Diglycidyl ether of bisphenol-A (DGEBA) based epoxy/ silica hybrid materials filled with various amounts of 3glycidoxypropyltrimethoxysilane (GPTMS) and silica nanoparticles were prepared, using 4,4 0 -diaminodiphenyl sulfone (DDS) as curing agent. The obtained hybrid materials were analyzed by means of Fouriertransform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the introduction of GPTMS and silica nanoparticles had synergistic effect. The addition of GPTMS not only ameliorated the compatibility between silica and the epoxy matrix but also increased the crosslinking density of the epoxy system; meanwhile the nano-silica further reinforced the inorganic network of the hybrid system. Consequently, the hybrid materials showed much improved heat-resistant properties. The storage modulus of the hybrid systems showed no obvious decrement in the glass transition region and kept at a high value even in the temperature region up to 3008C. The integral thermal stability of the resulting hybrid materials was also improved compared with the corresponding pure epoxy resin. POLYM. ENG.
A pilot test of in-situ
combustion (ISC) was carried out in Jiang
oil field, Junggar basin, China, and a favorable result was obtained.
In this work, we systematically studied the changes of crude oil properties
during the combustion process. Crude oils were characterized by means
of rheology test, SARA (saturates, aromatics, resins, and asphaltenes)
fractionation and analyses, CHNO elemental analyses, and acid number
(AN) measurements. Furthermore, analyses of FTIR and GC-MS on the
resins were carried out to investigate the functional groups and polar
compounds. Moreover, influence of particular inclined formations and
sampling wells’ locations are also considered to interpret
the effects of ISC process in the field. During the fireflood process,
the crude oil’s viscosity reduced significantly and the reduction
varied according to different sampling wells with different dip angles
and distances. The crude oil was greatly upgraded based on SARA fractions
analyses. The content of saturates varied among those wells, and a
higher value happened and was accompanied by the decrease of aromatics
content during the early stage of ISC. Non-hydrocarbons content increased
within the period of 4 years of investigation. It was found that the
greater the asphaltenes content is, the higher will be the oil recovery
(OR) obtained. The AN of oil increased remarkably during the ISC process.
To some extent, the CHNO contents and H/C and O/C ratios of the oil
samples could reflect the degree of oil modification; however, these
values had not been found to correlate with the production performance.
Polar compounds in the resins fraction such as carboxylic acids, ketones,
and alcohols are detected, and the polar compounds that contribute
to the increase of AN values of oils could be mostly from short-chain
carboxylic acids, alkylphenols, and long-chain fatty acids.
The research on the flowability of waxy oil has spanned
more than
a century and is still attracting much attention. How to improve the
flowability of waxy oil to ensure safe and efficient pipeline transportation
and storage is of great practical importance for the industry. In
this work, we have systematically reviewed the research advances in
improving the flowability of waxy oil. First, the crystallization
properties and phase behavior of waxes are described based on their
chemical structure, thermodynamic properties, and solution phase properties,
with emphasis on the solventized layer properties of wax crystals.
Then, the mechanisms, process, and research progress in flow improvement
of waxy oil are discussed from three major aspects: process improvement,
equipment improvement, and chemical treatment, with emphasis on the
summary of waxy oil pour point depressants in recent years. The remaining
challenges and perspectives for future research on flow improvement
of waxy oil are presented.
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