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51.
Maysa T. Resende Charles Linder Zeev Wiesman 《Journal of the American Oil Chemists' Society》2021,98(5):495-508
Linseed contains high levels of polyunsaturated fatty acids (PUFA), such as α-linolenic acid (> 50% ALA-18:3), that are naturally protected against thermal oxidation by their encapsulation within linseed oil bodies (OB) by multiple components including antioxidant proteins and mucilage emulsifying agents. Linseed OB emulsions (LSE) can be produced by grinding linseed seeds, adding water, adjusting pH, and sonication. This is a process that can encapsulate externally added PUFA to minimize their thermal oxidation, as it does for the intrinsic ALA PUFA. Fish oil (FO) encapsulation into this LSE platform to form linseed fish oil emulsions (LSFE) offers the possibility of a nutritive delivery system of the biologically essential FO PUFA eicosapentaenoic acid and docosahexaenoic acid. In this study, 1H low-field nuclear magnetic resonance (LF-NMR) is used to characterize LSE's and LSFE's chemical and structural properties as well as their stability and changes under thermal oxidation (55 °C for 96 hours). 1H LF-NMR data processing was developed to generate one-dimensional (1D) T1 (spin–lattice), 1D T2 (spin–spin), and 2D (T1 vs. T2) relaxation time spectra that can characterize OB emulsions and monitor their time domain fingerprints (spectrum peaks) of chemical and structural changes during the oxidation process. The 1H LF-NMR analysis were further supported and correlated with conventional peroxide value test, self-diffusion, droplet size distribution, zeta potential estimation of surface stability, and gas chromatography–mass spectrometry analysis of fatty acid profile changes under thermal oxidation conditions. The 1D and 2D LF-NMR relaxation spectra showed that the LSE and LSFE did not suffer intense oxidation process, due to PUFA assembly in OB oxidative protection. These results were further confirmed by the supportive analytical methodologies. The results of this study demonstrate the efficacy of 1H LF-NMR methodology to monitor PUFA's rich oil and emulsion thermal oxidation. 相似文献
52.
Multi-rate model predictive control of particle size distribution in a semibatch emulsion copolymerization reactor 总被引:1,自引:0,他引:1
Mustafa T. Dokucu Myung-June Park Francis J. Doyle III 《Journal of Process Control》2008,18(1):105-120
A multi-rate model predictive controller algorithm is presented for the in-batch closed-loop control of the full particle size distribution (PSD) in a semibatch emulsion copolymerization system. The lack of frequent measurements of the PSD and the measurement delay of these measurements are addressed through the use of frequent density measurements from which the current conditions of the system are estimated. The high dimensionality of the discretized full PSD is reduced by the use of model order reduction based on principal component analysis. This method effectively reduces the size of the problem while preserving the main characteristics of the population balance system. Disturbances that perturb the surfactant and monomer amounts inside the semibatch vinyl acetate–butyl acrylate reactor are considered to demonstrate the performance of the proposed control algorithm. 相似文献
53.
Shih Hao Huang Hwa Seng Khoo Shang Yu ChangChien Fan Gang Tseng 《Microfluidics and nanofluidics》2008,5(4):459-468
Monodisperse copolymer particles carrying surface carboxyl groups in the range of 50–200 μm were prepared by in situ UV polymerization
of ethyleneglycol dimethacrylate (EGDMA) with acrylic acid (AA) via a microfluidic flow-focusing device (MFFD). The design
of the coaxial orifices in the MFFD enables the confinement of the comonomer liquid thread to the central axis of the microchannel,
which can avoid the wetting problem of comonomer liquid with the microchannel and can successfully produce monodisperse copolymer
microspheres with coefficient of variance below 5%. The effects of concentration of EGDMA and AA on droplet diameters and
the distribution of carboxyl group on particle surfaces were examined. It has been found that, increasing the concentration
of AA would decrease particle sizes, but increase the distribution of carboxyl group on particle surfaces. Bioconjugation
of the carboxylated copolymer particles with the anti-rabbit IgG–Cy3 conjugates was successfully demonstrated. By increasing
the concentration of AA accompanied with decreasing the particle sizes, high efficiency of bioconjugation on carboxylated
copolymer particles was achieved. The rapid continuous synthesis of carboxylated copolymer particles via a microfluidic device
provides a reliable control of particle sizes and composition for massive production in biotechnological applications. 相似文献
54.
55.
氧化还原引发乳液聚合单体水溶性与动力学之间的关系 总被引:1,自引:0,他引:1
本文研究了以过硫酸钾/焦亚硫酸钠为氧化还原引发体系,在苯乙烯、醋酸乙烯酯为具体单体的乳液聚合中,单体水溶性与动力学之间的关系。通过实验考察了聚合温度、搅拌速率、电解质浓度对聚合反应转化率~时间关系的影响,并讨论了单体水溶性、自由基水相反应和聚合速率等之间的内在联系。同时得出该氧化还原引发下苯乙烯和醋酸乙烯酯体系的表观活化能分别为47.06kj/mol和约70kJ/mol。 相似文献
56.
本文分析了塑料瓶的表面结构特性及其对贴标胶的要求,简介乳液胶的合成过程,讨论了聚会温度、搅拌速度、增粘剂和改性剂对贴标胶的影响。 相似文献
57.
介绍聚偏二氯乙烯共聚物性能、品种及主要用途和国内外生产应用概况,分析了国内开发及市场现状提出对开发此类产品的建议。 相似文献
58.
59.
The extraction of copper from aqueous sulfate media into ELMs using the extractant LIX 984N-C was studied. Appropriately characterized emulsions on the basis of viscosity and internal drop sizes were used to study the effect of different parameters on extraction. The effects of stirring speed, surfactant concentration, pH of the external continuous phase, carrier concentration, internal phase stripping acid concentration and initial copper concentration are reported. These results show that LIX 984N-C efficiently extracts copper at low pH values typical of leach solutions. It was found that LIX 984N-C could extract up to 80% copper from aqueous solutions at pH value of 1. Performance of LIX 984N-C was also compared with LIX 84 and LIX 84-I at different pH values. Results indicate that LIX 984N-C could open up new avenues for extraction of copper into ELMs, not only from dilute solutions, but also from sulfuric acid leach solutions. 相似文献
60.
酚醛树脂基活性炭微球的电化学性能研究Ⅰ.酚醛树脂基微球制备过程的研究 总被引:1,自引:4,他引:1
选用线型酚醛树脂为原料,采用乳化法可制得微球。为了揭示微球的成型,考察了在制备过程中酚醛树脂乙醇溶液的浓度、搅拌速率、成球终温、固化剂及表面活性剂的数量对酚醛树脂基微球的影响。研究结果表明:微球球径随着树脂溶液浓度的降低而减小,亦随搅拌速率的降低而减小;当搅拌速率为400r/min左右,表面活性剂的浓度在0.28mol/L~0.74mol/L,固化剂量的质量分数为6.0%(基于酚醛树脂)时,可得到球形度良好的微球。在高于树脂软化点以上成球终温对成球影响不大。 相似文献