A hydrophilic silane was obtained from the reaction of ethylene carbonate and 3-aminopropyldiethoxymethylsilane. This silane
undergoes rearrangement to yield an AB2-type hyperbranched polymer under anhydrous conditions but hydrolyzes and condenses to produce linear siloxanes under acid
hydrolysis. The hydrolysis and condensation reactions as a function of time, HCl concentration and water content were studied
by 29Si NMR. The compositions of the silanol containing hydrolysis intermediates and the siloxanes condensation products were identified
under different conditions. The instantaneous composition was found to depend on the specific combination of the acid and
the water. Under certain conditions the intermediate silane-diols were stable and did not condense even under mild acidic
conditions. 相似文献
Based on the previously reported potent and selective sulfone hydroxamate inhibitors SC-76276, SC-78080 (SD-2590), and SC-77964, potent MMP inhibitors have been designed and synthesized to append a boron-rich carborane cluster by employing click chemistry to target tumor cells that are known to upregulate gelatinases. Docking against MMP-2 suggests binding involving the hydroxamate zinc-binding group, key H-bonds by the sulfone moiety with the peptide backbone residues Leu82 and Leu83, and a hydrophobic interaction with the deep P1’ pocket. The more potent of the two triazole regioisomers exhibits an IC50 of 3.7 nM versus MMP-2 and IC50 of 46 nM versus MMP-9. 相似文献
Polymer Nanocomposites are advanced engineering composites with enhanced properties. These materials play a central role in various industrial sectors. The growing awareness of the key parameters (which influence the physical properties) with different combination of matrix-reinforcement, are making them more attractive in various applications. Machining of these materials is a challenging task for engineers with their properties (hardness and brittleness) due to various combinations of matrix-reinforcement. Therefore, the aim of present work is to investigate the machining behaviour of Silicon Dioxide (silica) Epoxy Nanocomposite due to straight cutting by using Wire Electrochemical Spark Cutting (WECSC) process.
Method
A specific number of experiments were conducted based on one parameter at-a-time approach to study the effect of influencing input parameters.
Result
The effect of various process parameters namely voltage supply, electrolyte concentration, wire velocity, pulse-on time and silica particle concentration (Cp) such as 3%, 4% and 5% (weight percent) on performance measures such as material removal rate (MRR) and surface roughness were demonstrated experimentally.
Conclusion
WECSC has been found effective technique for cutting of Silicon Dioxide Epoxy Nanocomposite. It is reported that MRR increases with decrease in silica particle concentration in Silicon Dioxide Epoxy Nanocomposite.
This review reports on recent advances in the design of biodegradable polymers built from petroleum and renewable resources using reactive extrusion processing. Reactive extrusion represents a unique tool to manufacture biodegradable polymers upon different types of reactive modification in a cost‐effective way. Partially based on our ongoing research, ring‐opening polymerization of biodegradable polyesters will be approached as well as the chemical modification of biodegradable polymers, particularly natural polymers. The development of environmentally friendly polymer blends as well as (nano)composites from natural polymers, including natural fibers and nanoclays, through reactive extrusion, as an efficient way to improve the interfacial adhesion between these components, will be also discussed.
Complexes were formed between egg albumin and oxidized lipids, such as thermally oxidized corn oil and autoxidized linoleic
acid, under a standardized set of conditions. No complex could be obtained under these conditions when lysine, glycine, bactopeptone,
gelatin or sodium caseinate were substituted for egg albumin. Lactalbumin was equally as reactive, casein much less and fresh
egg white superior to egg albumin in their complexing ability with oxidized corn oil. As the time of reaction was increased,
the amount of the complex formed also increased. Optimum complex formation took place at a concentration of 1% protein, a
pH of 7 and 60C. The ease of formation of these complexesin vitro indicated that similar complexing could readily take placein vivo under suitable pathological conditions.
This work was supported by research grant no. C-1932 from the National Institutes of Health, U. S. Public Health Service,
Department of Health, Education, and Welfare. 相似文献