肉豆蔻酸作为结构导向剂合成层状介观羟基磷灰石

采用肉豆蔻酸作为结构导向剂,在Et OH/H_2O混合溶剂体系中制备出层状介观羟基磷灰石(M-LMHA),样品利用X-射线粉末衍射、红外光谱和透射电镜进行表征。结果表明,样品M-LMHA具有高度有序的层状介观结构,其层间距约为4.2 nm,为生物分子自组装应用提供了必要条件。     

层状溶致液晶中纳米羟基磷灰石的合成

在一定的pH值条件下,将Ca(NO3)2和(NH4)2HPO4分别溶于C34H62O11(聚乙二醇辛基苯基醚)/C8H17OH/H2O体系层状溶致液晶溶剂层中,混合并经陈化即可在溶剂层中生成具有一定微观形貌的羟基磷灰石纳米粒子(HA),其直径可以达到10 nm,长度在100 nm以下.产物在不同温度下焙烧,分别用FTIR,XRD和TEM等对产物的结构及形貌进行分析表征.对不同反应物浓度条件下所得HA的微观形貌进行分析对比,并提出了改善团聚的有效措施.     

介孔羟基磷灰石的合成及药物释放性能研究

本文采用水热合成法,制备出介孔羟基磷灰石,该材料具有较高比表面积和较大的孔容,药物缓释性能测试表明,材料具有较高的药物组装率和较好药物缓释性能,因此,可以作为药物缓释载体,从而更好地实现对骨组织的修复。     

肉豆蔻酸-2-羟基-3-磺酸钠丙酯的合成

以亚硫酸氢钠、环氧氯丙烷、磷酸钠和肉豆蔻酸等为原料,合成了肉豆蔻酸-2-羟基-3-磺酸钠丙酯,探索了反应温度、催化剂、反应时间、反应物物质的量比等因素对合成的影响。结果表明,适宜的反应条件为:①合成3-氯-2-羟基丙磺酸钠:环氧氯丙烷滴加到亚硫酸氢钠溶液中,反应时间3.5 h,反应温度85℃,②合成环氧丙磺酸钠:3-氯-2-羟基丙磺酸钠加入磷酸钠溶液中,反应温度55℃,反应时间4.0 h;③合成肉豆蔻酸-2-羟基-3-丙磺酸钠:环氧丙磺酸钠溶液滴加到90℃的肉豆蔻酸溶液中,反应时间3.0 h,产率为85.2%。对产品进行了红外光谱表征,产品显示了较好的表面活性。     

层状纳米羟基磷灰石的结晶性能及形成机理

在前期利用模板剂法制备层状纳米羟基磷灰石（nano-hydroxyapatite,n-HA）的基础上,利用透射电子显微镜、X射线衍射和Fourier变换红外光谱等研究并讨论工艺参数对材料结晶性能影响以及形成机理。结果表明：反应24h后,HA晶体形成且层状结构清晰;在碱性条件下,生成的产物主要是n-HA,酸性条件下则生成CaHPO4;乙醇与水的质量比为2.0时,纳米晶体形状、大小相对均一。工艺参数的变化会影响表面活性剂的堆积参数,沿着表面活性剂模板生长的羟基磷灰石颗粒有不同的微观结构及形貌。     

固定化脂肪酶合成肉豆蔻酸异丙酯的研究

采用固定化脂肪酶(Novozym 435)在有机溶剂体系中催化肉豆蔻酸和异丙醇酯化合成了肉豆蔻酸异丙酯.研究了各种因素如有机溶剂种类、反应物摩尔比、反应温度及酶用量等因素对酯化率的影响.结果表明,肉豆蔻酸异丙酯合成的较佳条件为:1.14 g肉豆蔻酸,0.45 g异丙醇,0.02 g Novozym 435,10 mL石油醚(其中加入0.5 g 3A分子筛吸水),在55℃下振荡反应4 h,酯化率为99.2%(肉豆蔻酸可基本完全转化为肉豆蔻酸异丙酯).实验过程中固定化酶稳定性较好,可连续使用7批左右.     

