空心玻璃微珠对聚氨酯泡沫燃烧和力学性能的影响

通过向聚氨酯发泡体系中添加空心玻璃微珠,制备出空心玻璃微珠聚氨酯三相泡沫.研究了空心玻璃微珠添加量、聚磷酸铵(APP)用量、膨胀阻燃体系(IFR)浓度等因素对聚氨酯泡沫燃烧和力学性能的影响.结果表明,单独添加空心玻璃微珠对聚氨酯泡沫的氧指数和水平燃烧速度影响不大.添加APP或IFR后,空心玻璃微珠聚氨酯三相泡沫的阻燃效...     

空心玻璃微珠复合聚酰亚胺泡沫的泡孔结构与性能

通过填充空心玻璃微珠,采用预聚法制备了空心玻璃微珠复合聚酰亚胺泡沫,研究了空心玻璃微珠填充量对复合聚酰亚胺泡沫的泡孔结构、热性能和压缩性能的影响规律。结果表明,随着空心玻璃微珠填充量的增加,聚酰亚胺泡沫泡孔结构变得精细,并且热稳定性、玻璃化转变温度和压缩性能都随之提高。当填充量(空心玻璃微珠与均苯四甲酸酐的质量比)达到20%时,泡沫5%热失重温度提高了13.9℃,玻璃化转变温度提高了8.1℃,压缩强度提高了约21%,压缩模量提高了约12%。     

空心玻璃微珠改性饰面型防火涂料性能研究

利用隧道燃烧法测定了空心微珠改性防火涂料的防火性能,考察了空心微珠类型和添加量对涂料防火性能的影响,结合试件背火面温度变化探讨了空心微珠的防火机理.结果表明空心微珠可显著提高防火涂料的防火性能,添加适当的量可以使涂料的防火性能达到二级标准.     

水成膜泡沫灭火剂性能的实验室测定方法

水成膜泡沫灭火剂(aqueous film-form ingfoam,AFFF)是一类能够在烃类液体表面形成水膜的泡沫灭火剂[1-2]。在目前用于扑灭油类火灾的灭火剂中,AFFF由于其水成膜及泡沫的双重灭火作用具有最佳灭火效果。而且由于AFFF中绝大部分的组分是水,在国际范围的“淘汰哈龙行动”中作为哈     

空心微珠表面化学镀Ni-Co-P合金

以无机非金属粉煤灰空心微珠为芯材, 利用化学镀工艺对其表面进行金属化改性, 可以得到表面完整包覆的导电粉体, 该粉体具有中空, 质轻, 粒度细, 高强度, 耐高温, 导电性能好等多种优异性能, 可部分代替金属和铁氧体微粉作为电磁波吸收剂. 采用SnCl2和PdCl2进行敏化-活化处理后, 在空心微珠表面化学包覆Ni-Co-P合金层, 利用XRD、EDS、SEM和镶嵌金相等方法对样品进行形貌观察和分析表征, 结果表明, 使用PdCl2作活化剂可以得到优质均匀的Ni-Co-P合金镀层, 镀层光亮, 均匀, 包覆完整. 化学镀后镀层呈非晶态, 450 ℃氢气气氛下热处理后出现结晶相Ni3P和六方晶系的α-Co单质.     

空心玻璃微珠/TiO2复合微球的制备及其性能研究

本文以脲为沉淀剂,通过化学沉淀法成功实现了锐钛矿型二氧化钛壳层在空心玻璃微珠表面的可控组装,从而制备出玻璃/二氧化钛核壳空心微球,并通过XRD、SEM、EDX和拉曼光谱对其结构、形貌、粒径、壳厚和化学组成进行了表征.提出了二氧化钛在空心玻璃微珠表面的定向生长的可能机制和形成过程.     

环氧树脂-玻璃微珠多孔复合材料的水声性能

为提高薄板吸声材料的吸声性能,用改性环氧树脂和空心玻璃微珠等原料合成了25mm厚环氧树脂-玻璃微珠多孔复合材料,在脉冲声管中测试了合成材料试样的声压反射系数和吸声系数,研究了合成工艺参数对其水下声学性能的影响.测试结果表明:环氧树脂-玻璃微珠多孔复合材料是一种良好的水下吸声材料,其吸声性能受到空心玻璃微珠的种类及其含量和固化剂种类等参数的影响.制备了填充多种空心玻璃微珠低频吸声性能良好的环氧树脂-玻璃微珠声学材料.合理地设计实验工艺参数,可以得到水下声学性能更佳的环氧树脂-玻璃微珠多孔复合材料.     

