scholarly journals Polymer Concentration Maximizes Encapsulation Efficiency in Electrohydrodynamic Mixing Nanoprecipitation

2021 ◽  
Vol 3 ◽  
Author(s):  
Kil Ho Lee ◽  
Faiz N. Khan ◽  
Lauren Cosby ◽  
Guolingzi Yang ◽  
Jessica O. Winter
Keyword(s):  
Ethylene Oxide ◽  
Encapsulation Efficiency ◽  
Polymer Concentration ◽  
Interaction Parameters ◽  
Solubility Parameters ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
The Relationship ◽  
Coumarin 6 ◽  
Hansen Solubility

Encapsulation in self-assembled block copolymer (BCP) based nanoparticles (NPs) is a common approach to enhance hydrophobic drug solubility, and nanoprecipitation processes in particular can yield high encapsulation efficiency (EE). However, guiding principles for optimizing polymer, drug, and solvent selection are critically needed to facilitate rapid design of drug nanocarriers. Here, we evaluated the relationship between drug-polymer compatibility and concentration ratios on EE and nanocarrier size. Our studies employed a panel of four drugs with differing molecular structures (i.e., coumarin 6, dexamethasone, vorinostat/SAHA, and lutein) and two BCPs [poly(caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO) and poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO)] synthesized using three nanoprecipitation processes [i.e., batch sonication, continuous flow flash nanoprecipitation (FNP), and electrohydrodynamic mixing-mediated nanoprecipitation (EM-NP)]. Continuous FNP and EM-NP processes demonstrated up to 50% higher EE than batch sonication methods, particularly for aliphatic compounds. Drug-polymer compatibilities were assessed using Hansen solubility parameters, Hansen interaction spheres, and Flory Huggins interaction parameters, but few correlations were EE observed. Although some Hansen solubility (i.e., hydrogen bonding and total) and Flory Huggins interaction parameters were predictive of drug-polymer preferences, no parameter was predictive of EE trends among drugs. Next, the relationship between polymer: drug molar ratio and EE was assessed using coumarin 6 as a model drug. As polymer:drug ratio increased from <1 to 3–6, EE approached a maximum (i.e., ∼51% for PCL BCPs vs. ∼44% PS BCPs) with Langmuir adsorption behavior. Langmuir behavior likely reflects a formation mechanism in which drug aggregate growth is controlled by BCP adsorption. These data suggest polymer:drug ratio is a better predictor of EE than solubility parameters and should serve as a first point of optimization.

Rheological and Morphological Characterization of Triblock Copolymer (PEO-PPO-PEO)-Clay Gel in Aqueous Solution

2005 ◽  
Vol 898 ◽  
Author(s):  
Jun Jiang ◽  
Chunhua Li ◽  
Miriam Rafailovich ◽  
Jonathan Sokolov
Keyword(s):  
Ethylene Oxide ◽  
Triblock Copolymer ◽  
Polymer Concentration ◽  
Pluronic F127 ◽  
High Concentration ◽  
Thermal Gelation ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Scanning Electron ◽  
Gel Transition

AbstractThermal gelation and structure properties of high concentration triblock copolymer poly (ethylene oxide)99-poly(propylene oxide)69-poly(ethylene oxide)99 (Pluronic F127)-clay aqueous solutions were characterized by rheological measurements and scanning electron microscopy (SEM). The sol-gel transition temperature, as well as the viscosity of the F127 solution was found to depend both on the concentration of polymer and clay filler. In all cases, Pluronic F127 gels are pseudoplastic, showing the shear-thinning behavior. Above the gel transition, the viscosity of the solutions increased with increasing the clay concentration. The corresponding macrostructure of the gels was studied by lyophilizing thick samples and scanning them with a scanning electron microscope (SEM). A well-ordered network of porosity was observed as a function of polymer concentration and orientation.

Effect of Formation Nonuniformity on the Mechanical Strength of Aramid Paper

2011 ◽  
Vol 236-238 ◽  
pp. 1265-1270
Author(s):  
Hui Fang Zhao ◽  
Mei Yun Zhang
Keyword(s):  
Tensile Strength ◽  
Standard Deviation ◽  
Ethylene Oxide ◽  
Mechanical Strength ◽  
Great Influence ◽  
Fiber Distribution ◽  
Tear Strength ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
The Relationship

Aramid paper was manufactured using poly (m-phenyleneisophthalamide) (PMIA) fibers and fibrids, and poly(ethylene oxide) (PEO) was used as dispersant to improve the uniformity of fiber distribution. The Paper Perfect Formation Analyzer (PPF) and the BFT-1 type β Formation tester were used to determine the formation of the aramid paper, and the relationship between the formation and the mechanical strength of aramid paper was discussed. Results showed that the tensile strength and tear strength of aramid paper before hot calendering is affected strongly by its grammage standard deviation, but is less affected by its formation nonuniformity as a function of the scale of foramtion, the R2 correlation between tensile strength and grammage standard deviation was 0.63, and the R2 correlation between tear strength and grammage standard deviation was 0.73. However, the nonuniformity of formation in the range of scale of formation 0.8-22.7mm has great influence on the tensile strength of aramid paper after hot calendering, and the R2 correlation between tensile strength and formation nonuniformity in this range of scale of formation was greater than 0.58.

scholarly journals Melt Rheological Behavior and Morphology of Poly(ethylene oxide)/Natural Rubber-graft-Poly(methyl methacrylate) Blends

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 724
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Say Aik Lai ◽  
Chin Han Chan
Keyword(s):  
Ethylene Oxide ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Poly Methyl Methacrylate ◽  
Linear Viscoelastic ◽  
Solution Casting Method ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
The Relationship ◽  
Pmma Blends

The influence of morphology on the rheological properties of poly(ethylene oxide) (PEO) and natural rubber-graft-poly(methyl methacrylate) (NR-g-PMMA) blends in the melt was investigated. The blends were prepared at different blend compositions by a solution-casting method. Linear viscoelastic shear oscillations measurements were performed in order to determine the elastic and viscous properties of the blends in the melt. The rheological results suggested that the blending of the two constituents reduced the elasticity and viscosity of the blends. The addition of an even small amount of NR-g-PMMA to PEO changed the liquid-like behavior of PEO to more solid-like behavior. Morphological investigations were carried out by optical microscopy to establish the relationship between morphology and melt viscosity. Depending on the blend compositions and viscosities, either droplet–matrix or co-continuous morphologies was observed. PEO/NR-g-PMMA blends exhibited a broad co-continuity range, and phase inversion was suggested to occur at the PEO/NR-g-PMMA blend with a mass ratio of 60/40 (m/m), when NR-g-PMMA was added to PEO as a matrix.

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