scholarly journals Synthesis and Characterization of Polymeric Microspheres Template for a Homogeneous and Porous Monolith

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3639
Author(s):  
Nur Faezah Ibadat ◽  
Clarence M. Ongkudon ◽  
Suryani Saallah ◽  
Mailin Misson
Keyword(s):  
Mechanical Strength ◽  
Heat Dissipation ◽  
Scale Up ◽  
Particle Morphology ◽  
Poly Vinyl Alcohol ◽  
Polymeric Microspheres ◽  
Polymeric Microsphere ◽  
Porous Monolith ◽  
Evaporation Technique

Monolith is an emerging technology applicable for separation, filtration, and chromatography due to its interconnected pore structure. However, the current templates used to form monolith pores are associated with poor heat dissipation, uneven pore size distribution, and relatively low mechanical strength during monolith scale-up. Templates made from polymeric microsphere particles were synthesized via a solvent evaporation technique using different types of polymer (polystyrene, polycaprolactone, polypropylene, polyethylene, and poly (vinyl-alcohol) at varied polymer (10–40 wt%) and surfactant (4–10%) concentrations. The resulting microsphere particles were tested as a monolith template for the formation of homogenous pores. Among the tested polymers, polystyrene at 10 wt% concentration demonstrated good particle morphology determined to around 1.94–3.45 µm. The addition of surfactant at a concentration of 7–10 wt% during microsphere synthesis resulted in the formation of well-shaped and non-aggregating microsphere particles. In addition, the template has contributed to the production of porous monoliths with enhanced thermal stability. The thermogravimetric analysis (TGA) indicated monolith degradation between 230 °C and 450 °C, implying the material excellent mechanical strength. The findings of the study provide insightful knowledge on the feasibility of polymeric microsphere particles as a pore-directing template to fabricate monoliths with desired pore structures.

Preparation of Melamine Molecularly Imprinted Polymeric Microspheres by Two-Step Seed Swelling Polymerization

2013 ◽  
Vol 668 ◽  
pp. 128-131 ◽  
Author(s):  
Na Qi ◽  
Jun Chen ◽  
Yu Ping Zhang ◽  
Yi Jun Zhang ◽  
Lian Yang Bai
Keyword(s):  
Binding Capacity ◽  
Stationary Phases ◽  
Particle Diameter ◽  
Scatchard Analysis ◽  
Polymeric Microspheres ◽  
Molecularly Imprinted ◽  
Factors Affecting ◽  
Polymeric Microsphere ◽  
Mercury Analyzer

Melamine molecularly imprinted polymeric microsphere (MIPM) was initially prepared by two-step seed swelling polymerization methods. Factors affecting the particle morphologies including emulsifier, dispersant, the water-oil ratio, and etc were optimized in order to obtain the MIPMs with a final narrow particle diameter of 3-5 μm. Characterization of the resulted polymeric microspheres was investigated by scanning electron microscope (SEM), infrared absorption spectroscopy (IR), and mercury analyzer (MA), respectively. When the initial concentration of melamine was 1.0 mmol L-1, the affinity capacity of MIPMs was 2.0 times than that of NIPMs. Scatchard analysis suggested melamine were recognized by the prepared MIPMs with two classes of binding sites. The apparent maximum binding capacity and dissociation constant were calculated to be 43.2 μmol g-1 (Qmax1) and 2.2×10-4 mol L-1 (Kd1) for high affinity site, whilst to be 102.3 μmol g-1 (Qmax2) and 1.3×10-3 mol L-1 (Kd2) for low affinity site, respectively. Obvious molecular effects towards melamine were further confirmed by the comparative HPLC experiments using NIPMs and MIPMs as the stationary phases, respectively.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

Spectral Investigation on the Growth and Characterization of NLO Crystals of Thiourea Succinic Acid Single Crystal.

2015 ◽  
Vol 2 (2) ◽  
pp. 70-73
Author(s):  
Kannan.P ◽  
Thambidurai.S ◽  
Suresh.N
Keyword(s):  
Single Crystal ◽  
Succinic Acid ◽  
Slow Evaporation Technique ◽  
Absorption Studies ◽  
Dta Analysis ◽  
Evaporation Technique ◽  
Ft Ir ◽  
Ir Spectroscopic ◽  
Thermal Stability Of

Growth of optically transparent single crystals of thiourea succinic acid (TUSA) was grown successfully from aqueous solution by slow evaporation technique. The crystal structure was elucidated using the single crystal XRD. The various functional groups and the modes of vibrations were identified by FT-IR spectroscopic analysis. The optical absorption studies indicate that the optical transparency window is quite wide making its suitable for NLO applications. Thermal stability of the crown crystal carried out by TGA-DTA analysis.

Preparation and characterization of poly(vinyl alcohol)/gum tragacanth/cellulose nanocomposite film

2021 ◽  
pp. 50672
Author(s):  
Majid Alizadeh Moghadam ◽  
Reza Mohammadi ◽  
Ehsan Sadeghi ◽  
Mohammad Amin Mohammadifar ◽  
Mohammad Nejatian ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Nanocomposite Film ◽  
Poly Vinyl Alcohol ◽  
Gum Tragacanth

scholarly journals Equilibrium, Thermodynamic, Reuse, and Selectivity Studies for the Bioadsorption of Lanthanum onto Sericin/Alginate/Poly(vinyl alcohol) Particles

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 623
Author(s):  
Talles Barcelos da Costa ◽  
Meuris Gurgel Carlos da Silva ◽  
Melissa Gurgel Adeodato Vieira
Keyword(s):  
Vinyl Alcohol ◽  
Economic Value ◽  
Poly Vinyl Alcohol ◽  
Thermodynamic Quantities ◽  
High Demand ◽  
Batch System ◽  
Equilibrium Data ◽  
Selectivity Studies ◽  
Amorphous Character

In a scenario of high demand, low availability, and high economic value, the recovery of rare-earth metals from wastewater is economically and environmentally attractive. Bioadsorption is a promising method as it offers simple design and operation. The aim of this study was to investigate lanthanum bioadsorption using a polymeric bioadsorbent of sericin/alginate/poly(vinyl alcohol)-based biocomposite. Batch system assays were performed to evaluate the equilibrium, thermodynamics, regeneration, and selectivity of bioadsorption. The maximum capture amount of lanthanum at equilibrium was 0.644 mmol/g at 328 K. The experimental equilibrium data were better fitted by Langmuir and Dubinin–Radushkevich isotherms. Ion exchange mechanism between calcium and lanthanum (2:3 ratio) was confirmed by bioadsorption isotherms. Thermodynamic quantities showed that the process of lanthanum bioadsorption was spontaneous (−17.586, −19.244, and −20.902 kJ/mol), endothermic (+15.372 kJ/mol), and governed by entropic changes (+110.543 J/mol·K). The reusability of particles was achieved using 0.1 mol/L HNO3/Ca(NO3)2 solution for up to five regeneration cycles. The bioadsorbent selectivity followed the order of lanthanum > cadmium > zinc > nickel. Additionally, characterization of the biocomposite prior to and post lanthanum bioadsorption showed low porosity (9.95 and 12.35%), low specific surface area (0.054 and 0.019 m2/g), amorphous character, and thermal stability at temperatures up to 473 K. This study shows that sericin/ alginate/poly(vinyl alcohol)-based biocomposites are effective in the removal and recovery of lanthanum from water.

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