层状纳米羟基磷灰石/茶氨酸药物释药性能研究

本文以层状纳米羟基磷灰石为载体制备了羟基磷灰石/茶氨酸药物,并对其体外释药性能进行了初步研究.羟基磷灰石/茶氨酸药物在起始阶段具有很快的药物释放速率,50 min时的累积释放量接近80％,最终的释药量可达90％以上.而且在释药初期,载药量高的样品比载药量低的样品具有更高的累积释药百分量.     

介孔羟基磷灰石的制备及其应用的研究进展

介孔羟基磷灰石材料是一种新型功能材料,其特有的结构和性质让它备受各界关注。以下是对介孔羟基磷灰石的制备及其应用进行综述,讨论了介孔羟基磷灰石的研究进展并展望了其发展趋势。     

层状纳米羟基磷灰石的制备及影响因素

以表面活性剂磷酸酯为模板剂制备了具有层状结构的纳米羟基磷灰石(nano-hydroxyapatite,n-HA),该层状结构呈规则的周期性排列,层间距约为3.5 nm.用透射电子显微镜、广角X射线衍射、小角X射线衍射和Fourier变换红外光谱对材料的相组成、微观结构和形貌进行分析和表征.研究了液相体系中表面活性剂的浓度及反应温度对n-HA结构和形貌的影响.结果表明:反应温度和表面活性剂的浓度会显著影响材料的结构,最佳合成条件下可以形成相对均一的层状长条形n-HA.     

1,3-二环己基碳化二亚胺(DCC)为脱水剂低温合成丙炔酸酯的研究

以丙炔醇为原料,氧化合成丙炔酸,在1,3-二环己基碳化二亚胺(DCC)脱水剂作用下,低温合成丙炔酸酯。与传统浓硫酸催化酯化相比,本方法副反应少、产率高。并且发现丙炔酸酚酯的产率与酚上取代基团存在关系,对位为给电子取代基的酚类,能获得更高的产率。并用此法首次高选择性的合成出丙炔酸双酯。     

The synthesis and characterization of the molecular sieve SAPO-16 as well as other SAPO and CoAPO phases using bis(cyclopentadienyl) cobalt(III) hydroxide as a structure directing agent

The clathrate type molecular sieve SAPO-16 was prepared via a hydrothermal synthesis using bis(cyclopentadienyl)cobalt(III) hydroxide, Cp₂CoOH, as a template and characterized by XRD, FT-IR, UV-Vis and SEM. Additionally, the preparation and characterization of possibly new isostructural SAPO-UTD-3 and CoAPO-UTD-3 materials is reported.NSF Presidential Young Investigator 1991–1996.     

Synthesis of organized hydroxyapatite (HA) using triton X-100

In this article, highly organized HA nanostructure was developed using a nonionic surfactant p-(1,1,3,3-tetramethylbutyl) phenoxypoly(oxyethylene) glycol (triton X-100) as the template. The obtained well-organized architectural units were examined using transmission electron microscopy (TEM), SEM, XRD and FTIR. High-resolution transmission electron (HRTEM) revealed that HA nanorods were well assembled in order along the c-axis. FTIR results indicated the possible interactions between triton X-100 and HA. The mechanism of the assembly of well-oriented nanostructure was proposed. The composites containing nanosized hydroxyapatite with structural features close to that of human bone should be useful and important for the practical applications, especially in the development of biomimetic materials.     

Stabilization of immiscible polymer blends using structure directing metal organic frameworks (MOFs)

We have developed a novel approach for compatibilizing immiscible polymer blends using metal organic frameworks (MOFs). For the first time we demonstrated that the droplet diameter of the dispersed phase in a 1:1 immiscible polymer blend composed of 6FDA-DAM:DABA [copolymer of 4,4-hexafluoroisopropylidene diphthalic anhydride (6FDA), 2,4,6-trimethyl-1,3-phenylenediamine and 3,5-diaminobenzoic acid (DABA)], and polybenzimidazole (PBI), is dramatically reduced obtaining a uniform microstructure with the incorporation of as low as 5% (w/w) of the zeolitic imidazolate framework-8 (ZIF-8). This indicates a large improvement in the compatibility of the immiscible polymers with the inclusion of ZIF-8. As the ZIF-8 loading was further increased to 10% (w/w), the droplet diameter further decreased resulting in even higher compatibility. The compatibilizing effect can be attributed to a reduction in the interfacial energy of the immiscible polymers due to the interfacial localization of ZIF-8. This MOF based compatibilization of immiscible polymer blends can open up opportunities for the combination of different properties of polymers in membrane-based separations and in more applications.     

