scholarly journals Microencapsulation of Photochromic Solution with Polyurea by Interfacial Polymerization

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3049
Author(s):  
Yuhua Zhang ◽  
Xi Zhang ◽  
Yurong Yan ◽  
Zhonghua Chen
Keyword(s):  
Particle Size ◽  
Interfacial Polymerization ◽  
Uv Light ◽  
Thermogravimetric Analyzer ◽  
The Core ◽  
Oxygen Ion ◽  
Particle Size Analyzer ◽  
Photochromic Materials ◽  
Addition Amount ◽  
Uniform Particle Size

Photochromic materials are interesting materials because of their color-changing property under UV light and visible light irradiation. However, they are vulnerable to many factors, such as pH oxygen, ion, solvent, etc. because of the unsaturated bonds existing on the photochromic molecular. Microencapsulation of the photochromic materials can separate them from the surroundings. Here, photochromic microcapsules using 3,3-Diphenyl-3H-naphtho[2,1-b] pyran (NP)/solution as core and polyurea as shell via interfacial polymerization were prepared, and bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate (HALS 770) was used as photostabilizer. Fourier transform infrared spectroscopy (FTIR), a laser particle size analyzer, a scanning electron microscope (SEM), a thermogravimetric analyzer and an ultraviolet-visible spectrophotometer were used for characterization. The results showed that the microcapsules had a uniform particle size of about 0.56 μm when the percentage of the oil phase (core) in the emulsion was less than 15%, the addition amount of the emulsifier was 0.4%, and the stirring rate was 1800r/min. The microcapsules showed better performance in thermal stability when the core/shell ratio was 1:1. The photostabilizer had little impact on the color-changing property of the microcapsule, but it could protect the microcapsules from UV light radiation aging.

Preparation of Uniform Microcapsules Containing Ionic Liquid for Caprolactam Extraction

2012 ◽  
Vol 557-559 ◽  
pp. 619-623 ◽  
Author(s):  
Dong Xuan Chen ◽  
Xiao Kun OuYang ◽  
Yang Guang Wang ◽  
Li Ye Yang ◽  
Di Yu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Ionic Liquid ◽  
Phase Inversion ◽  
Extraction Process ◽  
Inversion Method ◽  
Nitrogen Gas ◽  
Thermogravimetric Analyzer ◽  
Particle Size Analyzer ◽  
Phase Inversion Method

Microencapsulating ionic liquid is an effective way to overcome the loss of ionic liquid in the extraction process. A phase inversion method was used to form microcapsules containing 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM] [PF6]. The oil phase, composed of [BMIM][PF6], polysulfone and dichloromethane, was dropped into the 0.2 wt% gelatin aqueous solution using nitrogen gas pressure to form droplets. As dichloromethane evaporated completely, polysulfone microcapsules containing [BMIM] [PF6] were obtained. The microcapsules were characterized using a polarizing microscope, a laser particle size analyzer and a thermogravimetric analyzer. Moreover the microcapsules were performed some effect on caprolactam extraction from water.

Self-Healing Epoxy Coating Modified by Double-Walled Microcapsules Based Polyurea for Metallic Protection

2019 ◽  
Vol 821 ◽  
pp. 313-320
Author(s):  
Yan Xuan Ma ◽  
Ying Rui Zhang ◽  
Jia Tong Liu ◽  
Meng Yao Li ◽  
Ya Qian Xu
Keyword(s):  
Chemical Structure ◽  
Interfacial Polymerization ◽  
Electrochemical Impedance ◽  
Self Healing ◽  
High Corrosion Resistance ◽  
Hexamethylene Diamine ◽  
Thermogravimetric Analyzer ◽  
The Core ◽  
Core Content ◽  
Scanning Electronmicroscopy

The effectiveness of preploymer and 1,6-Hexamethylene diamine encapsulated by double-walled microcapsules based polyurea (PUA) was explored for healing the cracks generated in epoxy coatings. Double-walled microcapsules were systhesized by interfacial polymerization at the interface between the prepolymer droplets and the 1,6-Hexamethylene diamine droplets to form the polyurea shell. The effect of synthetic stirring speed on the morphology of the microcapsules was observed by scanning electronmicroscopy (SEM) and optical microscopy (OM). The chemical structure as well as the thermal properties and the core content were characterized by Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analyzer (TGA) respectively. Electrochemical impedance spectroscopy (EIS) studies of the artificial scratched area showed that the coating containing 2wt% and 5wt% microcapsules could effectively prevent further corrosion of the coating with high corrosion resistance efficiencies of 61.61% and 45.99% after immersing for 144h in seawater.

