Material encapsulation in poly(methyl methacrylate) shell: A review

Material encapsulation is a relatively new technique for coating a micro/nanosize particle or droplet with polymeric or inorganic shell. Encapsulation technology has many applications in various fields including drug delivery, cosmetic, agriculture, thermal energy storage, textile, and self-healing polymers. Poly(methyl methacrylate) (PMMA) is widely used as shell material in encapsulation due to its high chemical stability, biocompatibility, nontoxicity, and good mechanical properties. The main approach for micro/nanoencapsulation of materials using PMMA as shell comprises emulsion-based techniques such as emulsion polymerization and solvent evaporation from oil-in-water emulsion. In the present review, we first focus on the encapsulation techniques of liquid materials with PMMA shell by analyzing the effective processing parameters influencing the preparation of PMMA micro/nanocapsules. We then describe the morphology of PMMA capsules in emulsion systems according to thermodynamic relations. The techniques to investigation of mechanical properties of capsule shell and the release mechanisms of core material from PMMA capsules were also investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48039.     

Comparison of co-current and counter-current flow in a bifunctional reactor containing ammonia synthesis and 2-butanol dehydrogenation to MEK

In this study, a multi-tubular thermally coupled packed bed reactor in which simultaneous production of ammonia and methyl ethyl ketone (MEK) takes place is simulated. The simulation results are presented in two co-current and counter-current flow modes. Based on this new configuration, the released heat from the ammonia synthesis reaction as an extremely exothermic reaction in the inner tube is employed to supply the required heat for the endothermic 2-butanol dehydrogenation reaction in the outer tube. On the other hand, MEK and hydrogen are produced by the dehydrogenation reaction of 2-butanol in the endothermic side, and the produced hydrogen is used to supply a part of the ammonia synthesis feed in the exothermic side. Thus, 30.72% and 31.88% of the required hydrogen for the ammonia synthesis are provided by the dehydrogenation reaction in the co-current and counter-current configurations, respectively. Also, according to the thermal coupling, the required cooler and furnace for the ammonia synthesis and 2-butanol dehydrogenation conventional plants are eliminated, respectively. As a result, operational costs, energy consumption and furnace emissions are considerably decreased. Finally, a sensitivity analysis and optimization are applied to study the effect of the main process parameters variation on the system performance and obtain the minimum hydrogen make-up flow rate, respectively.     

Effects of Ketone Bodies on Brain Metabolism and Function in Neurodegenerative Diseases

Under normal physiological conditions the brain primarily utilizes glucose for ATP generation. However, in situations where glucose is sparse, e.g., during prolonged fasting, ketone bodies become an important energy source for the brain. The brain’s utilization of ketones seems to depend mainly on the concentration in the blood, thus many dietary approaches such as ketogenic diets, ingestion of ketogenic medium-chain fatty acids or exogenous ketones, facilitate significant changes in the brain’s metabolism. Therefore, these approaches may ameliorate the energy crisis in neurodegenerative diseases, which are characterized by a deterioration of the brain’s glucose metabolism, providing a therapeutic advantage in these diseases. Most clinical studies examining the neuroprotective role of ketone bodies have been conducted in patients with Alzheimer’s disease, where brain imaging studies support the notion of enhancing brain energy metabolism with ketones. Likewise, a few studies show modest functional improvements in patients with Parkinson’s disease and cognitive benefits in patients with—or at risk of—Alzheimer’s disease after ketogenic interventions. Here, we summarize current knowledge on how ketogenic interventions support brain metabolism and discuss the therapeutic role of ketones in neurodegenerative disease, emphasizing clinical data.     

甲乙酮装置剩余丁烯的循环利用

对甲乙酮装置剩余丁烯的循环利用进行了研究,采用聚结器脱水-净化的方法,脱除了剩余丁烯中的仲丁醇、仲丁醚、甲乙酮和水分等杂质,使得剩余丁烯得到了循环使用,满足了水合工段的进料要求,同时提高了甲乙酮的产品质量。     

人工颅骨用复合材料中微量甲基丙烯酸甲酯的气相色谱法测定

采用氢气焰离子化检测器(FID),以正丁醇为外标物,PEG-20M为固定相,甲醇作为溶剂,气相色谱法测定复合材料人工颅骨中微量MMA的含量。其相对标准偏差<0.022,平均回收率(n=4)为98.0％～99.1％。此方法操作简便,用于实际样品分析可得到满意的结果。     

