Colloidal microstructure of binary systems and model creams stabilized with an alkylpolyglucoside non-ionic emulsifier

The aim of this study was to examine the lyotropic potential of an alkylpolyglucoside mixed emulsifier (Cetearyl glucoside&Cetearyl alcohol), which belongs to the new generation of natural (sugar) surfactants, and to elaborate the potential stabilization mechanism and relation between the colloid microstructure and water distribution within the systems. Polarization and ordinary light as well as transmission electron microscopy, wide and small-angle X-ray diffraction, thermal analysis and rheological measurement were employed for the systems characterization.It was suggested that Cetearyl glucoside&Cetearyl alcohol stabilizes the o/w creams by synergistic effects of viscoelastic hydrophilic gel of lamellar type and lipophilic gel network built up from cetostearyl alcohol semi-hydrates as well as by lamellar liquid crystalline bilayers surrounding the oil droplets. The hydrophilic gel consists of mixed cetearyl glucoside/cetearyl alcohol crystalline bilayers entrapping the water interlamellarly by hydrogen bonding. It is also showed that oil addition into the chosen binary system influences the creams microstructure significantly, which particularly reflects onto the mode of water distribution within the creams and consequently their potential of skin hydration.     

Sunlight curable hybrid organic–inorganic methacrylic‐based coatings: analysis of the cure mechanism and functional properties

An experimental ultraviolet (UV) polymerizable hybrid organic–inorganic protective coating, mainly intended for the surface protection of porous calcareous stone substrates, has been recently proposed and patented. The hybrid product evidenced an extraordinary hydrophobicity character, able to guarantee a high protection of the stone against water actions, as well as a high traspirability. Furthermore, it is able to equal the performance of commercial available coatings, with the important adjunctive advantage to be free solvent. The application of this product involves the use of a “dual curing” treatment, necessary to harden the coating applied on the substrate, representing this latter a technological limit. The dual curing treatment consists of 6 hr of exposure to a UV‐lamp plus 1 hr at 140°C in oven. In order to avoid this procedure, not easy to realize in situ, two different modifications of the composition of the hybrid product are proposed in this paper. The first one allows the photopolymerization of the hybrid coating only by sunlight exposure. The second one, even though requiring a UV exposure to photo‐polymerize the coating, does not need the subsequent thermal treatment at 140°C. Several experimental characterizations were performed on the newly developed hybrid products, in order to select an optimal composition for the formulations. The selected innovative products were, finally, applied on a calcareous stone substrate, typical of Apulia Region (Pietra Leccese, PL). Both coatings exhibit excellent water‐repellent action and a slight variation of the natural stone color. Copyright © 2014 John Wiley & Sons, Ltd.     

二氧化碳/环氧丙烷/马来酸酐三元共聚物对PPC/PHB共混物力学性能的影响

采用稀土三元催化剂制备了二氧化碳-环氧丙烷-马来酸酐三元共聚物(PPCMA).用红外和核磁谱图确定了PPCMA的结构及马来酸酐单元的含量,3 wt％马来酸酐投料量的PPCMA(共聚物中马来酸酐单元含量4.1％)的玻璃化转变温度(Tg)和起始热分解温度(Td-5％)分别为13.4℃和217℃,拉伸强度为2.88 MPa,断裂伸长率为1669％,与二氧化碳-环氧丙烷共聚物(PPC)相比,引入少量马来酸酐的PPCMA有望成为一种韧性材料,并可对PPC和聚3-羟基丁酸酯(PHB)共混体系进行改性.当在PPC/PHB共混体系中添加10 wt％的PPCMA时,所得共混材料的拉伸强度为18.2 MPa,断裂伸长率则提高到85％,较没有添加PPCMA的样品提高了4.25倍,因此PPCMA的加入能有效提高PPC/PHB共混体系的韧性,改善PPC/PHB共混体系的力学性能.偏光显微镜的研究表明PPC/PHB共混体系加入PPCMA后,很快形成大量尺寸小的PHB球晶,且结晶速度大幅度提高,因此PPCMA在一定意义上可视为一种特殊的“成核剂”.     

