硅酸钠模数测定方法的探究

详细阐述了硅酸钠中氧化钠和二氧化硅含量测定的理论依据,在分析和总结现阶段测定二氧化硅含量存在问题的基础上,提出了改进的方法。通过采用过饱和氟化钠溶液,酸度计监测滴定终点的实验准确测定了二氧化硅含量,进而提高了硅酸钠模数测定的准确性和重复性。     

高模数硅酸钠的制造方法

本发明介绍用金属精炼工业中（如在硅铁和金属硅的制造过程中）副产的大量工业废物二氧化硅和干法硅酸钠，生产模数高达３．５以上高模数硅酸钠的方法。     

硅烷偶联剂对地聚合物力学性能及微观结构的影响

研究了硅烷偶联剂对偏高岭土基地聚合物韧性的影响,通过抗压,抗折,孔径分布,红外光谱,X射线衍射和扫描电镜等测试,分析了硅烷偶联剂对地聚合物力学性能和微观结构的影响.结果表明:硅烷偶联剂的掺入使抗折强度先升高再降低,而抗压强度降低.当激发剂浓度为38％,硅烷偶联剂掺量为1wt％时,地聚合物的抗折强度为11.1 MPa,较纯地聚合物提高了2.3 MPa,折压比提高了30％.     

多孔氮化硅微观组织结构对力学性能的影响

通过添加造孔剂苯甲酸,利用气氛压力烧结技术制备出了不同气孔率(40%～70%)的多孔氮化硅陶瓷,研究了显微结构对材料力学性能的影响;通过分析发现发育较好的长柱状β-氮化硅晶粒保证了材料获得良好的室温力学性能;而材料密度低、晶粒发育不完全是多孔氮化硅陶瓷力学性能下降的主要原因。本文制备的多孔氮化硅断裂形式为沿晶和穿晶断裂模式,当陶瓷气孔率为52%时,弯曲强度为195MPa。     

高温处理对单向碳纤维增强无机聚合物复合材料力学性能的影响

采用料浆浸渍辅助超声处理工艺成功制备了单向碳纤维增强无机聚合物基复合材料,并在1100 ℃、1200 ℃、1300 ℃和1400 ℃下对其进行高温处理.研究了无机聚合物和复合材料的热稳定性、相演变过程、力学性能变化等.结果表明,经高温处理后复合材料和无机聚合物均完成陶瓷化过程,析出白榴石晶相,并且由于碳纤维和基体之间界面反应的存在,与无机聚合物相比复合材料具有较差的热稳定性.随处理温度的提高,复合材料力学性能先升高再降低,经1200 ℃高温处理后复合材料达到最高的弯曲强度和断裂功,比处理前复合材料分别提高了28%和11%;高温处理后复合材料强度的提高主要是由于基体完成陶瓷化,基体和纤维的界面结合强度提高,界面能够有效传递载荷;随处理温度继续升高,界面反应造成碳纤维损伤严重,并且由于基体和碳纤维热失配形成的残余应力也逐渐升高,二者共同作用造成复合材料性能急剧下降.     

硅酸钠模数对SiO2气凝胶结构和表面改性机制的影响

以粉煤灰为原料制备五种不同浓度的硅酸钠溶液,采用溶胶-凝胶法对硅酸钠溶液进行处理,在常压干燥条件下获得了疏水性SiO₂气凝胶。通过测试气凝胶的密度、比表面积和接触角,研究了硅酸钠溶液模数m对气凝胶结构的影响,阐述了气凝胶表面疏水改性的亲核取代S_N1化学反应机制。研究结果表明,气凝胶的疏水性能与其表面连接的硅甲基—Si—(CH₃)₃数目有直接关系,当硅酸钠模数m=2.50时,气凝胶的疏水性能最佳。气凝胶的密度和比表面积均随硅酸钠模数的增大而增大,当硅酸钠模数m=0.75时,气凝胶的密度和比表面积最小,其值分别为0.073 9 g/cm³和588.5 m²/g。     

地聚合物微观结构研究进展

地聚合物是一种新型的高性能无机聚合物材料,它是由硅氧四面体和铝氧四面体通过氧原子连接构成的一种三维网络结构的聚合物。地聚合物具有优异的性能和节能环保的优势,成为了当前研究的热点。本文从地聚合物的结构和性能特点出发,阐述了地聚合物的反应机理,重点介绍了地聚合物微观结构的研究现状。最后,指出了地聚合物微观结构研究存在的问题。     