水发泡淀粉挤出泡沫的结构与性能

以水为发泡剂,普通玉米淀粉为原料,采用双螺杆挤出机制备淀粉泡沫材料,研究了发泡剂用量及聚乙烯醇的加入量对泡沫材料结构与性能的影响。 用扫描电子显微镜观察了泡沫材料截面的形态,用万能材料试验机测试了泡沫材料的力学性能。 结果表明,水的质量分数为8%时淀粉泡沫径向膨胀率和发泡倍率最高,分别为22倍和17.6倍,压缩模量最高（4.07 MPa）。 加入质量分数10%的聚乙烯醇(PVA)使淀粉泡沫的孔径变大至1.29 mm,壁厚增加至82.43 μm,同时压缩模量增加至9.70 MPa。     

甲基三氯硅烷改性三聚氰胺阻燃疏水泡沫的制备及其性能

以软质三聚氰胺泡沫为基材,甲基三氯硅烷作为改性剂,使用化学气相沉积法成功制备得到包含二维聚硅氧烷涂层和三维多孔网络骨架结构的三聚氰胺改性泡沫。这种独特的结构赋予三聚氰胺改性泡沫优异的疏水、油水分离、吸油以及阻燃性能,其水接触角、吸油量、氧指数、热释放速率、热释放速率峰值和总热释放量下降比例分别可以达到104（°）、155.6 g/g、38.5%、57.4%、59.5%和31.1%。兼具独特结构、优异疏水和阻燃性能的三聚氰胺改性泡沫的设计制备,为今后多功能油水分离材料的设计以及处理油污问题的解决提供了一种新的途径。     

THIEC改性三聚氰胺甲醛树脂泡沫的制备及其性能表征

首先,采用三-(2-羟乙基)异氰酸脲酯(THIEC)作为增韧剂对三聚氰胺甲醛树脂(蜜胺树脂)进行化学改性,以提高树脂的韧性。然后,将改性蜜胺树脂与表面活性剂、发泡剂、固化剂、成核剂等充分混合搅拌,采用普通热发泡法制得三聚氰胺甲醛树脂泡沫(蜜胺泡沫)。用扫描电子显微镜(SEM)、氧指数仪、万能电子试验机、导热系数仪对蜜胺泡沫的形态结构、阻燃性能、力学性能及热绝缘性能进行了测试和分析。探究了发泡剂、固化剂用量对蜜胺泡沫表观密度及形态的影响。结果表明:当THIEC、发泡剂、固化剂、成核剂的用量依次为蜜胺树脂质量的15%、10%、6%、2%,发泡温度为80℃时,蜜胺泡沫的压缩强度达到150kPa、极限氧指数为34、导热系数为0.027W/(m·K),综合性能良好。     

Superabsorbent polymer with improved permeability and absorption rate using hollow glass microspheres

Itaconic acid-vinyl sulfonic acid based super absorbent polymer (SAP) was synthesized by aqueous solution polymerization using ammonium persulfate as the initiator, tetra (ethylene glycol) diacrylate as the internal crosslinking agent, and sodium hydroxide as the neutralizing agent. Surface-crosslinking was introduced to improve the low absorbency under load of the itaconic acid-based SAP. Hollow glass microspheres were added during surface-crosslinking to improve the absorption properties and permeability of the SAP. Hollow glass microspheres increased the specific surface area of SAP and acted as an incompressible filler resulting in the improvement of gel strength and the relief of gel blocking by preventing adhesion between SAP particles. The surface-crosslinked SAP with 2 wt% hollow glass microspheres showed the highest permeability and absorbency under load. The absorption rate of the synthesized material was also increased.     

Low-density polycarbonate composites with robust hollow glass microspheres by tailorable processing variables

Polycarbonate (PC) composites with low weight have been required for mobile applications. Herein, the incorporation of 15 phr (parts per hundred of resin) soda-lime borosilicate hollow glass microspheres (HGMs) into a PC matrix reduced the specific gravity by 15.2%. The microsphere preservation rate was systematically examined depending on HGM compressive strength, and processing conditions for extrusion (side-feeding vs. main-feeding vs. screw configuration) and injection molding (mild condition for edge gate vs. extreme condition for pinpoint gate). Various transition temperatures such as glass transition temperatures and heat distortion temperature were investigated as a function of HGM. The coefficient of thermal expansion of the 15 phr HGM-embedded PC composites was reduced by 51.9%. The rheological behavior of the composites was also probed. The toughness was reduced due to the ductile-to-brittle transition of PC caused by the incorporation of fillers despite the enhanced modulus. The incorporation of the robust hollow glass microspheres into a PC composite via a delicately designed screw configuration and suitable processing conditions can be used for low-density composites such as mobile applications.     

