Rheological Investigation of Lipid Polymer Hybrid Nanocarriers for Oral Delivery of Felodipine (Conference Paper )#

The rheological behavior among factors that are present in Stokes law can be used to control the stability of the colloidal dispersion system. The felodipine lipid polymer hybrid nanocarriers (LPHNs) is an interesting colloidal dispersion system that is used for rheological characteristic analysis. The LPHNs compose of polymeric components and lipids. This research aims to prepare oral felodipine LPHNs to investigate the effect of independent variables on the rheological behavior of the nanosystem. The microwave-based technique was used to prepare felodipine LPHNs (H1-H9) successfully. All the formulations enter the characterization process for particle size and PDI to ascertain the colloidal properties of the prepared nanosystem then use coaxial rotational digital rheometer for rheological evaluation. The outcomes show that all felodipine LPHNs formulations (H1-H9) had a nanosize and homogenous structure that ascertain colloidal features of the nanodispersion system. The rheogram chart indicates that all of the felodipine LPHNs formulations (H1-H9) show pseudoplastic flow (non-Newtonian flow) that have shear-thinning property. The microwave-based method prepares felodipine LPHNs formulations (H1-H9) that show excellent physical texture that ascertains its ability as a technique for the preparation of nanoparticles. All of the felodipine LPHNs formulations (H1-H9) show pseudoplastic flow that supports the physical stability of the nanosystem.

Pickering Emulsion Stabilized By Hydrophobically Modified Spherical Cellulose Nanocrystals With Special Response To pH

The aims of this study were to study the performance changes of S-CNCs (spherical cellulose nanocrystals) modified by OSA (octenyl succinic anhydride) stabilized Pickering oil-in-water (O/W) emulsions. The Fourier transform infrared (FTIR) spectroscopy and contact angle change of the MS-CNCs (modified spherical cellulose nanocrystals) prove the successful modification of OSA and the improvement of hydrophobicity. The effect of a series of MS-CNCs concentration on the volume mean diameter, emulsion ratio, stability and micro-rheological characteristic viscosity of the emulsion was studied. The results show that the emulsifying ability of the S-CNCs have been greatly improved. In addition, at a concentration of 10g/l, the volume mean diameter reaches the nanometer level (0.95 µm), and the emulsion ratio reaches 100%, while still maintaining its unique ultra-low viscosity characteristics. Furthermore, the emulsion still exhibits high-strength resistance to ionic strength, but exhibits unique responsiveness to pH (pH≤5) at special stages.

Design and Application of an In Situ Test Device for Rheological Characteristic Measurements of Liquefied Submarine Sediments

Liquefied submarine sediments can easily lead to submarine landslides and turbidity currents, and cause serious damage to offshore engineering facilities. Understanding the rheological characteristics of liquefied sediments is critical for improving our knowledge of the prevention of submarine geo-hazards and the evolution of submarine topography. In this study, an in situ test device was developed to measure the rheological properties of liquefied sediments. The test principle is the shear column theory. The device was tested in the subaqueous Yellow River delta, and the test results indicated that liquefied sediments can be regarded as “non-Newtonian fluids with shear thinning characteristics”. Furthermore, a laboratory rheological test was conducted as a contrast experiment to qualitatively verify the accuracy of the in situ test data. Through the comparison of experiments, it was proved that the use of the in situ device in this paper is suitable and reliable for the measurement of the rheological characteristics of liquefied submarine sediments. Considering the fact that liquefaction may occur in deeper water (>5 m), a work pattern for the device in the offshore area is given. This novel device provides a new way to test the undrained shear strength of liquefied sediments in submarine engineering.

Development of a Matrix Analysis Methodology for Characterization of Short-Term Aging in Asphalt Binders Modified by Synthetic Wax

In this study, an innovative methodology is proposed to characterize the short-term aging of asphalt binders using the matrix analysis method. The rotational viscosity and complex shear modulus of asphalt binders were chosen as target rheological properties for the analysis of aging. A set of square matrices was developed based on test temperatures and the synthetic additive wax content. Transformational short-term aging matrices were obtained that characterize the trend of the aging process as a function of binder type, temperature sweep, and additive percentage. The results of the matrix analysis show that the trend of short-term aging depends on the binder performance grade and the rheological characteristic chosen for the analysis of aging. In addition, transformational aging matrices can provide detailed information about the range of the aging rate and the trend in aging for each binder type. Furthermore, the components of the transformational matrices clearly show the sensitivity of the binders to aging. In conclusion, the matrix analysis of aging can be used to compare the effects of short-term aging of different asphalt binders.