毕赤酵母表面展示脂肪酶催化合成肉豆蔻酸糖酯

研究了毕赤酵母表面展示脂肪酶(CALB)全细胞催化剂的较佳活性条件,结果显示,适宜的反应温度为50~60℃。以CALB为催化剂,比较了不同底物对糖酯合成的影响。以1,2-O-异亚丙基-D-呋喃葡萄糖(Ip Glc)为酰基受体,肉豆蔻酸为酰基供体,考察了有机溶剂种类、CALB的添加量、底物摩尔比、分子筛的添加量、初始水活度对合成6-O-肉豆蔻基-1,2-O-异亚丙基-α-D-呋喃型葡萄糖酯(Ip Glc-C14)的影响,得到较佳的合成条件为:丙酮5 m L、CALB(干粉)0.3 g、n(Ip Glc)∶n(肉豆蔻酸)=1∶3(其中Ip Glc 0.5 mmol)、4A分子筛0 g、初始水活度a_w=0.11、反应温度50℃、200 r/min反应72 h。在此条件下,Ip Glc-C14的收率为91.25%。比较了CALB和固定化脂肪酶Novozym 435对Ip Glc-C14合成的反应进程的影响,结果显示使用Novozym 435的反应速率快,而CALB的最终收率较高。     

Crystallization of poly(lactic acid) enhanced by phthalhydrazide as nucleating agent

The effect of phthalhydrazide compound on the nonisothermal and isothermal crystallization behavior of bio-based and biodegradable poly(lactic acid) (PLA) was investigated by differential scanning calorimetry and polarized optical microscopy. The nonisothermal melt crystallization of PLA started much earlier in the presence of phthalhydrazide even at a phthalhydrazide content as low as 0.1 wt%. The isothermal crystallization kinetics was analyzed by the Avrami model. It was found that the Avrami exponent of the PLA crystallization was not significantly influenced by the addition of phthalhydrazide, indicating that the crystallization mechanism almost did not change in the composites. The crystallization half-time of PLA/phthalhydrazide composites decreased significantly with increase in phthalhydrazide loading. The observation from optical microscopy showed that the presence of phthalhydrazide increased the number of nucleation sites. The above observations indicate that phthalhydrazide is an efficient nucleating agent of PLA.     

以氨基磺酸为磺化剂合成三聚氰胺系高效减水剂

以三聚氰胺(M)和甲醛(F)为原料,氨基磺酸(A)为磺化剂,合成了M系高效减水剂。探讨了反应物配比、反应温度、反应时间和体系pH等对M系高效减水剂分散性能的影响。研究结果表明:当n(M)∶n(F)∶n(A)=1∶5∶1.7,羟甲基化阶段的反应温度为70℃、反应时间为1.5 h和pH为8.5,磺化阶段的反应温度为90℃、反应时间为3 h和pH为12,酸性缩聚阶段的pH为6、反应温度为90℃和反应时间为1 h,碱性重整阶段的反应温度为60℃、反应时间为1 h和pH为8.5时,合成的减水剂具有良好的综合性能;当w(减水剂)=0.5%(相对于水泥质量而言)时,减水剂的分散性能良好,水泥净浆初始流动度达245 mm;当w(减水剂)=0.6%时,混凝土的减水率达到13.8%且具有较高的坍落度保持率。     

Crystallization of poly(lactic acid) accelerated by cyclodextrin complex as nucleating agent

Poly(lactic acid) (PLA) is a well-known biodegradable and biocompatible polyester with intrinsically slow crystallization rate. To extend its applications to the field where heat resistance is required, increasing the crystallization rate of the material becomes critical. In this note, the nucleation effect of supramolecular inclusion complex (IC), organized by non-covalent interactions through threading α-cyclodextrin molecules onto PLA chains, on the crystallization of PLA was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy. The formation of IC was confirmed by wide-angle X-ray diffraction and DSC measurements. It was found that the presence of PLA-IC significantly promoted the crystallization of PLA from both the non-isothermal and isothermal crystallization experiments. The nucleation mechanism was also discussed to some extent.