Stimuli-responsive multilayer chitosan hollow microspheres via layer-by-layer assembly

Novel stimuli-responsive multilayer chitosan hollow microspheres with chitosan as the unique component have been fabricated by the sequential layer-by-layer electrostatic assembly technique from the sacrificial templates (polystyrene sulfonate, PSS) with chitosan (CS) as the polycation and carboxymethyl chitosan (CMCS) as the polyanion, respectively. Their hollow structure was confirmed by the TEM analysis. The DLS analysis indicated that the multilayer chitosan microcapsules were pH and ionic strength dual-responsive. Due to the biocompatibility of the single component chitosan used, the multilayer chitosan microcapsules are expected to be used in the controlled release of drugs.     

Photocatalytic reduction of dichromate by titanium dioxide supported on hollow glass microbeads

The photocatalytic reduction of dichromate using TiO2/beads as a photocatalyst was studied. The results showed that 3.8 × 10-4 mol/dm3 of dichromate can be completely reduced into Cr3 after illumination for 35 min with a 375 W medium pressure mercury lamp. The effects of factors such as the amount of TiO2/beads , initial concentration of dichromate, initial pH, nitrogen and oxygen atmosphere, and concentration of Fe3 on the photocatalytic reduction of dichromate were investigated. A possible mechamism of the photocatalytic reaction was proposed. After illumination for 200 h, no significant loss of photocatalytic activity of TiO2/beads was observed.     

Photocatalytic decomposition of oil films floating on water using TiO_2 supported on hollow glass microbeads by sunlight

The feasibility of photocatalytic decomposition of oil films floating on water using TiO2 supported on hollow glass microbeads was studied.The results showed that 100% of ethylbenzene and 78% of dodecane can be photocatalytically removed after 8 h illumination with sunlight.The TiO2 supported on the hollow glass microbeads was not easily detached from the beads.After 150 h illumination there was no significant loss of the photocatalytic activity of TiO2 Some intermediate products of photocatalytic decomposition of dodecane were detected.     

CTAB-assisted synthesis and photocatalytic property of CuO hollow microspheres

CuO hollow microspheres have been fabricated through a simple hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The effects of reaction temperature, surfactant, and the molar ratio of Urea/Cu(Π) on the morphologies of the resulting products were investigated. The possible formation mechanism of CuO hollow dandelion-like architectures was proposed. The hierarchical CuO hollow microspheres exhibited a high photocatalytic activity for decolorization of Rhodamine B (RhB) under UV-light illumination.     

空心球壳型V2O5的制备研究

无机空心微球含可容纳大量客体的中空部分,具有比表面积大、密度小、表面渗透能力强、稳定性好等特点,在化学、生物、材料科学和光电领域均有重要的应用,如控制释放胶囊(药物、颜料、化妆品、油墨)、催化剂及催化剂载体、分离材料、声学隔音材料以及电子学元件等。[1-3]空心球壳材料的制备方法通常有喷雾干燥法,乳液法[4],模板合成法[5]。近年来以胶体粒子为模板合成空心材料引起了人们的高度重视,其中聚苯乙烯微球(PSt)由于其形貌规整,粒径均一而被广泛用作形成空心结构的有机模板[6]。通过对锂离子电池正极材料的广泛研究,发现空心球壳型…     

Adsorption of polyamides and polyamide–silane mixtures at glass surfaces

The individual and combined adsorption behavior of polyamides and two different silanes to multicomponent glass surfaces was probed with a combination of x‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and static contact angle measurements. Samples were analyzed with and without solvent rinsing to separate the weakly bound (physisorbed) and more strongly bound (chemisorbed) species. High‐resolution XPS on N 1s revealed that the polyamides adsorb to the glass surfaces via protonated amine species at the acidic (OH) sites on the glass surface. Angle‐resolved XPS confirmed this by showing that the alkyl portion of the polymer is oriented away from the glass interface. In competitive coadsorption studies it was found that amino‐terminated silanes preferentially adsorb to the glass surface, relegating the polyamide to a physisorbed outer layer. When mercaptoterminated silanes were competitively coadsorbed the polyamide was preferentially adsorbed even when present at a concentration twenty times less than that of the silane. Altogether, this work reveals the strong interaction between surface silanols and amino‐functionalized organics. Copyright © 2003 John Wiley & Sons, Ltd.     

Stabilization of layer-by-layer engineered multilayered hollow microspheres

Polymer multilayered hollow microspheres prepared by layer-by-layer (LbL) self-assembly attract more and more interest due to their unique application, especially as drug delivery system (DDS). Unfortunately, the multilayered hollow microspheres assembled via weak linkages could fuse and/or aggregate in high ionic strength media or strong acidic or basic media. This severely restricts the practical applications of the multilayered hollow microspheres as DDS in human physiological medium. In the present work, the progress in stabilization of the multilayered hollow microspheres is reviewed, with emphasis on the assembling process and their crosslinking mechanism.