共查询到20条相似文献,搜索用时 65 毫秒
1.
80年代以后发展起来的纳米材料被称为“2 1世纪最有前途的材料” ,已成为材料学中跨世纪的研究热点[1 ] 。纳米级无机粒子 /聚合物复合材料是纳米材料中的一种具有重要价值的新型材料 ,可广泛应用于橡胶、塑料、纤维三大合成材料之中[2 ] 。其中 ,纳米级SiO2 是纳米材料中的重要一员 ,它被称作跨世纪的高科技材料[3] 。因此 ,本文就纳米级SiO2 填充PVC/CPE复合材料进行探讨。1 实验部分自制 纳米级 (和普通超细 )SiO2 ,平均粒径约为 5 0nm ,比表面积约为 30 0m2 /g ,经过特殊表面处理 ,再用偶联剂、分散剂处理 ,1 2 0… 相似文献
2.
3.
4.
5.
6.
7.
以二甲基二乙氧基硅烷为硅源,在水溶液中成功制备了SiO2修饰纳米ZrO2颗粒;利用透射电子显微镜、热重分析仪、X射线衍射仪、红外光谱仪分析了样品的形貌和结构;将SiO2/ZrO2与α-Al2O3制成陶瓷材料,考察了其机械性能.结果表明,所制备的SiO2/ZrO2晶粒均一,直径约为10nm,硅原子在SiO2/ZrO2中以Si―O―Zr键合形式存在,SiO2不影响ZrO2的晶型.引入SiO2使得ZrO2晶粒细化、尺寸均匀性提高;SiO2/ZrO2/Al2O3陶瓷气孔率小,具有致密的显微结构和优异的机械性能. 相似文献
8.
纳米/微米碳酸钙的结构表征和热分解行为 总被引:10,自引:0,他引:10
采用棕榈酸对纳米碳酸钙进行有机表面改性, 运用SEM﹑TEM、XRD、FTIR 及TG-DTG 对表面改性前后的纳米碳酸钙进行表征, 并与微米碳酸钙的微晶结构及热分解特性进行比较. FTIR 分析结果确证了棕榈酸与纳米碳酸钙表面是以化学键合和物理吸附方式相结合, 粒子表面存在羧基等有机官能团的红外吸收特征. 对比研究发现, 碳酸钙微晶纳米化后, 其红外V3特征吸收峰出现约35 cm-1 的蓝移现象, 并且明显窄化. 初步解释了纳米碳酸钙红外吸收峰蓝移的原因, 认为尺寸效应和晶体场效应是影响纳米碳酸钙红外光谱特征的主要因素. 微晶结构的变化使得纳米碳酸钙的热分解反应表现出反常特性, 热分解温度较微米碳酸钙下降了40.6 ℃. 相似文献
9.
采用高压剪切分散(HPSH)的方法先将纳米SiO2分散在合成聚氨酯原料中,再应用原位聚合的方法制备了纳米SiO2/聚氨酯复合树脂。 用热重分析、动态机械热分析(DMTA)和扫描电子显微镜等测试技术研究了纳米SiO2的用量及其分散方法对聚氨酯树脂的热稳定和力学性能的影响。 结果表明,二苯甲基二异氰酸酯(MDI)中的-NCO和纳米SiO2表面的-OH发生了化学反应,SiO2表面的包覆率约为7%;通过高压剪切分散的方法能够使纳米SiO2在聚氨酯基体中均匀的分散开来,粒径为30~40 nm,而超声处理的纳米SiO2会聚集约为200 nm聚集体。 当SiO2的添加质量分数为3%时复合树脂(HPSH处理SiO2)的拉伸强度和断裂伸长率均达到最大值,分别为84.3 MPa和438.7%。 此外,与纯树脂相比,复合树脂(4%纳米SiO2)的Tg、Td和T-50%分别增加了17.2、9和21 ℃。 相似文献
12.
The effects of the modified layered double hydroxide (LDH) of Co/Al (OCoAl‐LDH) and the modified LDH of Co/Fe (OCoFe‐LDH) on the combustion behaviors of polyvinyl chloride (PVC) during pyrolysis processes were compared and investigated. The thermal degradation and combustion behavior of the PVC composites were investigated by thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), and cone calorimetry (CONE). The results indicate that the incorporation of LDHs brought about the improved thermal stability and reduced heat release of PVC composites at a high temperature. The smoke‐suppression properties of the composites are investigated by steady‐state tube furnace (SSTF), and the results indicated that the toxic gases such as CH4, CO, and NxO were inhibited by both of the two LDHs, but the OCoFe‐LDH has a better effect on the smoke suppression. Subsequently, the char layer was investigated by scanning electron microscopy–energy‐dispersive spectrometry (SEM‐EDS) and Raman analysis. The results indicate that the LDHs can promote the dechlorination of PVC during the thermal oxidation process and can inhibit the production of HCl in inert gas. Generally, OCoAl‐LDH and OCoFe‐LDH can be potential catalysts for waste disposal and can improve the fire safety of PVC. 相似文献
13.
