氧化铝纤维先驱体的化学合成

将金属铝在氯化汞催化剂的作用下，溶解在甲酸和乙酸的混合水溶液中，制取羧酸铝溶液，此溶液在合适温度下降，浓缩得到具有纤维成型能力的高粘度流体，然后利用干纺技术得到透明无色纤维。实验表明，当铝，甲酸、乙酸和水的摩尔比为１：４：３：２４时，铝完全解得到无色透明且在室温下期稳定的羧酸铝溶液。     

聚酰胺羧酸中空纤维膜的初步研究

测定了聚酰胺羧酸 ( PAm A) /DMAc溶液的相混合参数 ,采用干 /湿法纺丝技术制备了聚酰胺羧酸 ( PAm A)中空纤维膜 ,讨论了铸膜液组成、浓度、后处理等因素对膜性能的影响。     

静电纺丝模板法制备莫来石纤维工艺研究

采用静电纺丝制备的PVP纤维为模板,以非水解溶胶-凝胶法制备的莫来石溶液为浸渍液,利用模板浸渍技术制备出莫来石纤维。研究优化铝离子浓度、浸渍时间和浸渍次数等工艺参数发现,铝离子浓度为0.2mol/L,纤维全部为莫来石相,纤维表面光滑、纤维较长;浸渍时间为1min和3min时,纤维出现坍塌和断裂现象,浸渍时间为2min时,纤维表面光滑,直径分布均匀,平均直径约为240nm,很好地遗传了PVP模板的纤维结构。随着浸渍次数增加,莫来石纤维直径也逐渐增加,纤维的交联现象严重。     

同轴静电纺丝法制备多孔镁铝尖晶石纤维

为制备多孔镁铝尖晶石纤维,首先以无水氯化铝、无水氯化镁、无水乙醇为原料,二氯甲烷为溶剂,采用非水解溶胶-凝胶法制备出干凝胶,再引入纺丝助剂聚乙烯吡咯烷酮(PVP)和助溶剂N,N-二甲基甲酰胺(DMF)制成静电纺丝溶液,利用多针头同轴静电纺丝法制备镁铝尖晶石凝胶-PVP前驱体纤维,经900℃煅烧合成出多孔镁铝尖晶石纤维。借助XRD和SEM研究了PVP用量(3、4和5 g)、阳离子浓度(0.216、0.288和0.360 mol·L~(-1))、静电纺丝电压(22、24和26 k V)及内液流速(0.1、0.3和0.5 m L·h~(-1))对多孔镁铝尖晶石纤维相组成和形貌的影响。结果发现:当PVP用量为4 g,阳离子浓度为0.288 mol·L~(-1),纺丝电压为24 k V,内液流速为0.3 m L·h~(-1)时,纤维物相为纯镁铝尖晶石相,纤维连续,并呈现明显的多孔结构。     

溶胶–凝胶法制备多晶钇铝石榴石纤维

以廉价的铝粉、工业盐酸和醋酸钇为主要原料,通过溶胶–凝胶法制备了高性能的多晶钇铝石榴石纤维。采用X射线衍射、Fourier变换红外光谱、扫描电镜和热重–差示扫描热分析等表征了不同温度下焙烧所得纤维的物相组成、纤维形貌以及前驱体纤维的热分解特性。结果表明:纤维经热处理到900℃时可获得纯相的钇铝石榴石晶体。经1550℃热处理后,所得到的多晶钇铝石榴石纤维的平均晶粒尺寸在200nm左右,拉伸强度在485MPa。     

多喷头静电纺丝制备镁铝尖晶石纳米纤维的研究

本文以无水氯化铝、无水氯化镁、无水乙醇为原料,二氯甲烷为溶剂,采用非水解溶胶-凝胶法制备出干凝胶前驱体,加入纺丝助剂聚乙烯吡咯烷酮(PVP)制成纺丝液,采用多喷头静电纺丝法制备镁铝尖晶石/PVP前驱体纤维,最后经煅烧制成纳米镁铝尖晶石纤维,利用DTA-TG、XRD、FTIR和SEM表征了镁铝尖晶石纤维的形成过程。结果表明,经500℃煅烧后,纤维中有机物基本排除,但此时纤维为无定形态。经700℃煅烧纤维出现镁铝尖晶石相,而经900℃煅烧所得纤维中镁铝尖晶石发育更加完全,纤维表面光滑,直径细小,分布在100nm~300nm范围。     

添加氧化硼对氧化铝纤维形貌的影响

以硝酸铝、酒石酸为原料,添加的纺丝助剂为聚乙烯吡咯烷酮(PVP),用溶胶-凝胶法制备了氧化铝纤维。在纤维制备时,添加氧化硼,研究了氧化硼对纤维形貌的影响。结果表明,添加氧化硼的凝胶纤维在1200℃烧结后,物相主要为α-Al2O3,纤维的直径为22μm,纤维表面变粗糙。     

碳酸铝铵低温热分解制备a-Al2O3超细粉末

利用硫酸铝铵溶液和碳酸氢铵溶液的沉淀反应制备碳酸铝铵前驱体，通过在碳酸铝铵中同时添加α–Al2O3籽晶和硝酸铵, 使得α相的转变温度从1150℃降低到950℃, 获得了尺寸均匀、团聚较小、平均粒径为90 nm的球形α–Al2O3超细粉末. 相变过程为：无定型→g→g+α→α，并没有出现高温过渡型相q相.     

