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11.
聚六亚甲基碳酸酯二醇增韧环氧树脂的结构与性能 总被引:6,自引:0,他引:6
采用羟基封端的脂肪族碳酸酯-聚六亚甲基碳酸酯二醇对环氧树脂进行了增韧,通过扫描隧道显微镜,扫描电子显微镜,差示扫描量热分析以及动态力学性能分析等方法研究了增韧EP的结构与性能的关系。 相似文献
12.
Liquid viscosity and density of six binary mixtures of HFC-134a with glycols [ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (400), and polypropylene glycol (2000)] have been measured in the temperature range from 273 to 333 K. The viscosity was measured by a rolling-ball viscometer calibrated with standard liquids of viscosities and densities (JS5, JS10, JS20, and JS50). The density was measured with a glass pycnometer. The uncertainties of the measurements were estimated to be less than 3.4 % for viscosity and 0.04 % for density, respectively. An equation is given to represent the obtained viscosity values as a function of weight fraction and temperature. 相似文献
13.
The nature of the interaction of monomer, and the early stages of growth of oligomers of ethylene on a rather more uniform surface of Cr/SiO2 catalyst than hitherto studied has been investigated by differenceFTIR spectroscopy using C2D4 and C2H4 as reactants both with and without subsequent treatment of the catalyst with CO andTHF. The active catalyst was prepared by reaction of vapour phase CrO2Cl2 with the vicinal hydroxyls of the silica surface. Three distinct kinds of methylene groups were detected. Arguments are given for assigning the peaks at 2935 and 2860 cm–1 to CH2 groups directly bound to the active site and those at 2920 and 2850 to CH2s in the growing chain well removed from the Cr. The peaks at 2160 and 2165 cm–1 are attributed to CD2 groups hydrogen bonded to surface hydroxyls. 相似文献
14.
This paper highlights the possibility of inverse gas chromatography for the surface characterization of common fillers (CaCO3, talc, SiO2,) for paints and coatings. Divided solids are described, on the one hand, by the dispersive component of their surface energy and, on the other, by a specific parameter indicating their acid-base interaction potential. The role of the surface morphology at a molecular level is also examined. It is demonstrated that steric effects play an important role in the adsorption of probes on lamellar solids like talc. The consequences of surface treatments as well as examples of practical applications are also reported. 相似文献
15.
The crystallization behavior of well-defined star-shaped cubic silsesquioxane-poly(ethylene oxide) (CSSQ-PEO) and linear PEO were studied in terms of differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS). It was found in DSC analysis that the glass transition temperature (Tg) and the crystallization temperature (Tc) of CSSQ-PEO are different from those of linear PEO. The presence of CSSQ in PEO reduced the overall crystallization growth rate. This effect can be ascribed to the reduction of the mobility of the PEO crystallites in the presence of CSSQ and the star structure of the polymer. The Ozawa method is qualitatively satisfactory for describing the nonisothermal crystallizations of linear PEO and CSSQ-PEO. The presence of CSSQ leads to the diffusion- and nucleation-controlled mechanisms in the crystallization process of CSSQ-PEO whilst only the nucleation-controlled mechanism was observed in the case of linear PEO. The apparent activation energy required for crystallization was calculated using the Kissinger method. The isothermal crystallization morphology of PEO and CSSQ-PEO were also examined by cross-polarizing optical microscopy (CPOM). The CPOM images indicated the spherulite growth is slower in CSSQ-PEO as compared to linear PEO. It was also investigated that more number of PEO spherulites in CSSQ-PEO were observed, which sizes are markedly smaller than the spherulites developed in linear PEO. Wide-angle X-ray scattering (WAXS) studies showed that the crystallization peaks for linear PEO and CSSQ-PEO appeared at different temperature revealing the crystallization process and crystal growth rate are different from each other. However, no significant distortion of the crystal structure of PEO was evaluated in the presence of CSSQ. 相似文献
16.
17.
热重分析对高分子材料中碳酸钙的定量研究 总被引:1,自引:0,他引:1
碳酸钙是高分子材料中常用的无机填料,在高温时会同二氧化碳而失重。利用热重分析可准确定出高分子材料中碳酸钙的含量,同时还可测出聚合物,挥发物的含量,热重分析法样品用量小,灵敏度高,所需时间短。 相似文献
18.
19.
在聚全氟乙丙烯(FEP)中添加 TiO_2和 Al_2O_3,通过热压成型的方法制备了 FEP/TiO_2复合材料和 FEP/Al_2O_3复合材料,研究了氧化物添加量对复合材料介电常数、介电损耗和高频击穿性能的影响。结果表明,随氧化物含量的增加,复合材料的介电常数和介电损耗均增加;在同一添加量下,TiO_2对复合体系的介电性能影响较大。FEP/TiO_2复合材料的高频击穿性能随 TiO_2含量的增加而下降,在 TiO_2含量为4.0%(质量分数,下同)时,复合材料的损伤阈值已降为 FEP 材料损伤阈值的48.9 %。而 FEP/Al_2O_3复合材料的高频击穿性能随 Al_2O_3含量的增加而升高,当 Al_2O_3含量为1.2%时,复合材料的损伤阈值已增大到 FEP 材料损伤阈值的2倍,达到313 J/m~2。 相似文献
20.