Preparation of Polyurea Microcapsules by Interfacial Polymerization of Isocyanate and Chitosan Oligosaccharide

(2-((1-(4-chlorophenyl)-1H-pyrazol-3-yl)oxy)-N-(3,4-dichlorophenyl)-propanamide) is a new oil-soluble compound with good fungicidal activity against Rhizoctonia solani. Chitosan oligosaccharide (COS) is the depolymerization product of chitosan and can be developed into biological pesticides, growth regulators, and fertilizers due to its various bioactivities. COS is an oligomer of β- (1 → 4)-linked d –glucosamine and can be taken as a polyamine. In this study, microcapsules were prepared by interfacial polymerization of oil-soluble methylene diphenyl diisocyanate and water-soluble COS. The effects of several key preparation parameters, e.g., emulsifier dosage, agitation rate during emulsification, and core/shell ratio, on properties of the microcapsules such as the encapsulation efficiency, particle size, and size distribution were investigated. The microcapsules were characterized by infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy, etc., and the encapsulation efficiency and release behaviors were investigated. The results show that the microcapsules have a smooth surface and 93.3% of encapsulation efficiency. The microcapsules showed slow-release behavior following a first-order kinetic equation, and the accumulative release rates of the microcapsules with core/shell mass ratios of 8.0/4.0, 8.0/5.0, and 8.0/6.0, were 95.5%, 91.4%, and 90.1%, respectively, on day 30. Due to many high biological activities, biodegradability, and the pure nature of COS, microcapsules formed from COS are promising for applications in controlled release of pesticides, growth regulators, and fertilizer.

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Optimization of Processing Conditions and Properties of Epoxy Microcapsule

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.654.11 ◽

2014 ◽

Vol 654 ◽

pp. 11-15

Author(s):

Xiu Lan Cai ◽

Da Tian Fu ◽

Ai Lan Qu

Keyword(s):

Average Diameter ◽

Decomposition Temperature ◽

Core Material ◽

Formaldehyde Resin ◽

Core Shell ◽

Agitation Rate ◽

Processing Conditions ◽

Mass Ratio ◽

Shell Mass ◽

Optimum Processing

A series of microcapsules were prepared by interfacial polymerization method using epoxy and urea formaldehyde resin as core material and shell material, individually. The effects of processing conditions on the properties of epoxy microcapsules were systematically investigated based on w(Core), average diameter and decomposition temperature of microcapsules through the method of orthographic factorial design and the most optimum processing conditions were included. The results indicated that core/shell mass ratio was the most important factor on w(Core), average diameter and decomposition temperature of microcapsules. The optimum processing conditions were concluded: 1:1 for the core/shell mass ratio, 300 rpm for agitation rate and 0.8% DBS as emulsifier. The microcapsules prepare in the optimum processing conditions were well encapsuled and presented thin shell and smooth surface. Moreover, the addition of 10% microcapsules can improve the mechanical properties of epoxy matrix greatly.

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Design and Characterization of a Novel ZnO–Ag/Polypyrrole Core–Shell Nanocomposite for Water Bioremediation

Nanomaterials ◽

10.3390/nano11071688 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1688

Author(s):

Fatma Mohamed ◽

Abeer Enaiet Allah ◽

Khulood A. Abu Al-Ola ◽

Mohamed Shaban

Keyword(s):

High Efficiency ◽

Interfacial Polymerization ◽

Antimicrobial Properties ◽

Core Shell ◽

Order Kinetic ◽

Mixed Solution ◽

Adsorption Model ◽

Operation Process ◽

Order Kinetic Model ◽

Enhanced Adsorption

Incorporating nanostructured metal and metal oxide in a polymer matrix is a strategic way to develop a novel candidate for water bioremediation. In this study, under microwave irradiation, a ZnO–Ag/polypyrrole (PPy) nanocomposite with a core/shell structure was prepared by interfacial polymerization of pyrrole in the presence of ZnO nanoparticles and AgNO3 as an oxidant. The antimicrobial behavior of the ZnO–Ag core combined with the electrical properties of the conducting PPy shell created a special ZnO–Ag/PPy nanocomposite with inherent adsorption behavior and antimicrobial properties. More impressively, the as-prepared ZnO–Ag/PPy displayed enhanced adsorption of Cd2+ and PO43− ions in the mixed solution. At pH 8, it had overall removal efficiencies of 95% and 75% for Cd2+and PO43− ions, respectively. The Freundlich adsorption model, rather than the Langmuir adsorption model, better fits the adsorption isotherm results. The adsorption kinetics also followed the pseudo-second-order kinetic model. Additionally, the engineered nanocomposite demonstrated antifungal activity against different fungi, as well as remarkable antibacterial activity against Gram-negative and Gram-positive bacteria. The synergistic combination of crystallinity, coherence of the ZnO–Ag core in the PPy matrix, and the negative zeta potential all contribute to this nanocomposite’s high efficiency. Our results have significant consequences in the wastewater bioremediation field using a simple operation process.

