白炭黑与单分散二氧化硅粒子补强橡胶的差异

比较白炭黑与单分散二氧化硅粒子补强橡胶的差异。单分散纳米二氧化硅粒子表面光滑，粒子之间作用较弱，有利于分子链问的相对运动；与单分散二氧化硅粒子相比，纳米二氧化硅粒子链具有4个方面的特性：①纳米粒子链的弹性，②纳米粒子链的重聚性，③链的粒子粗糙表面的活性，④链的粒子问“脖颈”和支链的形态结构性。纳米二氧化硅粒子链补强橡胶的分散结构比单分散二氧化硅粒子补强橡胶更加复杂；高分子链与二氧化硅粒子链组成的复合团聚体对橡胶的补强、增韧起关键作用。     

包裹定向排列纳米氯化银的二氧化硅纳米纤维

介绍了一种通过静电作用合成AgCl–SiO2复合材料的新方法. 这种方法能够制备出线条均匀的纳米二氧化硅纤维，直径范围在30~100 nm，纤维的长度大于20 mm. 所包裹的AgCl纳米粒子在纤维中呈规则排列. 沿着二氧化硅纤维生长方向，同一条二氧化硅纤维包裹多条氯化银纳米线.     

帝斯曼化学公司投资皮肤护理品用二氧化硅

日前帝斯曼化学公司通过其风险基金子公司向以色列凝胶技术公司投资了200万美元。以色列凝胶技术公司是一家基于凝胶技术开发生产陶瓷和玻璃制品的私有企业。帝斯曼表示将使用以色列凝胶技术公司的技术生产二氧化硅微粒和纳米级二氧化硅粒子,然后将这些二氧化硅粒子封人活性中间体中,用于皮肤护理。     

气相二氧化硅的增稠触变性及其在牙齿漂白剂中的应用

1前言 气相二氧化硅是由卤硅烷在氢氧焰中高温水解制得的一种无定形二氧化硅产品。有机卤硅烷在高温水解缩合后得到粒径为7～40纳米的原生粒子，随着粒子远离火焰，温度降低，粒子之间相互碰撞、粘附和熔结形成聚集体。二氧化硅聚集体是由众多粒子熔结在一起，形状很不规则，主要为支链形。而聚集体又因氢键和范德华力的吸引而相互连在一起形成二氧化硅附聚体。[第一段]     

硅溶胶的应用研究

硅溶胶是二氧化硅胶体粒子在水中均匀扩散形成的胶体溶液，是一种用途广泛的新型化工原料。随着制造技术的进步和对胶体二氧化硅粒子表面性质的深入研究，硅溶胶在科研及各工业领域的应用范围日益扩大。     

硅溶胶中氨水的去除

通过pH值、电导牢和二氧化硅解离量的测定，研究了Stober二氧化硅溶胶的提纯过程。发现离心水洗很难完全去除体系中的氨水，并且残留的氨水会影响二氧化硅粒子的化学稳定性。对二氧化硅溶胶进行酸处理后再提纯，可以大大加速提纯过程并消除氨水对二氧化硅粒子化学稳定性的影响。     

气相二氧化硅在应用中要注意的问题

气相二氧化硅是由卤硅烷在氢氧焰高温水解制得的一种无定形二氧化硅产品，有机卤硅烷在高温水解缩合后得到粒径为7～40纳米的原生粒子，随着粒子远离火焰，温度降低，粒子之间相互碰撞、粘附和熔结形成聚集体（100～500nm）。二氧化硅聚集体是由众多粒子熔结在一起，形状很不规则，主要为支链形。而聚集体又因氢键和范德华力的吸引而相互连在一起形成二氧化硅附聚体（10～100μm）。     

无机微粒表面的接枝聚合反应

介绍无机微粒表面接枝聚合反应的研究动态，讨论了将聚合物接枝的二氧化硅、二氧化钛等粒子表面的有关方法。     

气相二氧化硅增稠触变性及其在密封胶中的应用

1前言 气相二氧化硅是由卤硅烷在氢氧焰高温水解制得的一种无定形二氧化硅产品，有机卤硅烷在高温水解缩合后得到粒径为7～40纳米的原生粒子，随着粒子远离火焰，温度降低，粒子之间相互碰撞、粘附和熔结形成聚集体。二氧化硅聚集体是由众多粒子熔结在一起，形状很不规则，主要为支链形。而聚集体又因氢键和范德华力的吸引而相互连在一起形成二氧化硅附聚体。     

二氧化硅空心粒子制备条件研究

本实验采用Stober法制备二氧化硅实心内核,并采用两种不同的配比,即二氧化硅实心粒子和TEOS用量不同,制备二氧化硅外壳,通过模板法最终制得二氧化硅空心粒子。并且对产品进行SEM表征、TEM表征、XRD表征及红外光谱表征,结果表明,二氧化硅实心粒子用量多且TEOS用量少的配比方法所制得的二氧化硅空心微球效果更好,但两种配比均可成功制得纳米SiO_2空心粒子。     

红泥在皮肤清洁产品中的应用评价

介绍了一种新型洁肤用添加剂——红泥,并对红泥在皮肤清洁产品中的作用进行了研究,结果表明,红泥能显著提高活性剂型洁面剂、皂类洁面剂和面膜的清洁功效,是一种高效的洁肤用化妆品原料。     

Stress transmission in silica particulate epoxy composite by X-ray diffraction

Stress on particles in silica particulate epoxy composite under constant load was investigated by X-ray diffraction. Microdeformation of the crystal lattice of silica could be detected as a shift of the X-ray diffraction peak induced by the applied stress. When a tensile stress was applied to the particulate composite, incorporated particles were found to be subjected to a stress several times larger than the applied stress. The stress concentration onto particles in particulate composite material, which was considered to result in a mechanical reinforcement of the composite, depends on the volume fraction and size of particles. Quantitative relationships between the stress concentration coefficient, particle diameters and the increment of macroscopic Young's modulus with the incorporation of filler were stated.     

A Review on the Potential Use of Chitosan-Based Delivery System in Mild Facial Cleansing Formulation

The facial cleansing products segment has grown over the years and most surfactant-based systems do not retain many of the active ingredients on the skin. Development of a positively charged vesicle as the delivery vehicle for personal cleansing products is based on the negatively charged nature of the skin surface. Chitosan has the potential to be used as a vesicle to encapsulate active ingredients and can be used in facial formulations that are based on amphoteric surfactant with or without the addition of nonionic surfactant. This review briefly summarizes the potential of chitosan nanoparticles as the delivery system in facial cleansing formulations.     

Lipid/surfactant compounds as a new tool to optimize skin-care properties of personal-cleansing products

Surfactants are commonly used in personal-care products to increase cleansing performance and to create pleasing foam. However, surfactants can also damage the skin by removing skin lipids and causing corneocytes to swell, resulting in increased skin roughness and transepidermal water loss. Newly established methods help to quantify these effects in controlled consumer studies. In addition, in vitro experiments with skin cell cultures show the potential inflammatory action of surfactants, which in the in vivo situation may provoke skin irritation. These detrimental effects are even enhanced by frequent treatment with surfactant-based personal-care products. Together with the use of mild surfactant combinations, the addition of surfactant-compatible lipid compounds has proved a convenient way of not only counteracting the negative side effects of surfactants but also exerting positive skin effects. In a controlled consumer study, analysis of skin lipids after skin cleansing revealed the lipid-layer strengthening efficacy of lipid/surfactant mixtures that can be solubilized in the personal-care formulation or disperses as waxy particles. As a result, skin roughness after cleansing treatment, as measured by fast optical in vivo topometry of the skin, is improved, and consumers perceive that their skin is smooth and cared for.     

Effects of silica aerogel particle sizes on the thermal–mechanical properties of silica aerogel – unsaturated polyester composites

Silica aerogels with a surface area as high as 773?m²?g^?1 and a density of 0.077?g?cm^?3 were produced from rice husk via sol–gel process and ambient pressure drying. A particulate composite material was prepared by adding silica aerogel particles of three different particle sizes (powder, granules and bead) to unsaturated polyester resin with a fixed volume fraction of 30%. Thermogravimetric and thermal conductivity studies revealed that silica aerogel composites were having higher thermal stability and thermal insulation than the neat resin. It was suggested that the preservation of aerogel pores from resin intrusion is important for better thermal properties. Larger silica aerogel particles have more porous area (unwetted region) which results in a lower degradation rate and lower thermal conductivity of the base polymer. However, the addition of silica aerogel into resin has reduced the tensile modulus of the polymer matrix where smaller particle size displayed higher toughness than those with bigger particle size.     