氧化钛/氧化铝复合纤维的制备工艺

以硝酸铝、氯化钛和酒石酸为原料,聚乙烯吡咯烷酮（PVP）为纺丝助剂,用溶胶-凝胶法制备了氧化钛/氧化铝复合纤维。结果表明,凝胶纤维在1200℃烧结后,纤维的物相为α-Al2O3和（TiO0.86）3.38,纤维的直径为22μm,纤维表面光滑,粗细均匀。     

氧化钛/氧化铝复合纤维的制备工艺

以硝酸铝、氯化钛和酒石酸为原料,聚乙烯吡咯烷酮(PVP)为纺丝助剂,用溶胶-凝胶法制备了氧化钛/氧化铝复合纤维。结果表明,凝胶纤维在1200℃烧结后,纤维的物相为α-Al2O3和(TiO0.86)3.38,纤维的直径为22μm,纤维表面光滑,粗细均匀。     

利用铝厂污泥合成莫来石/刚玉复相材料

采用铝型材厂污泥和粘土为原料合成莫来石刚玉复相材料，主要探讨不同Al2O3／SiO2比值对形成的晶相结构影响。采用XRD和SEM表征各样品的晶相，结果表明各样品都形成2种晶相：莫来石固溶体和刚玉相，其中No．2配方中莫来石和刚玉的比例为：71．6：28．4，莫来石在扫描电镜下呈柱状交织，为较佳配方。     

Preparation of Mullite Fiber

Transparent mullite fibers have been prepared using aluminum carboxylates (ACs) and tetraethyl orthosilicate (TEOS) as starting materials. The ACs are derived from the catalyzed dissolution of elemental aluminum in a mixture of formic acid and acetic acid. The solubility of aluminum in the acids is influenced by the concentrations of the acids, water, and additives and the preparation temperature. A 1:4:3:24 molar ratio of aluminum, formic acid, acetic acid, and water dissolves the aluminum completely to give a colorless, clear solution suitable for fiber synthesis. The mixture of the ACs and TEOS, in the presence of ethyl alcohol as a mutual solvent at 50°–60°C, is concentrated to give a spinnable dope, from which mullite precursor fibers can be drawn. Heat treatment of the precursor at 1250°C yields crystallized and transparent mullite fibers.     

耐水硅胶材料制备工艺条件优化实验研究

运用正交实验设计及方差分析方法,以耐水硅胶材料的比表面积和孔容为考察指标,研究了在硅胶制备过程中硫酸铝溶液质量分数、原料硫酸与硫酸铝物质的量比等因素对实验结果影响的显著性。结果表明,硫酸铝溶液质量分数及原料硫酸与硫酸铝物质的量比对实验结果影响最为显著。最优工艺参数：硫酸铝溶液质量分数为6%,原料硫酸与硫酸铝物质的量比为2∶1,酸泡过程硫酸与硫酸铝物质的量比为6∶1,碱泡过程中稀氨水质量分数为0.1%,老化时间为1.5 h。在最优工艺条件下,可得到比表面积不低于300  m²/g、孔容不低于0.7 mL/g的具有良好耐水性的吸附分离材料。     

莫来石纺丝溶胶的流变特性及可纺性研究

本文以氢氧化铝为铝源,以硅溶胶为硅源,采用溶胶-凝胶技术制备了莫来石纺丝溶胶,采用稳态及动态两种测试模式,研究了纺丝溶胶的粘度及流变性能,并采用干法纺丝制备连续莫来石凝胶纤维,评价了溶胶的可纺性。结果表明,温度对溶胶的非牛顿指数及结构粘度指数影响不大,这将有利于纺丝工艺的调节;高固含量有利于莫来石凝胶纤维的纺丝成纤,制备的凝胶纤维更细,纺丝稳定性更好。     

PVA作纺丝助剂制备莫来石-氧化铝长纤维

用氯化铝和铝粉为原料制备了铝溶胶,再向铝溶胶加入硅溶胶、封端剂和聚乙烯醇（PVA）纺丝助剂,制得莫来石-氧化铝溶胶,研究了纺丝助剂加入量对溶胶纺丝性能的影响。研究发现,溶胶在浓缩时,胶粒间发生缩合反应,形成线性或非线性的分子链,生成可纺的黏性溶胶;在溶胶中加入纺丝助剂,铝/硅离子或胶粒与纺丝助剂的活性基团发生缩聚反应,生成有机-无机的杂化分子链,提高了溶胶的纺丝性能;在加入封端剂的同时,加入质量分数为1%的PVA,凝胶纤维的最大长度可达100 cm。凝胶纤维在1 200 ℃下烧结1 h后,得到的陶瓷纤维的物相为γ-Al₂O₃和莫来石相,纤维表面光滑、直径均匀。     

