聚二甲基丙烯酸乙二醇酯壁材微胶囊的制备及其表征

采用界面自由基聚合的方法,制备了以聚二甲基丙烯酸乙二醇酯(PEGDMA)为壁材,薄荷素油(DPO)与石蜡或者三辛癸酸甘油酯(GTCC)的混合物为芯材的微胶囊.微胶囊壁材是二甲基丙烯酸乙二醇酯(EGDMA)单体通过界面自由基聚合形成的高聚物PEGDMA.提出了该界面自由基聚合形成PEGDMA的机理过程.利用光学显微镜和扫描电镜探究了乳化剂类型、芯材组成和固化温度对微胶囊形貌的影响.用傅里叶红外光谱对微胶囊的化学结构进行了表征.利用紫外分光光度计测出了未被微胶囊包埋的芯材占总芯材的百分比(free oil).并用热重分析仪分析了微胶囊的热稳定性能,讨论了固化时间对微胶囊热性能的影响.结果表明,采用阿拉伯树胶为乳化剂,芯材组成为质量比M_(DPO)/M_(GTCC)=1∶1,在60℃下固化1 h,制备出的微胶囊为饱满的球形状,表面光滑.同时测得该体系中芯材的free oil为26.5 wt%.PEGDMA微胶囊在60℃固化温度下反应3 h,具有很好热稳定性,且固化温度升高能提高微胶囊的热稳定性.所制备的微胶囊无毒,在个人护理品和医药领域具有广泛的应用前景.     

改性胺微胶囊固化剂制备工艺的优化与性能

以改性胺1618固化剂为囊芯、脲醛树脂为壁材单体,采用界面聚合技术,成功制备了一种新型聚脲改性胺微胶囊固化剂。通过正交设计试验,考察了芯壁质量比、乳化剂种类和质量分数及搅拌速率对微胶囊包覆率、粒径大小及分布情况的影响,并确定了最佳制备工艺条件。采用马尔文激光粒度仪、扫描电镜对微胶囊粒径大小、分布情况及表面形貌进行表征,采用热重分析仪及傅里叶变换红外光谱对其化学结构进行表征,通过拉伸试验对自修复材料的断裂力学性能进行研究。结果表明,该微胶囊含有固化剂芯材,其热稳定温度为198°C,当芯壁质量比为0.7∶1、乳化剂为阿拉伯胶、乳化剂质量分数为1.5%、搅拌速率为800r/min时,所制备的微胶囊包覆率达到79.8%,平均粒径为207.5nm,呈规则的球形,分散性及表面致密性好。当基体材料中加入质量分数为1%的微胶囊后,拉伸强度提高64%,弹性模量提高287%。     

具有薄荷香味的相变微胶囊的制备与表征

利用界面聚合法,以异佛尔酮二异氰酸酯与己二胺为单体聚合形成的聚脲为外壳,以正十八烷、薄荷素油的混合物为芯材,制备了具有薄荷香味的相变微胶囊。利用光学显微镜、扫描电镜、红外光谱仪、差示扫描量热仪、热重分析仪等对微胶囊的形貌、化学结构和热性能进行了表征。结果表明:制备的微胶囊为球形,平均粒径约7.0μm,有较高的储热能力和较好的热稳定性;芯材中添加8.3%的正十四醇或高熔点石蜡,可很好地抑制相变微胶囊的过冷现象。     

高效氯氰菊酯微胶囊的制备、表征及释放性能

以高效氯氰菊酯为芯材, 乙基纤维素为壁材, 采用溶剂蒸发法制备了微胶囊, 并对其理化性能进行表征, 通过单因素实验研究了工艺参数对微胶囊外观形貌、 粒径大小及分布、 包封率、 载药量和缓释性能的影响. 结果表明, 乳化剂种类和剪切时间可以显著影响微胶囊的外观形貌; 随着乳化剂用量增大, 微胶囊粒径减小, 分布变窄, 当Tween-80用量从4%增加至8%时, 微胶囊平均粒径从59.9 μm减少到29.8 μm, 跨距也从1.21减少到0.72. 随着芯壁比(质量比)减小, 微胶囊粒径和包封率均逐渐增大, 载药量逐渐减小, 当芯壁比为1:1.75时, 包封率可以达到70%以上. 微胶囊释放动力学模型符合Ritger-Peppas模型(lgQ=lgk+nlgt); 平均粒径相近而载药量不同时, 初期载药量最小的样品释放速率慢, 累积释放率低; 载药量相近而平均粒径不同时, 粒径大的样品释放速率低, 累积释放率也低.     