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Solubilization of Charged Porphyrins in Interpolyelectrolyte Complexes: A Computer Study

Polymers ◽

10.3390/polym13040502 ◽

2021 ◽

Vol 13 (4) ◽

pp. 502

Author(s):

Karel Šindelka ◽

Zuzana Limpouchová ◽

Karel Procházka

Keyword(s):

Dissipative Particle Dynamics ◽

Water Soluble ◽

Coarse Grained ◽

Core Shell ◽

Computer Study ◽

Interpolyelectrolyte Complex ◽

The Core ◽

Porphyrin Derivatives ◽

Oppositely Charged ◽

Positively Charged

Using coarse-grained dissipative particle dynamics (DPD) with explicit electrostatics, we performed (i) an extensive series of simulations of the electrostatic co-assembly of asymmetric oppositely charged copolymers composed of one (either positively or negatively charged) polyelectrolyte (PE) block A and one water-soluble block B and (ii) studied the solubilization of positively charged porphyrin derivatives (P+) in the interpolyelectrolyte complex (IPEC) cores of co-assembled nanoparticles. We studied the stoichiometric mixtures of 137 A10+B25 and 137 A10−B25 chains with moderately hydrophobic A blocks (DPD interaction parameter aAS=35) and hydrophilic B blocks (aBS=25) with 10 to 120 P+ added (aPS=39). The P+ interactions with other components were set to match literature information on their limited solubility and aggregation behavior. The study shows that the moderately soluble P+ molecules easily solubilize in IPEC cores, where they partly replace PE+ and electrostatically crosslink PE− blocks. As the large P+ rings are apt to aggregate, P+ molecules aggregate in IPEC cores. The aggregation, which starts at very low loadings, is promoted by increasing the number of P+ in the mixture. The positively charged copolymers repelled from the central part of IPEC core partially concentrate at the core-shell interface and partially escape into bulk solvent depending on the amount of P+ in the mixture and on their association number, AS. If AS is lower than the ensemble average ⟨AS⟩n, the copolymer chains released from IPEC preferentially concentrate at the core-shell interface, thus increasing AS, which approaches ⟨AS⟩n. If AS>⟨AS⟩n, they escape into the bulk solvent.

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Biological activities and plant growth regulators producing from some microalgae biomass cultivated in different wastewater concentrations

Biomass Conversion and Biorefinery ◽

10.1007/s13399-021-01610-x ◽

2021 ◽

Author(s):

Walaa M. Elakbawy ◽

Sanaa M. M. Shanab ◽

Emad A. Shalaby

Keyword(s):

Plant Growth ◽

Plant Growth Regulators ◽

Growth Regulators ◽

Biological Activities ◽

Microalgae Biomass

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Analyzing the Carotenoid Composition of Melilot (Melilotus officinalis (L.) Pall.) Extracts and the Effects of Isolated (All-E)-lutein-5,6-epoxide on Primary Sensory Neurons and Macrophages

Molecules ◽

10.3390/molecules26020503 ◽

2021 ◽

Vol 26 (2) ◽

pp. 503

Author(s):

Györgyi Horváth ◽

Eszter Csikós ◽

Eichertné Violetta Andres ◽

Tímea Bencsik ◽

Anikó Takátsy ◽

...

Keyword(s):

Liquid Chromatography ◽

Sensory Neurons ◽

Biological Activities ◽

Water Soluble ◽

Soluble Form ◽

Primary Sensory Neurons ◽

Isolation And Identification ◽

Melilotus Officinalis ◽

Carotenoid Composition ◽

Anti Inflammatory

Melilotus officinalis is known to contain several types of secondary metabolites. In contrast, the carotenoid composition of this medicinal plant has not been investigated, although it may also contribute to the biological activities of the drug, such as anti-inflammatory effects. Therefore, this study focuses on the isolation and identification of carotenoids from Meliloti herba and on the effect of isolated (all-E)-lutein 5,6-epoxide on primary sensory neurons and macrophages involved in nociception, as well as neurogenic and non-neurogenic inflammatory processes. The composition of the plant extracts was analyzed by high performance liquid chromatography (HPLC). The main carotenoid was isolated by column liquid chromatography (CLC) and identified by MS and NMR. The effect of water-soluble lutein 5,6-epoxide-RAMEB (randomly methylated-β-cyclodextrin) was investigated on Ca2+-influx in rat primary sensory neurons induced by the activation of the transient receptor potential ankyrin 1 receptor agonist to mustard-oil and on endotoxin-induced IL-1β release from isolated mouse peritoneal macrophages. (all-E)-Lutein 5,6-epoxide significantly decreased the percent of responsive primary sensory neurons compared to the vehicle-treated stimulated control. Furthermore, endotoxin-evoked IL-1β release from macrophages was significantly decreased by 100 µM lutein 5,6-epoxide compared to the vehicle-treated control. The water-soluble form of lutein 5,6-epoxide-RAMEB decreases the activation of primary sensory neurons and macrophages, which opens perspectives for its analgesic and anti-inflammatory applications.

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