METHODS OF TRANSPORTATION AND NON-ISOTHERMAL MOVEMENT OF RHEOLOGICAL COMPLEX OILS

The article examines the non-isothermal effect of rheological compound oil and clarifies some methods of transportation of complex rheological characteristic oil and the effect of viscous liquids in pipes. The article presents several ways to improve oil transportation. These methods include the transportation of complex rheological oil with gas-saturated, thermally prepared, heated water. The most common method is to transport oil by heating with complex rheological properties. The pipeline through which heated oil is transported is called the hot pipeline. The article clarifies the movement of viscous liquids in pipes. Keywords: rheological oils, complex rheological properties, gas-saturated, thermally prepared, graphoanalysis, Gas-saturated transportation

A Study of Viscoelastic Model of Polymers in Shear Flow Based on Molecular Dynamic Simulations

In this study, the rheological properties and physical significations of an incompressible viscoelastic (inCVE) the inCVE model was investigated by employing molecular dynamics calculations. Polypropylene (PP) and polystyrene (PS) polymers were selected as candidate materials, the corresponding cell models consisting of five chains of 80 (PP) and 30 (PS) units were built successively. The energy minimization and anneal treatment were launched to optimize the unfavorable structures. The periodic boundary condition, COMPASS force field and the Velocity-Verlet algorithm were employed to calculate the shear flow behavior of chains. The sample data were collected and fitted based on the Matlab platform, and the analysis of the variance (ANOVA) method was performed to determine the validity of the model. Experimental results reveal that the inCVE model matches well with the pseudo-plastic fluids. Compared with the Ostwald-de Waele power law model and Cross model, it is effective and robust, and exhibits a three-stage rheological characteristic. Moreover, it characterizes the stress yield, activation energy, temperature dependence and viscoelastic response of polymers.

A Review on Structural Configurations of Magnetorheological Fluid Based Devices Reported in 2018–2020

Magnetorheological fluid (MRF) is a kind of smart materials with rheological behavior change by means of external magnetic field application, which has been widely adopted in many complex systems of different technical fields. In this work, the state-of-the-art MRF based devices are reviewed according to structural configurations reported from 2018 to 2020. Based on the rheological characteristic, the MRF has a variety of operational modes, such as flow mode, shear mode, squeeze mode and pinch mode, and has unique advantages in some special practical applications. With reference to these operational modes, improved engineering mechanical devices with MRF are summarized, including brakes, clutches, dampers, and mounts proposed over these 3 years. Furthermore, some new medical devices using the MRF are also investigated, such as surgical assistive devices and artificial limbs. In particular, some outstanding advances on the structural innovations and application superiority of these devices are introduced in detail. Finally, an overview of the significant issues that occur in the MRF based devices is reported, and the developing trends for the devices using the MRF are discussed.

Surface Properties of Poly(Hydroxyurethane)s Based on Five-Membered Bis-Cyclic Carbonate of Diglycidyl Ether of Bisphenol A

Poly(hydroxyurethane)s (PHU) are alternatives for conventional polyurethanes due to the use of bis-cyclic dicarbonates and diamines instead of harmful and toxic isocyanates. However, the surface properties of poly(hydroxyurethane)s are not well known. In this work, we focus on the analysis of the surface properties of poly(hydroxyurethane) coatings. Poly(hydroxyurethane)s were obtained by a catalyst-free method from commercially available carbonated diglycidyl ether of bisphenol A (Epidian 6 epoxy resins) and various diamines: ethylenediamine, trimethylenediamine, putrescine, hexamethylenediamine, 2,2,4(2,4,4)-trimethyl-1,6-hexanediamine, m-xylylenediamine, 1,8-diamino-3,6-dioxaoctane, 4,7,10-trioxa-1,13-tridecanediamine, and isophorone diamine, using a non-isocyanate route. The structures of the obtained polymers were confirmed by FT-IR, 1H NMR and 13C NMR spectroscopy, and thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses were performed. The rheological characteristic of the obtained polymers is presented. The static contact angles of water, diidomethane, and formamide, deposited on PHU coatings, were measured. From the measured contact angles, the surface free energy was calculated using two different approaches: Owens–Wendt and van Oss–Chaudhury–Good. Moreover, the wetting envelopes of PHU coatings were plotted, which enables the prediction of the wetting effect of various solvents. The results show that in the investigated coatings, a mainly dispersive interaction occurs.