涂布纸用丁苯胶乳研究进展

介绍了近年来国外涂布纸用丁苯胶乳在单体组成、粒子结构、涂布纸表面强度与抗起泡性的平衡性、涂料高剪切流动性、胶乳稳定性、添加剂和加料顺序等方面的研究进展。     

Functional lignin-SiO2 hybrids as potential fillers for phenolic binders

Functional lignin-SiO₂ hybrid fillers were synthesized and characterized with a view to their potential application in binders for phenolic resins. The properties of these fillers and of composites obtained from them with phenolic resin were compared with those of systems with lignin or silica alone. The chemical structure of the materials was investigated by Fourier transform infrared spectroscopy. Surface properties of lignin-SiO₂ fillers were tested using inverse gas chromatography (IGC). IGC was used for determination of surface energy and surface heterogeneity of the studied fillers. IGC made it possible to assess the adhesion between the tested fillers and phenolic resins. Interactions of functional fillers with phenolic resins were also evaluated by IGC. The results indicated that lignin-SiO₂ interacted strongly with the phenolic resin, more strongly than pure lignin. This was proved by SEM observations: thanks to the stronger interactions of lignin-SiO₂ hybrid with phenolic resins, a more homogeneous composite was obtained. Thermo-mechanical properties of lignin–silica and resin systems were investigated by DMTA. DMTA results showed that phenolic binders with lignin-SiO₂ fillers have better thermo-mechanical properties than systems with lignin or silica alone: higher glass transition temperature and a smaller decrease in storage modulus. Lignin fillers can thus provide new, promising properties for a phenolic binder combining the good properties of lignin as a plasticizer and of silica as a filler improving mechanical properties.     

Vinyl ethers with polysulfide and hydroxyl functions and polymers therefrom as binders for lithium–sulfur batteries

Bis‐[3‐(vinyloxyethoxy)‐2‐hydroxypropyl‐]polysulfides (BVPS) have been prepared by reacting ethylene glycol vinyl glycidyl ether (EGVGE) with Na₂S₄ in the presence of NaHCO₃ and a phase transfer catalyst, triethylbenzylammonium chloride. The polysulfides obtained are inactive in radical polymerization but polymerize readily upon thermal initiation (140°C, 1 h) or in the presence of cationic catalysts [BF₃·OEt₂, CF₃COOH, H(AuCl₄)·4H₂O, LiBF₄‐dimethoxyethane, 20–70°C]. Polymerization leads to the formation of crosslinked polymers. It has been shown that BVPS and their polymers can be used as active binders in cathode compositions of lithium–sulfur power sources. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4051–4055, 2006     

Electroviscous effect in dilute suspensions of ionic polymer latices

The viscosity of dilute suspensions of ionic polymer latices was measured using a variable-shear capillary viscometer, a rotational viscometer and an Ubbelohde viscometer. The viscosity of the suspension was much larger than the Einstein theoretical value and showed a marked shear-thinning behaviour, due to the electroviscous effect. The dependence of the reduced viscosity of latex suspensions on latex concentration, salt concentration and solvent was essentially the same as that of linear ionic polymer solutions. Counterion effect was also investigated.     

无机复合涂层对多孔氮化硅性能影响的研究

利用溶胶-凝胶法制备在多孔氮化硅的表面制备了无机复相陶瓷涂层,利用扫描电镜、红外光谱等手段研究了涂层的形貌和结构,并采用三点弯曲法研究了材料的力学性能,讨论了涂层前后基体的性能变化,结果表明:涂层对基体的抗弯有明显的提高,最大提高20%;用涂层封孔后后,材料的气孔率和吸水率明显下降,对多孔氮化硅介电性能影响很小。     

锂离子电池硅基负极黏结剂的研究新进展

硅具有较高的理论比容量,被认为是极具应用前景的锂离子电池负极材料。然而,硅在充放电过程中会产生巨大的体积变化,导致电极粉化脱落和容量的迅速下降,限制了硅基负极材料的应用。黏结剂是锂离子电池中一个不可或缺的组成部分,对体积变化较大的硅基负极而言,除了满足作为锂离子电池黏结剂的基本要求外,对黏结剂的结构和性能又提出了新的要求,黏结剂的选择对于增强硅基电极结构的稳定性并实现长期循环具有更加重要的意义。总结了近年来硅基负极材料黏结剂的研究进展,重点介绍了用于硅基负极材料的交联类黏结剂、导电类黏结剂和自修复类黏结剂等几种黏结剂的性能特点和应用,为选择和设计更加适合的硅基负极黏结剂提供研究建议。     