硅酸钠及碳酸钠对次氯酸钠溶液稳定性的影响

以不同浓度的硅酸钠、碳酸钠及二者混合物作稳定剂,研究它们对有效氯含量为0.5%（质量分数,下同）的次氯酸钠溶液化学稳定性的影响。测定稳定化处理后次氯酸钠溶液中有效氯的含量,结果表明：54 ℃下恒温密闭静置14 d后,加入硅酸钠、碳酸钠以及二者混合物作稳定剂的次氯酸钠溶液的有效氯,最高分别可保留初始浓度的88.16%、86.81%和92.85%;而不加任何稳定剂的次氯酸钠溶液在同样条件下其有效氯含量仅仅可保留初始浓度的76.58%。实验结果表明,硅酸钠和碳酸钠的混合物可以作为次氯酸钠溶液的良好稳定剂。     

Synthesis and mechanical properties of lightweight hybrid geopolymer foams reinforced with carbon nanotubes

A lightweight hybrid geopolymer foams reinforced with carbon nanotubes (CNTs) was exploited by adding the CNTs into geopolymeric matrix through hydrogen peroxide method. The synergistic effects of nanotubes and foaming agent on the phase evolution, microstructure, and mechanical properties were investigated. After introduction of nanotubes, the geopolymer foams reinforced with CNTs (CNTs/KGP) still showed amorphous structure. Porosity of the foams increased with the H₂O₂ content and decreased with the increase in CNTs content. The addition of CNTs (1-9 wt%) in foams refined the distribution of pore size from 523 to 352 μm. Compression strength of the CNTs/KGP samples elevated with the increasing content of CNTs, which was contributed to the crack propagation and bridging of CNTs in foams. The CNTs/KGP foams with considerable porosity show potential applications in adsorption, filtration, membrane supports, other industries, etc     

不同模数的水玻璃在晋宁磷矿正浮选中的应用

水玻璃是一种无机胶体,在胶磷矿选矿中被广泛用作石英、硅酸盐等脉石矿物的抑制剂、矿泥分散剂和pH值调整剂等。在云南晋宁胶磷矿选矿中不同模数的水玻璃作为抑制剂和矿泥分散剂,以高模数（模数为3．1）水玻璃的选矿效率最高,选别效果更为明显。     

Effect of high temperature on the mechanical properties of hierarchical porous cenosphere/geopolymer composite foams

A hierarchical porous cenosphere/geopolymer composite foam (FHCs/KGP) was fabricated by the simultaneous incorporation of O₂ pore from hydrogen peroxide and cenosphere filler addition. Effects of both H₂O₂ content and high-temperature treatment on the microstructure, porosity and strength of porous FHCs/KGP foams were investigated systematically. The obtained FHCs/KGP foams showed typical amorphous structure and desirable porosity from 65 to 82%. The composites could crystallize in situ to FHCs/leucite foams above 1000℃. Compression strength of the FHCs/leucite foams showed a maximum value of 5 ± 0.3 MPa when treated at 1000°C. The improvement of mechanical properties for the composite foams was attributed to crack deflection, fractured microspheres and the good bond between the FHCs and matrix. This study could open opportunities to employ cellular foams as alternatives in structure and filtration applications.     

Effects of high-temperature exposure on properties of lightweight geopolymer foams incorporating diatomite powders

A kind of metakaolin-based geopolymer foams incorporating diatomite powders (GKGP) with open cellular was presented by addition of diatomite powder via hydrogen peroxide method. Impacts of high-temperature exposure on the microstructure, pore structure, and mechanical properties of the GKGP samples were investigated. The GKGP foams achieved a typical amorphous phase structure at room temperature. Open porosity of the samples reached approximately 74%. After high-temperature exposure treatment, the KGP matrix is basically transformed into leucite crystal phase. The compression strength of the leucite foams was also enhanced with increasing temperature to 1200℃ (9.28 MPa). The lightweight foamed GKGP samples with high open porosity might have great potential for membranes and industries, etc.     