Superhard transparent hybrid nanocomposites for high fidelity UV-nanoimprint lithography

Transparent hyperbranched acrylate nanocomposites were produced using different combinations of silica nanoparticles and silicon-based sol–gel precursors. The nanocomposites were processed using a dual-cure UV polymerization and condensation scheme. The viscosity of hybrid suspensions was found to be one to two orders of magnitude lower than that of particulate composites with the same equivalent silica fraction. The Vickers microhardness of the polymer was 112 MPa. It was equal to 190 MPa and 148 MPa for the hybrid composites and particulate composites with 20 vol% SiO₂, respectively, and it was equal to 287 MPa for the hybrid material with 30 vol% SiO₂. Light-trapping textures in the form of random sub-micron pyramidal features were replicated in the hybrid composites from a nickel template using UV-nanoimprint lithography. After optimization of the dual-cure process sequence, a very high replication fidelity was obtained for all investigated compositions, leading to a haze above 99% over the visible light spectrum and a very effective light scattering performance in a broad angular exposure.     

Smoke formation from burning polystyrene and its suppression

Studies have been made of the influence on smoke generation from polystyrene of the incorporation of a number of apparently inert solids, the smoke-producing tendency being expressed in terms of the maximum specific optical density of smoke per unit weight of polymer consumed. Of the compounds investigated, by far the most efficient smoke suppressant is pyrogenic silica, the effect of which is, over a wide range, directly proportional to the total surface area of the material introduced. Examination of partially burned polystyrene-pyrogenic silica composites reveals the presence at the surface of a hard rigid skin, which is not observer with polystyrene alone of with polymer samples containing other additives. The formation of a protective skin is also indicated by the kinetics of forced burning of these composites where the weight loss is a linear function of log time and by measurements of the rate of change of thickness of polymer samples during combustion. Thermogravimetric experiments in which polystyrene and pyrogenic silica are heated in contact with one another show that the silica encourages the formation of a carbon residue from the polymer. A mechanism of skin production is proposed which involves the build-up of layers of tangential spherical silica particles cemented together by cross-linked polystyrene.     

Sekundäres Alkansulfonat Eigenschaften und Einsatzmöglichkeiten in kosmetischen Präparaten

Secondary Alkanesulfonate – Properties and Applications in Cosmetic Preparation Large amounts of secondary alkanesulfonate are used since several years in the production of cleansing and washing agents. Laboratory and practical tests have shown that this new surfactant, produced commercially, can be used in cosmetic preparations as well. Secondary alkanesulfonate in combination with other surfactants such as alkylethersulfates, exhibit special properties when used for the production of cleansing agents for hair and skin. Further interesting effects are achieved by incorporating secondary alkanesulfonate into soaps and emulsifier mixtures. The commercial production of secondary alkanesulfonate by a continuous process is described briefly. A prognosis on the future market for cosmetic body cleansing agents is given.     

护肤品成分分析

介绍了市场上的一些护肤品、卸妆油、凝胶和洗面奶等知名品牌,从产品的成分进行分析,为消费者提供一个选择性参考。同时,为了让更多的消费者深入了解这些品牌产品,从产品功效性、安全性以及产品附加值方面做了简要分析。     

硅胶粒径对太阳能吸附制冷系统性能的影响

针对以硅胶-水为工质对的太阳能吸附式制冷系统,实验研究了不同粒径的硅胶材料对吸附床传热传质特性及系统制冷能力的影响。三组对比实验的硅胶材料平均粒径分别为1mm、3mm和5mm,在太阳辐射接近的条件下完成实验测试,结果表明粒径中等的硅胶材料表现最优,其制冷系数COP和按照循环周期定义的比制冷功率SCP2均最高。小粒径材料虽然使吸附剂填充量有所增加,但是会导致吸附床轴向传质阻力增加,影响其末端吸附能力的发挥。而材料的粒径过大,则会降低吸附床的吸附剂填充量及其传热性能,从而导致预热脱附和冷却过程的时间延长,不利于系统的制冷性能改善。实验结果表明,吸附剂粒径是影响太阳能吸附式制冷系统工作性能的一个重要因素,在系统设计中需要给予重视。