丙烯酸共聚物囊壁的正十八烷微胶囊的制备和性能表征

以二丙烯酸1,4-丁二醇酯为交联剂, 成功制备了甲基丙烯酸甲酯-甲基丙烯酸共聚物为壁材, 正十八烷为囊芯的相变材料微胶囊. 采用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和热重分析仪(TG)分别考察了单体与芯材投料比、单体浓度和交联剂的含量对微胶囊形貌、相变热性能、热稳定性能的影响. 实验结果表明: 随着单体与芯材投料比或单体浓度的增加, 微胶囊表面均变得致密, 壁厚增加; 随着交联剂含量的增加, 微胶囊的表面变得更加致密光滑, 热稳定性显著增强; 随着单体与芯材投料比的增大, 微胶囊热焓值减小, 被包裹的囊芯含量减少.     

十八烷/聚(St-MMA)相变微胶囊制备及表征

采用乳液聚合的方法,分别选取聚苯乙烯(PS)、聚甲基丙烯酸甲酯(PMMA)或苯乙烯和甲基丙烯酸甲酯的共聚物为壁材,正十八烷为芯材,十二烷基苯磺酸钠(SDBS)为乳化剂,制作相变储能微胶囊。用粒径分析仪、透射电子显微镜(TEM)、热重分析仪(TG)和示差扫描量热测试仪(DSC)对微胶囊的形貌、相变热性能和热稳定性分别进行表征。结果表明:壁材选取两者共聚物,当两种单体的比例为St∶MMA=1∶5,SDBS用量为1.5g(总质量的3%)时,微胶囊粒径大小均匀,粒子分散性好,壁材的包裹性好。微胶囊的放热峰为起始温度为27.3℃,终止温度为31.9℃,相变温度为28.9℃,相变焓为48.4J/g。TG表明长期使用温度不能超过131℃。IR分析微胶囊中含有芯材和壁材。这种十八烷/聚(St-MMA)相变微胶囊可以用于诸能材料。     

不同相对分子质量羟乙基纤维素对甲维盐微胶囊制备的影响

采用原位聚合法以三聚氰胺-甲醛树脂为壁材制备了甲维盐微胶囊。 探讨了不同黏均相对分子质量羟乙基纤维素作为乳化剂对微胶囊表面形貌、粒径及其分布、包覆率与载药量的影响,对使用不同黏均相对分子质量羟乙基纤维素作为乳化剂制备的微胶囊的释放性能进行了表征。 结果表明,以相对分子质量较小的羟乙基纤维素制备的微胶囊外形规则、致密且无黏连现象。 随羟乙基纤维素黏均相对分子质量的增加所得微胶囊的平均粒径及粒径分布逐渐增大,包覆率与载药量逐渐减小。 释放性能的研究表明,采用相对分子质量较小的羟乙基纤维素制备的微胶囊的释放性能较好。     

细粒径石蜡微胶囊相变材料的制备与性能

采用阳离子和非离子复配乳化剂,通过原位聚合制备以丙烯酸酯为壁材,石蜡为芯材的细粒径微胶囊相变材料.采用傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、差示扫描量热(DSC)、热重(TG)及激光粒度仪分析表征了微胶囊相变材料的化学结构、表面形貌和热性能.结果表明,乳化剂的种类和壁材单体的配比对微胶囊性能有重要的影响.当采用阳离子和非离子复配乳化剂,壁材中单体甲基丙烯酸甲酯(MMA)与丙烯酸(AA)的质量比为9∶1时,微胶囊相变材料呈球形且表面光滑紧凑,尺寸仅为0.2~0.35μm,具有良好的储热能力,相变潜热高达169 J/g;微胶囊中壁材对石蜡芯材的分解具有明显热阻滞作用,分解温度比纯石蜡提高了150℃.     

乳化工艺对微胶囊型硬脂酸相变材料热性质的影响

以硬脂酸为芯材, 碳酸钙为壁材, 采用原位聚合法制备了微胶囊型相变材料; 通过扫描电子显微镜、 红外光谱及差热-热重分析对其表面形貌和热性质进行了表征; 通过改变乳化剂的种类及用量, 研究了乳化工艺对微胶囊型相变材料表面形貌、 相变温度和包覆率的影响. 实验结果表明, 在选用的3种乳化剂十二烷基苯磺酸钠、 十六烷基三甲基溴化铵和曲拉通X-100中, 十二烷基苯磺酸钠相对效果最好, 乳化剂与芯材最佳质量比为0.5%, 相变温度为112.24 ℃时, 封装率达到92.1%.     