Synthesis of heat and ambient cured one-part geopolymer mixes with different grades of sodium silicate

The use of solid activators in the manufacture of geopolymer enhances its commercial viability as it aids the development of a one-part “just add water” geopolymer mixture, similar to the conventional Portland cement-based materials. This study is aimed to synthesize heat and ambient cured one-part geopolymer mixes. Appropriate combinations of low calcium (Class F) fly ash, slag and hydrated lime as the aluminosilicate source materials were activated by three different grades of sodium silicate and a combination of sodium silicate and sodium hydroxide powders. A conventional two-part geopolymer mix with the commonly used sodium hydroxide and sodium silicate solutions was also made for comparison. Effects of the type and amount of the solid activator, the amount of fly ash replacement with slag and hydrated lime and water content on short term mechanical properties of the heat cured one-part geopolymer mixtures including workability of the fresh mix, hardened density and compressive strength were evaluated. Subsequently, effects of ambient curing on the properties of the developed one-part geopolymer mixes were also investigated. Moderate to high compressive strength of over 37 MPa developed for the heat and ambient cured one-part geopolymer mixes. The 28-days compressive strengths of the ambient cured one-part geopolymer mixtures, regardless of the type of activator and geopolymer source materials, were comparable to those of the counterpart heat cured one-part geopolymer mixes. Such one-part geopolymer mixes could enhance the commercial viability and large-scale applications of the geopolymer in the construction industry.     

添加乙醇对水玻璃溶液的影响机制

通过测量质量损失、红外光谱分析、核磁共振分析等方法研究了不同浓度水玻璃溶液中滴加无水乙醇时溶液体系的变化规律。随无水乙醇的加入,溶液体系会出现分层现象,上层为澄清的乙醇水溶液,下层为有流动性的硅酸钠胶体溶液;同时发现,要形成稳定的硅酸钠胶体溶液,滴加的乙醇量存在一临界值,当超过该临界值时,硅酸钠胶体溶液变成不流动的沉淀固体。提出一种机制来解释无水乙醇的作用：乙醇分子与水分子之间的结合拉近了硅酸钠胶粒之间的距离,这有助于排除多余的水,从而降低水玻璃溶液的干燥时间及干燥过程中的能量消耗。     

Effects of layered silicate structure on the mechanical properties and structures of protein‐based bionanocomposites

In this work, a nonconventional protein source of pea protein isolate (PPI) was filled with montmorillonite (MMT) and rectorite (REC) by solution intercalation respectively, and then the reinforced PPI‐based nanocomposites were produced by hot press. The structure and interaction in the nanocomposites were investigated by FTIR, XRD, DSC, DMA, and pH and Zeta‐potential tests whereas the reinforcing effect was verified by tensile test. Furthermore, the origin of enhancing mechanical performances and the effects of layered silicate structure were explored. Although the MMT with lower negative‐charge surface and smaller apparent size of crude particles was easier to be exfoliated completely, the exfoliated REC nanoplatelets with more negative‐charge could form stronger electrostatic interaction with positive‐charge‐rich domains of PPI molecules, and hence produced the highest strength in two series of nanocomposites. In this case, the newly formed hydrogen bonds and electrostatic interaction on the surface of silicate lamellas guaranteed the transferring of the stress to rigid layered silicates. The cooperative effect of newly formed physical interaction between layered silicates and PPI molecules as well as the spatial occupancy of intercalated agglomerates of layered silicates destroyed the original microphase structure of PPI matrix and cleaved the entanglements among PPI molecules. It was not in favor of enhancing the elongation and strength. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of synthetic sodium aluminium silicate on the properties of nylon 6

Compounds were prepared from nylon 6 and synthetic sodium aluminium silicate (SSAS), varying the concentration of SSAS, up to 15% (wt/wt). Mechanical and rheological properties as well as optical properties were measured. There was a substantial increase in flexural modulus and flexural strength with added SSAS. However, the percentage elongation at break decreased rapidly with increasing amount of SSAS. All the compositions had much higher shear and extensional viscosity than nylon 6 alone. At lower concentrations, the filler induced dull yellow appearance, which disappeared as the concentration of SSAS increased. © 2001 Society of Chemical Industry     

含碱硅酸钠溶液的回收和利用工艺研究

添加石灰作为脱硅剂,对含硅酸钠的碱浸脱硅液进行脱硅处理后回收。将脱硅后的碱液对高硅铝土矿进行循环脱硅,考察钙硅物质的量比、苛碱浓度、初始硅浓度及脱硅时间对脱硅率的影响,并在较佳溶液脱硅条件下验证循环脱硅效果。脱硅结果表明,在碱性条件下[ρ（Na₂O）≈100 g/L],将石灰按钙硅物质的量比为1.2进行添加,反应2 h后溶液中二氧化硅质量浓度从约为7 g/L降至约为1 g/L。循环脱硅的结果表明,碱液经5次循环后,铝土矿中的n（Al）/n（Si）均大于7。这不仅为氧化铝工业生产提供了理论指导,也为碱液循环利用提供了一种有效途径。