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基于季戊四醇的二代硅碳烷液晶树状物--端基含36个丁氧基偶氮苯基团 总被引:2,自引:1,他引:1
以基于季戊四醇的二代硅碳烷树状氯化物PCSi-2G-Cl为脚手架、4一-丁氧基-4’-羟己氧基偶氮苯(M—C4)为介晶基元,合成了以季戊四醇为核、端基含36个丁氧基偶氮苯的新型硅碳烷液晶树状物PCSi-2GC4。利用红外光谱(IR)、核磁共振(^1H NMR)、元素分析(EA)、偏光显微镜(POM)和差示扫描量热法(DSC)进行了表征。PCSi-2G-C4与M—C4同为向列相,说明树状物相态由介晶基元相态决定。PCSi-2G-C4的熔点比M—C4降低13℃,清亮点比M—C4降低15℃。 相似文献
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以基于季戊四醇的二代硅碳烷树状氯化物PCSi-2G-Cl为脚手架、4-硝基-4'-羟己氧基偶氮苯(M-NO2)为介晶基元, 合成了以季戊四醇为核、端基含36个硝基偶氮苯的新型硅碳烷液晶树状物PCSi-2G-NO2.利用红外光谱(IR)、核磁共振(1H NMR)、元素分析(EA)、偏光显微镜(POM)和差示扫描量热法(DSC)进行了表征,PCSi-2G-NO2显示近晶相, 其液晶相行为是K57SE76SA111I110SA75SE56K.而对应的介晶基元M-NO2则为向列相,树状物与修饰单元在熔点、清亮点和液晶态温度区间等方面也存在较大差异. 相似文献
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合成了外围含4-丁氧基偶氮苯介晶基元的三代硅碳烷液晶树状物PCSi-3G-C4.以4-[4-(6-羟基已氧基)苯基]丁氧基偶氮苯介晶基团对端基官能团为Si-Cl的三代硅碳烷树状物PCSi-3G-Cl脚手架进行功能化,并利用元素分析、红外光谱(IR)、核磁共振(NMR)、偏光显微镜(POM)、差示扫描量热法(DSC)对其结构与液晶性进行表征.结果表明,与对应的液晶基元相似PCSi-3G-C4显示向列相,但二者在熔点、清亮点和液晶态温区等方面存在一定差异. 相似文献
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哑铃型树枝状液晶大分子的合成与性能研究 总被引:1,自引:1,他引:0
以基于1,6-己二醇的硅碳烷树状物为前驱体,4-[4-(6-羟己氧基)苯基偶氮]丁氧基苯(MC4)为介晶基元,合成了一至二代哑铃型树枝状液晶大分子,其外围分别含6个和18个偶氮苯基团.利用红外光谱(IR)、核磁共振氢谱(1HNMR)和元素分析(EA)对其进行了结构表征.通过差示扫描量热法(DSC)、偏光显微镜(POM)和X射线衍射(XRD)对其热行为和液晶性进行表征,确认树枝状液晶大分子为向列相液晶.与对应的液晶基元相比,树枝状液晶大分子的熔点和清亮点均明显降低. 相似文献
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高分子液晶电流变流体的研究 总被引:2,自引:0,他引:2
研究以聚硅氧烷侧链高分子液晶作为分散相 ,制备均相的电流变流体 (ER流体 ) ,测试其在电场下表观粘度、剪切应力等流变学性质的变化。结果发现 :以硅油作分散介质 ,含6 6 7%的高分子液晶的流体 ,在剪切速率为 30 0s- 1时 ,电场强度 (E)从 0升至 2kV/mm ,流体的剪切应力从 2 0 0Pa·s上升至 540 0Pa·s ,表观粘度由 2 0 0 0mPa·s上升至 10 0 0 0mPa·s ,并且 ,流体在80℃时仍有很强的电流变效应 ,能在较宽的温度范围内使用 相似文献
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板料弯曲回弹影响因素的有限元模拟研究 总被引:4,自引:0,他引:4
通过静态力学、动态力学实验方法,研究了热致性液晶聚合物(LCP)的种类对环氧树脂共混物在不同温度下的拉伸强度和应力-应变曲线的影响,通过TEM观察了共混物的相形态结构.结果表明,反应型液晶聚合物(LCPU)比其它种类的液晶聚合物对环氧树脂的改性效果更好;在不同温度下,其拉伸强度和应力~应变行为均比其它材料优越;固化物的动态力学结果表明:反应型的液晶聚合物键入了固化网络,出现新的松弛,TEM结果表明,反应型的液晶聚合物在基体材料中形成大小在nm数量级的液晶聚集微区,没有反应基团的液晶聚合物PHBHT在10%的加入量下,与环氧的共混物结构也有液晶聚集微区产生,但是聚集区大小在微米量级. 相似文献
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Bruschi ML de Freitas O Lara EH Panzeri H Gremião MP Jones DS 《Drug development and industrial pharmacy》2008,34(3):267-278
Precursor systems of liquid crystalline phase were prepared using the surfactant PPG-5-Ceteth-20, isopropyl myristate, and water; gelatin microparticles containing propolis were then added into these systems. Homogeneity of dispersion, the in-system microparticle morphology, and sedimentation behavior of each formulation were evaluated. The rheological and mechanical properties (hardness, compressibility, and adhesiveness), the work of syringing, and the propolis release profile were also evaluated. All the formulations exhibited pseudoplastic flow and thixotropy, and they displayed storage modulus, loss modulus, dynamic viscosity, and loss tangent that depended on temperature, frequency, and composition. Mechanical properties varied significantly among the formulations being affected by changes in the composition and temperature. Raising the concentration of surfactant and adding propolis microparticles significantly decreased the work of syringing. The drug release was non-Fickian (anomalous) and there was no significant difference between the tested systems in the times required for 10%, 30%, and 50% release of the initial drug loading. 相似文献
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Li Tao Swathi Pinamanenni Krishnaswamy Raghavan 《Drug development and industrial pharmacy》2019,45(5):819-825
BMS-830216 is a diprotic acid prodrug of two pKa values (<2 and 6.8) with high apparent solubility at pH ≥ 7. At?~?pH 4 solutions of BMS-830216 appear to be surface active, in which their surface tension can be reduced from 72 to 65 dynes when its concentrations is above the critical aggregation concentration (CAC~0.2?mM). Additionally, at this pH, BMS-830216 tends to form liquid crystalline phases (at ≥ 2?mg/mL) in acetate buffer when using tris salt. Furthermore, after raising the concentration beyond 20?mg/g, formation of gel-like dispersions was noted. These gel-like dispersions exhibited a strong elastic strength, significantly impacting the dissolution behavior of the tris salt. Mechanistically, it is likely that BMS-830216 tris salt in solution first forms a lamellar phase followed by formation of a gel phase at higher concentrations (≥20?mg/mL). As indicated by SAXS, the lamellar phase formed seems to have two d-spacing values (~5?nm and ~10?nm (weak), which seems to correspond to two molecules connected tail by tail (5?nm). Further investigation is needed for phase identification, as their properties can affect the physical behavior of BMS-830216 in the development of pharmaceutical dosage forms. 相似文献