共查询到20条相似文献,搜索用时 171 毫秒
1.
2.
3.
4.
溶胶-凝胶法制备碳化硅研究进展 总被引:1,自引:0,他引:1
碳化硅陶瓷材料因其优良的物理、化学性质而备受关注,作为先进材料可广泛用于石油化工、机械工业、宇航和汽车工业.相比较传统的制备方法,溶胶-凝胶法具有合成温度低、纯度高和均匀性好等优点.在简述溶胶-凝胶法基本原理的基础上,较系统地评述了溶胶-凝胶法制备碳化硅纳米微粉、碳化硅一维纳米材料、碳化硅纳米复合陶瓷和多孔碳化硅陶瓷材料及其他碳化硅材料的研究现状,提出了今后溶胶-凝胶法制备碳化硅材料的主要研究方向. 相似文献
5.
《合成材料老化与应用》2017,(1)
溶胶-凝胶法是制备载体硅胶的主要工艺,考察一次溶胶-凝胶与多次溶胶-凝胶工艺对载体硅胶表面形态、孔结构、以及所负载催化剂性能的影响。实验结果表明:采用多次溶胶-凝胶工艺可获得多峰孔分布的孔结构,所负载的催化剂活性高,获得聚合物粒子形态好。 相似文献
6.
7.
采用溶胶-凝胶法合成掺Eu(BA),的SiO2发光材料。研究了凝胶玻璃中苯甲酸和稀土离子的配位情况,稀土离子的掺入浓度对发光性能的影响。通过红外光谱和荧光光谱证明了溶胶-凝胶法可以在SiO2中原位合成Eu(BA)3。 相似文献
8.
采用高温固相法、热聚合法和改良溶胶-凝胶法制备锂离子电池负极材料Li4Ti5O12。通过X-射线衍射、扫描电镜、恒电流充放电及电化学阻抗等技术和手段表征合成产物的结构、形貌及电化学性能。结果表明:溶胶-凝胶法合成的粉末为纯相Li4Ti5O12,而高温固相法和聚合法合成的Li4Ti5O12则存在TiO2杂相。高温固相法合成的Li4Ti5O12粉末晶粒最大,溶胶-凝胶法合成的粉末晶粒最小,分布最为均匀,晶粒尺寸约为80nm。高温固相法、热聚合法和溶胶-凝胶法制备的Li4Ti5O12粉末首次放电容量分别为161.6mAh/g、165.9mAh/g和171.5mAh/g,循环25次后的容量保持率分别为84.7%、87.7%和94.3%,溶胶-凝胶法合成的Li4Ti5O12粉末电化学性能最好。 相似文献
9.
采用高温固相法、热聚合法和改良溶胶-凝胶法制备锂离子电池负极材料Li4Ti5O12。通过X射线衍射、扫描电镜、恒电流充放电及电化学阻抗表征了合成产物的结构、形貌及电化学性能。结果表明,溶胶-凝胶法合成的粉末为纯相Li4Ti5O12,而高温固相法和聚合法合成的Li4Ti5O12则存在TiO2杂相。高温固相法合成的Li4Ti5O12粉末晶粒最大,溶胶-凝胶法合成的粉末晶粒最小,分布最为均匀,晶粒尺寸约为80 nm。高温固相法、热聚合法和溶胶-凝胶法制备的Li4Ti5O12粉末首次放电容量分别为161.6、165.9 mA·h/g和171.5 mA·h/g,循环25次后的容量保持率分别为84.7%、87.7%和94.3%,溶胶-凝胶法合成的Li4Ti5O12粉末电化学性能最好。 相似文献
10.
溶胶-凝胶法的应用研究 总被引:6,自引:0,他引:6
为研究溶胶-凝胶法的应用,文章通过研究溶胶-凝胶法的基本原理、工艺过程的影响因素,总结溶胶-凝胶法的优缺点。结果表明,水的加入量、温度、醇盐的滴加速度、反应液的pH都会影响溶胶-凝胶法的产品质量。溶胶-凝胶法可制得的材料主要有以下几大类型:单晶、纤维材料、涂层和薄膜材料、超细粉末材料及复合材料等,有很大的发展前景。 相似文献
11.