Hydrolyzable‐emulsifier‐containing polymer latices as dispersants and binders for waterborne carbon black paint

Poly(styrene‐co‐butyl methacrylate) and poly(styrene‐co‐butyl acrylate) latices were prepared by emulsion polymerization with alkali‐hydrolyzable and nonhydrolyzable cationic emulsifiers and were used as a dispersant and binder for waterborne carbon black (CB) paint. CB was dispersed in the latex solutions and then coated on filter paper pretreated with dilute aqueous Na₂CO₃ under mild conditions. The styrene (St)‐rich rigid copolymer latices easily dispersed the CB but fixed a little amount of the pigment on the paper surface. In contrast, the methacrylate‐ and acrylate‐rich soft latices tended to increase the adhesibility on it. We also demonstrated that the hydrolyzable‐emulsifier‐containing latices always had a higher adhesibility than the nonhydrolyzable‐emulsifier‐containing ones. Thus, the hydrolyzable‐emulsifier‐containing latices with an appropriate St content had the highest paintability, rapid adhesion, quick drying, reduced fading, superior fastness, and so on. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3869–3873, 2013     

单个圆形非均匀多孔颗粒绕流的数值模拟

多孔颗粒两相流在工业过程中普遍存在,但多孔颗粒的内部结构几乎都是不均匀的,这可能影响颗粒与流体间的相互作用.采用基于本征相平均速度的体积平均宏观控制方程描述多孔颗粒内部和外部的流体流动,采用改进的格子Boltzmann方法(LBM)求解广义的宏观控制方程,并对二维流体流过非均匀多孔颗粒进行了数值模拟研究.通过随机分布难...     

Polypeptide conjugate binders that discriminate between two isoforms of human carbonic anhydrase in human blood

Two binder candidates 4‐C37L34‐B and 3‐C15L8‐B from a 16‐membered set of 42‐residue polypeptide conjugates designed to bind human carbonic anhydrase II (HCAII), were shown to bind HCAII with high affinity in a fluorescence‐based screening assay. Two carbonic anhydrase isoforms with 60 % homology exist in human blood with HCAI being present in five‐ to sevenfold excess over HCAII. The ability of the binders to discriminate between HCAI and HCAII was evaluated with regard to what selectivity could be achieved by the conjugation of polypeptides from a 16‐membered set to a small organic molecule that binds both isoforms with similar affinities. The polypeptide conjugate 4‐C37L34‐B bound HCAII with a K_D of 17 nM and HCAI with a K_D of 470 nM , that is, with a 30‐fold difference in affinity. The corresponding dissociation constants for the complexes formed from 3‐C15L8‐B and the two carbonic anhydrases were 60 and 390 nM , respectively. This demonstration of selectivity between two very similar proteins is striking in view of the fact that the molecular weight of each one of the conjugate molecules is little more than 5000, the fold is unordered, and the polypeptide sequences were designed de novo and have no prior relationship to carbonic anhydrases. The results suggest that synthetic polypeptide conjugates can be prepared from organic molecules that are considered to be weak binders with low selectivity, yielding conjugates with properties that make them attractive alternatives to biologically generated binders in biotechnology and biomedicine.     

丙烯酸酯乳胶涂料的制备及其在室内设计中的应用

基于互穿网络聚合法合成了丙烯酸酯乳胶涂料乳化剂,选用二烷基磺基琥珀酸盐、聚氧乙烯烷酚基醚、聚二甲基硅氧烷、聚氨酯类增稠剂、乙二醇、2-甲基-4-噻唑啉-3-酮、5-氯-2-甲基-4-异噻唑啉-3-酮等助剂,加入不同的颜料,完成丙烯酸酯乳胶涂料的制备,并分别对其防腐耐霉性、摩擦系数、耐磨性、抗冲击性能进行分析.结果表明:...     