可聚合添加剂和极压添加剂对矿物油极压抗磨和抗疲劳性能的影响

选用重极压齿轮油和二聚酸 /司本 - 80添加剂制备了多种不同配比的油样 ,进行了疲劳和胶合试验 ,同时分析了磨损表面形貌和抗磨机理 .结果表明 :聚合添加剂的耐疲劳性能较好 ,其与极压添加剂经合理复配可以更好地提高油样的耐疲劳及抗胶合综合性能 .这是两类添加剂协同作用的结果     

Fluorocarbon polymerizable surfactants: viscometric behavior, micellar polymerization and interactions with associating polymers

 The micellar aggregation of two fluorocarbon surfactants bearing a polymerizable acrylamido group and differing only in the degree of amido substitution (CONH or CONC₂H₅) has been investigated by viscometry. The two surfactants exhibit distinct solution properties with a micellar growth occurring at a much lower concentration for the N-monosubstituted sample which shows in addition a shear thickening and rheopectic behavior. The ability of the latter surfactant to form hydrogen bonding is responsible for this difference in behavior. Micellar copolymerization of acrylamide with these surfactants or with a hydrocarbon analogue gives copolymers with a polysoap-like behavior. The copolymers in aqueous solution show a pronounced intramolecular hydrophobic aggregation expressed by relatively low-viscosity values when compared with those of other hydrophobically modified water-soluble polymers reported in the literature. Surfactant–polymer mixed systems do not show a strong incompatibility between fluorocarbon and hydrocarbon moieties. Received: 24 March 1998 Accepted: 30 June 1998     

Effect of citric acid concentration as emulsifier on perovskite phase formation of nano‐sized SrMnO3 and SrCoO3 samples

In this study the effects of citric acid concentration, used as organic emulsifier, on the perovskite phase formation of the nano strontium manganite or cobaltite samples were studied. Stoichiometric perovskites in the absence and presence of citric acid were prepared by drying a solution containing molar ratio of Sr(NO₃)₂/Mn(NO₃)₂·4H₂O and Sr(NO₃)₂/Co(NO₃)₂·6H₂O = 1 followed by calcination at 900 °C for 5 h. Citric acid concentration, selected to be 0.0, 0.3, 0.6, 1.0, 1.3, 2.5 and 5 times of the total number of moles of the nitrate ions. The results revealed that increase in the citric acid concentration, larger than number of moles of the nitrate ions equivalent, deteriorates the perovskite phase formation. Instead, a new phase of carbonates and metal oxides are appeared. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

钼改性页硅酸镍催化剂催化顺酐加氢性能

通过蒸氨法合成了一系列钼改性的页硅酸镍催化剂, 考察了钼含量对催化剂结构及其催化顺酐液相加氢性能的影响. 采用氮气物理吸附-脱附、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)、 透射电子显微镜(TEM)、 氢气程序升温还原(H₂-TPR)、 氨气程序升温脱附(NH₃-TPD)、 吡啶吸附红外光谱(Py-IR)和原位X射线光子能谱(XPS)等手段对催化剂的结构和形貌等进行了表征. 结果表明, 助剂Mo的引入对催化剂结构形貌及其催化性能影响显著. Mo的引入提高了活性金属Ni的还原度, 增加了催化剂表面金属Ni⁰的数量, 金属Ni在还原过程产生氢溢流, 溢流氢将部分MoO₃还原为具有酸性的MoO_x物种, 由于金属Ni⁰与具有Lewis酸(L酸)特性的MoO_x及Ni^σ+的协同效应, 显著提高了催化剂对顺酐C≡C和C≡O的加氢活性. 当Mo含量(质量分数)为3%时, 其催化活性最高, 在160 ℃和5 MPa H₂气条件下, 反应3 h顺酐的转化率为100%, 产物γ-丁内酯的选择性为27%.     

A novel cationic emulsifier used for preparing slow-cracking and rapid-setting asphalt: Synthesis,surface activity,and emulsification ability

A novel cationic emulsifier including nonionic fatty alcohol polyoxyethylene ether was synthesized in two steps from epichlorohydrin, octadecyl dimethyl amine, and fatty alcohol polyoxyethylene ether, and the intermediate product could also be used as an emulsifier. Their structures were characterized by FTIR, and the surface activities were investigated by surface tension, electrical conductivity, and HLB. The obtained results indicated that the critical micelle concentration (CMC) of the final product was low, 0.442 mmol/L, and the surface tension at the CMC was 41.02 mN/m. The hydrophile-lipophile balance (HLB) value was 12, which meet the requirements of asphalt emulsifiers. A series of experiments of the emulsified asphalt prepared by the emulsifiers were performed. The results showed that the emulsified asphalt could be stably stored for more than 5 days when the emulsifier was 2 wt% and the pH value was between 3 and 4. The result of demulsification experiments showed that the emulsifier is a slow-cracking and rapid-setting asphalt emulsifier.