Fine Spherical Tungsten Powder Prepared by Precipitation Reaction

2011 ◽  
Vol 117-119 ◽  
pp. 967-970
Author(s):  
Tao Lin ◽  
Yan Jun Li ◽  
Cheng Yi Wu ◽  
Zhi Meng Guo
Keyword(s):  
Particle Size ◽  
Tungsten Powder ◽  
Sodium Dodecyl ◽  
Precipitation Reaction ◽  
Mechanical Agitation ◽  
Ammonium Tungstate ◽  
Fine Tungsten ◽  
Strong Acids ◽  
Addition Amount ◽  
Uniform Particle Size

The spherical tungsten powder was prepared by chemical reaction with ammonium tungstate and strong acids under ultrasonic and mechanical agitation. After precipitation reaction, the precipitate was dried and grinded, and then reduced into tungsten powder with hydrogen. The effects of acid kinds and dispersant on the fine tungsten powder were studied in this paper. The result shows that the acid kinds and its addition amount have great effect on the shape of tungsten particles. The tungsten powder with uniform particle size and spherical could be prepared by adding 17ml sulfric acid into 100ml ammonium tungstate. The tungsten particles can be finer and more dispersive, and have a spherical with addition of dispersant SDS (Sodium dodecyl sulfate). The particle size is about 1.5 micrometer.

Effect of Heat Treatment on Chemical Structure of a Bio-Filler from Vetiver Grass

2011 ◽  
Vol 410 ◽  
pp. 71-74 ◽  
Author(s):  
Wimonlak Sutapun ◽  
Yupaporn Ruksakulpiwat ◽  
Nitinat Suppakarn
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Particle Size ◽  
Crystalline Structure ◽  
Chemical Structure ◽  
Fiber Surface ◽  
Thermogravimetric Analyzer ◽  
Heat Treated ◽  
Particle Size Analyzer ◽  
Ftir Spectrometer

In this work, the effect of heat treatment on chemical and crystalline structure of vetiver powder was studied. The vetiver powder was heat treated at 170°C, the temperature below thermal decomposition of hemicellulose, for 2-6 hours. The chemical structure, crystalline structure, and thermal decomposition of untreated and heat-treated vetiver were examined via FTIR spectrometer X-ray diffractometer, and thermogravimetric analyzer, respectively. In addition, the particle size and size distribution, fiber surface, and specific surface area were investigated by particle size analyzer, scanning electron microscope, and BET surface analyzer, repectively. It was founded that some waxes, lignin, and hemicellulose were removed by the thermal treatment. This resulted in smaller particle size of heat-treated vetivers. In addition, moisture content was minimized from 7 to 4 wt% by the treatment. However, removal of those compositions did not influence crystal structure of cellulose and surface functional groups of heat-treated vetiver.

Preparation and Application of VE Microcapsules with Polyurethane Shell for Skin-Care Textiles

2011 ◽  
Vol 331 ◽  
pp. 402-406 ◽  
Author(s):  
Guo Ping Yao ◽  
Jin Huan Zheng ◽  
Hui Fen Chen
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Vitamin E ◽  
Interfacial Polymerization ◽  
Chain Extender ◽  
Skin Care ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Skin Care Product ◽  
The Mean

Vitamin E (VE) microcapsules with polyurethane (PU) shell are successfully prepared via interfacial polymerization of polyurethane with toluene-2,4-diisocyanate (TDI) as the isocyanate, polyethylene glycol as the polyol, and 1,4-butanediol (BD) as the chain extender. In the preparation process, VE emulsion, prepolymer and microencapsulation of VE are studied using a particle size analyzer, butylamine titration, optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Based on the present research, VE microcapsules prepared have smooth surfaces and spherical appearances, the mean particle size of about 550 nm. Vitamin E microcapsules have been glued effectively to textiles, and a kind of skin-care product has been developed.