Electrochemical detection of large channels in porous rocks

An electrochemical method for studying channels in porous rocks and similar insulators, has been developed. In principle, the method consists of displacing a nonconducting liquid from the pores by an inflow of an ionically conducting solution. The conductance is monitored continually as the rate of flow through the rock is gradually increased. The rate of conductance increase is interpreted in terms of a simple model, based on Poiseuille flow through a capillary network, to provide information about the sizes and numbers of large pores in the rock. Three rock samples have been analysed.     

HPLC法快速测定水性涂料或乳液中游离甲醛含量

建立了一种快速、简捷、经济、准确的高效液相色谱方法测定水性涂料或乳液中甲醛含量。前处理采用溶剂直接溶解,低温离心或过滤,取适量上清液与2,4-二硝基苯肼衍生后进行液相色谱分析。该方法测定甲醛的检出限为0.012μg/L,回收率为95%～105%,相对标准偏差小于2%,在0.05～5 mg.L-1线性范围内,相关系数R2为0.9999。     

Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore-forming agent

In this work, the effects of porosity and different particle sizes of pore-forming agent on the mechanical properties of porous alumina ceramics have been reported. Different grades of porous alumina ceramics were developed using corn cob (CC) of different weight contents (5, 10, 15, and 20 wt%) and particle sizes (<63 µm, 63-125 µm and 125-250 µm) as the pore-forming agent. Experimental results showed that total porosity and pore cavity size of the porous alumina ceramics increased with rising addition of CC pore former. Total porosity increased with increasing particle size of CC with the Al₂O₃-^<63CC₅ sample exhibiting the lowest total porosity of 41.3 vol% while the highest total porosity of 68.1 vol% was exhibited by the Al₂O₃-^125-250CC₂₀. The particle size effect of CC on the mechanical properties revealed that diametral tensile strength and hardness of the porous alumina ceramics deteriorated with increasing particle size of CC pore former. The Al₂O₃-^<63CC₅ sample exhibited the highest diametral tensile strength and hardness of 25.1 MPa and 768.2 HV, respectively, while Al₂O₃-^125-250CC₂₀ exhibited the lowest values of 1.1 MPa and 35.9 HV. Overall, porous alumina ceramics with the smallest pore sizes under each particle size category exhibited superior mechanical properties in their respective categories.     

水性金属防腐蚀涂料所用基料现状及发展

按涂料所用树脂分类,评述了丙烯酸体系、环氧体系、无机硅酸锌体系和聚氨酯体系等4类水性防腐蚀涂料体系,重点介绍它们的合成技术进展。尽管水性防腐蚀涂料与溶剂型相比还存在不足,但只要设计和施工得当,水性防腐蚀涂料在许多情况下可以胜任。指出当前水性防腐蚀涂料的研究重点是新型成膜聚合物和防腐蚀颜填料的选择与制备,涂料配方及合成工艺的优化,建议我国涂料企业应抓住"量大面广"品种,大力发展水性金属用防腐蚀涂料产品。     

水性基料在超薄型钢结构防火防腐涂层体系构建中的应用

探讨了市面上不同树脂水分散体作为超薄型钢结构防火防腐涂料基料的可能性,通过长时间浸泡涂层考察各水性树脂的耐水性、涂层致密性以及填料溶失程度,结果表明:水性基料不适用于含有水溶性填料的单涂层体系。通过热重分析对比发泡填料体系和各树脂的热降解行为,选择热降解温程较为相似的乙酸乙烯酯共聚物和环氧共聚物作为优化涂层防火功能的主要基料。通过垂直燃烧实验测试被涂覆试样的背板温度,优化了防火涂层的颜基比;并通过调整基料复配比例,使得涂层在灼烧后可以得到膨胀厚实且粘附稳定、致密均匀的发泡层。以此为基础,构建了防腐—防火—封闭的多层防火防腐体系,该体系具有良好的耐腐蚀性及耐火性,尤其是长期浸泡后的可持续耐火性与溶剂型同类产品相当。     

Stereolithography as a manufacturing method for a hierarchically porous ZSM-5 zeolite structure with adsorption capabilities

