH_4的吸附值分别为17.40 wt%和2.25 wt%。与同类材料相比,FNOPs具有较突出的CO_2吸附能力。首先,缺电子的Fe元素与富电子的CO_2分子之间的相互作用力提高了FNOPs对CO_2的吸附能力;其次,FNOPs中氮原子提供了相互作用点,也可通过偶极-偶极相互作用来提高FNOPs对CO_2的吸附值。
    关键词: 多孔高分子;二茂铁;气体吸附
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