大豆分离蛋白-十二烷基硫酸钠微胶囊的制备与表征

以大豆分离蛋白(SPI)和十二烷基硫酸钠(SDS)为壁材, 以十六烷为芯材, 通过复凝聚法制备了微胶囊. 首先确定了SPI和SDS发生复凝聚的适宜pH、SPI/SDS配比、壁材浓度等. 在确定的实验条件下进行复凝聚, 凝聚物产率可达85%. 改变搅拌转速和芯壁比, 考察它们对微胶囊性能的影响. 用光学显微镜观察了微胶囊形貌. 用气相色谱测定了微胶囊的载药量和包覆率. 芯壁比为2、搅拌转速为400 r/min时所制备微胶囊的载药量可达61%. 随着芯壁比的增大, 微胶囊粒径及载药量都逐渐增大.     

二次配体结构和[CuCl4]2－构型对层间隧道结构的影响研究

设计合成的质子配体, N,N,N’,N’-四(对甲基苄基)乙二胺(SL1)和N,N,N’,N’-四苄基乙二胺(SL2), 是连有大体积取代基团的含N双齿配体, 它可通过二次球形配位, 与第一络合物[CuCl4]2－形成层间隧道框架结构. 环戊醇分子和乙醇分子分别被填入由SL1和SL2构筑的隧道中, 形成包结化合物. 晶体结构分析结果表明, 这样的配体易于与指导基团通过NH＋…Cl－氢键作用进行双齿配位并形成1D带和2D层结构; SL1 2D层间的苄基呈平行堆砌, 形成1D亲水性隧道框架, SL2 2D层间的苄基呈交错堆砌, 形成了1D疏水性隧道框架. 实验结果表明, 层间隧道框架结构的孔径及极性与第二配体的分子长度、指导基团的构型以及客体分子的形状大小有关.     

多氮杂大环配体La~(3+)、Gd~(+3)络合物的合成

在NaOH存在下，N，N′，N″，N-四乙酸-1，4，7，10-四氮杂环十二烷、N，N′，N″，N-四乙酸-1，4，8，11-四氮杂环十四烷、N，N′，N″，N-四甲磷酸-1，4，7，10-四氮杂环十二烷和N，N′，N″，N-四甲磷酸-1，4，8，11-四氮杂环十四烷分别与LaCl3·7H2O或GdCl3·6H2O通过大环配体络合物直接合成法，得到八个络合物，产率为46．7％～90．7％。     

Sensitive Spectrophotometric Determination of Benzoylperoxide with N,N,N′,N′-Tetramethyl-p-phenylenediamine

Abstract

A highly sensitive spectrophotometric determination of benzoylperoxide (BPO) based on the color developing reaction between N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) and BPO in the presence of cerium(IV) in weakly acidic media is proposed. The calibration graph is linear in the range 0–6000 ng BPO per 10 ml with an apparent molar absorptivity of 4.73 × 10⁵ 1 mol^?1 cm-1 at 612 nm. The proposed method is about 50-fold more sensitive than N-ethyl-2-naphthylamine (NENA), and application to assays of flour is described.     

Screening of N,N‐bidentate and N,N,N‐tridentate pyridine‐based ligands in the catalytic allylic oxidation of cyclic olefins

A variety of chiral N,N‐bidentate and N,N,N‐tridentate ligands based on the pyridine framework, namely C2‐symmetric dipyridylmethane and terpyridine, N‐(p‐toluensulfinyl)iminopyridines and two kinds of iminopyridines, has been assessed in the asymmetric copper(I)‐catalysed allylic oxidation of cyclic olefins. Catalytic activity and enantioselectivity were found to be highly dependent upon the framework of the ligands, which afforded cycloalkenyl benzoates in low to moderate yields and enantioselectivities. The best yields (up to 70%) and enantioselectivities (up to 53% enantiomeric excess) were obtained with an iminopyridine based on camphane and quinoline skeletons. Copyright © 2014 John Wiley & Sons, Ltd.     