Hierarchically porous structures are important in adsorption applications and can be used in gas treatment. Hierarchy in adsorbents offers flow channels on different scales, resulting in fast gas flow into a structure. Additive manufacturing, a technology capable of forming intricate geometries, was seen as a potential method to form porous adsorption structures. Stereolithography was chosen as the fabrication method for hierarchically porous zeolite structures because of its high resolution and superior forming capability. The focus of this study was on tailoring the properties of light-cured resin to maximize stability during shaping and shape retention in the debinding stage. Successful slurry preparation was required for demonstrating that monoliths with channel geometry and retained adsorption properties can be manufactured with stereolithography. The final printed structures exhibited hierarchical porosity consisting of flow channels, macropores between the primary particles and the characteristic microporosity of zeolite framework. The structure was manufactured by using blue light to cure layers of resin containing ZSM-5 zeolite. An appropriate debinding heat-treatment cycle was generated based on the TGA and DSC thermal analysis results. The properties of the porous structure were analysed by comparing the BET surface area, XRD patterns and SEM images of as-received powder and a debound piece. The measured BET adsorption properties of the final monoliths remained comparable to the as-received ZSM-5 powder. Based on this study, stereolithography can be utilized to manufacture porous zeolite structures.     

Flooding and floating in latex paint

Flooding and floating are problems in many paint applications. If pigment concentration is uniform on the surface but not through the thickness of the film, one refers to ‘flooding’ (horizontal separation). If, however, concentration differences are visible across the surface of the paint film, one refers to ‘floating’ (vertical separation). In this article, the influence of pigment, filler, additives, and processing conditions on the flooding and floating of colored latex paint were investigated. It was discovered that too broad a distribution of pigment and filler particle size can lead to flooding and floating. Different levels of pigment (TiO₂) or filler (kaolin) loading cause diverse degrees of flooding and floating. Waterborne coatings that do not exhibit flooding or floating may show these conditions when diluted. Using dispersants or thickeners with hydrophobic constituents, increasing viscosity, reducing surface tension, etc., all help to prevent or reduce flooding and floating. Comparison tests revealed little influence of processing conditions on flooding or floating.     

Preparation and performance in paper coating of silicone‐modified styrene–butyl acrylate copolymer latex

Silicone‐modified styrene–butyl acrylate copolymer latex was synthesized by emulsion copolymerization by using octamethylcyclotetrasiloxane (D₄), styrene, and butyl acrylate as raw materials, potassium persulfate as initiator and propylmethacrylate triethoxysilane (KH‐570) as crosslinking agent. The infrared spectra studies showed that the vinyl monomers were completely copolymerized with D₄. The prepared silicone‐modified copolymer latex with the interpenetrating polymer networks tended to have higher stability, and better toluene and water resistance than styrene–butyl acrylate latex. The glossiness of coated paper was improved with silicone‐modified copolymer latex, and it was at a maximum when D₄ was about 3% of total monomers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 333–336, 2001     

具有不同孔隙率多孔介质内的蒸发特性

制作了具有3种不同孔隙率（0.85、0.75和0.60）的多孔镍粉样本,并进行了毛细抽吸实验和蒸发冷却实验（包括稳态冷却实验,初始状态为干态和湿态的冷却实验）,以探究多孔介质抽吸和蒸发过程规律。毛细抽吸实验发现孔隙率大的镍粉样本抽吸速率更快,且根据毛细单管抽吸实验和毛细抽吸理论分析结果表明：孔隙率大的镍粉样本具有更大孔径是其抽吸速率更快的根本原因。稳态冷却实验结果表明孔隙率0.85的镍粉样本具有最快的蒸发速率,0.60镍粉样本蒸发速率最慢,这是受到多孔样本抽吸速率主导的结果。在初始干态冷却实验中,孔隙率为0.85的镍粉样本具有最大的瞬态冷却热通量,但要达到最大冷却温度幅度须取得瞬态冷却热流与冷却时间的平衡,因此孔隙率0.75样本冷却温度幅度最大。在初始湿态实验中,孔隙率为0.85的镍粉样本具有最高的烧干温度和最长的烧干时间,表现出最强的抗烧干性能,但是孔隙率0.75样本剧烈蒸发过热度最小且剧烈蒸发时间最长,最能有效抑制样本热端温度升高。