硅溶胶系列FCC催化剂制备技术研究

介绍了以硅溶胶为粘结剂的催化裂化催化剂国内外研究现状,以及硅溶胶的性能、特点和影响硅溶胶稳定性的因素。综述了由硅酸钠经离子交换法制备和硅酸钠与无机酸反应制备催化剂的方法。含硅粘结剂的催化剂抗磨损能力和焦炭选择性较好,催化剂的强度可以通过添加表面活性剂和铝盐得到改善。     

亚熔盐分解钾长石矿样中钾铝硅的分离

采用KOH亚熔盐法常压低温分解河北钾长石矿粉,回收过量碱后,用硫酸溶解固渣,得含高浓度钾、铝、硅的母液;采用溶胶?凝胶法和分步醇析法从母液中制备硅凝胶、钾明矾和硫酸钾,钾明矾热解制备氧化铝. 结果表明,钾长石矿中各组分含量分别为K2O 13.13wt%,Al2O3 16.66wt%,SiO2 58.28wt%. 在H+浓度3.80 mol/L及95℃条件下母液易形成硅凝胶,脱硅率达98%以上,SiO2含量大于99.0%,比表面积大于700 m2/g,孔容约为1.0 cm3/g,孔径为5?6 nm;对脱硅母液分步醇析,在25℃、醇料体积比为1时,优先析出钾明矾,铝析出率达98%,降温至5℃并增大醇料体积比至2,可从母液中结晶析出硫酸钾,钾回收率达89%.     

甩丝法制备多晶氧化铝纤维

使用溶胶-凝胶法制备氧化铝质量分数为80%的多晶氧化铝纤维。以结晶氯化铝、铝粉和硅溶胶为主要原料制备出不同粘度的胶体,采用甩丝法制备纤维。研究了胶体粘度、甩丝盘转速对纤维直径和拉伸强度影响。并对热处理过程中升温制度对纤维拉伸强度的影响进行了研究。结果表明：当胶体粘度为20,Pa·s、甩丝盘转速为6,000,r/min、升温速度为240,℃/h时得到的纤维拉伸强度较高,该纤维经1,200,℃烧成后,平均单丝拉伸强度超过1,100,MPa,是一种性能较优异的氧化铝纤维。     

Modification of E-glass fiber surfaces with polyacrylic acid polymers from an aqueous solution

The research reported in the article focuses on modifying glass fiber surfaces with polyacrylic acid (PAA) compounds. E-glass fibers were treated with aqueous polyacrylic acid solution. Polyacrylic acid exchanges its protons with the ions present in the glass surface. Hydrolyzed metal cations may form salt complexes with the dissociated polyacrylic acid. Angular dependent electron spectroscopy for chemical analysis (ESCA) demonstrated that the atomic concentrations of aluminum and calcium in the glass fiber surface were constant throughout the analyzed interval. The cation exchange property of glass fiber was studied using direct current plasma (DCP), which showed that both calcium and aluminum ions were extracted by low concentration polycrylic acid solutions. ESCA studies of were extracted by low concentrationb polyacrylic acid solutions. ESCA studies of the PAA-treated glass fiber showed that the amount of PAA of the glass surface increases with increased acid concentration. A broadened and shifted ESCA peak of the carbon (0 CO) indicates the formation of salt complexes between the polyacrylic acid and metal ions on the glass surface. Polyacrylie acid was modified by an esterification reaction with glycidyl acrylate (GA) in aqueous solution in order to insert organofuctional groups into the PAA chain.     

Influence of erodent particle types on solid particle erosion of polyphenylene sulphide composite under low particle speed

The influence of erodent particle types on solid particle erosion of randomly oriented short glass fiber and mineral particle reinforced polyphenylene sulphide (PPS) was investigated. The solid particle erosion studies were carried out using low speed solid particle erosion test rig with 150 to 212‐μm brown fused aluminum oxide (Al₂O₃), 150 to 200‐μm silica sand and 150 to 250‐μm glass bead. Glass bead eroding particles appear spherical in shape whereas aluminum oxide and silica sand eroding particles have sharp and angular edges. The erosion tests were conducted at six different contact angles of 15, 30, 45, 60, 75, and 90°, respectively. The results showed a strong dependence of the eroding particle types on the erosive wear behavior of PPS composite. The peak erosion rate occurred at 45° contact angle for silica sand eroding particles while the peak erosion rate occurred at 30° contact angle for aluminum oxide and glass bead particles. The morphologies of eroded surfaces were characterized by the scanning electron microscopy. In case of aluminum oxide and silica sand, the erosive wear mechanism occurs firstly by the erosion of matrix, followed by the fracture of un‐supported fibers and their detachment; however, the erosive wear mechanism occurs different for glass bead particles. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers