脂质体中生物矿化的研究进展

生物矿化是指在有机体内形成矿物的过程。以脂质体作为模板，不仅可以模拟生物矿化过程中有机基质的调控作用和生物大分子的指导作用，而且可以提供生物矿化所需的特殊隔室，使反应物富集、定位，催化矿化反应的发生。本文综述了近年来在脂质体中模拟生物矿物磷酸钙、碳酸钙和草酸钙等矿化的研究进展，并讨论了膜控制晶体生长的机理。     

超重力场中合成立方形纳米CaCO3颗粒与表征

在超重力场中合成了平均表观粒径在１７．５￣２１．５ｎｍ之间，粒度分布窄的立方形纳米ＣａＣＯ３颗粒，探讨了超重力水平对颗粒粒度，反应时间的影响，并对颗粒进行了ＴＥＭ、ＸＲＤ、ＴＧ和ＤＴＡ等表征。与常重力场中合成纳米ＣａＣＯ３相比，粒度分布较窄，随着超重力水平的提高，产物粒径减小，反应时间明显降低。     

尿素水解法制备晶须碳酸钙

采用尿素水解法合成了晶须碳酸钙,研究了原料配比、反应时间等合成条件对晶须产率的影响,采用SEM、TG和X-射线衍射技术等方法对晶须进行了表征。结果表明,本方法体系简单,条件易于控制,且随尿素比例的增加、反应时间的延长,晶须的产率得以提高。     

轻质碳酸钙／聚丙烯共混物中聚丙烯β—晶的成核结晶研究

用Ｘ射线衍射和差示扫描量热法研究了轻质碳酸钙／聚丙烯共混物（Ｌ－ＣａＣＯ３／ＰＰ）中ＰＰβ－晶的成核结晶现象，发现ＰＰβ－晶的成核结晶与ＰＰ的来源和Ｌ－ＣａＣＯ３在共混物中的含量有关，铝酸酯偶联剂对共混体系的ＰＰβ－晶的成核结晶有显著的增强作用。分析认为共混物中ＰＰβ－晶的成核结晶现象是ＰＰ中存在的某些杂质（主要是催化剂残余物）与Ｌ－ＣａＣＯ３组成的复合成核剂作用的结果，而铝酸酯是这种复合成核剂的     

纳米碳酸钙复合的微球体制备及其尺寸控制

利用两亲嵌段共聚物聚苯乙烯-丙烯酸(简称PAS)在水相中构成的空间立体三维框架结构和亲水链聚丙烯酸在水相空间的伸展及其上羧酸基对钙离子的沉积作用,合成了球形纳米碳酸钙复合物,并通过控制共聚物的浓度初步实现了复合物宏观尺寸的调控,制备出粒径约2 μｍ,4 μｍ,8 μｍ的球形纳米复合物。XRD分析结果表明复合物中碳酸钙粒子属方解石型纳米微晶,有较大的晶格畸变率,微晶尺寸随球形复合物的增大反而减小。热分析研究显示,复合物中有机物含量大于12 ％,热分解稳定性的提高认为通过羧酸Ｃａ-Ｏ键合使碳酸钙与聚合物有效复合。     

St / AA共聚物的组成对碳酸钙结晶及形貌影响的研究

在聚苯乙烯-丙烯酸两亲共聚物(简称PAS)溶液中制备CaCO₃，用XRD、FTIR和SEM等研究随着PAS的亲水AA和亲油St单元组成的变化所引起的聚合物分子链段、溶解性质和胶束空间构象等的改变对CaCO₃晶型和形貌的影响。结果显示：随着亲水性AA单元组成的提高，可以由AA链段的晶面匹配成核调控碳酸钙为方解石纳米晶，并因PAS在水溶液中溶解性不同，形成了多种碳酸钙形貌的聚集体；当St和AA的物质的量比为3∶1时，合成出类珍珠岩层碳酸钙结构。根据PAS的结构性质和在水溶液中的溶解行为初步探讨了类珍珠岩层碳酸钙的形成机理，认为是PAS基质模板和羧酸根对钙的键合作用形成这一特殊形貌碳酸钙。     

IGC反气相色谱法分析氧化铝包覆碳酸钙二元复合物表面能的研究

Spindly calcium carbonate coated with AlOOH has been successfully prepared by bubbling carbonization method. SEM and XRD analysis results suggested an amorphous filiform the coating layer of AlOOH. Inverse gas chromatography (IGC) analysis indicated that γ_s^D, the London component of surface energy of calcium carbonate increased after being coated with AlOOH, especially when with the coating weight quantity of 4%. And the reduction of the γ_s^D value with the ascending column temperature became more obvious along with the increase of the coating weight quantity, which might be due to the desorption of water from the surface. In addition, the surface acid- alkali capacity of calcium carbonate also increased after coating.     

Novel synthesis with an atomized microemulsion technique and characterization of nano-calcium carbonate （CaCO3）/poly（methyl methacrylate） core-shell nanoparticles

The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The polymer chains were anchored onto the surface of nano-CaCO3 through use of a cou- pling agent, triethoxyvinyl silane （TEVS）. Ammonium persulfate （APS）, sodium dodecyl sulfate （SDS） and n-pentanol were used as the initiator, surfactant and cosurfactant, respectively. The polymeriza- tion mechanism of the core-shell latex particles is discussed. The encapsulation of nano-CaCO3 by PMMA was confirmed using a transmission electron microscope （TEM）. The grafting percentage of the core-shell particles was investigated by thermogravimetric analysis （TGA）. The nano-CaCO3/PMMA core-shell par- ticles were characterized by Fourier transform infrared （FTIR） spectroscopy and differential scanning calorimetry （DSC）. The FTIR results revealed the existence of a strong interaction at the interface of the nano-CaCO3 particle and the PMMA, which implies that the polymer chains were successfully grafted onto the surface of the nano-CaCO3 particles through the link of the coupling agent, In addition, the TGA and DSC results indicated an enhancement of the thermal stability of the core-shell materials compared with that of the pure nano-PMMA, The nano-CaCO3/PMMA particles were blended into a polypropylene （PP） matrix by melt processing. It can also be observed using scanning electron microscopy （SEM） that the PMMA chains grafted onto the CaCO3 nanoparticles interfere with the aggregation of CaCO3 in the polymer matrix （PP matrix） and thus improve the compatibility of the CaCO3 nanoparticles with the PP matrix.     

连续流动法测定卷烟纸和造纸法再造烟叶中碳酸钙含量北大核心CSCD

取卷烟纸或造纸法再造烟叶细条(约0.5cm×2.5cm)样品0.500g,与0.5mol·L^(-1)盐酸溶液4.5 mL反应完全,加入95.5 mL水,混匀后过滤,于滤液中加入5g活性碳,振荡30min,过滤,收集滤液。采用连续流动法通过碘酸钾、碘化钾与样品溶液中剩余H+的显色反应来计算剩余H+的含量,从而推算样品中碳酸钙的含量。结果表明:(1)碳酸钙的线性范围为5.007~30.042mg;(2)方法的检出限(3s)为0.11mg;(3)连续测定6次所得结果的相对标准偏差为0.34%~0.86%;(4)加标回收率为96.6%~103%。方法的测定值和电位滴定法的测定值基本相符,但与离子色谱法所测结果之间有一定差异。     

Improving Anti-frosting Performance for Super-hydrophobic Nanocomposite Coatings

Super-hydrophobic surfaces with water contact angle (WCA) higher than 150o have attracted great attention these years1, due to their scientific values and potential technological applications as antifouling coatings, non-sticking coatings, and so on. Alth…