Study of the effect of BDMA catalyst in the epoxy novolac curing process by isothermal DSC

Epoxy novolac/anhydride cure kinetics has been studied by differential scanning calorimetry under isothermal conditions. The system used in this study was an epoxy novolac resin (DEN431), with nadic methyl anhydride as hardener and benzyldimethylamine as accelerator. Kinetic parameters including the reaction order, activation energy and kinetic rate constants, were investigated. The cure reaction was described with the catalyst concentration, and a normalized kinetic model developed for it. It is shown that the cure reaction is dependent on the cure temperature and catalyst concentration, and that it proceeds through an autocatalytic kinetic mechanism. The curing kinetic constants and the cure activation energies were obtained using the Arrhenius kinetic model. A suggested kinetic model with a diffusion term was successfully used to describe and predict the cure kinetics of epoxy novolac resin compositions as a function of the catalyst content and temperature. Copyright © 2003 Society of Chemical Industry     

甲醇气相羰化合成醋酸甲酯的产物分析

以热导池为检测器,分别采用8/100间苯二甲酸+GDX-103、Porapak-Q分析甲醇气相羰化的液相产物和气相产物,确定了气相色谱分析的操作条件,测定了各组分的校正因子,并应用于甲醇绿色羰化合成醋酸甲酯的催化剂评选,得到了满意的结果。     

N-油酰基肌氨酸钠对除盐水缓蚀性能的探讨

对N-油酰基肌氨酸钠单体的缓蚀性能以及与常用除盐水缓蚀剂的协同作用作了探讨,发现在一定浓度下,单体对经过加氨调节后的高温除盐水(氨后除盐水)有良好的缓蚀作用,且与大多数除盐水缓蚀剂有良好的协同效应。在此基础上研制了一种复合药剂,并对其缓蚀、阻蚀性能作了研究。动电位极化曲线扫描图谱表明,该复合药剂属于抑制阳极腐蚀的阳极型缓蚀剂,其适用的水质条件为[Cl~-+SO_4~(2-)]不超过50 mg／L,pH不低于8.0；与阻垢剂复配,可以适用于含Ca~(2+)不超过45 mg／L的水质条件。     

Study of Friction and Wear Performance of Zinc Dialkyldithiophosphate in the Presence of Trace Ketone

This study reports the influence of methyl isopropyl ketone on the tribological performance of zinc dialkyldithiophosphate. The lubricity and friction and wear tests of 500 SN neutral base stock oil containing zinc dialkyldithiophosphate with methyl isopropyl ketone were carried out by MQ-800 four-ball and MM-200 block-on-ring tribometers respectively. The experimental results show that methyl isopropyl ketone decreases the wear resistance and the load-carrying capacity of zinc dialkyldithiophosphate. The friction reduction of zinc dialkyldithiophosphate was lowered as well because of the addition of ketone. The friction and wear mechanism of zinc dialkyldithiophosphate with trace ketone was studied by optical microscopy IR, SEM, XPS and ferrography. The variations of the tribological performance of zinc dialkyldithiophosphate with ketone could be partly attributed to the decreases of active species, such as phosphorus and zinc, which are responsible for the formation of anti-wear films, on the rubbing surface due to the existence of ketone.     

PDB-18C6对TI(Ⅰ),An(Ⅲ),Cu(Ⅱ)的吸附及从α轰击的金靶中分离~(199)TI

本文研究了用冠醚树脂二苯并-18-冠-6甲醛聚合物(简称PDB-18C6)对T1(Ⅰ),Au(Ⅲ),Cu(Ⅱ)的吸附行为。实验表明,在盐酸溶液中冠醚树脂的吸附效率顺序为Au(Ⅲ)>T1(Ⅰ)>Cu(Ⅱ)。用高氯酸和乙二醇乙醚淋洗T1(Ⅰ),Au(Ⅲ),它们的回收率一般在82-98.9％和98-100％。还在1.2m回旋加速器的外靶装置上,用25-27MeV的α粒子轰击金靶,累计束流强度为27μA·h,经处理分离后得到仅含0.50％~(200)T1的较高纯度的~(199)T1。