12.
13.
Tanzeela Nazir Adeel Afzal Humaira M. Siddiqi Zahoor Ahmad Michel Dumon 《Progress in Organic Coatings》2010
Hybrid organic–inorganic polymer films composed of an epoxy resin crosslinked with a flexible diamine hardener, and a silica reinforcing phase were produced and their thermo-mechanical properties were determined. Two types of hybrid epoxy–silica polymer films, named EAS-1 and EAS-2, were obtained by hydrolysis and condensation of various amounts of tetraethoxysilane within epoxy network matrix. In EAS-2 hybrids, minor amounts of an amine silane coupling agent were added to enhance interfacial compatibility. FTIR spectroscopy confirmed the formation of organic and inorganic networks. The grafting of amine silane on to the epoxy resin influenced the size and distribution of hyper-branched clusters of silica as indicated by transmission electron microscopy (TEM). The dynamic mechanical and thermal analysis (DMTA) and thermo-gravimetric analysis (TGA) results showed an increase in the storage modulus, the glass-transition temperature, and the thermal stability of hybrid polymer films as compared to the neat matrix. The integration of amine silane coupling agent produced smaller, effectively dispersed silica nanoparticles and consequently improved the ultimate properties of polymer films. 相似文献
14.
An amino‐functional silane coupling agent, which is an important component for epoxy molding compound (EMC), has been used by diverse methods, such as integral addition into a mixed powder and pretreatment on silica or on resin. However, the homogeneous dispersion of the amino‐functional silane coupling agent in mixed powder is limited with integral addition, and the possibility of white gel formation, sometimes causing gate blocking during the transfer‐molding process, due to the aggregation of silica with the coupling agent cannot be completely removed by it. The pretreatment of the amino‐functional silane coupling agent on silica has been adopted as an alternative process, but the process is expensive and limited in mass production. Although the pretreatment of the coupling agent on resin as another method has also been used by some EMC manufacturing companies, it has hardly been known in which resin phase, the epoxy or hardener, the silane coupling agent should be pretreated for better mechanical properties of EMC. In this study, the pretreatment of the amino‐functional silane coupling agent on epoxy or phenol resin, essential components of EMC, has been investigated with respect to the reaction during the pretreatment and the properties of EMC according to the different pretreatment methods. In the case of the pretreatment on epoxy, the amino‐functional silane coupling agent rapidly forms an adduct with epoxy via a ring‐opening reaction, whereas its alkoxy groups are well preserved. The glass‐transition temperature and flexural strength of the EMC by the application of the pretreatment method on epoxy are lower than those by the pretreatment on phenol. It is thought that the degree of linkage between the resin matrix and silica becomes lower because of the confinement of aminopropyltriethoxy silane (APTS) within the epoxy matrix through an irreversible reaction with epoxy in advance. In the case of the pretreatment on phenol, most of the alkoxy groups in the coupling agent are assumed to be replaced with protonic nucleophiles such as phenol, generating an equivalent amount of alcohol. Because the adduct between the phenol and amino‐functional silane coupling agent can be easily regenerated during the manufacturing process, it is thought that the pretreatment method of APTS on phenol helps APTS disperse well within EMC. Actually, the glass‐transition temperature and flexural strength of EMC by the application of the pretreatment method on phenol are higher than those by the integral addition method and the pretreatment on epoxy. However, they become lower as the degree of reaction of silane with phenol increases. The pretreatment of the amino‐functional silane coupling agent on phenol shows lots of advantages over the previous methods. From the viewpoint of the process, the homogeneous dispersion of the coupling agent can be obtained with consistency, and the possibility of white gel formation can also be completely removed by it. From the perspective of properties, through a controlled pretreatment on phenol resin, better mechanical properties of EMC can be obtained than those through the pretreatment on epoxy. In addition, the pretreatment process on phenol is simple and feasible for mass production. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2171–2179, 2006 相似文献
15.