SINTESIS DAN KARAKTERISASI NANOPARTIKEL KITOSAN – EKSTRAK KULIT BUAH MANGGIS (Garcinia Mangostana)

2013 ◽  
Vol 14 (3) ◽  
Author(s):  
Eriawan Rismana ◽  
Susi Kusumaningrum ◽  
Olivia Bunga P ◽  
Idah Rosidah ◽  
Marhamah Marhamah
Keyword(s):  
Particle Size ◽  
Sodium Tripolyphosphate ◽  
Chitosan Solution ◽  
The Other ◽  
Ionic Gelation ◽  
Garcinia Mangostana ◽  
Particle Size Analyzer ◽  
Cadmium Lead ◽  
Solvent Residue ◽  
Mold And Yeast

The chitosan – Garcinia Mangostana extract nanoparticles has been prepared by ionic gelation reaction by mixture 0.2 % chitosan solution in acetic acid with Garcinia Mangostana extract and it’s continued by reaction process with 0.1 % sodium tripolyphosphate. The particle size of material was determined by Particle Size Analyzer (PSA) that it showed in the range of 200 – 500 nm. The color, pH, water, α- mangostin, mercury, arsenic, cadmium, lead, totally microbe aerobic, totally mold and yeast, and solvent residue contents of nanoparticles were also examined by many methods that these resulted are yellow, 4.50 – 5.50, 89 – 90 %, 1.05 %, < 0.005 ppm, < 0.01 ppm, < 0.01 ppm, < 0.05 ppm, < 10 CFU/g, < 10 CFU/g and not detected, respectively. The other characterization was also observed that it’sincluded stability andTLC chromatogram. A mixture of nanoparticles with cosmetics bases was showed that it’s increased stability, homogeneity and easy to formed.

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

scholarly journals Awareness of aerosol-related transmission of COVID-19 among the dentists of Nepal

BDJ Open ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Nashib Pandey ◽  
Buddha Bahadur Basnet ◽  
Sushmit Koju ◽  
Anju Khapung ◽  
Alka Gupta
Keyword(s):  
Social Sciences ◽  
Particle Size ◽  
High Efficiency ◽  
Emergency Services ◽  
Uv Light ◽  
Ventilation System ◽  
Age Groups ◽  
Air Filtration ◽  
Online Questionnaire ◽  
Dental Practitioners

Abstract Objective To access the awareness of dental practitioners of Nepal towards COVID-19 transmission through aerosols. Materials and methods The study involved 384 dentists from all over Nepal and was conducted for a period of 3 months. A self-reported online questionnaire was developed using Google forms and the link was shared. It emphasized the awareness related to the aerosol and ventilation system in their daily practices was prepared. The data were analyzed in Statistical Package for Social Sciences version 20.0 software. Results The majority of participants were female 52.9% (n = 203) and within the age groups of <30 years 57% (n = 219). Participants from Bagmati Province were 60.4% (n = 232), with least from Sudurpaschim Province 0.5% (n = 2). 60% of participants provided only emergency services during the COVID-19 pandemic and few (7%) provided consultations via telephone. The current ventilation system used was a well-ventilated room with open windows 65.4% (n = 251). However, 52.8% (n = 203) preferred specialized operatory incorporating high-efficiency particulate air (HEPA) filters and ultraviolet (UV) light. More than 60% of respondents were unaware of the particle size of the aerosol. Conclusions The obtained results signify the need for the proper ventilation system with appropriate air filtration systems in dental clinical setups.

scholarly journals Preparation and application of carbon and hollow TiO2 microspheres by microwave heating at a low temperature

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 200-209
Author(s):  
Caiyun Zhang ◽  
Chunhong Li ◽  
Bolin Ji ◽  
Zhaohui Jiang
Keyword(s):  
Low Temperature ◽  
Microwave Heating ◽  
Raw Material ◽  
Carbon Microspheres ◽  
Microwave Assisted ◽  
The Core ◽  
Good Crystallinity ◽  
Carbon Core ◽  
Microwave Assisted Method ◽  
Uniform Particle Size

Abstract A fast, simple, and energy-saving microwave-assisted approach was successfully developed to prepare carbon microspheres. The carbon microspheres with a uniform particle size and good dispersity were prepared using glucose as the raw material and HCl as the dehydrating agent at low temperature (90°C) in an open system with the assistance of microwave heating. The carbon microspheres were characterized by elemental analysis, XRD, SEM, FTIR, TG, and Raman. The results showed that the carbon microspheres prepared under the condition of 18.5% (v/v) HCl and heating for 30 min by microwave had a narrow size distribution. The core–shell structure of the carbon core and TiO2 shell was prepared with (NH4)2TiF6, H3BO3 using the microwave-assisted method. The hollow TiO2 microspheres with good crystallinity and high photocatalytic properties were successfully prepared by sacrificing the carbon microspheres.

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