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排序方式: 共有391条查询结果,搜索用时 15 毫秒
1.
2.
A series of ethynyl and ethenyl end-capped imide resins were synthesised by the reaction of 9,9-bis(4-aminophenyl) fluorene
(BAF) with pyromellitic dianhydride (PMDA)3/3′, 4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA)/2,2-bis(3,4-dicarboxy
phenyl) hexafluoropropane dianhydride (6F) and 3-ethynyl aniline/maleic anhydride. Structural characterisation was done by
infra red and elemental analysis. Thermal characterisation was done by differential scanning calorimetry and thermogravimetric
analysis. The decomposition temperatures of cured resins were above 200°C in nitrogen atmosphere. Char yield at 800°C ranged
from 59–65.5%. 相似文献
3.
Heating rate effect on the DSC kinetics of oil shales 总被引:1,自引:0,他引:1
M. V. Kök 《Journal of Thermal Analysis and Calorimetry》2007,90(3):817-821
This research was aimed to investigate the combustion and kinetics of oil shale samples (Mengen and Himmetoğlu) by differential
scanning calorimetry (DSC). Experiments were performed in air atmosphere up to 600°C at five different heating rates. The
DSC curves clearly demonstrate distinct reaction regions in the oil shale samples studied. Reaction intervals, peak and burn-out
temperatures of the oil shale samples are also determined. Arrhenius kinetic method was used to analyze the DSC data and it
was observed that the activation energies of the samples are varied in the range of 22.4–127.3 kJ mol−1 depending on the oil shale type and heating rate. 相似文献
4.
A set of seven bituminous coal chars has been characterised by IR spectroscopy (FTIR), thermogravimetry (TG) and elemental analysis. FTIR study provided suitable information to establish differences between coal samples according to their chemical compositions. The reactivity of these samples was also studied and correlated with the coal parameters of mean vitrinite reflectance, fuel ratio and H/C ratio. The data suggest that reactivity as determined can be correlated with the mean vitrinite reflectance, fuel ratio and H/C ratio (0.90). The order of reactivity of samples were; Amasra (S1) (R m= 0.65)>Azdavay (S4) (R m=0.99)»Armutcuk (S2) (R m=0.81)»Acenta (S3) (R m=0.92)>Ac2l2k (S6) (R m=1.11) Cay (S5) (R m=1.03)>Sogutozu (S7) (R m=2.14). 相似文献
5.
在Ar气流中热处理KOH-煤焦制大比表面积活性炭 总被引:2,自引:1,他引:2
本文将煤焦与KOH混合,在Ar气流中进行低温、高温二次热处理,制得了比表面积为2918m2/g的活性炭。考查了操作条件对产品性能的影响,同时用X射线衍射分析研究了煤焦制活性炭过程中的结构变化特征 相似文献
6.
7.
中国无烟煤焦气化活性的研究——水蒸气与二氧化碳气化活性的比较 总被引:2,自引:7,他引:2
在常压和920℃~1050℃下,采用热重方法,进行了六种中国典型无烟煤焦水蒸气与二氧化碳气化活性比较的研究。结果表明,无烟煤焦与水蒸气气化反应的活性与无烟煤的煤化程度相对应,无烟煤煤化程度越高,水蒸气气化反应活性越小。无烟煤焦与二氧化碳气化反应的活性与煤中矿物质的催化作用有密切关系,煤中矿物质的催化作用越大,二氧化碳气化反应活性越大。无烟煤焦与二氧化碳气化反应活性明显小于与水蒸气气化反应活性,后者比前者大10倍左右。初步探讨了无烟煤焦与水蒸气和二氧化碳的气化机理。 相似文献
8.
Curing of diglycidyl ether of bisphenol-A (DGEBA) with phosphorus containing amide amines i.e. bis[3(3’-aminobenzamido phenyl)]methyl
phosphine oxide (MB),bis[3(4’-aminobenzamido phenyl)]methyl phosphine oxide (PB), tris[3(3’-aminobenzamidophenyl)] phosphine
oxide (MT) and tris[3(4’-aminobenzamido phenyl)] phosphine oxide (PT)and conventionally used curing agent 4,4’-diaminodiphenyl
sulfone (D) was studied by DSC. The amines MB, PB, MT and PT were synthesised in the laboratory and were characterized by
determining elemental composition, melting point, and amine equivalent. Structural characterization was done by 1H-NMR and FTIR. The onset temperature of curing depended on the nucleophilicity of the amines and was in the orderMT≈MB<PT<PB<D.
The exothermic peak temperatures were in the orderD>PB>PT>MT≈MB. The char residue of cured epoxy resin was significantly higher
when phosphorus was incorporated in the cured network. Using mixed amine formulations based on amine D and P-containing amines
and the molar ratio of these amines could easily control the curing characteristics. A linear relationship between char yield
and P-content was observed in such formulations.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
煤焦在燃烧过程中孔隙结构变化的模拟 总被引:4,自引:1,他引:4
煤焦在燃烧过程中的物理特性,如比表面积和孔径分布会发生连续变化,直接测量煤焦在燃烧过程中的孔隙结构变化很困难,但可以通过合适的数学模型来观察,二维的圆柱孔模型已大量用来对煤焦气化与燃烧过程中表面积和孔隙结构的变化进行模拟,这个模型把孔隙分成两大部分--大孔与小孔,因为小孔构成比表面的绝大部分,所以在反应过程中比表面积的变化可以由单一小孔模型来拟合,本文采用了用Tseng和Edgar提出的孔模型对几 相似文献
10.
Pengcheng Li Jie Dai Yi Xu Qichao Ran Yi Gu 《Journal of polymer science. Part A, Polymer chemistry》2019,57(14):1587-1592
A difunctional benzoxazine (coPh‐apa) with a conjugated alkyne group is synthesized by the oxidative coupling reaction from a monocycle‐benzoxazine (Ph‐apa) containing an alkyne group. A model compound, 1,4‐diphenylbutadiyne (coPa), is used to study the curing reaction process of coPh‐apa by DSC, Fourier transform infrared spectroscopy, and 13C NMR, and the results suggest that the conjugated alkyne groups are involved in the crosslinking reaction via the trimerization reaction of the conjugated alkynyl groups and the Diels–Alder reaction. Furthermore, thermal properties of the polybenzoxazine are studied by dynamic thermomechanical analysis and thermogravimetric analysis. A glass‐transition temperature (Tgs) of as high as 412 °C and a char yield of 75.6% at 800 °C under nitrogen are obtained with the aid of the conjugated alkyne groups. Its excellent heat resistance dominates most thermosetting resins and will serve for heat shields. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1587–1592 相似文献