Syntheses and structural determinations of the nine-coordinate rare earth metal: Na4[DyIII(dtpa)(H2O)]2·16H2O,Na[DyIII(edta)(H2O)3]·3.25H2O and Na3[DyIII(nta)2(H2O)]·5.5H2O

Three complexes, Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and Na₃[Dy^III (nta)₂(H₂O)]?·?5.5H₂O, have been synthesized in aqueous solution and characterized by FT–IR, elemental analyses, TG–DTA and single-crystal X-ray diffraction. Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O crystallizes in the monoclinic system with P2₁/n space group, a?=?18.158(10)?Å, b?=?14.968(9)?Å, c?=?20.769(12)?Å, β?=?108.552(9)°, V?=?5351(5)?ų, Z?=?4, M?=?1517.87?g?mol^?1, D _c?=?1.879?g?cm^?3, μ?=?2.914?mm^?1, F(000)?=?3032, and its structure is refined to R ₁(F)?=?0.0500 for 9384 observed reflections [I?>?2σ(I)]. Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O crystallizes in the orthorhombic system with Fdd2 space group, a?=?19.338(7)?Å, b?=?35.378(13)?Å, c?=?12.137(5)?Å, β?=?90°, V?=?8303(5)?ų, Z?=?16, M?=?586.31?g?mol^?1, D _c?=?1.876?g?cm^?3, μ?=?3.690?mm^?1, F(000)?=?4632, and its structure is refined to R ₁(F)?=?0.0307 for 4027 observed reflections [I?>?2σ(I)]. Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O crystallizes in the orthorhombic system with Pccn space group, a?=?15.964(12)?Å, b?=?19.665(15)?Å, c?=?14.552(11)?Å, β?=?90°, V?=?4568(6)?ų, Z?=?8, M?=?724.81?g?mol^?1, D _c?=?2.102?g?cm^?3, μ?=?3.422?mm^?1, F(000)?=?2848, and its structure is refined to R ₁(F)?=?0.0449 for 4033 observed reflections [I?>?2?σ(I)]. The coordination polyhedra are tricapped trigonal prism for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O and Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, but monocapped square antiprism for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O. The crystal structures of these three complexes are completely different from one another. The three-dimensional geometries of three polymers are 3-D layer-shaped structure for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 1-D zigzag type structure for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and a 2-D parallelogram for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O. According to thermal analyses, the collapsing temperatures are 356°C for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 371°C for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and 387°C for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, which indicates that their crystal structures are very stable.     

Cerium Salt Promoted Homocoupling Reaction of Dialkylanilines in Water

Highly regioselective homocoupling of N,N-dialkylanilines can be achieved in water with cerium reagents, in which various N,N,N′,N′-tetraalkylbenzidines are obtained from N,N-dialkylanilines either by direct oxidation by cerium（Ⅳ）reagents or by cerium（Ⅲ） reagents in the presence of hydroperoxide.     

二硝酸根(N, N, N'', N''－四正丁基丙二酰胺)合铀酰(Ⅱ)配合物的合成和结构

配合物[UO₂(Bu₂NCOCH₂CONBu₂)(NO₃)₂]晶体属单斜晶系,P2₁/c空间群,a=10.744(2),b=13.229(5),c=20.011(8)β,β=99.21(3)°,V=2808(2)β³,D_c=1.07g·cm^-3,Z=4,配合物分子中具有直线结构的铀酰离子由六个氧原子配位,其中四个来自硝酸根,另外两个来自羰基,形成平面六角形,六角形的平面与铀酰离子的直线垂直,两个硝酸根处于相邻位置.     

Analysis of amides in the air by sampling with SPME and detection by GC-FID

This paper proposes a solid-phase microextraction (SPME) method for the passive sampling and determination of N,N-dimethylacetamide (DMA) and N,N-dimethylformamide (DMF) in air by capillary GC with flame ionization detection. The optimized conditions for SPME method were grab sampling, polydimethylsiloxane/divinylbenzene fiber, extraction for 90 min at 25 +/- 2 degrees C, desorption for 3 min at 220 degrees C, and relative humidity 45 +/- 2%. Under these conditions, the method presented good linearity (R = 0.996), repeatability (%RSD 2.79 and 9.85 for DMF and DMA, respectively), and detection limit (0.021 and 0.024 mg/m3 for DMF and DMA, respectively).     

Combining [Arene–Ru] with Azocarboxamide to Generate a Complex with Cytotoxic Properties

Azocarboxamide (azcH) has been combined for the first time with [Ru–Cym] to generate metal complexes with N,N‐ and N,O‐coordination mode, [(Cym)Ru(azc)Cl] and [(Cym)Ru(azcH)Cl]⁺[PF₆]^?. Geometric and electronic structures of the complexes are reported along with their in vitro activities against different tumour cell lines and preliminary results on solution chemistry. Compound [(Cym)Ru(azc)Cl] exhibited remarkable cytotoxic properties. It was cell‐type specific and had comparable IC₅₀ values towards both cancer cells and their drug‐resistant subline. A tenfold increase in the sensitivity towards [(Cym)Ru(azc)Cl] was noted for the tumour cells with depleted intracellular glutathione (GSH) level, suggesting the essential role of GSH in cell response to this compound.