The thermal decomposition behavior of RDX-base propellants 总被引:1,自引:0,他引:1
In this paper, the thermal decomposition of cyclotrimethylenetri-nitramine (RDX)-base propellants involving many components has been investigated by differential scanning calorimeter (DSC). The decomposition characters at different heating rates and the activation energies are determined by DSC measurement. The results show that the decomposition of RDX is accelerated obviously during the decomposition of nitroglycerin (NG). Though the content of dibutyl-benzene-dicarbonate (DBP) ingredient in the propellants is less, it has a remarkable effect on the initial decomposition temperature of the propellants. The azido-nitromine compound (DIANP) brings about the shift of the peak of decomposition of RDX and nitrocellulose (NC) to lower temperature due to its liquefying or dissolving. 相似文献
14.
Shul"ga Yu. M. Martynenko V. M. Tarasov B. P. Fokin V. N. Chapysheva N. V. 《Russian Chemical Bulletin》2002,51(1):96-98
The volative products of thermal decomposition of deuterofullerite C60D19 were studied by mass spectrometry. It was found that D2, CD4, and C6D6 molecules are present in the gas phase above deuterofullerite heated to 773 K. Deuterocarbons appear in the gas phase already at 673 K. 相似文献
15.
16.
D. M. S. Valladao L. C. S. De Oliveira J. Zuanon Netto M. Ionashiro 《Journal of Thermal Analysis and Calorimetry》1996,46(5):1291-1299
Thermogravimetry-derivativc thermogravimetry and differential scanning calorimetry were used to study the thermal behaviour of furosemide, hydrochlorothiazide, spironolactone, and amiloride hydrochloride. The results revealed the extents of their thermal stability and also permitted interpretations concerning their thermal decompositions.The authors thank FAPESP (Proc. 90/2932-4) and CNPq for financial support, and Hoechst of Brazil, Prodome Química e Farmaceutica Ltda, Campinas, Brazil, and Biolab. Industrias Farmaceuticas, Brazil, for supplying the diuretic agents used in this study. 相似文献
17.
B. L. Korsunskii N. V. Chukanov G. V. Sitonina E. M. Sogomonyan V. V. Nedel'ko O. V. Anan 'ina T. S. Larikova 《Russian Chemical Bulletin》1993,42(3):445-448
The thermal decomposition of nitrourea in the solid phase proceeds with a pronounced self-acceleration, the maximum reaction rate being reached at extremely high extents of conversion. A significant increase in the specific surface is simultaneously observed: the specific surface increases 33-fold by the time when the maximum reaction rate is reached, and the mean particle size becomes equal to 230 Å. In a closed system an increase in the pressure of the gas evolved is followed by an abrupt decrease. A mechanism for the process, in which an intermediate, isocyanic acid, and the heterogeneous character of the reaction play the key role is proposed on the basis of kinetic measurements and data on the composition of the decomposition products.The NMR spectra were recorded by Yu. A. Strelenko at the Institute of Organic Chemistry, Russian Academy of Sciences. The mass-spectra were obtained by L. L. Gumanov at the Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 492–495, March, 1993. 相似文献
18.
Emma Jakab Erika Mészáros Mária Omastová 《Journal of Thermal Analysis and Calorimetry》2007,88(2):515-521
The thermal stability of polypyrrole
(PPy) samples has been studied by thermogravimetry/mass spectrometry and pyrolysis-gas
chromatography/mass spectrometry in inert atmospheres. PPy has been prepared
by chemical oxidative polymerization using ferric sulfate as an oxidant and
anionic surfactants, such as dodecylbenzenesulfonic acid and sodium dodecylbenzenesulfonate
as co-dopants. For comparison we have studied polypyrrole (PPy-SO4)
prepared without any additive. It was found that the presence of anionic surfactants
improved the thermal stability of PPy. The decomposition of PPy doped with
ferric sulfate and anionic surfactants occurs at relatively high temperature
indicating that chemical interactions exist between the polymer and the surfactants. 相似文献
19.
The changes in specific surface area and structure disorder of mechanically activated arsenopyrite were investigated. The rate of nonoxidative decomposition of mechanically activated arsenopyrite was increased almost 10-times when compared with nonoxidative decomposition of a non-activated sample. An empirical linear relationship was found (r=0.996) between the rate constant of decomposition and the ratio of specific surface to transmission of the absorption band of arsenopyrite at $\bar \nu = 370 cm^{ - 1} $ . This relationship enables us to arrange the reaction 4FeAsS→4FeS+As4 among structure-sensitive reactions. 相似文献
20.
Thermal decomposition of anhydrous Cu(HCOO)2 (1) affords H2, CO, CO2, H2O, HCuOOH, CuHCOO, Cu, and the polymeric product, which contains -CH2O,-C(O)OH-, and -RCH-0- groups. Dccomposition of1 proceeds in stages with formation of copper(I) formate as an intermediate. Possible pathways of decomposition ofI, including isomeric forms of the HCO2 radical as intermediates, were analyzed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1406–1412, June, 1996. 相似文献