16.
在碱性环境下,采用四氯化钛作为钛源、白炭黑作为硅源,有机硅烷偶联剂(KH550)做结构导向剂,通过溶胶-凝胶法合成有机硅烷偶联剂插层层状钛硅酸盐(KH-LTS)。样品的结构和稳定性通过X-射线衍射、红外光谱、紫外-可见光谱、差热热重、扫描电镜和透射电镜进行表征。结果表明,复合材料KH-LTS具有有序的层状介观结构,其层间距约为3.2 nm,实验结果为交换插层及石油的裂解催化提供了依据。 相似文献
17.
硅烷偶联剂封端改性水性聚氨酯的研究 总被引:5,自引:1,他引:4
以聚醚多元醇(GE210)、异佛尔酮二异氰酸酯(IPDI)和α,α-二羟甲基丙酸(DMPA)为原料合成了基础聚氨酯(PU)预聚体,然后以1,4-丁二醇进一步扩链制得了水性聚氨酯(WPU)乳液,最后以偶联剂γ-氨丙基三甲氧基硅烷对PU分子进行封端,得到了稳定的改性PU乳液。通过对偶联剂的用量和封端条件等研究,确定了适合硅烷改性WPU的方式。实验结果表明,当w(硅烷偶联剂)=4%~5%时(占树脂的质量分数),硅烷偶联剂封端改性WPU乳液具有较低的表面张力,其胶膜的力学性能和耐水耐溶剂性能均相当优异。 相似文献
18.
从溶聚丁苯橡胶(SSBR)、顺丁橡胶(BR)、天然橡胶(NR)、补强材料和硅烷偶联剂等方面阐述在平衡高性能轮胎湿地抓着性能、滚动阻力和耐磨性能方面新型材料,包括改性SSBR和BR、液体BR、环氧化NR、白炭黑与其他无机填料共沉形成的杂合材料、新型硅烷偶联剂等的应用技术和发展趋势。 相似文献
19.
A series of thermosensitive organic–inorganic hybrid gels containing nanosilica or modified nanosilica were prepared from N‐isopropylacrylamide (NIPAAm), and N,N′‐methylene‐bis‐acrylamide (NMBA) and nanosilica (AE200) or modified AE200 (mAE200); and NIPAAm, NMBA, 3‐(trimethoxysilyl) propyl methacrylate (TMSPMA) as coupling agent and AE200 or mAE200 in this study. The effect of inorganic nanosilica on the swelling behaviors and mechanical properties were investigated by adding different amount of nanosilica and modified nanosilica. Results showed that the swelling ratios of the hybrid gels decrease with increasing nanosilica content. Existence of silane coupling agent would also reduce the swelling ratios of the hybrid gels. Adding coupling agent or nanosilica would improve the gel strength. Modification of nanosilica by grafting amino‐silane via sol–gel process was carried out and the effect of addition of modified silica on gel properties was also investigated. Results showed that the hybrid gels containing modified silica would have higher swelling ratios and moduli than those containing unmodified silica. Gels containing both silane coupling agent and silica would have higher crosslinking density because the silica would be better crosslinked with coupling agent. POLYM. COMPOS., 31:1712–1721, 2010. © 2010 Society of Plastics Engineers. 相似文献
20.
开发了一种以腰果酚改性胺为固化剂的无溶剂环氧防腐涂料,介绍了环氧树脂、固化剂、稀释剂以及填料等原料的选择,探讨了环氧树脂与腰果酚改性胺的固化机理,并考察了硅烷偶联剂对涂层防腐性能的影响。检测结果表明,环氧树脂与腰果酚改性胺的固化主要以环氧基与胺基之间的反应为主;硅烷偶联剂可以提高涂层的附着力,有效地增强涂膜的耐水性。 相似文献